HK1147560B - Position information providing system indoor transmitter and method for providing position information - Google Patents

Description

Indoor transmitter of position information providing system and position information providing method

Technical Field

The present invention relates to a technique for providing position information. The present invention more particularly relates to a technique of providing position information even in an environment where signals transmitted from satellites transmitting positioning signals cannot reach.

Background

As a conventional positioning system, a Global Positioning System (GPS) is known. However, in the case of using GPS in a city, for example, a standing building becomes an obstacle and a position information providing device of a user cannot receive a signal transmitted from the GPS satellite, and in addition, an error occurs in distance measurement using a signal due to diffraction or reflection of the signal by the building, and as a result, accuracy of positioning often deteriorates.

In addition, there is also a technique of receiving a weak GPS signal penetrating through a wall or a roof indoors, but the accuracy of positioning is also degraded due to unstable reception conditions.

In the above, positioning was described by taking GPS as an example, and the above phenomenon is common to positioning systems using satellites. The Satellite positioning System is not limited to GPS, and includes systems such as GLONASS (GLObal NAvigation Satellite System) in the russian republic and Galileo in europe.

Here, a technique related to the provision of position information is disclosed in, for example, japanese patent laid-open No. 2006-67086 (patent document 1).

Patent document 1: japanese laid-open patent publication No. 2006-67086

Disclosure of Invention

Problems to be solved by the invention

However, according to the technique disclosed in japanese patent laid-open No. 2006-67086, the reader or writer is inherent to the system that provides the position information, and there is a problem of lack of versatility. Further, in order to avoid interference, it is necessary to suppress transmission output power, and the range in which position information can be received is limited, and there is a problem that not only continuous position information cannot be acquired, but also a large number of transmitters are required to cover a wide range.

In addition, regarding acquisition or notification of the position information, for example, if it is a fixed telephone, the setting place is known in advance, and therefore the place where the fixed telephone is dialed can be determined from the telephone dialed from the fixed telephone. However, with the spread of mobile phones, mobile communication has become common, and therefore, there are an increasing number of cases where positional information of a sender cannot be notified as in a fixed telephone. On the other hand, with respect to the report at the time of emergency, laws and regulations concerning inclusion of position information in the report from the portable telephone are also gradually perfected.

In the case of a mobile phone having a conventional positioning function, since position information can be acquired at a location where signals from satellites can be received, the position of the mobile phone can be notified. However, there is a problem that the conventional positioning technology cannot acquire the position information in a place where radio waves cannot be received, such as an indoor place or an underground street.

Thus, for example, the following techniques are also considered: a plurality of transmitters capable of transmitting signals similar to GPS signals are arranged indoors, and the position is obtained based on the same principle of trilateration as GPS. However, in this case, time synchronization of the transmitters is required, which raises a problem of high cost of the transmitters.

Further, since transmission of radio waves becomes complicated by reflection in a room or the like, there is a problem that an error of about several tens of meters is easily generated even if an expensive transmitter as described above is provided.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a position information providing system that provides position information without degrading accuracy even in a place where radio waves from satellites that transmit signals for positioning cannot be received.

Another object of the present invention is to provide a position information providing system for providing position information based on a signal that does not need to be time-synchronized with the time of a satellite that transmits a signal for positioning.

Another object of the present invention is to provide a position information providing system that reduces the cost of a transmitter that transmits a signal for positioning.

Another object of the present invention is to provide a position information providing system that can easily install and maintain a transmitter installed indoors or the like.

Another object of the present invention is to provide an indoor transmitter capable of transmitting a signal that provides position information without degrading accuracy even in a place where radio waves from a satellite that transmits a signal for positioning cannot be received.

Another object of the present invention is to provide an indoor transmitter capable of transmitting a signal for providing position information based on a signal that does not require time synchronization with the time of a satellite transmitting a signal for positioning.

Another object of the present invention is to provide an indoor transmitter that can be easily installed and maintained.

Another object of the present invention is to provide a method for providing location information without degrading accuracy even in a location where radio waves from a satellite transmitting a signal for positioning cannot be received.

Still another object of the present invention is to provide a method of providing location information based on a signal that does not need to be time-synchronized with the time of a satellite transmitting a signal for positioning.

Means for solving the problems

According to one embodiment, there is provided a position information providing system capable of providing position information using a first positioning signal that is a spectrum spread signal from a plurality of satellites. The position information providing system includes an indoor transmitter. The indoor transmitter includes: a first storage unit that stores position data for specifying a location where an indoor transmitter is installed; a generation unit that generates a second positioning signal, which is a spread spectrum signal and is a signal obtained by quadrature modulation having position data; and a transmission unit that transmits the spread spectrum signal. The position information providing system further includes a position information providing device. The position information providing device includes: a receiving unit that receives a spread spectrum signal; a second storage unit for storing code patterns (reference numerals パタ - ン) related to the first positioning signal and the second positioning signal; a determining unit that determines a code pattern corresponding to the spread spectrum signal received by the receiving unit, based on the code pattern stored in the second storage unit; a determination unit that determines which of the first positioning signal and the second positioning signal is received, based on a signal demodulated using the code pattern determined by the determination unit; a position information derivation unit that derives position information of the position information provision device by switching processing according to the result of the determination; and an output unit that outputs the position information derived by the position information derivation unit. The position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter. The generation unit generates, as the second positioning signal, a first phase signal obtained by quadrature-modulating the first data and a second phase signal obtained by quadrature-modulating the second data.

Preferably, the position information deriving unit acquires the position data from the signal obtained by the demodulation when receiving the second positioning signal transmitted from the one indoor transmitter. When a plurality of first positioning signals are received, the position information deriving unit calculates position information from the plurality of spread spectrum signals.

Preferably, the position information providing means is capable of communicating with a communication means that provides the position information associated with the first data through a communication line. When the receiving unit receives the second positioning signal, the position information deriving unit communicates with the communication device based on the first data included in the first phase signal, thereby acquiring the position information associated with the first data.

Preferably, the indoor transmitter further includes: a plurality of digital filters; and a selection unit that selects one of the plurality of digital filters. The generating unit generates a second positioning signal having position data as a spread spectrum signal, based on the bandwidth defined by the digital filter selected by the selecting unit.

Preferably, the position information deriving unit extracts the second data from the second phase signal when the receiving unit receives the second positioning signal. The output unit displays the installation location based on the second data.

Preferably, the second positioning signal comprises a first phase signal and a second phase signal. The first phase signal includes first data that enables a determination of an indoor transmitter. The second phase signal includes second data indicating an installation location of the indoor transmitter. The generation unit performs modulation of the first phase signal and modulation of the second phase signal independently.

Preferably, the first storage portion stores spreading code data for spectrum spreading. The indoor transmitter further includes a data input unit that receives an input of the spread code data and writes the received spread code data into the first storage unit. The generation unit generates a second positioning signal, which is a spectrum spread signal, based on spread code data input from the outside of the indoor transmitter.

Preferably, the generation unit is a logic circuit that can be programmed according to firmware supplied from the outside.

Preferably, the second positioning signal has the same form as the first positioning signal. The second positioning signal includes position data, and the first positioning signal includes navigation messages. The position information deriving unit of the position information providing device includes a calculating unit that calculates the position of the position information providing device from each of the navigation messages when the plurality of first positioning signals are received.

Preferably, the position data is data directly indicating the position of the indoor transmitter only by the position data. The output unit outputs position information derived from only the position data as an image representing the measured position.

According to another embodiment, there is provided an indoor transmitter capable of providing position information using a second positioning signal of the same data format as a first positioning signal which is a spread spectrum signal from a plurality of satellites. The indoor transmitter includes: a first storage unit that stores position data for specifying a location where an indoor transmitter is installed; a generation unit that generates a second positioning signal, which is a spread spectrum signal and is a signal obtained by quadrature modulation having position data; and a transmission unit that transmits the spread spectrum signal. The position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter. The generation unit generates, as the second positioning signal, a first phase signal obtained by quadrature-modulating the first data and a second phase signal obtained by quadrature-modulating the second data.

According to still other embodiments, there is provided a position information providing method for providing position information using a first positioning signal that is a spectrum spread signal from a plurality of satellites. The method comprises the following steps: a generation step of generating a second positioning signal, which is a spread spectrum signal and is obtained by orthogonal modulation, based on position data for specifying a location where an indoor transmitter is installed; transmitting a spread spectrum signal; receiving a spread spectrum signal; determining a code pattern corresponding to the received spread spectrum signal according to code patterns related to the first positioning signal and the second positioning signal; judging which positioning signal of the first positioning signal and the second positioning signal is received according to a signal obtained by demodulating the determined code pattern; deducing position information by switching processing according to the judgment result; and outputting the derived position information. The position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter. The generating step comprises the steps of: a first phase signal and a second phase signal are generated as a second positioning signal, the first phase signal being a signal obtained by quadrature-modulating the first data, and the second phase signal being a signal obtained by quadrature-modulating the second data.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, it is possible to provide position information without degrading accuracy even in a place where radio waves from a satellite transmitting a signal for positioning cannot be received.

Drawings

Fig. 1 is a diagram showing a configuration of a position information providing system 10 according to a first embodiment of the present invention.

Fig. 2 is a block diagram showing a hardware configuration of the indoor transmitter 200-1.

Fig. 3 is a diagram conceptually showing one mode of data storage in the EEPROM243 included in the indoor transmitter 200-1.

Fig. 4 is a functional block diagram for explaining the structure of a modulator 245a for performing modulation conforming to a signal format in a circuit implemented by the FPGA 245.

Fig. 5 is a diagram showing the spectral intensity distribution of the signal of the L1C/a code and the signal of the L1C code.

Fig. 6 is a functional block diagram showing the configuration of the text data generating device 245 b.

Fig. 7 is a functional block diagram showing the configuration of the text data generating device 245 c.

Fig. 8 is a diagram showing a configuration of a signal 500 transmitted by a transmitter mounted on a GPS satellite.

Fig. 9 is a diagram showing a first configuration of the L1C interchange signal.

Fig. 10 is a diagram showing a second configuration of the L1C interchange signal.

Fig. 11 is a block diagram showing a hardware configuration of the position information providing apparatus 100.

Fig. 12 is a flowchart showing a procedure of processing performed by the position information providing apparatus 100.

Fig. 13 is a diagram showing a screen display on the display 440 of the positional information providing apparatus 100.

Fig. 14 is a block diagram showing the configuration of a positional information providing apparatus 1000 according to a modification of the first embodiment of the present invention.

Fig. 15 is a diagram showing a situation in which the position information providing apparatus according to the second embodiment of the present invention is used.

Fig. 16 is a diagram showing a usage mode of the position information providing apparatus according to the third embodiment of the present invention.

Fig. 17 is a block diagram showing a hardware configuration of a mobile phone 1200 according to a third embodiment of the present invention.

Fig. 18 is a block diagram showing a hardware configuration of an information providing server 1230 according to the third embodiment of the present invention.

Fig. 19 conceptually shows one mode of data storage in hard disk 1450 included in information providing server 1230.

Description of the reference numerals

10: a location information providing system; 110. 111, 112: a GPS satellite; 120. 121, 122: a transmitter; 100-1, 100-2, 100-3, 100-4, 1000, 1160, 1170: a position information providing device; 130: a building; 200-1, 200-2, 200-3, 1110, 1120, 1130, 1210: an indoor transmitter; 210: a wireless I/F; 220: an external synchronous connection port; 221: an external clock port; 230: a reference clock I/O module; 240: a digital processing module; 250: a simulation module; 1010. 1308: an antenna; 1140. 1150: an area; 1220: the internet; 1382: a memory card; 1462: CD-ROM.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same components are denoted by the same reference numerals. Their names and functions are also the same. Thus, detailed description thereof will not be repeated.

< first embodiment >

A position information providing system 10 according to a first embodiment of the present invention will be described with reference to fig. 1. Fig. 1 is a diagram showing a configuration of a position information providing system 10. The position information providing system 10 includes GPS (Global Positioning Satellite) satellites 110, 111, 112, 113 and position information providing devices 100-1 to 100-4 functioning as devices for providing position information, wherein the GPS satellites 110, 111, 112, 113 fly above the ground at an altitude of about 2 kilometers and transmit signals for Positioning (hereinafter, referred to as "Positioning signals"). The positional information providing devices 100-1 to 100-4 are collectively referred to as the positional information providing device 100. The position information providing apparatus 100 is a terminal having a conventional positioning apparatus, such as a mobile phone, a car navigation system, and other mobile body positioning apparatuses.

Here, the positioning signal is a signal obtained by performing so-called spectrum spreading, and is, for example, a so-called GPS signal. However, the signal is not limited to a GPS signal. In the following, for the sake of simplicity, the positioning system will be described by taking GPS as an example, but the present invention is also applicable to other satellite positioning systems (Galileo, quasi-zenith satellites, etc.).

The center frequency of the positioning signal is 1575.42MHz, for example. The spread frequency of the positioning signal is, for example, 1.023 MHz. In this case, the frequency of the positioning signal is the same as the frequency of a C/A (Coarse and Acquisition) signal of the L1 band of the existing GPS. Therefore, since the front end (front end) of the existing positioning signal receiving circuit (for example, GPS signal receiving circuit) can be used, the position information providing apparatus 100 can receive the positioning signal by merely changing software for performing signal processing from the front end without adding a new hardware circuit.

The positioning signal may also be modulated with a 1.023MHz square wave. In this case, for example, if the data channel is the same as that of a positioning signal for which a new transmission is planned on the L1 frequency band, the user can receive the positioning signal using a receiver capable of receiving and processing a new GPS signal. Further, the frequency of the rectangular wave is preferably 1.023 MHz. The frequency used for modulation can be determined by balancing the existing C/a signal and/or spectral separation to avoid interference with other signals.

The GPS satellite 110 is equipped with a transmitter 120 that transmits a positioning signal. The GPS satellites 111, 112, and 113 are also provided with the same transmitters 121, 122, and 123, respectively.

As described below, the position information providing apparatuses 100-2, 100-3, and 100-4 having the same functions as the position information providing apparatus 100-1 can also be used in places where it is difficult for buildings 130 and other radio waves to reach. That is, the indoor transmitter 200-1 is mounted on the ceiling of the first floor of the building 130. The position information providing apparatus 100-4 receives the positioning signal transmitted from the indoor transmitter 200-1. Similarly, the indoor transmitters 200-2 and 200-3 are installed on the ceilings of the second floor and the third floor of the building 130, respectively. Here, the time of each of the indoor transmitters 200-1, 200-2, and 200-3 (hereinafter referred to as "ground time") may be independent of the time of the GPS satellites 110, 111, 112, and 113 (referred to as "satellite time"), and synchronization is not required. However, each satellite time needs to be synchronized individually. Thus, each satellite time is controlled by an atomic clock loaded on each satellite. It is also preferable that the ground times, which are the times of the indoor transmitters 200-1, 200-2, and 200-3, be synchronized with each other as necessary.

A spectrum spread signal transmitted as a positioning signal from each transmitter of the GPS satellite is generated by modulating a navigation message with a Pseudo Noise code (PRN) code. The navigation message contains time data, orbit information, almanac (almanac), ionosphere correction data, etc. The transmitters 120 to 123 also hold data (PRN-ID) for identifying the transmitters 120 to 123 themselves or the GPS satellites on which the transmitters 120 to 123 are mounted, respectively.

The position information providing apparatus 100 has data for generating each pseudo noise code and a code generator. When receiving the positioning signal, the position information providing apparatus 100 can determine from which satellite or which indoor transmitter the received signal was transmitted, by performing a demodulation process described below using the code pattern of the pseudo noise code assigned to each transmitter of each satellite or each indoor transmitter. Further, since the L1C signal, which is one of the positioning signals, includes the PRN-ID in the data, it is possible to prevent the signal from being captured and tracked by an erroneous code pattern, which is likely to occur when the reception level is low.

(transmitter mounted on GPS satellite)

Since the configuration of a transmitter mounted on a GPS satellite is well known, an outline of the configuration of a transmitter mounted on a GPS satellite will be described below. Each of the transmitters 120, 121, 122, and 123 includes an atomic clock, a storage device for storing data, an oscillation circuit, a processing circuit for generating a positioning signal, an encoding circuit for performing spectrum spread encoding on a signal generated by the processing circuit, a transmission antenna, and the like. The storage device stores a navigation message including ephemeris (ephemeris), an almanac of each satellite, ionosphere correction data, and the like, and PRN-ID.

The processing circuit generates a message for transmission using the time information from the atomic clock and each data stored in the storage device.

Here, a code pattern of a pseudo noise code for performing spectrum spread coding is predetermined for each of the transmitters 120 to 123. The code patterns differ from transmitter to transmitter (i.e., from GPS satellite to GPS satellite). The coding circuit uses this pseudo-noise code to spread the spectrum of the text. Each of the transmitters 120 to 123 converts the encoded signal into a high frequency signal and transmits the high frequency signal to the space through a transmission antenna.

As described above, the transmitters 120-123 transmit spread spectrum signals that do not cause harmful interference with other transmitters. Here, "not to cause harmful interference" is to be able to be ensured by an output level limited to a degree that no interference is generated. Alternatively, the spectrum can be separated. For example, the signal is transmitted through a carrier wave called L1 band. Each transmitter 120, 121, 122, 123 transmits a positioning signal having the same frequency, for example, in accordance with the spread spectrum communication method. Therefore, even when the positioning signals transmitted from the satellites are received by the same position information providing apparatus 100-1, the positioning signals are received without interfering with each other.

In addition, in the case of positioning signals from terrestrial indoor transmitters, signals from a plurality of indoor transmitters can be received without interfering with each other, as in the case of signals transmitted from satellites.

(hardware configuration of indoor transmitter 200-1)

The indoor transmitter 200-1 is explained with reference to fig. 2. Fig. 2 is a block diagram showing a hardware configuration of the indoor transmitter 200-1.

The indoor transmitter 200-1 includes a wireless interface (hereinafter referred to as "wireless I/F") 210, a digital processing module 240, a reference clock input/output module (hereinafter referred to as "reference clock I/O module") 230 electrically connected to the digital processing module 210 and supplying a reference clock for operating each circuit part, an analog processing module 250 electrically connected to the digital processing module 210, an antenna (not shown) electrically connected to the analog processing module 250 and transmitting a signal for positioning, and a power supply (not shown) for supplying a power supply potential to each part of the indoor transmitter 200-1.

The power source may be built in the indoor transmitter 200-1 or may be configured to receive power supply from the outside.

(Wireless communication interface)

The wireless I/F210 is an interface for wireless communication, and is used for receiving commands from the outside, receiving data of setting parameters and programs (Firmware) with an external device, or transmitting data to the outside as necessary, by short-range wireless communication, for example, wireless communication such as Bluetooth (registered trademark) or the like, PHS (personal handyphone System), or a cellular phone network.

By providing such a wireless I/F210, even after the indoor transmitter 200-1 is installed on an indoor ceiling or the like, it is possible to change setting parameters such as position data (data indicating a place where the indoor transmitter 200-1 is installed) to be transmitted by the indoor transmitter 200-1 or to adapt to a different communication method by changing firmware.

Although the present embodiment assumes a wireless interface, a wired interface may be used in consideration of wiring at an installation site, labor and time for installation, and the like.

(digital processing module)

The digital processing module 240 includes: a processor 241 for controlling the operation of the indoor transmitter 200-1 in accordance with a command or a program from the wireless I/F210; a RAM (Random Access Memory) 242 loaded on the processor 241 and storing a program to be executed by the processor 241; an EEPROM (electrically Erasable Programmable Read Only Memory) 243 for storing setting parameters and the like in data from the wireless I/F210; a Field Programmable Gate Array (hereinafter, referred to as "FPGA") 245 that generates a baseband signal to be transmitted by the indoor transmitter 200-1 under the control of the processor 241; an EEPROM 244 for storing firmware of the FPGA 245 in data from the wireless I/F210; and a digital/analog converter (hereinafter, referred to as a "D/a converter") 247 that converts the baseband signal output from the FPGA 245 into an analog signal and supplies to the analog module 250.

That is, the digital processing module 240 generates data serving as a signal source of a signal transmitted as a signal for positioning by the indoor transmitter 200-1. The digital processing module 240 transmits the generated data as a bit stream to the analog processing module 250.

For example, when the FPGA 245 is powered on, the firmware program stored in the EEPROM 244 is loaded into the FPGA 245, which is not particularly limited. The firmware program information (bit stream data) is loaded into a configuration Memory (configuration Memory) constituted by an SRAM (static random Access Memory) 246 within the FPGA 245. The individual bits of the loaded bitstream data become the source of information for the circuits implemented on the FPGA 245, the circuits determined by the firmware program being implemented by customizing the resources provided in the FPGA 245. In the FPGA 245, high versatility and flexibility can be achieved by having configuration data externally without depending on hardware in this way.

The processor 241 stores the following information as parameters set to the indoor transmitter 200-1 in the SRAM 246 (register) of the FGPA 245 based on the data stored in the EEPROM243 in accordance with the external command received from the wireless I/F210.

1) Pseudo-spreading code (PRN code)

2) Sender ID

3) Transmitter coordinates

4) Text (which is shaped within the FPGA 245 to the same format as the navigation text from the satellite)

5) Selection parameters for digital filters

Further, as will be described later, band pass filters for 1MHz, 2MHz, and 4MHz (center frequency: 1575.42MHz) are preprogrammed into the FPGA 245, for example, and the "selection parameter of the digital filter" is a parameter for determining which band pass filter is selected.

Further, a program for operating the processor 241 is stored in advance in the EEPROM243, and the program is read from the EEPROM243 and transferred to the RAM 242 when the indoor transmitter 200-1 is started.

Further, the storage device for storing programs or data is not limited to the EEPROM243 or 244. Any storage device may be used as long as it can store data at least in a nonvolatile manner. As described later, when data is input from the outside, the data may be written to a storage device. The data structure of the data stored in the EEPROM243 is described later.

(analog processing Module)

The analog processing module 250 modulates a carrier wave of 1.57542GHz using the bit stream output from the digital processing module 240 to generate a transmission signal, and transmits the transmission signal to an antenna. The signal is transmitted using an antenna.

That is, a signal output from the D/a converter 247 of the digital processing module 240 is up-converted by an up-converter 252, only a signal of a predetermined frequency bandwidth is amplified by a Band Pass Filter (BPF)253 and an operational amplifier 254, up-converted again by an up-converter 255, the signal of the predetermined frequency bandwidth is taken out by a SAW (Surface acoustic wave) filter, and then converted into a signal of a set intensity by a variable attenuator (variable attenuator)257 and an RF switch 258, and transmitted from an antenna.

The clocks used in the up-converters 252 and 255 are further multiplied by a frequency multiplier (frequency multiplier)251 using the clock supplied from the reference clock I/O block 230 to the FPGA 245.

In addition, the setting of the levels of the variable attenuator 257 and the RF switch 258 is controlled according to a control signal from the processor 241 via the FPGA 245. The RF switch 258 effectively changes the signal intensity in accordance with so-called PM (Pulse Modulation) Modulation. Both the variable attenuator 257 and the RF switch 258 operate as part of an "individual variable function of IQ modulation amplitude" described later.

In this way, a signal having the same configuration as that of a signal for positioning from a satellite is transmitted from the indoor transmitter 200-1. In this case, the content of the signal is not exactly the same as that contained in the positioning signal transmitted from the satellite. An example of the configuration of the signal transmitted from the indoor transmitter 200-1 will be described later (fig. 8).

In the above description, the FPGA 245 is used as an arithmetic processing device for realizing digital signal processing in the digital processing module 240, but any other arithmetic processing device may be used as long as the modulation function of the wireless device can be changed by software.

In fig. 2, the clock signal (Clk) is supplied from the digital processing block 240 to the analog processing block 250, but the clock signal may be directly supplied from the reference clock I/O block 230 to the analog processing block 250.

In the present embodiment, the digital processing module 240 and the analog processing module 250 are shown separately for clarity of explanation, but may be physically mixed in one chip.

(reference clock I/O Module)

The reference clock I/O block 230 supplies a clock signal for specifying the operation of the digital processing block 240 or a clock signal for generating a carrier wave to the digital processing block 240.

In the "external synchronization mode", the reference clock I/O block 230 supplies a clock signal to the digital processing block 240 and the like by the driver 234 based on a synchronization signal supplied from an external clock generator to the external synchronization connection port 220.

On the other hand, in the "external clock mode", the reference clock I/O block 230 selects an external clock signal supplied to the external clock port 221 by a multiplexer (multiplexer)232, synchronizes a clock signal output from a PLL (Phase Locked Loop) circuit 233 with the external clock, and supplies the synchronized clock signal to the digital processing block 240 and the like.

On the other hand, in the "internal clock mode", the reference clock I/O block 230 selects the internal clock signal generated by the internal clock generator 231 by the multiplexer 232, synchronizes the internal clock with the clock signal output from the pll (phase Locked loop) circuit 233, and supplies the synchronized clock signal to the digital processing block 240 and the like.

Further, the internal state of the transmitter (for example, "PLL control" signal) can be monitored based on a signal output from the wireless I/F210 through the processor 241. Alternatively, the digital input/output interface 260 may also receive an input of a code pattern of a pseudo noise code for spreading and modulating a signal transmitted from the indoor transmitter 200-1, or the wireless I/F210 may also receive an input of other data to be transmitted from the indoor transmitter 200-1. The other data is, for example, text data (position data) indicating a place where the indoor transmitter 200-1 is installed. Alternatively, when the indoor transmitter 200-1 is installed in a department store or other commercial establishment, the data for advertisement can be input to the indoor transmitter 200-1 as the other data.

When the code pattern of the pseudo spread code (PRN code) is inputted to the indoor transmitter 200-1, it is written in a predetermined area in the EEPROM 243. The written PRN-ID is then included in the signal used for positioning. Other data is also written in an area of the EEPROM243 that is secured in advance according to the type of the data.

(data structure of data stored in EEPROM 243)

The data structure of data stored in the EEPROM243 of the indoor transmitter 200-1 will be described with reference to fig. 3.

Fig. 3 is a diagram conceptually showing one mode of data storage in the EEPROM243 included in the indoor transmitter 200-1. The EEPROM243 includes areas 300-350 for storing data.

A transmitter ID as a number for identifying a transmitter is stored in the area 300. The transmitter ID is, for example, a number and/or an english alphabet, or other combination, which is written in a nonvolatile manner into the memory at the time of manufacturing the transmitter.

The PRN-ID of the pseudo spreading code assigned to the transmitter is stored in the area 310. The name of the transmitter is stored as text data in the area 320.

A code map of the pseudo spreading code allocated to the transmitter is stored in region 330. The code pattern of the pseudo-spread code is a code pattern selected from a limited number of code patterns that are assigned in advance for use in the position information providing system according to the embodiment of the present invention, from among code patterns belonging to the same series as the pseudo-spread code for the satellite, and is different from the code pattern of the pseudo-spread code assigned to each satellite.

The number of code patterns of the pseudo spreading code allocated for use in the position information providing system is limited, but the number of indoor transmitters differs depending on the size of the installation place of each transmitter or the configuration of the installation place (the number of floors of a building, etc.), and a plurality of indoor transmitters larger than the number of code patterns may be used. Thus, there may be multiple transmitters with code patterns of the same pseudo-spreading code. In this case, the installation location of the transmitter having the same code pattern may be determined in consideration of the output power of the signal. Thus, it is possible to prevent a situation where a plurality of positioning signals using a code pattern of the same pseudo-spread code are received at the same time by the same position information providing apparatus.

The area 340 stores position data for specifying the location where the indoor transmitter 200-1 is installed. The position data is expressed as a combination of latitude, longitude, and altitude, for example. In addition to or instead of the position data, the address, the name of the building, and the like may be stored in the area 340. In the present invention, data that can specify the installation location of the transmitter 200-1 from only the data, such as "a combination of latitude, longitude, altitude", "an address, a name of a building", "a combination of latitude, longitude, altitude, an address, and a name of a building", is collectively referred to as "location specifying data".

Also, filter selection parameters for selecting a filter are stored in the area 350. For example, the bandwidth of the band pass filter is not particularly limited, but "1 MHz", "2 MHz", and "4 MHz" are selected in accordance with the filter selection parameters "0", "1", and "2", respectively.

Here, as described above, the PRN-ID, the name of the communicator, the code pattern of the pseudo-spread code, the position determination data, and the filter selection parameter can be changed to other data input via the wireless interface 210.

(Structure of FPGA 245)

The circuit implemented by the FPGA 245 shown in fig. 2 is explained below.

First, fig. 4 is a functional block diagram for explaining the configuration of a modulator 245a in a circuit implemented by the FPGA 245, the modulator 245a being configured to modulate the following signals in accordance with their respective signal formats: a signal for positioning, i.e., a baseband signal of a C/a (coarse/access: coarse/acquisition) code, which is loaded on an L1 band (1575.42MHz) of a carrier of the current GPS signal; or a signal for positioning used in the L1 band of a new positioning satellite system (for example, a quasi-zenith satellite system in japan), that is, a baseband signal of L1C code.

Here, for example, BPSK (Binary Phase Shift Keying) modulation is performed on the C/a code, and QPSK (quadrature Phase Shift Keying) modulation is performed on the L1C code. As will be apparent from the following description, the modulation method for converting a digital value into an analog signal is not limited to BPSK modulation and QPSK modulation, and other methods that can be realized by the FPGA 245 may be employed.

Here, although the configuration shown in fig. 4 is basically the configuration of the QPSK modulator, if the signal applied to the I phase and the signal applied to the Q phase are the same signal, the result is a circuit configuration capable of simultaneously realizing both BPSK modulation and QPSK modulation by using the equivalent property of BPSK modulation. However, independent circuits may be programmed in each mode according to the modulation scheme implemented by the modulator 245 a.

Referring to fig. 4, the modulator 245a includes: PRN code registers 2462 and 2464 that receive and store the PRN code stored in EEPROM 243; and message code registers 2466 and 2468 that receive and store message data in a signal format corresponding to the C/a code or L1C code from the message data generator 245b or 245C as will be described later.

Here, the PRN code set in the EEPROM243 is externally input to the PRN code registers 2462 and 2464, and as described above, the same data is stored in both the message code registers 2466 and 2468 in BPSK modulation, while different data of I-phase data and Q-phase data is stored in the message code registers 2466 and 2468 in QPSK modulation.

The modulator 245a further includes: a multiplier 2452 that multiplies the time-series data read out from the PRN code register 2462 by the time-series data read out from the text code register 2466; a multiplier 2454 that multiplies the time-series data read out from the PRN code register 2464 by the time-series data read out from the text code register 2468; a level control circuit 2456 which is controlled by a level control signal LVC 1 from the processor 241 and changes the intensity of the signal input from the multiplier 2452; a level control circuit 2458 controlled by a level control signal LVC2 from the processor 241, for changing the intensity of the signal input from the multiplier 2454; an FIR (Far Infrared Rays) filter 2460 that functions as a band-pass filter of a bandwidth selected according to a filter selection parameter for an output from the level control circuit 2456; and an FIR filter 2462 that functions as a band-pass filter of a bandwidth selected according to a filter selection parameter for the output from the level control circuit 2458.

The modulator 245a further includes: a clock circuit 2472 that generates a modulation reference clock conforming to the signal format from the clock signal from the reference clock I/O block 230; a lookup table (lookup table)2474 that outputs data corresponding to a preset sine wave and a cosine wave as an I-phase modulation signal and a Q-phase modulation signal, respectively, in synchronization with a signal from the clock circuit 2472; a multiplier 2464 that multiplies the sine wave equivalent signal output from the lookup table 2474 and the signal from the FIR filter 2460; a multiplier 2466 that multiplies the cosine wave equivalent signal output from the lookup table 2474 and the signal from the FIR filter 2462; an adder 2468 that adds the signals from the multipliers 2464 and 2466; and an output buffer 2470 for buffering the output from the adder 2368 and outputting to the D/a converter 247.

Data contained in a signal output from the modulator 245a to the D/a converter 247 as described above is as follows.

(case of outputting a signal compatible with the existing GPS signal)

When the firmware of the FPGA 245 is configured as a circuit that outputs a signal compatible with the current GSP signal (a signal compatible with the L1C/a code: L1C/a interchange signal), the modulator 245a modulates the "latitude/longitude/altitude" information of the transmitter into a text together with the Q-phase signal and the I-phase signal, thereby generating a BPSK modulated signal. Here, the "compatible signal" refers to a signal that can be received by the receiver using the common front end unit because the signals have the same signal format.

(case of outputting a signal compatible with the L1C signal: L1C interchange signal)

Next, a circuit configuration in which the firmware of the FPGA 245 outputs a signal compatible with the L1C signal will be described below.

First, the L1C signal from the satellite will be briefly described as a premise.

As described above, the L1C signal from the satellite is QPSK modulated, and the Q-phase signal is loaded with a pilot signal for the supplement of the modulated receiver. The Q-phase signal is at a 3dB level higher than the I-phase signal. On the other hand, navigation messages and the like are loaded in the I-phase signal.

Here, the reason why the pilot signal for the supplement is added to the Q-phase signal is as follows.

That is, the C/a code of the current GPS signal is 1023 chips of signal, the period is 1msec, and the same signal continues for 20 cycles, so that S/N can be increased by integration (integration), whereas the L1C signal is 10230 chips of signal, the period is 10msec, so that the same signal has only 1 cycle, and S/N cannot be increased by integration. Therefore, the Q-phase signal of the signal from the satellite needs to be used as a complement.

In contrast, a signal compatible with the L1C signal from the indoor transmitter 200-1 can be loaded with the transmitter ID on the Q-phase signal. This is because the intensity of the signal transmitted from the indoor transmitter 200-1 is stronger than the intensity of the signal transmitted from the GPS satellite, and therefore, a signal for supplement is not necessary. This is based on the following situation: signals from GPS satellites are weak when propagating on the ground, and therefore, signals for compensation are required, while in the case of an indoor transmitter, signal strength needs to be increased in order to prevent multipath or unstable propagation. On the other hand, position determination data, such as latitude/longitude/altitude data, is loaded on the I-phase signal.

Fig. 5 is a diagram showing the spectral intensity distributions of the signal of L1C/a code and the signal of L1C code. Fig. 5 also shows the spectrum strength of signals of P-code, which is a military code transmitted from a satellite together with C/a code through the L1 band, and M-code, which is a code mainly used for military transmitted from a satellite together with L1C signal through the L1 band.

As shown in fig. 5, regarding the C/a code, a main peak exists in the center frequency of 1575.42MHz, and a side lobe (sidelobe) signal exists in the periphery thereof. On the other hand, to suppress interference with the C/a code, the L1C code has a Null point at the center frequency of 1575.42MHz, two main peaks on both sides thereof, and a sidelobe signal on the outside thereof.

Therefore, only the main peak can be extracted by a band pass filter having a bandwidth of 1MHz for the C/a code, and only the main peak can be extracted by a band pass filter having a bandwidth of 2MHz for the L1C code.

As described above, since the intensity of the signal at the location where the signal transmitted from the indoor transmitter 200-1 is received is greater than that in the case where the signal transmitted from the GPS satellite is received on the ground, only the target frequency component is transmitted, and interference with other signals can be suppressed.

(text data generating device 245b)

Fig. 6 is a functional block diagram showing the configuration of the text data generating device 245b in the case where the firmware of the FPGA 245 is set to transmit a signal compatible with the C/a code of the L1 band.

As described below, the text data generating device 245b performs the following processing: position determination data or the like supplied from the outside is loaded in a signal format on a portion equivalent to the navigation message within the C/a code of the L1 band.

The text data generating device 245b includes: a command interface 2482 that receives commands 2480 from processor 241; a TOW command analyzer 2484 that reads information of TOW (Time of week: Time of week) within the C/a code of the L1 band according to a command provided from the command interface 2482; a command analyzer 2488 that reads the contents of commands other than the TOW command; a TOW generator 2486 that generates TOW information based on a signal from the TOW command analyzer 2484; and a text bank (messagebank)2490 that receives and stores the TOW information from the TOW generator 2486 and the text information from the command analyzer 2488.

The message memory 2490 includes 30-bit memory banks 01 and 02 for storing TOW information, and 30-bit memory banks 03 to 10 for storing message information. Each of the banks 01 to 10 has an area 2490a for storing 24-bit information, and the CRC generator 2492 generates a CRC code (6 bits) for error detection from the 24-bit data and stores the CRC code in the area 2490b subsequent to the area 2490a of each bank.

The sequence counter (sequence counter)2494 sequentially supplies read signals to the banks 01 to 10 in synchronization with the MSG clock MSGClock based on the clock from the reference clock I/O block 230, and accordingly reads data from the banks 01 to 10 and stores the data in the text register 2496.

The data of the text register 2496 is written into both the text code registers 2466 and 2468. The subsequent processing is described as the operation of the modulator 245a in fig. 4.

(text data generating device 245c)

Fig. 7 is a functional block diagram showing the configuration of the text data generating device 245c when the firmware of the FPGA 245 is set to transmit a signal compatible with the L1C code.

As described below, the text data generating device 245c performs the following processing: position determination data or the like, transmitter ID, and the like supplied from the outside are loaded in a signal format onto a portion equivalent to the navigation message and pilot signal in the L1C code.

The text data generating device 245c includes: a command interface 2502 that receives commands 2500 from the processor 241; a text command analyzer 2504 for analyzing the content of data transmitted as a text according to a command supplied from the command interface 2502; a text storage 2506 that receives and stores the text information for phase I from the text command analyzer 2504; and a text storage 2508 that receives and stores text information for the Q-phase from the text command analyzer 2504.

The text memory 2506 includes memory banks I00 to I10 each having a capacity of 150 bits for storing information for I phase. The text storage 2508 includes: memory banks Q00 to Q02 each having a capacity of 48 bits for storing Q-phase information; memory banks Q03 to Q05 each having a capacity of 63 bits for storing Q-phase information; and 75-bit capacity memory banks Q06-Q08 for storing Q-phase information. The capacity of each of the Q-phase banks is not limited to these values, and for example, the capacities of the banks Q00 to Q08 may all be set to the same capacity as that of the I-phase bank, that is, 150 bits.

Here, the transmitter ID is stored in the text storage 2508 for the Q phase, for example. On the other hand, the I-phase message storage 2506 can store not only the "position specifying data" but also "advertisement data", "traffic information", "weather information", and "disaster information" supplied from the outside of the indoor transmitter 200-1 via the wireless I/F210, for example. The disaster information includes, for example, earthquake prediction, earthquake occurrence information, and the like. Here, the "external" includes a server device operated by an enterprise, a government agency, or the like that provides the above-described information. These pieces of information may be transmitted from the external server apparatus in real time, or may be periodically updated. Alternatively, the operation manager of the indoor transmitter 200-1 may update the data as needed. For example, when the indoor transmitter 200-1 is installed in a department store, the operation manager may provide data for advertisement to the indoor transmitter 200-1 as one of business activities of the department store.

The following configuration can be adopted: the configuration is not particularly limited, and is an error correction code in which BCH is added to the data stored in the banks Q00 to Q08, and an error detection code is added to the data stored in the banks I00 to I10. Thus, the data of the banks Q00 to Q08 which repeatedly contain transmitter IDs having short data lengths can be determined in advance by obtaining correct data every time the data is received in a short cycle. This allows the reception data to be specified earlier on the Q-phase side than on the I-phase side, and the process can be shifted to the acquisition process of the position information (inquiry to the server) as described later.

The text data generating device 245c further includes: a sequence manager (sequence manager)2510 for reading out data included in the I-phase signals from the banks I00 to I10 in the order corresponding to the commands from the command interface 2502; and a sequence manager 2512 for reading out data included in the Q-phase signals from the banks Q00 to Q08 in the order corresponding to the commands from the command interface 2502.

The message data generation device 245c further includes a message register 2514, and the message register 2514 sequentially reads data from the sequence manager 2510 and the sequence manager 2512 in synchronization with the MSG clock MSGClock based on the clock from the reference clock I/O module 230, and individually writes the data into the message code registers 2466 and 2468.

The data of the text register 2514 is written to both the text code registers 2466 and 2468. The subsequent processing is described as the operation of the modulator 245a in fig. 4.

When the signal generated by the text data generating device 245c is transmitted from the indoor transmitter 200-1, the receiver side (position information providing device side) is also provided with memory areas divided by I00 to I10 corresponding to the 150-bit text banks I00 to I10 on the I-phase transmitter side, and is also provided with memory areas divided by Q00 to Q08 corresponding to the Q-phase text banks Q00 to Q08. Thus, the content of the receiver-side storage area is updated every time some data of the data stored in the banks I00 to I10 or the banks Q00 to Q08 is newly received. Therefore, the data stored in the banks I00 to I10 and Q00 to Q08 include an identifier that can identify which bank the data is.

The text message generated by the text message data generating device 245c transmitted from the indoor transmitter 200-1 is summarized as follows. Further, the signal generated by the message data generating means 245c is hereinafter referred to as "L1C interchange message"

The L1C interchange telegraph is composed of an I-phase signal and a Q-phase signal. Independent separate messages are modulated in the I-phase signal and the Q-phase signal respectively. Specifically, short information such as a transmitter ID is modulated in the Q-phase signal. The data length of the Q-phase signal is shorter than that of the I-phase signal, so that the receiver can quickly capture the Q-phase signal and can immediately acquire the ID. However, the ID itself does not have a direct meaning (e.g., location information), so the receiver cannot know the location from the sender ID alone. Therefore, in some cases, the receiver can access a site of a server device that provides location information, for example, via a mobile phone network, transmit the transmitter ID to the server device, and acquire location information associated with the transmitter ID from the server device.

On the other hand, position determination data is modulated in the I-phase signal. In some cases, the electric text included in the I-phase signal may be variable. For example, in addition to the location information, variable messages such as traffic information, weather information, disaster information, and the like can be modulated in the I-phase signal. Thus, when the indoor transmitter 200-1 is connected to an external network, the variable message is updated in real time, and appropriate information can be provided to the user of the receiver. The I-phase signal contains the location information itself so that the user of the receiver can learn his location without connecting the receiver to the network. Therefore, even when the communication line is blocked due to a disaster, for example, the receiver can be located as long as the L1C compatible message can be received. In this case, if the receiver can transmit the location as a portable telephone, the receiver of the signal can easily determine the sender (i.e., the victim) of the signal.

Thus, the I-phase signal and the Q-phase signal have a difference in modulated information itself and a difference in structure such as a signal length. The receiver only needs to receive at least one signal in order to obtain the position information. In one case, the receiver is configured to be able to receive any signal, but in another case, the user of the receiver can select which of the I-phase signal and the Q-phase signal to receive as needed. This selection is achieved by the user inputting settings into the receiver that specify which signal is received. Alternatively, the receiver may be configured to automatically switch from the I-phase signal reception mode to the Q-phase signal reception mode when, for example, the connection to the server via the communication line fails due to a timeout due to the congestion of the communication line. This enables setting according to the application of the receiver, thereby improving convenience.

(data structure of signal transmitted from indoor transmitter 200-1)

First, a description will be given of a configuration of a signal compatible with the C/a code of the L1 band to which the message generated by the message data generating device 245b is loaded.

(L1C/A interchange signal)

The positioning signal transmitted from the transmitter is explained with reference to fig. 8. Fig. 8 is a diagram showing a configuration of a signal 500 transmitted by a transmitter mounted on a GPS satellite. The signal 500 is composed of 5 subframes 510 to 550 of 300 bits. The transmitter repeatedly transmits the subframes 510 to 550. The sub-frames 510 to 550 are, for example, 300 bits each and are transmitted at a bit rate of 50bps (bit second). Thus, in this case, each subframe is transmitted within 6 seconds.

The first subframe 510 includes a transmission overhead (transport overhead)511 of 30 bits, time information 512 of 30 bits, and text data 513 of 240 bits. In detail, the time information 512 includes time information acquired when the subframe 510 is generated and a subframe ID. Here, the subframe ID is an identification number for distinguishing the first subframe 510 from other subframes. The text data 513 includes a GPS week number, clock information, health information of the GPS satellite, orbit accuracy information, and the like.

The second sub-frame 520 contains 30 bits of transmission overhead 521, 30 bits of time information 522, and 240 bits of text data 523. The time information 522 has the same structure as the time information 512 in the first subframe 510. Textual data 523 includes ephemeris. Here, ephemeris (ephemeris, broadcast ephemeris) is orbit information of a satellite which transmits a positioning signal. Ephemeris is high-precision information that is sequentially updated by a regulatory authority that manages the navigation of the satellite.

The third subframe 530 has the same structure as the second subframe 520. That is, the third subframe 530 includes a transmission overhead 531 of 30 bits, time information 532 of 30 bits, and text data 533 of 240 bits. The time information 532 has the same structure as the time information 512 in the first subframe 510. The textual data 533 includes ephemeris.

The fourth sub-frame 540 contains 30 bits of transmission overhead 541, 30 bits of time information 542, and 240 bits of text data 543. The text data 543 includes almanac information, summary of satellite health information, ionospheric delay information, UTC (Coordinated Universal Time) parameters, and the like, unlike the other text data 513, 523, 533.

The fifth sub-frame 550 contains 30 bits of transmission overhead 551, 30 bits of time information 552, and 240 bits of text data 553. The textual data 553 contains a summary of almanac information and satellite health information. The textual data 543, 553 is composed of 25 pages, respectively, and the different information described above is defined on each page. Here, the almanac information is information indicating an approximate orbit of a satellite, and includes not only information about the satellite but also information about all GPS satellites. When the transmission of the sub-frames 510 to 550 is repeated 25 times, the same information is transmitted back to the first page.

The sub-frames 510 to 550 are transmitted from the transmitters 120, 121, and 122, respectively. When the sub-frames 510 to 550 are received by the position information providing device 100, the position of the position information providing device 100 is calculated based on the maintenance and management information, the time information 512 to 552, and the text data 513 to 553 included in the transmission overhead 511 to 551.

The signal 560 has the same data length as the respective text data 513 to 553 contained in the sub-frames 510 to 550. The difference between signal 560 and sub-frames 510 to 550 is that signal 560 has data indicating the position of the transmission source of signal 560, instead of the track information indicated as ephemeris (textual data 523 and 533).

That is, signal 560 contains a 6-bit PRN-ID 561, a 15-bit transmitter ID562, an X-coordinate value 563, a Y-coordinate value 564, a Z-coordinate value 565, a height correction factor (Zhf)566, an address 567, and a reserve 568. Instead of the text data 513 to 553 contained in the sub-frames 510 to 550, a signal 560 is transmitted from the indoor transmitters 200-1, 200-2, 200-3.

The PRN-ID 561 is an identification number of a code pattern of a set of pseudo noise codes assigned in advance to a transmitter (for example, the indoor transmitters 200-1, 200-2, and 200-3) which is the transmission source of the signal 560. The PRN-ID 561 is a number assigned to a code pattern generated from a code sequence of the same sequence, unlike an identification code of a code pattern of a set of pseudo noise codes assigned to each transmitter mounted on each GPS satellite. The position information providing device acquires any one of code patterns of pseudo noise codes assigned to the indoor transmitter from the received signal 560, thereby determining whether the signal is a sub-frame 510-550 transmitted from a satellite or a signal 560 transmitted from the indoor transmitter.

The X-coordinate value 563, the Y-coordinate value 564, and the Z-coordinate value 565 are data indicating the position where the indoor transmitter 200-1 is mounted. The X-coordinate value 563, the Y-coordinate value 564, and the Z-coordinate value 565 are expressed as latitude, longitude, and altitude, for example. The altitude correction factor 566 is used to correct the altitude determined from the Z coordinate value 565. Further, the height correction coefficient 566 is not a necessary data item. Therefore, this coefficient may not be used in the case where accuracy of the height or more determined from the Z-coordinate value 565 is not required. In this case, data indicating "NULL (NULL)" is stored in the region allocated for the altitude correction coefficient 566, for example.

In the reserved area 568, "address, name of building", "data for advertisement", "traffic information", "weather information", and "disaster information" (for example, earthquake information) are assigned.

(L1C interchange signal)

Next, a description will be given of a configuration of a signal compatible with L1C code to which the message generated by the message data generating device 245c is applied.

The data structure of the I-phase signal is explained below.

(Structure 1 of I phase Signal)

Fig. 9 is a diagram showing a first configuration of the L1C interchange signal. In fig. 9, six subframes are transmitted. A signal 810 is transmitted by a transmitter as a first subframe. The signal 810 includes a 30-bit transmission overhead 811, 30-bit time information 812, a 6-bit PRN-ID813, a 15-bit transmitter ID 814, an X-coordinate value 815, a Y-coordinate value 816, and a Z-coordinate value 817. The first 60 bits of the signal 810 are the same as the first 60 bits of each of the sub-frames 510-550 transmitted by the GPS satellites.

In the reserved area 818, "address, name of building", "data for advertisement", "traffic information", "weather information", and "disaster information" are assigned.

The signal 820 is transmitted by the transmitter as a second subframe. The signal 820 contains a 6-bit sub-frame ID 821, an altitude correction factor 822, and a transmitter location address 823. The third to sixth subframes are similarly transmitted by defining other information in advance for 144 bits (height correction coefficient 822, transmitter position address 823 in signal 820) following the subframe ID of signal 820. The information contained in each subframe is not limited to the above information. For example, advertisements related to the location information, URLs (Uniform Resource Locators) of internet sites, and the like may be stored in a predefined area in each subframe.

Signals 830 to 870 represent transmission examples of the signals 810 and 820 and third to sixth subframes having the same structure as the signal 820. That is, the signal 830 includes a first sub-frame 831 and a second sub-frame 832. The first sub-frame 831 has the same header as the sub-frames 510 to 550 transmitted from the GPS satellite. The second sub-frame 832 is a frame corresponding to the signal 820.

Signal 840 includes a first sub-frame 831 and a third sub-frame 842. The first sub-frame 831 is the same as the first sub-frame 831. The third subframe has the same structure as signal 820.

This structure is repeated until the signal 870 for transmitting the sixth subframe 872. The signal 870 includes a first sub-frame 831 and a sixth sub-frame 872.

When the transmitter repeatedly transmits the signals 830 to 870, the first subframe 831 is transmitted every time each signal is transmitted. After the first subframe 831 is transmitted, one of the other subframes is interpolated. That is, the transmission order of the frames is first sub-frame 831 → second sub-frame 832 → first sub-frame 831 → third sub-frame 842 → first sub-frame → sixth sub-frame 872 → first sub-frame 831 → second sub-frame 832.

(Structure of I phase Signal 2)

Fig. 10 is a diagram showing a second configuration of the L1C interchange signal. The structure of the text data may also be defined separately from the sub-frames 510-550.

Fig. 10 is a diagram conceptually showing a second configuration of the L1C interchange signal 910. Referring to fig. 10, signal 910 includes a transmission overhead 911, a preamble 912, a PRN-ID 913, a transmitter ID 914, a first variable 915, an X-coordinate value 916, a Y-coordinate value 917, a Z-coordinate value 918, and a parity/CRC 919. Signal 920 has the same structure as signal 910. Here, a second variable 925 is included instead of the first variable 915 in the signal 910.

Each signal having a length of 150 bits. 6 signals having the same structure are transmitted. The signal having such a configuration may be a signal transmitted from an indoor transmitter.

Since each signal shown in fig. 10 also has a PRN-ID, the position information providing apparatus 100 can identify the transmission source of the received signal based on the PRN-ID. If the transmission source is an indoor transmitter, the signal includes an X-coordinate value, a Y-coordinate value, and a Z-coordinate value. Thus, the position information providing apparatus 100 can display the position in the room.

[ Structure of position information providing apparatus 100-1 (receiver) ]

The position information providing apparatus 100 is explained with reference to fig. 11. Fig. 11 is a block diagram showing a hardware configuration of the position information providing apparatus 100.

The position information providing apparatus 100 includes an antenna 402, an RF (Radio Frequency) front-end circuit 404 electrically connected to the antenna 402, a Down converter 406 electrically connected to the RF front-end circuit 404, an a/D (Analog to Digital) converter 408 electrically connected to the Down converter 406, a baseband processor 410 electrically connected to the a/D converter 408, a memory 420 electrically connected to the baseband processor 410, a navigation processor 430 electrically connected to the baseband processor 410, and a display 440 electrically connected to the navigation processor 430.

The memory 420 includes a plurality of areas for storing code patterns of pseudo noise codes, which are data for identifying the respective transmission sources of the positioning signal. For example, in a case where 48 code patterns are used, the memory 420 includes areas 421-1 to 421-48 as shown in FIG. 11. In other cases, if more than 48 code patterns are used, more areas are reserved in the memory 420. Conversely, there may be a case where a code pattern having a smaller number of areas than those secured in the memory 420 is used.

For example, when 48 code patterns are used, for example, when 24 satellites are used in a satellite positioning system, 24 pieces of identification data (PRN codes) for identifying each satellite and 12 pieces of backup data are stored in the areas 421-1 to 421-36. At this time, for example, a code pattern of pseudo noise codes with respect to the first satellite is saved in the area 421-1. The code pattern is read from the region 421-1 and cross-correlation processing is performed with the received signal, whereby tracking of the signal and interpretation of the navigation message included in the signal can be performed. Here, although a method of saving and reading out a code pattern is exemplified, a method of generating a code pattern by a code pattern generator may be used. The code pattern generator is implemented, for example, by combining two feedback shift registers. Further, the structure and action of the code pattern generator can be easily understood by those skilled in the art. Therefore, detailed description thereof will not be repeated here.

Similarly, the code pattern of the pseudo noise code assigned to the indoor transmitter which transmits the positioning signal is stored in the areas 421-37 to 421-48. For example, a code pattern of pseudo noise codes assigned to the first indoor transmitter is stored in the area 421 to 37. In this case, although 12 indoor transmitters having code patterns can be used in the present embodiment, it is preferable that each of the indoor transmitters be arranged so that no indoor transmitter using the same code pattern exists within a range that can be received by the same position information providing apparatus. In this way, for example, 12 or more indoor transmitters can be installed on the same floor of the building 130.

As described above, when the L1C swap signal is received, the memory 420 sets memory areas corresponding to the banks I00 to I10 and Q00 to Q08, respectively.

The baseband processor 410 includes: a correlator unit (correlator)412 that receives an input of the signal output from the a/D converter 408; a control unit 414 for controlling the operation of the correlator unit 412; and a determination unit 416 for determining the source of the positioning signal based on the data output from the control unit 414. The navigation processor 430 includes: an outdoor positioning unit 432 for measuring the position of the outdoor position information providing device 100 based on the signal output from the determination unit 416; and an indoor positioning unit 434 for deriving information indicating the position of the indoor position information providing device 100 from the data output from the determination unit 416.

The antenna 402 can receive the positioning signals transmitted from the GPS satellites 110, 111, and 112 and the positioning signal transmitted from the indoor transmitter 200-1. In addition, in the case where the position information providing apparatus 100 is implemented as a portable telephone, the antenna 402 can transmit and receive a signal for a wireless telephone or a signal for data communication in addition to the above-described signal.

The RF front-end circuit 404 receives a signal received by the antenna 402, and performs noise cancellation, filtering processing for outputting only a signal having a predetermined bandwidth, and the like. The signal output from the RF front-end circuit 404 is input to a down-converter 406.

Down converter 406 amplifies the signal output from RF front-end circuit 404 and outputs the amplified signal as a center frequency. The signal is input to the a/D converter 408. The a/D converter 408 performs digital conversion processing on the input center frequency signal to convert the center frequency signal into digital data. The digital data is input to the baseband processor 410.

In the baseband processor 410, the correlator unit 412 performs correlation processing between the code pattern read out from the memory 420 by the control unit 414 and the received signal. For example, the correlator unit 412 performs matching between two code patterns having different code phases for one bit supplied from the control unit 414 and the digital data transmitted from the a/D converter 408. The correlator unit 412 tracks the positioning signal received by the position information providing apparatus 100 using each code pattern, and specifies a code pattern having an arrangement that matches the bit arrangement of the positioning signal. Thus, the position information providing apparatus 100 can determine from which satellite the received positioning signal is transmitted or from which indoor transmitter the received positioning signal is transmitted. In addition, the position information providing apparatus 100 can perform demodulation and interpretation of a text using the determined code pattern.

Specifically, the determination unit 416 performs the determination as described above, and transmits data corresponding to the determination result to the navigation processor 430. The determination unit 416 determines whether or not the PRN-ID included in the received positioning signal is a PRN-ID assigned to a transmitter other than the transmitter mounted on the GPS satellite.

Here, a case where 24 GPS satellites are used in the positioning system will be described as an example. In this case, when the spare codes are included, for example, 36 pseudo noise codes are used. At this time, PRN-01 to PRN-24 are used as numbers (PRN-IDs) for identifying the respective satellites, and PRN-25 to PRN-36 are used as numbers for identifying the spare satellites. A spare satellite refers to a satellite that transmits in addition to the originally transmitted satellite. That is, such a satellite is a satellite transmitted in preparation for a failure of a GPS satellite or a transmitter mounted on the GPS satellite.

It is assumed that the code patterns of the 12 pseudo noise codes are allocated to transmitters other than the transmitter mounted on the GPS satellite (for example, the indoor transmitter 200-1). At this time, a number different from the PRN-ID assigned to the satellite, for example, PRN-37 through PRN-48, is assigned to each of the transmitters. Thus, there are 48 PRN-IDs in this example. Here, the PRN-37 to PRN-48 are allocated to each indoor transmitter, for example, according to the arrangement of the indoor transmitters. Therefore, if a transmission output power is used to the extent that the signals transmitted from the indoor transmitters do not interfere with each other, the same PRN-ID may be used by different indoor transmitters. With this configuration, a larger number of transmitters can be used than the number of PRN-IDs allocated to terrestrial transmitters.

Therefore, the determination unit 416 refers to the code pattern of the pseudo noise code stored in the memory 420, and determines whether or not the code pattern acquired from the received positioning signal matches the code pattern assigned to the indoor transmitter. When the code patterns match, the determination unit 416 determines that the positioning signal is a signal transmitted from an indoor transmitter. If the signals do not match, the determination unit 416 determines that the signal is a signal transmitted from a GPS satellite, and refers to the code pattern stored in the memory 420 to determine to which satellite the acquired code pattern is assigned. Although an example using a code pattern is shown as a determination method, the determination may be performed by comparing other data. For example, a comparison using the PRN-ID may be used for the determination.

When the received signal is a signal transmitted from each GPS satellite, the determination unit 416 transmits data acquired from the specified signal to the outdoor positioning unit 432. The data obtained from the signal contains navigation messages. On the other hand, when the received signal is a signal transmitted from the indoor transmitter 200-1 or the like, the determination unit 416 transmits data acquired from the signal to the indoor positioning unit 434. This data is coordinate values set in advance as data for specifying the position of the indoor transmitter 200-1. Alternatively, a number identifying the transmitter may be used in other situations.

In the navigation processor 430, the outdoor positioning unit 432 performs the following processing: the position of the position information providing apparatus 100 is calculated based on the data transmitted from the determination unit 416. Specifically, the outdoor positioning unit 432 calculates the propagation time of each signal using data included in signals transmitted from 3 or more GPS satellites (preferably 4 or more), and calculates the position of the position information providing apparatus 100 based on the calculation result. This process is performed using a method known as satellite positioning. This process can be easily understood by those skilled in the art. Thus, a detailed description thereof will not be repeated here.

On the other hand, in the navigation processor 430, the indoor positioning unit 434 performs positioning processing in a case where the position information providing apparatus 100 is present indoors, based on the data output from the determination unit 416. As will be described later, the indoor transmitter 200-1 transmits a positioning signal including data (position specifying data) for specifying a location. Therefore, when the position information providing apparatus 100 receives such a signal, it is possible to extract data contained in the signal and use the data as the position of the position information providing apparatus 100. The indoor positioning unit 434 performs this process. The data calculated by the outdoor positioning unit 432 or the data read by the indoor positioning unit 434 is used for display on the display 440. Specifically, these data are embedded in data for displaying a screen, and an image indicating the measured position or an image of the read position (for example, a place where the indoor transmitter 200-1 is installed) is generated and displayed on the display 440.

The positional information providing apparatus 100 further includes a communication unit 450, and the communication unit 450 transmits and receives data to and from an external device, for example, a positional information providing server (not shown) under the control of the control unit 414.

In the configuration shown in fig. 11, in the signal processing from the reception of the positioning signal to the generation of information to be displayed on the display, the antenna 402, the RF front-end circuit 404, the down converter 406, and the a/D converter 408 are configured by hardware, and the processing of the baseband processor 410 and the navigation processor 430 can be executed by a program stored in the memory 420, which is not particularly limited. Further, the processing of the correlator unit 412 may be realized by hardware instead of software.

The control process of the position information providing apparatus 100 is explained with reference to fig. 12. Fig. 12 is a flowchart showing a procedure of processing performed by the baseband processor 410 and the navigation processor 430 of the position information providing apparatus 100.

In step S610, the position information providing apparatus 100 acquires (tracks, captures) a positioning signal. Specifically, the baseband processor 410 receives an input of the positioning signal (data after digital conversion processing) received from the a/D converter 408. The baseband processor 410 generates a code pattern with different code phases reflecting possible delays as a replica (replica) of the pseudo noise code, and detects whether or not the code pattern is correlated with the received positioning signal, respectively. The number of generated code patterns is, for example, twice the number of bits of the code patterns. For example, when the chip rate (chip rate) is 1023 bits, 2046 code patterns having a one-half bit delay, that is, a code phase difference can be generated. Then, a process of obtaining a correlation with the received signal using each code pattern is executed. The baseband processor 410 can determine the satellite that transmitted the positioning signal from the code pattern by locking the code pattern when output power equal to or higher than a predetermined intensity is detected in the correlation process. There is only one pseudo noise code having the bit arrangement of the code pattern. Thus, a pseudo noise code used for spectrally spread encoding the received positioning signal is determined.

As described later, the process of obtaining the correlation between the signal acquired by reception and the code pattern of the replica generated in the inside of the position information providing apparatus 100 may be realized as parallel processing.

In step S612, the baseband processor 410 determines the transmission source of the positioning signal. Specifically, the determination unit 416 determines the transmission source of the signal based on a PRN-ID (for example, the memory 420 in fig. 11) corresponding to the transmitter that uses a code pattern of a pseudo noise code used for modulation to generate the signal. If the positioning signal is a signal transmitted from the outside, the control proceeds to step S620. If the positioning signal is a signal transmitted indoors, the control proceeds to step S630. If the received signals include signals transmitted from the outside and the inside, respectively, the control proceeds to step S640.

In step S620, the position information providing apparatus 100 acquires data contained in the positioning signal by performing demodulation of the signal. Specifically, the indoor positioning unit 432 of the navigation processor 430 superimposes a code pattern (the above-mentioned "locked" code pattern, hereinafter, the "locked code pattern") temporarily stored in the memory 420 on the positioning signal, thereby acquiring the navigation message from the sub-frame constituting the signal. In step S622, the outdoor positioning unit 432 performs normal navigation message processing for calculating the position using the acquired 4 or more navigation messages.

In step S624, the outdoor positioning unit 432 executes processing for calculating the position of the position information providing apparatus 100 based on the processing result. For example, when the position information providing apparatus 100 is receiving each positioning signal transmitted from 4 or more satellites, the distance is calculated using the orbit information, time information, and the like of each satellite included in the navigation message demodulated from each signal.

In other cases, when the position information providing apparatus 100 receives the positioning signal (outdoor signal) transmitted from the satellite and the signal (indoor signal) from the indoor transmitter in step S612, the position information providing apparatus 100 demodulates the positioning signal to acquire the data included in the signal in step S640. Specifically, the outdoor positioning unit 432 superimposes the locked code pattern on the positioning signal transmitted from the baseband processor 410, thereby acquiring data in a subframe constituting the positioning signal. In this case, the position information providing apparatus 100 can be said to operate as a "hybrid" mode because it receives signals from satellites and signals from an indoor transmitter. Therefore, a navigation message having time data is acquired for the signal from each satellite, and data having the coordinate value and other position information is acquired for the signal from the indoor transmitter. That is, in step S642, the indoor positioning unit 434 acquires the X coordinate value 563, the Y coordinate value 564, and the Z coordinate value 565 from the positioning signal transmitted from the indoor transmitter 200-1, and acquires the navigation message from the positioning signal transmitted from the GPS satellite, and performs the processing. After that, control shifts to step S624. In this case, in step S624, signal allocation for determining a signal to be used for calculation of the position is performed based on the intensities of the indoor signal and the outdoor signal, for example. For example, when the intensity of the indoor signal is greater than the intensity of the outdoor signal, the indoor signal is selected, and the coordinate value included in the indoor signal is set as the position of the position information providing apparatus 100.

On the other hand, if the source of the positioning signal is indoors in step S612, for example, if the intensity of the indoor signal is equal to or higher than a predetermined level, then in step S630, the determination unit 414 determines whether or not the reception mode of the Q-phase signal is set. If the reception mode is not the Q-phase signal reception mode (for example, the reception mode of L1C/a or the reception mode of L1C I-phase signal), then in step S632, the position information providing apparatus 100 acquires data included in the positioning signal by demodulating the signal. Specifically, the indoor positioning unit 434 acquires the text data from the subframe constituting the positioning signal by superimposing the locked code pattern on the positioning signal transmitted from the baseband processor 410. The text data is text data included in the positioning signal transmitted from the indoor transmitter in place of the navigation text included in the positioning signal transmitted from the satellite. Thus, it is preferable that the format of the text data is the same format as that of the navigation text.

In step S634, the indoor positioning section 434 acquires coordinate values (i.e., data for specifying the installation location of the indoor transmitter (e.g., X-coordinate value 563, Y-coordinate value 564, Z-coordinate value 565 in signal 560 in fig. 8)) from the data. In addition, when text information indicating the installation location or the address of the installation location is included in the frame instead of the coordinate values, the text information is acquired. After that, the process shifts to step S650.

On the other hand, in step S630, in the case of the reception mode of the Q-phase signal, next in step S636, the position information providing apparatus 100 acquires data (transmitter ID) included in the signal by performing demodulation of the positioning signal. In step S638, the positional information providing apparatus 100 receives positional information corresponding to the transmitter ID from a server (not shown) by transmitting the transmitter ID via a network.

In step S650, navigation processor 430 executes a process of displaying position information on display 440 based on the calculation result of the position. Specifically, image data for displaying the acquired coordinates or data for displaying the installation location of the indoor transmitter 200-1 is generated and transmitted to the display 440. The display 440 displays the positional information of the positional information providing apparatus 100 on the display area according to such data.

A display mode of the positional information providing apparatus 100 will be described with reference to fig. 13. Fig. 13 is a diagram showing a screen displayed on the display 440 of the positional information providing apparatus 100. When the position information providing apparatus 100 receives a positioning signal transmitted from each GPS satellite outdoors, the display 440 displays an icon 710 indicating that position information is acquired based on the positioning signal. When the user of the position information providing apparatus 100 moves indoors, the position information providing apparatus 100 cannot receive the positioning signals transmitted from the GPS satellites. Instead, the position information providing apparatus 100 receives a signal transmitted by the indoor transmitter 200-1, for example. As described above, the signal is transmitted in the same manner as the positioning signal transmitted from the GPS satellite. Thus, the position information providing apparatus 100 performs the same processing on the signal as that performed when the positioning signal is received from the satellite. When position information is acquired from the signal, position information providing apparatus 100 displays icon 720 on display 440, where icon 720 indicates that the position information is acquired from the signal transmitted from the transmitter installed indoors.

As described above, the position information providing apparatus 100 according to the first embodiment of the present invention receives radio waves transmitted from transmitters (for example, the indoor transmitters 200-1, 200-2, and 200-3) installed in a place where radio waves from GPS satellites cannot be received, such as an indoor place or an underground street. The position information providing apparatus 100 acquires information (for example, coordinate values and addresses) specifying the position of the transmitter from the radio wave, and displays the information on the display 440. Thus, the user of the position information providing apparatus 100 can know the current position. Thus, the position information can be provided even in a place where the positioning signal cannot be directly received.

This ensures stable indoor signal reception. In addition, the position information can be provided with stable accuracy of about several meters indoors.

The ground time (time of the transmitter such as the indoor transmitter 200-1) and the satellite time need only be independent of each other, and need not be synchronized. Therefore, an increase in cost for manufacturing the indoor transmitter can be suppressed. In addition, since it is not necessary to synchronize the time of the indoor transmitter after the operation of the position information providing system, the operation is easy.

Since each signal transmitted from each indoor transmitter includes information for specifying a location where the corresponding transmitter is installed, it is not necessary to calculate position information from each signal transmitted from a plurality of satellites, and therefore, it is possible to derive position information from a signal transmitted from one transmitter.

Further, since the position of the receiving place of the signal can be specified by receiving the signal transmitted from one indoor transmitter, the system for providing the position can be realized more easily than the GPS and other conventional positioning systems.

In this case, the position information providing apparatus 100 does not require dedicated hardware for receiving the signal transmitted by the indoor transmitter 200-1, and the position information providing apparatus 100 can be realized by using hardware of a conventional positioning system without changing software for signal processing. Therefore, since it is not necessary to design hardware for applying the technology according to the present embodiment from scratch, it is possible to suppress an increase in cost of the position information providing apparatus 100, and to easily spread the position information providing apparatus. In addition, for example, a position information providing device that prevents an increase or complication in circuit scale is provided.

Specifically, the memory 420 of the position information providing device 100 holds a PRN-ID that is predetermined for an indoor transmitter and/or a satellite. The positional information providing apparatus 100 performs the following processing according to a program: whether the received radio wave is a radio wave transmitted from a satellite or a radio wave transmitted from an indoor transmitter is determined based on the PRN-ID. The program is realized by an arithmetic processing device such as a baseband processor. Alternatively, the positional information providing apparatus 100 may be configured by changing the circuit element used for the determination to a circuit element including a function realized by the program.

When the position information providing apparatus 100 is implemented as a mobile phone, the acquired information may be stored in a nonvolatile memory 420 such as a flash memory (Flashmemory). Also, when a cellular phone is dialed, data held in the memory 420 may be transmitted to a dialing destination. In this way, the position information of the transmission source, that is, the position information acquired from the indoor transmitter as the position information providing apparatus 100 of the mobile phone, is transmitted to the base station relaying the call. The base station stores the location information together with the reception date and time as a call log. In addition, when the destination is an emergency contact destination (for example, a 110 number in japan), the location information of the transmission source may be directly notified. Thus, the notification from the transmission source of the mobile body is realized in the same manner as the notification from the transmission source of the conventional emergency contact with the fixed-line telephone.

Further, the transmitter installed in the specific location realizes the position information providing system by a transmitter capable of transmitting the same signal as the signal transmitted by the transmitter mounted on the positioning satellite. Thus, there is no need to redesign the transmitter from scratch.

The location information providing system according to the present embodiment uses a spread spectrum signal as a signal for positioning. Since the power per frequency can be reduced by this signal transmission, it is considered that the radio wave management becomes easier than, for example, a conventional RF tag. As a result, the construction of the position information providing system becomes easy.

After installation, the indoor transmitter 200-1 can change the setting parameters by the wireless I/F210. Therefore, it is possible to simplify the installation procedure of rewriting the position specifying data for specifying the installation location after installation. In addition, the receiver can be provided with "data for advertisement," traffic information, "weather information," and "disaster information" (for example, earthquake information) among the information transmitted as a text message in real time, and thus various services can be realized. Furthermore, the indoor transmitting apparatus 200-1 can rewrite the firmware of the FPGA 245 for signal processing itself. Therefore, the same hardware can be used for communication systems (modulation systems and the like) of various positioning systems.

In addition, since the bandwidth of the transmitted signal can be selectively limited by the digital bandwidth limiting filter, interference with other systems can be suppressed, and frequency utilization efficiency can be improved.

In addition, since different information can be provided by the I-phase signal and the Q-phase signal, the position information can be flexibly provided according to the situation. Since the amplitudes of the I-phase signal and the Q-phase signal can be adjusted individually, not only quadrature but also modulation of different phases can be performed. Further, since the transmission level is variable, the transmission power can be set to be lower than the standard for regulating the radio wave usage, such as the japanese radio wave law, for example, depending on the installation location.

< first modification >

A modification of the embodiment of the present invention will be described with reference to fig. 14. Fig. 14 is a block diagram showing the configuration of the positional information providing apparatus 1000 according to the present modification. In the present modification, a plurality of correlators may be used instead of the correlator unit 412 provided in the position information providing apparatus 100. In this case, since the processing for matching the positioning information with the duplicate is simultaneously performed in parallel, the calculation time of the position information becomes short.

The position information providing apparatus 1000 according to the present modification includes an antenna 1010, a band pass filter 1020 electrically connected to the antenna 1010, a Low Noise Amplifier (LNA)1030 electrically connected to the band pass filter 1020, a down converter 1040 electrically connected to the low noise amplifier 1030, a band pass filter 1050 electrically connected to the down converter 1040, an a/D converter 1060 electrically connected to the band pass filter 1050, a parallel correlator 1070 electrically connected to the a/D converter 1060 and including a plurality of correlators, a processor 1080 electrically connected to the parallel correlator 1070, and a memory 1090 electrically connected to the processor 1080.

The parallel correlator 1070 includes n correlators 1070-1 to 1070-n. Each correlator simultaneously performs matching between the received positioning signal and a code pattern generated for demodulating the positioning signal, based on a control signal output from the processor 1080.

Specifically, processor 1080 provides instructions to each of the parallel correlators 1070 to generate a code pattern (that offsets the code phase) that reflects the delays that may be present in the pseudo-noise code. This instruction is, for example, the number of satellites × 2 × 1023 (the length of the code pattern of the pseudo noise code used) in the current GPS. Each parallel correlator 1070 generates a code pattern having a different code phase by using a code pattern of a pseudo noise code defined for each satellite in accordance with a command given thereto. In this way, one code pattern that matches the code pattern of the pseudo noise code used for modulation of the received positioning signal exists among all the generated code patterns. Therefore, by configuring the number of correlators necessary for performing the matching process using each code pattern as the parallel correlators 1070 in advance, the code pattern of the pseudo noise code can be instantaneously determined. This process can be similarly applied to the case where the position information providing apparatus 100 receives a signal from an indoor transmitter. Thus, even in a case where the user of the position information providing apparatus 100 is located indoors, the position information can be acquired instantaneously.

That is, the parallel correlator 1070 can match the code pattern of the pseudo noise code specified for each satellite and the code pattern of the pseudo noise code specified for each indoor transmitter in parallel at maximum. Further, even when the number of correlators and the number of code patterns of pseudo noise codes assigned to the satellites and the indoor transmitters are not matched to all the code patterns of the pseudo noise codes specified for the satellites and the indoor transmitters at once, the time required for acquiring the position information can be significantly shortened by parallel processing using a plurality of correlators.

Here, since the satellite and the indoor transmitter transmit signals by a spectrum spreading method which is the same communication method and the same sequence can be used for the code patterns of the pseudo noise codes assigned to the satellite and the indoor transmitter, both the signals from the satellite and the transmissions from the indoor transmitter can be shared by the parallel correlators, and the reception processing can be performed in parallel without particularly distinguishing between the two.

In the position information providing apparatus 1000 in fig. 14, the antenna 1010, the band-pass filter 1020, the Low Noise Amplifier (LNA)1030, the down-converter 1040, the band-pass filter 1050, the a/D converter 1060, and the correlator 1070 are also configured by hardware in the signal processing from the reception of the positioning signal to the generation of information to be displayed on the display (not shown in fig. 14), and the operation processing for positioning (the control processing described in fig. 12) can be executed by the processor 1080 in accordance with a program stored in the memory 1090, which is not particularly limited.

< second embodiment >

The second embodiment of the present invention will be explained. The present embodiment is different from the first embodiment in that a plurality of transmitters are installed in the position information providing system according to the present embodiment.

Fig. 15 is a diagram showing a usage mode of the position information providing apparatus according to the second embodiment of the present invention. Referring to fig. 15, indoor transmitters 1110, 1120, and 1130 are installed on the ceiling of the same floor. Each indoor transmitter performs the same processing as the indoor transmitter 200-1 described above. That is, each indoor transmitter transmits a positioning signal including data indicating a place where each indoor transmitter is installed.

In this case, there are regions (i.e., spaces) where the signals transmitted from the respective adjacent transmitters can be received, depending on the installation position of the indoor transmitter. For example, the region 1140 is a region capable of receiving signals transmitted from the indoor transmitters 1110 and 1120, respectively. Similarly, the region 1150 is a region capable of receiving the positioning signals transmitted by the indoor transmitters 1120 and 1130, respectively.

Therefore, for example, when the position information providing device 1160 according to the present invention is present at the position shown in fig. 15, the position information providing device 1160 can acquire data indicating the installation position of the indoor transmitter 1110 included in the signal transmitted from the indoor transmitter 1110 as the position of the position information providing device 1160. Thereafter, when the user of the position information providing device 1160 moves to a position corresponding to the region 1140, for example, the position information providing device 1160 can receive a signal transmitted by the indoor transmitter 1120 in addition to the signal transmitted by the indoor transmitter 1110. In this case, it is possible to determine which signal includes the position specifying data as the position of the position information providing device 1160, for example, based on the strength of the received signal. That is, when signals transmitted from a plurality of indoor transmitters are received, the data having the highest reception intensity value among the signals may be used for displaying the position information. In the case where the intensity of each signal is assumed to be the same, the position of the position information providing apparatus 1160 may also be obtained by deriving an arithmetic sum of data included in these signals.

As described above, according to the position information providing device 1160 of the present embodiment, even when a plurality of signals for positioning are received indoors, it is possible to specify the transmission source of any one of the signals, and thus it is also possible to specify the installation position of the transmission source, that is, the transmitter installed indoors.

Here, "indoor" is not limited to the inside of a building or other structures, and may be any place where radio waves transmitted from GPS satellites cannot be received. Such places include, for example, underground streets, railway vehicles, and the like.

In this case, since the size of the area covered by one indoor transmitter can be limited, it is not necessary to increase the signal strength transmitted by the indoor transmitter, and it is easy to set the transmission power below the standard for regulating the regulations for radio wave use such as the japanese radio wave law, and it is not necessary to obtain a special license for the setting.

< third embodiment >

Next, a third embodiment of the present invention will be described. The position information providing apparatus according to the present embodiment is configured to perform, instead of specifying a position based on data included in an indoor transmitter, communication using a mobile telephone network by: in the case where data for identifying the transmitter (hereinafter referred to as "transmitter ID") is transmitted to a device that provides information about the transmitter, the position information can be acquired. Therefore, the position information providing apparatus according to the first embodiment or the second embodiment can be realized using a mobile phone. Further, according to the present embodiment, the position can be specified from the transmitter ID. In general, the position of a mobile phone is determined as the area of a base station that receives a signal transmitted from the mobile phone, but the position can be determined by the present embodiment. Thus, for example, even in a place where the number of base stations is small, the position of the mobile phone can be determined with high accuracy from the transmitter ID.

Since the configuration for performing position location based on a positioning signal from a satellite is common, the operation in the case of receiving a transmitter ID from an indoor transmitter will be mainly described below.

Fig. 16 is a diagram showing a usage mode of the position information providing apparatus according to the present embodiment. The position information providing apparatus is implemented as a portable telephone 1200. The cellular phone 1200 can receive a positioning signal transmitted by the indoor transmitter 1210. The indoor transmitter 1210 is connected to the internet 1220. An information providing server 1230 capable of providing information of the in-house transmitter 1210 is connected to the internet 1220. It is assumed that a plurality of transmitter IDs and position information corresponding to each of them are registered in a database on the information providing server 1230. A base station 1240 communicating with the cellular phone 1200 is connected to the internet 1220.

When the mobile phone 1200 receives the signal transmitted by the indoor transmitter 1210, the transmitter ID for identifying the indoor transmitter 1210 is acquired from the signal. The transmitter ID corresponds to the PRN-ID described above, for example. The portable phone 1200 transmits the transmitter ID (or together with the PRN-ID) to the information providing server 1230. Specifically, the portable telephone 1200 and the base station 1240 start communication with each other, and packet data including the acquired transmitter ID is transmitted to the information providing server 1230.

When recognizing the transmitter ID, the information providing server 1230 reads out the position specifying data associated with the ID by referring to the database associated with the transmitter ID. When the information providing server 1230 transmits the data to the base station 1240, the base station 1240 transmits the data. When mobile phone 1200 detects the arrival of the data, it can acquire the position of transmitter 1250 from the data in accordance with the reading operation of the user of mobile phone 1200.

Here, the configuration of the mobile phone 1200 will be described with reference to fig. 17. Fig. 17 is a block diagram showing a hardware configuration of portable telephone 1200. The portable telephone 1200 includes an antenna 1308, a communication device 1302, a CPU1310, operation buttons 1320, a camera 1340, a flash memory 1344, a RAM 1346, a data ROM 1348, a memory card drive device 1380, an audio signal processing circuit 1370, a microphone 1372, a speaker 1374, a display 1350, an LED (Light Emitting Diode) 1376, a data communication IF 1378, and a vibrator 1384, which are electrically connected to each other.

A signal received by the antenna 1308 is transmitted to the CPU1310 through the communication device 1302. The CPU1310 transmits the signal to the sound signal processing circuit 1370. Audio signal processing circuit 1370 performs predetermined signal processing on the signal, and transmits the processed signal to speaker 1374. Speaker 1374 outputs sound based on the signal.

Microphone 1372 receives sound emitted from mobile phone 1200, and outputs a signal corresponding to the emitted sound to sound signal processing circuit 1370. Audio signal processing circuit 1370 performs predetermined signal processing for a call based on the signal, and transmits the processed signal to CPU 1310. CPU1310 converts the signal into data for transmission, and transmits the data to communication apparatus 1302. When communication device 1302 transmits the signal through antenna 1308, base station 1240 receives the signal.

Flash memory 1344 holds data transmitted from CPU 1310. Conversely, CPU1310 reads data stored in flash memory 1344, and executes predetermined processing using the data.

RAM 1346 temporarily holds data generated by CPU1310 according to an operation performed on operation buttons 1320. Data ROM 1348 stores data or a program for causing mobile phone 1200 to execute a predetermined operation. CPU1310 reads the data or program from data ROM 1348, and causes mobile phone 1200 to execute predetermined processing.

Memory card drive 1380 receives the attachment of memory card 1382. The memory card drive 1380 reads data stored in the memory card 1382 and transmits the data to the CPU 1310. In contrast, memory card drive 1380 writes data output from CPU1310 into a data storage area secured in memory card 1382.

The sound signal processing circuit 1370 performs processing on a signal used in a call as described above. CPU1310 and audio signal processing circuit 1370 may be integrated.

Display 1350 displays an image defined by data output from CPU1310, based on the data. For example, in a case where the flash memory 1344 holds data (e.g., URL) for accessing the information providing server 1230, the display 1350 displays the URL.

LED 1376 realizes a predetermined light emitting operation based on a signal from CPU 1310. For example, in a case where LED 1376 is capable of displaying a plurality of colors, LED 1376 emits light in a color associated with data according to the data contained in the signal output from CPU 1310.

Data communication IF 1378 accepts the installation of a cable for data communication. Data communication IF 1378 transmits a signal output from CPU1310 to the cable. Alternatively, data communication IF 1378 transmits data received through the cable to CPU 1310.

Oscillator 1384 executes a transmission operation at a predetermined frequency based on a signal output from CPU 1310. The basic actions of the portable telephone 1200 can be easily understood by those skilled in the art. Thus, detailed description is not repeated here.

The portable telephone 1200 is also provided with an antenna 1316 for receiving positioning signals and a positioning signal receiving front end portion 1314.

Here, the positioning signal reception front end portion 1314 includes the antenna 402, the RF front end circuit 404, the down converter 406, and the a/D converter 408, which are implemented by hardware in the structure of the position information providing apparatus 100 illustrated in fig. 11. On the other hand, in the configuration of the position information providing apparatus 100, the processing of the baseband processor 410 and the navigation processor 430 realized by software can be executed by the positioning processing unit 1312 on the CPU1310 in accordance with a program loaded from the flash memory 1344 onto the RAM 1346. Here, the processing of the correlator unit 412 may be realized by hardware instead of software. The hardware configuration and the software configuration may be the same as those of the positional information providing apparatus 1000 described with reference to fig. 14.

A specific structure of the information providing server 1230 is explained with reference to fig. 18. Fig. 18 is a block diagram showing a hardware configuration of the information providing server 1230. The information providing server 1230 is implemented by a well-known computer system, for example.

The information providing server 1230 includes, as main hardware, a CPU1410, a mouse 1420 which receives an instruction from a user of the information providing server 1230, a keyboard 1430, a RAM 1440 which temporarily stores data generated by executing a program of the CPU1410 or data input by the mouse 1420 or the keyboard 1430, a hard Disk 1450 which stores large-capacity data in a nonvolatile manner, a CD-ROM (Compact Disk-Read Only Memory) drive device 1460, a monitor 1480, and a communication IF 1470. The hardware is interconnected by a data bus. A CD-ROM1462 is mounted on the CD-ROM drive device 1460.

The processing in the computer system implementing the information providing server 1230 is realized by the hardware and software executed by the CPU 1410. Such software is sometimes pre-stored on hard disk 1450. The software may be stored in the CD-ROM1462 or another data recording medium and distributed as a program product. Alternatively, the software is sometimes provided as a program product that can be downloaded by another information provider connected to the so-called internet. Such software is temporarily stored in hard disk 1450 after being read from the data recording medium by CD-ROM drive 1460 or other data reading devices or downloaded via communication IF 1470. The software is read from hard disk 1450 by CPU1410, and stored in RAM 1440 in the form of an executable program. CPU1410 executes the program.

The hardware of the computer system implementing the information providing server 1230 shown in fig. 18 is general hardware. Therefore, the essential part of the information providing server 1230 according to the present invention may be software stored in the RAM 1440, the hard disk 1450, the CD-ROM1462, or other data recording media, or software that can be downloaded via a network. The operation of the hardware of the computer system is well known. Thus, detailed description is not repeated.

The recording medium is not limited to the CD-ROM1462, the hard disk 1450, and the like, and may be a medium capable of holding a program in a fixed manner, such as a Magnetic tape, a Magnetic tape cartridge, an optical disk (MO (magneto optical disk)/MD (Mini Disc)/DVD (Digital versatile Disc)), an IC (Integrated Circuit) card (including a memory card), an optical card, a semiconductor memory such as a mask ROM, an EPROM, an EEPROM, or a flash ROM.

The program referred to herein includes not only a program directly executable by the CPU1410 but also a program in a source program format, a program after compression processing, an encrypted program, and the like.

A data structure stored in the information providing server 1230 is explained with reference to fig. 19. Fig. 19 conceptually illustrates one mode of data storage in hard disk 1450. Hard disk 1450 includes areas 1510-1550 for storing data. The data stored in these areas 1510 to 1550 are associated with each other.

A record No. for identifying the data record stored in the hard disk 1450 is stored in the area 1510. A transmitter ID for identifying a transmitter that transmits the positioning signal is stored in the area 1520. For example, the transmitter ID is a unique manufacturing number provided by the manufacturer of the transmitter or a unique number provided by the administrator of the system. Data (coordinate values) indicating the location where the transmitter is installed is stored in the area 1530. This data is saved to hard disk 1450, for example, when each of the transmitters is set. The specific name of the location where the transmitter is installed is stored in the area 1450. For example, data stored in hard disk 1450 is used so that a manager who manages the data (or a provider of a service that provides location information using information providing server 1230) can recognize the data. Data indicating the address at which the transmitter is stored in area 1550. This data is also used by the administrator as in the data stored in the area 1540. Since the data stored in each of the areas 1510 to 1550 are correlated, if the transmitter ID is specified, it is possible to specify the position coordinates, for example, the installation coordinates (area 1530) and the installation location name (1540), correlated with the transmitter ID. This makes it possible to specify the location of the transmitter ID in an area narrower than the coverage area of the base station.

The information providing server 1230 provides the position information of the transmitter as follows. Mobile phone 1200 generates packet data (hereinafter referred to as "request") requesting location information using the transmitter ID acquired from the determination result of the PRN-ID and data (URL or the like) for accessing information providing server 1230. The portable telephone 1200 sends the request to the base station 1240. The transmission is realized by a well-known communication process. The base station 1240 transmits to the information providing server 1230 upon receiving the request.

The information providing server 1230 detects the reception of the request. CPU1410 acquires the transmitter ID from the request, and searches hard disk 1450. Specifically, the CPU1410 performs matching processing of whether or not the acquired transmitter ID matches the transmitter ID stored in the area 1520. As a result of the matching process, if there is a transmitter ID matching the transmitter ID included in the data transmitted from mobile phone 1200, CPU1410 reads out the coordinate value associated with the transmitter ID (region 1530), and generates packet data for returning the position information to mobile phone 1200. Specifically, the CPU1410 generates packet data by attaching the address of the cellular phone 1200 to the header in addition to the data having the coordinate values. CPU1410 transmits the packet data to base station 1240 via communication IF 1470.

The base station 1240, when receiving packet data transmitted by the information providing server 1230, transmits the packet data according to an address included in the data. The base station 1240 may store the received packet data and the reception time in a nonvolatile storage device (e.g., a hard disk device). This keeps the history of the position information acquired by the user of mobile phone 1200, and thus can grasp the route traveled by the user.

When the radio wave from the base station 1240 reaches a certain range, the mobile phone 1200 receives the packet data transmitted from the base station 1240. When the user of mobile phone 1200 performs a predetermined operation (for example, an operation for viewing an electronic mail) to view the received data, display 1350 displays the coordinate values of the transmitter. This allows the user to know the general position. In this way, since it is not necessary to register coordinate values in advance for each transmitter installed indoors, the installation location of the transmitter can be changed more flexibly.

As described above, in the position information providing system according to the present embodiment, the signal transmitted from the transmitter installed on the ground includes data (transmitter ID) for identifying the transmitter, depending on the case. The data is stored in a server device that provides the location information of the transmitter in association with the location information. Mobile phone 1200 functioning as a location information providing device acquires the location information by transmitting a transmitter ID to the server device. When such an information providing method is used, it is not necessary to hold the positional information of the transmitter itself, and therefore, the installation location of the transmitter can be easily changed.

The embodiments disclosed herein are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined not by the above description but by the claims, and is intended to include all modifications equivalent in meaning and scope to the claims.

Industrial applicability

The position information providing system according to the present invention can be applied to, for example, a mobile phone having a positioning function, a mobile positioning terminal, a mobile monitoring terminal, and other terminals capable of receiving a signal for positioning. The transmitter according to the present invention can be applied to, for example, a transmitter installed indoors and other transmission devices.

Claims (15)

1. A position information providing system (10) capable of providing position information using a first positioning signal which is a spread spectrum signal from a plurality of satellites, the position information providing system comprising an indoor transmitter (200-1),

the indoor transmitter includes:

a first storage unit (243) for storing position data for specifying a location where the indoor transmitter is installed;

a generation unit (245) that generates a second positioning signal that is a spread spectrum signal and that is a digitally modulated signal having the position data; and

a transmission unit (250) for transmitting a second positioning signal generated as the spread spectrum signal,

the position information providing system further comprises a position information providing device (100),

the position information providing device includes:

a receiving unit (402) that receives a spread spectrum signal;

a second storage unit (420) for storing a code pattern relating to the first positioning signal and the second positioning signal;

a specifying unit (412) that specifies a code pattern corresponding to the spread spectrum signal received by the receiving unit, based on the code pattern stored in the second storage unit;

a determination unit (316) that determines which of the first positioning signal and the second positioning signal is received, based on a signal demodulated using the code pattern specified by the specification unit;

a position information derivation unit (430) for deriving position information of the position information provision device by switching processing according to the result of the determination; and

an output unit (440) for outputting the position information derived by the position information derivation unit,

wherein the position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter,

the generating unit generates, as the second localization signal, a first phase signal that is a signal obtained by digitally modulating the first data and a second phase signal that is a signal obtained by digitally modulating the second data.

2. The position information providing system according to claim 1,

the position information deriving unit acquires the position data from the signal obtained by the demodulation when the second positioning signal transmitted from one of the indoor transmitters is received,

when a plurality of first positioning signals are received, the position information deriving unit calculates the position information from spread spectrum signals from the plurality of satellites.

3. The position information providing system according to claim 1 or 2,

the position information providing device is capable of communicating with a communication device via a communication line, the communication device providing position information associated with the first data,

when the receiving unit receives the second positioning signal, the position information deriving unit acquires position information associated with the first data by communicating with the communication device based on the first data included in the first phase signal.

4. The position information providing system according to claim 1 or claim 2, further comprising:

a plurality of digital filters (2460, 2462); and

a selection unit that selects one of the plurality of digital filters,

the generating unit generates a second positioning signal having the position data as a spread spectrum signal, based on a bandwidth defined by the digital filter selected by the selecting unit.

5. The position information providing system according to claim 1 or claim 2,

when the receiving unit receives the second positioning signal, the position information deriving unit extracts the second data from the second phase signal,

the output unit displays the installation location based on the second data.

6. The position information providing system according to claim 1 or claim 2,

said second positioning signal comprises said first phase signal and said second phase signal,

wherein said first phase signal comprises first data capable of determining said indoor transmitter,

the second phase signal includes second data indicating an installation location of the indoor transmitter,

the generation unit modulates the first phase signal and the second phase signal independently.

7. The position information providing system according to claim 1 or claim 2,

the first storage portion stores spreading code data for spectrum spreading,

the position information providing system further comprises a data input unit (210) for receiving an input of the spread code data, writing the received spread code data into the first storage unit,

the generating unit generates the second positioning signal as a spectrum spread signal based on the spread code data input from the outside of the indoor transmitter.

8. The position information providing system according to claim 1 or claim 2,

the generating unit is a logic circuit that can be programmed by firmware supplied from the outside.

9. The position information providing system according to claim 1 or claim 2,

the second positioning signal has the same form as the first positioning signal, the second positioning signal includes the position data, and the first positioning signal includes a navigation message,

the position information deriving unit of the position information providing device includes a calculating unit that calculates the position of the position information providing device from each of the navigation messages when receiving the plurality of first positioning signals.

10. The position information providing system according to claim 1 or claim 2,

the position data is data directly indicating the position of the indoor transmitter only by the position data,

the output unit outputs the position information derived from only the position data as an image representing the measured position.

11. An indoor transmitter (200-1) capable of providing position information using a second positioning signal of the same data format as a first positioning signal, the first positioning signal being a spread spectrum signal from a plurality of satellites, comprising:

a first storage unit (243) for storing position data for specifying a location where the indoor transmitter is installed;

a generation unit (245) that generates a second positioning signal that is a spread spectrum signal and that is a digitally modulated signal having the position data; and

a transmission unit (250) for transmitting a second positioning signal generated as the spread spectrum signal,

wherein the position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter,

the generating unit generates, as the second localization signal, a first phase signal that is a signal obtained by digitally modulating the first data and a second phase signal that is a signal obtained by digitally modulating the second data.

12. An indoor transmitter according to claim 11, further comprising:

a plurality of digital filters (2460, 2462); and

a selection unit that selects one of the plurality of digital filters,

the generating unit generates a second positioning signal having the position data as a spread spectrum signal, based on a bandwidth defined by the digital filter selected by the selecting unit.

13. An indoor transmitter as defined in claim 11,

the first storage portion stores spreading code data for spectrum spreading,

the indoor transmitter further comprises a data input unit (210) for receiving an input of the spread code data and writing the received spread code data into the first storage unit,

the generating unit generates the second positioning signal as a spectrum spread signal based on the spread code data input from the outside of the indoor transmitter.

14. An indoor transmitter as defined in claim 11,

the generating unit is a logic circuit that can be programmed by firmware supplied from the outside.

15. A position information providing method for providing position information using a first positioning signal which is a spectrum spread signal from a plurality of satellites, the method comprising the steps of:

a generation step of generating a second positioning signal obtained by digital modulation as a spectrum spread signal based on position data for specifying a place where an indoor transmitter is installed;

transmitting a second positioning signal generated as the spread spectrum signal;

receiving a spread spectrum signal;

determining a code pattern corresponding to the received spread spectrum signal based on code patterns associated with the first positioning signal and the second positioning signal (S610);

determining which of the first positioning signal and the second positioning signal is received, based on a signal demodulated using the determined code pattern (S612);

deriving position information by switching processing according to the result of the determination (S620, S632, S636, S640); and

outputting the derived position information (S650),

wherein the position data includes first data capable of specifying the indoor transmitter and second data indicating an installation location of the indoor transmitter,

the generating step includes the steps of: a first phase signal obtained by digitally modulating the first data and a second phase signal obtained by digitally modulating the second data are generated as the second positioning signal.