JP2001091624A - Gps receiving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve satellite capture speed while suppressing the increase of power consumption compared to a conventional system by controlling the number and phase difference of dummy noise codes used for a GPS receiving device. SOLUTION: This GPS receiving device is provided with a GPS antenna 1; a frequency converting part for converting the frequency of a GPS signal received by the GPS antenna 1; a correlator 4 for taking the correlation between an output from the frequency converting part and dummy noise codes; a dummy noise code generating circuit 5 for generating the dummy noise codes to be supplied to the correlator 4; and a central control device 8 for computing a position upon receiving a signal from the correlator 4, and giving a command to the dummy noise code generating circuit 5. The dummy noise code generating circuit 5 generates only the requested number of dummy noise codes of different phases in response to the command from the central control device 8, and sets the phase difference of the dummy noise codes according to the command from the central control device 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a GPS receiver for receiving radio waves from a plurality of GPS satellites, measuring a radio wave arrival time between each of the GPS satellites and a receiving device, and obtaining the position and time of a receiving point. It concerns the device.

[0002]

2. Description of the Related Art A signal transmitted by a GPS satellite includes time data of the satellite, orbit data for calculating the position of the satellite, and the like, and is phase-modulated by a pseudo-noise code having a code different for each satellite. I have. The pseudo-noise code has a characteristic that when the same code is multiplied by the same phase, there is a correlation, but there is no correlation when a different code or the same code is out of phase by one chip or more. Therefore, if the received signal is multiplied by the pseudo noise code of the satellite to be received and the phase is shifted little by little, there is a correlation only when synchronization is achieved, and the amplitude of the demodulated signal increases.

[0003]

Generally, in a GPS receiving system, a plurality of pseudo-noise codes are generated at the time of capturing a satellite when correlating a GPS signal with a pseudo-noise code (Japanese Patent Laid-Open No. 6-235762). JP-A-62-245
No. 979). However, there are several stages in satellite acquisition, and each stage does not require the same number of pseudonoise codes with the same phase difference. On the other hand, to increase the speed of satellite acquisition, many pseudo-noise codes had to be generated, and of course, the circuit was correspondingly large, resulting in an increase in power consumption. .

[0004] The present invention has been made in view of such a point, and generates a required number of pseudo-noise codes at a required accuracy with a required accuracy, thereby enabling a satellite to be connected without increasing power consumption. It is an object to increase the speed of capturing.

[0005]

According to the first aspect of the present invention, in order to solve the above-mentioned problem, the number of generated pseudo-noise codes is reduced except when many pseudo-noise codes are required, By not operating the corresponding circuit, the speed of satellite acquisition is improved while suppressing an increase in power consumption. According to the second aspect of the present invention, the speed of satellite acquisition is improved by controlling the phase difference. According to the third aspect of the invention, the speed of satellite acquisition is further improved by combining the first and second aspects. In the invention of claim 4, the number of pseudo noise codes and the phase difference thereof are not determined by the CPU but by a control circuit provided separately from the CPU, so that the number of times of communication with the CPU is reduced. , Power consumption is reduced.

[0006]

(Embodiment 1) FIG. 1 is a first embodiment of the present invention. Hereinafter, the circuit configuration will be described. In FIG. 1A, reference numeral 1 denotes a GPS antenna,
Receives radio waves from a plurality of GPS satellites. 2 is the RF unit,
Reference numeral 3 denotes a carrier removal circuit, which passes through the
GPS signals from a plurality of GPS satellites received by the S antenna 1 are amplified at a high frequency, further mixed with a local oscillation frequency signal, and a down-converted signal is extracted. Reference numeral 4 denotes a correlator for obtaining a correlation between a signal from a satellite and a pseudo noise code. Reference numeral 5 denotes a pseudo-noise code generating circuit which generates a desired number of pseudo-noise codes and
To enter. Reference numeral 6 denotes a register for accumulating a correlation signal between the signal from the satellite multiplied by the correlator 4 and the pseudo noise code. Reference numeral 7 denotes an interface circuit which sends the correlation signal stored in the register 6 to the CPU 8 as necessary. Reference numeral 8 denotes a central control unit (CPU) which receives a signal from the correlator 4 to calculate a position and gives an instruction to the pseudo-noise code generation circuit 5. FIG. 1B shows details of the pseudo-noise code generation circuit 5. In the figure, PN1, PN2,
, PNn are n pseudo noise codes, and the codes are different from each other. The number n of pseudo noise codes generated simultaneously can be controlled by an instruction from the CPU 8.

(Embodiment 2) FIG. 2 is a second embodiment of the present invention. Hereinafter, the circuit configuration will be described. FIG.
In (a), 1 is a GPS antenna and a plurality of G antennas.
Receives radio waves from PS satellites. Reference numeral 2 denotes an RF unit, and 3 denotes a carrier removal circuit. GPS signals from a plurality of GPS satellites received by the GPS antenna 1 while passing through them are amplified in a high frequency, and further, a local oscillation frequency signal is mixed and down-converted. The extracted signal is taken out. Reference numeral 4 denotes a correlator for obtaining a correlation between a signal from a satellite and a pseudo noise code. 5 is a pseudo-noise code generation circuit,
A pseudo noise code having a desired phase difference is generated and input to the correlator 4. Reference numeral 6 denotes a register for accumulating a correlation signal between the signal from the satellite multiplied by the correlator 4 and the pseudo noise code. Reference numeral 7 denotes an interface circuit which sends the correlation signal stored in the register 6 to the CPU 8 as necessary. Reference numeral 8 denotes a CPU which receives a signal from the correlator 4 to perform position calculation and gives an instruction to the pseudo-noise code generation circuit 5. FIG. 2B shows details of the pseudo noise code generation circuit 5. In the figure, PN1, PN2,..., PNn are n pseudo noise codes having different phases, and have the same code. The phase of each pseudo noise code is slightly shifted as shown in FIG. 2C, and the phase difference can be controlled by an instruction from the CPU 8.

FIG. 3 shows a third embodiment of the present invention. Hereinafter, the circuit configuration will be described. 1 is G
A PS antenna that receives radio waves from a plurality of GPS satellites. Reference numeral 2 denotes an RF unit, and 3 denotes a carrier removal circuit. GPS signals from a plurality of GPS satellites received by the GPS antenna 1 while passing through them are amplified in a high frequency, and further, a local oscillation frequency signal is mixed and down-converted. The extracted signal is taken out. 4 is a correlator,
The correlation between the signal from the satellite and the pseudo-noise code is obtained. Reference numeral 5 denotes a pseudo-noise code generating circuit which generates a desired number of pseudo-noise codes having a desired phase difference and inputs the generated pseudo-noise codes to the correlator 4. Reference numeral 6 denotes a register for accumulating a correlation signal between the signal from the satellite multiplied by the correlator 4 and the pseudo noise code. Reference numeral 7 denotes an interface circuit which sends the correlation signal stored in the register 6 to the CPU 8 as necessary. 8 is CPU
The position is calculated by receiving the signal from the correlator 4 and an instruction is given to the pseudo-noise code generation circuit 5. FIG.
(B) shows the details of the pseudo-noise code generation circuit 5.
In the figure, PN1, PN2,..., PNn are n pseudo noise codes having different phases or codes. The phase or code of each pseudo noise code has a desired shift as shown in FIG. The number of pseudo noise codes and the phase difference can be controlled by a command from the CPU 8.

(Embodiment 4) FIG. 4 shows an embodiment 4 of the present invention. Hereinafter, the circuit configuration will be described. 1 is G
A PS antenna that receives radio waves from a plurality of GPS satellites. Reference numeral 2 denotes an RF unit, and 3 denotes a carrier removal circuit. GPS signals from a plurality of GPS satellites received by the GPS antenna 1 while passing through them are amplified in a high frequency, and further, a local oscillation frequency signal is mixed and down-converted. The extracted signal is taken out. 4 is a correlator,
The correlation between the signal from the satellite and the pseudo-noise code is obtained. Reference numeral 5 denotes a pseudo-noise code generating circuit which generates a desired number of pseudo-noise codes having a desired phase difference and inputs the generated pseudo-noise codes to the correlator 4. Reference numeral 6 denotes a register for accumulating a correlation signal between the signal from the satellite multiplied by the correlator 4 and the pseudo noise code. Reference numeral 9 denotes a control circuit, which gives a command for designating the number of pseudo noise codes or the phase difference to the pseudo noise code generation circuit 5. In the present embodiment, the number of pseudo-noise codes and the phase difference are represented by C
The control circuit 9 provided separately from the CPU 8 makes the determination instead of the PU 8 to reduce the number of times of communication with the CPU 8, thereby reducing power consumption.

[0010]

According to the present invention, the number of pseudo-noise codes and the phase difference thereof can be controlled, whereby the speed of satellite acquisition can be improved while suppressing an increase in power consumption as compared with the conventional system. Can be.

[Brief description of the drawings]

FIGS. 1A and 1B are explanatory diagrams showing a configuration of a first embodiment of the present invention, wherein FIG. 1A is an overall configuration diagram and FIG.

FIGS. 2A and 2B are explanatory diagrams showing the configuration and operation of a second embodiment of the present invention, wherein FIG. 2A is an overall configuration diagram, FIG.
(C) is an operation explanatory view.

FIGS. 3A and 3B are explanatory diagrams showing the configuration and operation of a third embodiment of the present invention, wherein FIG. 3A is an overall configuration diagram, FIG.
(C) is an operation explanatory view.

FIG. 4 is an overall configuration diagram of a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 GPS antenna 2 RF part 3 Carrier removal circuit 4 Correlator 5 Pseudo-noise code generation circuit 6 Register 7 Interface circuit 8 CPU 9 Control circuit

Claims (4)

[Claims] 1. A GPS antenna, a frequency converter for frequency-converting a GPS signal received by the GPS antenna, a correlator for correlating an output from the frequency converter with a pseudo-noise code, and a pseudo-signal given to the correlator. A pseudo-noise code generation circuit for generating a noise code; and a central control unit for receiving a signal from the correlator, performing position calculation and giving an instruction to the pseudo-noise code generation circuit, wherein the pseudo-noise code generation circuit is a central control device. A GPS receiver that generates a desired number of pseudo-noise codes having different phases according to a command from the GPS receiver. 2. A GPS antenna, a frequency converter for frequency-converting a GPS signal received by the GPS antenna, a correlator for correlating an output from the frequency converter with a pseudo-noise code, and a pseudo-signal given to the correlator. A pseudo-noise code generation circuit for generating a noise code; and a central control unit for receiving a signal from the correlator, performing position calculation and giving an instruction to the pseudo-noise code generation circuit, wherein the pseudo-noise code generation circuit is a central control device. A pseudo-noise code having a different phase with a desired phase difference in accordance with a command from the GPS receiver. 3. A GPS antenna, a frequency converter for frequency-converting a GPS signal received by the GPS antenna, a correlator for correlating an output from the frequency converter with a pseudo-noise code, and a pseudo-signal given to the correlator. A pseudo-noise code generation circuit for generating a noise code; and a central control unit for receiving a signal from the correlator, performing position calculation and giving an instruction to the pseudo-noise code generation circuit, wherein the pseudo-noise code generation circuit is a central control device. A GPS receiver which generates a desired number of pseudo-noise codes having different phases with a desired phase difference in accordance with a command from the GPS receiver. 4. The GPS receiving apparatus according to claim 1, wherein the pseudo-noise code generation circuit generates the pseudo-noise code in response to a command from a control circuit provided separately from the central control device. .