MXPA96002019A - Digital cellular telephone available for the - Google Patents

Abstract

A cellular telephone system has an antenna for receiving a location system signal such as a GPS and a cellular signal, a location system receiver coupled to the antenna, a mobile radio telephone transceiver, such as digital cellular, coupled to the antenna, and a processor coupled to the receiver of the global positioning system and to the cellular telephone transceiver. The receiver of the global positioning system employs a GPS demodulator to demodulate a first position signal, a second position signal, and a third position signal from a first, second, third terrestrial orbit satellite. The cellular telephone transceiver employs a reception channel to demodulate an input portion of the cellular signal and generate an intermediate frequency input signal in response to it, and a transmission channel to modulate an intermediate frequency output signal and to generate an output portion of the cellular signal in response to it. In addition, the cellular telephone transceiver employs an interface circuit to convert the input intermediate frequency signal and to convert a digital output signal. The processor determines an approximate location of the cellular telephone system, encodes an output speech information signal, and decodes the intermediate frequency signal from

Description

DIGITAL CELLULAR TELEPHONE AVAILABLE FOR GPS BACKGROUND OF THE INVENTION The present invention relates to a combined location system such as a Global Positioning System (GPS) receiver and a telephone transceiver, for example a digital cellular telephone transceiver where the digital cellular telephone processing resources are also used to perform functions for the receiver of the Global Positioning System. A system that has been found useful in navigating and locating mobile objects is the NAVSTAR global positioning system (GPS). In addition to NAVSTAR, other systems, such as GEOSTAR and GLONASS, based on satellite signals have been or are being developed. Other systems use terrestrial signals such as the LORAN system. Unfortunately, GPS and other radio location systems require a significant investment in receiving equipment in order to make use of the signals. Specifically, GPS requires an L-band antenna and a GPS receiver system installed in a housing, which is typically somewhat expensive. GPS receivers have been combined with cellular mobile units in order to provide location information to a base unit, however, little or no cost efficiency is obtained in such systems as discussed above. Such a system is illustrated in U.S. Patent No. 5,043,736, wherein a GPS receiver and a cellular telephone are combined so that the position information generated by the GPS receiver can be sent to a base station through the cellular transceiver. As shown, the GPS receiver and the cell phone are stand-alone systems, configured so that the location information from the GPS receiver can flow to the cell phone, and so that the synchronization and control information can flow from the phone cellular to the GPS receiver. SUMMARY OF THE INVENTION The present invention provides a receiver of the combined location system (for example GPS) and a radiotelephone for example a digital cell phone transceiver wherein the processing resources of the digital cellular phone are also used to carry out functions for the receiver of the Global Positioning System. The invention can be characterized as a telephone system employing an antenna, a location system receiver, a telephone transceiver and a processor. The antenna receives a location signal and a telephony signal, and preferably includes mechanically coupled, electrically independent antennas, tuned to receive each such signal. Specifically, an L-band antenna is preferably used to receive a GPS signal, and a UHF antenna is preferably used to receive a telephony signal. The antenna is coupled to the receiver of the global positioning system, and to the cell phone transceiver. The receiver of the global positioning system uses a GPS demodulator to demodulate a first position signal, a second position signal, and a third position signal, which integrate the GPS signal. The first, second and third position signals are transmitted from the first, second and third terrestrial orbit satellites, respectively, and the GPS demodulator generates a digital data stream in response to the demodulation of such signals. The cell phone transceiver has a receiver channel, a transmission channel and an interface circuit. The receiver channel is coupled to the antenna, demodulates an input portion of the cellular signal and generates an intermediate frequency input signal in response to such demodulation. Similarly, the transmission channel, which also couples to the antenna, modulates an intermediate output frequency signal and generates an output portion of the cellular signal in response to such modulation. The interface circuit is coupled to the receiver channel and the transmission channel. The interface circuit converts the input intermediate frequency signal into a digital input signal, and converts a digital output signal into the intermediate output frequency signal. The processor is coupled and shared by the receiver of the global positioning system and the cellular telephone transceiver. In practice, the processor is modified with a fixed program system and, under the control of such a fixed program system, determines an approximate location in which the cellular telephone system is located. Such determination is made based on the location information contained in the digital data stream provided by the GPS receiver. In addition, the processor encodes an output speech information signal and generates the intermediate output frequency signal. The processor also decodes the input intermediate frequency signal and generates an input speech information signal. The speech information signals are used, as is known in the art, to communicate analog voice information to and from a speaker and microphone within the housing of the cellular telephone system. Thus, in the above-described embodiment, a cellular telephone system is provided wherein the processing resources of the digital cellular telephone are also used in order to carry out functions for the receiver of the Global Positioning System. The sharing of processing resources results in a more cost-effective design than previous combinations of location and telephony transceiver. In one variation, the above-described embodiment has a luminous screen, such as a luminous liquid crystal display. The luminous screen is coupled to the processor, and displays information in response to a deployment signal. The deployment signal is generated by the processor in response to the determination of the approximate location of the cellular telephone system, and the information displayed indicates the approximate location. For example, the displayed information may be the latitude, longitude and altitude in the determined approximate location. In this variation, the present invention can thus be used by an operator of the cellular telephone system to visually display the location of the cellular telephone system. Having displayed the information, for example, the operator can verbally transmit the displayed information to, for example, emergency personnel in the case of an emergency, such as a car accident, the presence of a crime, or the breakdown of a car. . BRIEF DESCRIPTION OF THE DRAWING The foregoing and other aspects, features and advantages of the present invention will be more apparent from the following more particular description thereof, presented in conjunction with the following drawing, wherein: The figure is a block diagram of a combined global positioning system (GPS) receiver and digital cellular telephone transceiver, made in accordance with one embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION The following description of the best mode currently contemplated of practicing the invention, should not be taken in a limiting sense, but is made merely for the purpose of describing the general principles of the invention. The scope of the invention should be determined with reference to the claims. Referring to the figure, the front end of the receiver of the Global Positioning System (GPS) 10 (or GPS receiver) coupled to an L-band antenna and to a digital signal processor 14 (DSP controller) is shown. Also shown is the front end of a cellular phone 16 (or cellular transceiver), which is coupled to a UHF antenna 18 and to the DSP controller 14. The DSP controller 14 is coupled to a luminous user screen 16 such as a screen light emitting diode (LED) or a luminous liquid crystal display (LCD). The GPS receiver 10, the cellular transceiver 16, the DSP controller 14 and the luminous user display 20 are all housed within a housing of the cellular transceiver 22, as is known in the art. Note that the cellular transceiver housing 22 can, in practice, employ two housings, one for housing the radio frequency components and some digital components, and the other for housing the rest of the digital components and for serving as a headset cell phone, as known in the field. When two housings are used, a coiled "telephone handset" cable is used to couple the components within the two housings as a whole. Within the GPS receiver 10, the band antenna L 12 is coupled to a front end of the radio frequency 24. The front end of the radio frequency 20 is an L-band radiofrequency receiver that generates an intermediate frequency signal (IF) in response to the first, second, third and fourth position signals 26, 28, 30, 32 received from the first, second, third and fourth earth-orbiting satellites 34, 36, 38, 40, respectively. Note that although four position signals are preferred, the ground position can be determined based on only three such signals. However, if altitude information is desired, the signal of the fourth position is necessary for its determination. The position signals are received on two L-band frequencies: 1575.42 MHz and 1227.6 MHz. The synchronization of a pseudo-random dispersion code (PRN), which is 1023 MHz in amplitude, is acquired at the frequency of 1575.42 MHz The signals from each of the four earth-orbiting satellites 34, 36, 38, 40 arrive at the front end of the receiver of the Global Positioning System 10 at the above L-band frequencies. Each of the position signals 26, 28, 30, 32 has a different pseudo-random spreading code. (The ability to synchronize a dispersion code of 10.23 MHz in amplitude is not excluded in this modality). The signals received by the band antenna L 12 are passed to the front end of the radio frequency 24. The design of a front end of suitable radio frequency is well known in the art. Within the front end of the radio frequency, a L-band pre-selection filter is followed by a Low Noise Amplifier (LNA). A sub-converter that includes a frequency synthesizer, a mixer, and an Intermediate Frequency (IF) amplifier is designed with appropriate auxiliary circuitry so that the Noise Figure (NF) of the system is preserved and an Intersection Point is obtained. (IP) desirable. The design of such a subconverter is well known in the art. Cascaded subverters, multiple subverters, or a subverter with multiple IF outputs can be used for increased performance. (The intermediate frequency output capable of passing a PRN code of 10.23 MHz in amplitude is contemplated by the inventors.) An Intermediate Frequency (IF) suitable for operation is chosen with the sampling and classification circuit 46. The selection of the frequency intermediate depends on the particular implementation used by the present embodiment, and especially the sampling and classification circuit 46. The front end of radio frequency 24 is coupled within the receiver of GIPS 10 to a bandpass filter 42, and passes the intermediate frequency (IF) signal thereto Bandpass filter 42 is a low frequency intermediate frequency (IF) bandpass filter 42 which serves as a noise rejection filter before the digitalization is digitized. IF signal The bandpass filter 42 has a center frequency of less than 30 MHz and a bandwidth of about 1 MHz (for low resolution GPS C / A code signals) n) or approximately 10 MHz (for GPS P code signals at high resolution). The bandpass filter 42 is coupled within the GPS receiver to an automatic gain control 44 that amplifies or attenuates the IF signal as necessary to establish an adequate threshold for digitizing the signal. The automatic gain control 44 is coupled to a sampling and classification circuit 46 that samples and digitally filters the attenuated or amplified IF signal from the automatic gain control 44. The sampling and classification circuit 46 receives the position signals 26., 28, 30, 32 to an optimum threshold for its operation and generates from the position signals 26, 28, 30, 32, samples in phase and in quadrature phase of the position signals 26, 28, 30, 32 Preferably, the sampling and classification circuit 46 uses a sampling ratio of at least the Nyquist sampling ratio.

The sampling and classification circuit 46 is coupled to a specific application integrated circuit (ASIC) 48 of the Global Positioning System (GPS). The ASIC 48 of the GPS receives the digitally filtered and digitized IF signal from the sampling and classification circuit 46. The ASIC 48 of the GPS disperses the dispersed pseudo-random codes from the satellites 34, 36, 38, 40 using a very high precision time reference, as is commonly known in the art. The ability to simultaneously disperse three to eight signal channels is typical in the design of GPS ASIC 48. The ASIC 48 of the GPS tracks the satellite signals and measures the Arrival Time (TOA) with respect to its local register clock as well as demodulates the embedded data at 50 bps (bits per second) in the broadcast spectrum signals. The structure design of the GPS ASIC 48 is commonly known, an example of which is shown in the "Low Cost TIDGET GPS Module" of NAVSYS Corporation of Colorado, 1990. An appropriate GPS ASIC 48 is an integrated circuit commonly known and available. Preferably, however, a GPS ASIC simplified by the current mode is used to extract the GPS information from the spread spectrum modulation of the digitally filtered and digitized IF signal. The simplified GPS ASIC can be produced in a less expensive way than the currently available GPS ASICs, exploiting the cost efficiency obtainable with the current mode. The GPS ASIC 48 also engages the automatic gain control and adjusts the gain or attenuation applied by the automatic gain control 44 as a function of the amplitude of the digitally filtered and digitized IF signal received from the sampling circuit and classification. In this way, the GPS ASIC 48, together with the automatic gain control 44, functions as a closed loop negative feedback control system that reduces and increases the amplification (or increases and reduces the attenuation) applied by the control of automatic gain 44 in response to the increase or decrease in the amplitude of the digitally filtered IF signal. The GPS ASIC 48 is coupled to the DSP controller 14, and passes the GPS information extracted from the digitally filtered and digitized IF signal to the DSP controller 14. The Digital Signal Processor 14, extracts the GPS message data from input, TOA measurements and satellite location messages, and executes position determination algorithms based on triangulation. A location correction and update algorithm is also carried out using the Digital Signal Processor 14 based on Kalman filtering techniques and a location signal is generated in response to them. The design of the Kalman filter is well known in the art. The update of the high accuracy position can be done once per second or faster. Typically, an acquisition time of cold start necessary to obtain a fixed position is between 15 to 20 seconds. A reacquisition of the fixed position after a momentary loss of the signal is less than five seconds for a GPS receiver of three to five channels. After generating the location signal in this manner, the DSP controller 14 passes the location signal to the user's light display 20, which selectively displays the location of the GPS receiver and the combined cellular telephone transceiver as latitude, longitude and, preferably, altitude. Such a luminous display displays the location only when a momentary SPST switch is closed (eg, a "location" button, or a "second function" key) along with a numeric key, such as are typically found on the keyboard 49 of the cell phone handset.The keyboard 49 is coupled to the DSP controller 14. Advantageously, by selectively operating the luminous screen in this manner, the amount of energy consumed over time by the GPS receiver and the combined cellular telephone transceiver is reduced, from a power supply 51 coupled to the GPS receiver and to the cellular telephone transceiver. The power supply 51 is also coupled to the DSP controller 14, the keyboard 49 and the light display 20. After the momentary switching of SPST is released, the light display 20 can continue to display the location information accompanied by a lapse indication. of time during a prescribed period of time, for example, 10 seconds. The time lapse indication shows the time that has elapsed since the last fixed position was made by the present modality. In the event that the functions of the global positioning system are not selected, the display of the location information and the indication of time lapse is disabled. Note that in some embodiments, the determined latitude, longitude and altitude, instead of or in addition to being displayed on the luminous screen 20, can be transmitted to the base station 54 by the cellular transceiver 16, described below. Such transmission may be carried out in response to the pressure of the "location" button on the keyboard 49, or it may be sent in response to a research signal transmitted by the base station 54. However, these modalities are not preferred, since they require significant modifications to be implemented to the existing cellular infrastructure. Within the cellular transceiver 16, the UHF antenna 18 is coupled to a duplexer 50. The duplexer 50 transfers the output radiofrequency signals 52 (or cellular output signals) to the UHF antenna 18 for transmission to a base station 54 In addition, the duplexer 50 receives the input RF signals 56 (or cellular input signals) which are transmitted from the base station 54 and received in the UHF antenna 18. The duplexer 50 is coupled to a reception channel 58. which includes a radio-frequency-to-frequency-intermediate mixer, and a demodulator. The reception channel 58 is coupled to a synthesized local oscillator 60 that provides a modulation / demodulation signal to the reception channel 58, as is known in the art. The reception channel 58 is also coupled to an interface specific application integrated circuit (ASIC) 62. The interface ASIC 62 is used to implement an FM frequency translation keypad (FSK) receiver, a message processor of FM, transmission and reception synchronization generators, interfaces for CODECs, buffer storage, fading detection, FEC encoding and decoding, a fixed-point divider unit (for a Vocoder), a closed cycle phase (for the generation of a CODEO clock, miscellaneous input / output circuitry and adhesive logic for processor interfaces.) The interface ASIC 62 is coupled to a transmission channel 64 that generates the output radio frequency signal 52 (cellular signal of output.) The transmission channel 64 is coupled to the duplexer 50 and provides the output radio frequency signal 52 thereto for transmission through s UHF antenna 18. The transmission channel includes a-intermediate-frequency-to-frequency transmitter radius and a modulator mixer. The transmission channel 64 is coupled to the synthesized local oscillator 60, which generates the modulation / demodulation signal. The frequency-intermediate-to-radio-frequency transmitting mixer uses the modulation / demodulation signal to modulate the output radio frequency signal 52. The interface ASIC 62 is also coupled to the DSP controller 14, and the DSP controller 14 is used within the cellular transceiver 16 to carry out the following functions: analysis / synthesis by Vocoder (Voice Encoder), hands-free voice switching, digital channel demodulation / equalization, FM audio transmission / reception, FM SAT detection and generation, FM FSK transmission, message handling / FM call processing, processing / control digital call, user interface monitor / diagnosis / examination, coding / decoding / queuing of SACCH, authentication and key generation, privacy of signaling, voice recognition and voice response. The DSP controller 14 is also coupled to the synthesized local oscillator 60 and is used by the cellular transceiver 16 to analyze and adjust the timing and frequency of the modulation / demodulation signal generated by the synthesized local oscillator 60, as necessary to correct the synchronization error, or the clock ratio error. The DSP controller 14 also uses the user light display 20, to which it is coupled, to display information relating to the cellular transceiver 16. For example, the user light display 20 is used to display the telephone number that is being dialed. the cellular transceiver 16 and / or to display a meter of signal resistance indicative of the resistance of the input radio frequency signal 56. In this way, a GPS receiver 10 and a cellular transceiver 16 are combined within a cellular telephone housing 22, and share a common DSP controller 14 and a luminous display 20. Since the cellular phone housing, the DSP controller 14 and the luminous user screen 20 are typically two of the most expensive components involved in a GPS receiver 10 or a cellular transceiver 16, the substantial commercial advantage is obtained by the combination of these two devices and their DSP controller compartment 14 and the user light display 20. An additional advantage can be obtained by combining the L-band antenna 12 with the UHF antenna 18, thereby eliminating the need for two antennas. Such combination may include making the antennas a single antenna tuned to an intermediate frequency at the frequency of the position signals 26, 28, 30, 32 and the radio frequency signals 52, 56. However, preferably, the antennas 12, 18 are separated electrically as shown in the figure, in order to optimally tune each of the antennas for the particular range of frequencies that are to be received, and mechanically coupled into a single mechanical unit, in order to minimize the complexity of installation and maximize the aesthetic aspect.

Although the preferred embodiment of the invention has been described in the context of a digital cellular telephone that typically includes a powerful DSP such as the DSP controller 14 of the figure, it is equally applicable to other types of telephone systems, including analog cellular telephony, mobile satellite systems, personal communications service systems (PCS), line network, packet radio, mobile distribution and specialized radio systems, including Specialized Mobile Digital Radio (DSMR) and many other communications systems two ways. Typically, mobile satellite systems use a mobile portable or subscriber unit that communicates directly via a satellite to another portable or mobile or to a fixed access in a switched telephone network. Many different systems are in development (for example Inmarsat -P or ICO-Global, Iridium, Asia-Pacific Mobile Phone) and some are already in service for example the American Mobile Satellite Company (AMSC) and the Inmarsa systems - M and C. In addition, although the preferred embodiment has been described in the context of a GPS receiver, the combination can be made with a number of different types of radio positioning systems, such as GLONASS or LORAN. Although the invention disclosed herein has been described by means of specific embodiments and embodiments thereof, numerous modifications and variations could be made thereto by those skilled in the art, without departing from the scope of the invention set forth in the claims.

Claims (10)

1. NOVELTY OF THE INVENTION Having described the present invention, it is considered as a novelty and therefore the property described in the following claims is claimed as property. An integrated radio communication and location system comprising: an antenna system for receiving radio frequency signals; a telephony receiver coupled to the antenna system for emitting / receiving telephony radio signals, for example land mobile telephony, personal communications service or mobile satellite telephone signals; a receiver of the location system coupled to the antenna system to receive radio signals from the location system, for example signals from GPS, GLONASS, LORAN, and GEOSTAR; a controller, operated in accordance with a control program, coupled to the telephony receiver to control the operation of the telephony receiver according to the control program and coupled to the receiver of the tracking system to control the operation of the receiver of the tracking system; a digital signal processor coupled to the controller to process the telephony radio signals and to process the radio signals received from the location system and generate a signal indicative of the location of the integrated system in response thereto; also coupling the controller to the digital signal processor to receive the signal indicative of the location of the integrated system and generate a location signal in response to it, for example, the latitude, longitude and altitude of the integrated system; and a luus screen coupled to the controller to display information based on the signal and location information with respect to the telephony radio signals. The system according to claim 1, characterized in that the receiver of the location system carries out the demodulation, sampling, de-dispersion and time measurements in the radio signals of the location system. The system according to one or more of the preceding claims, characterized in that the digital signal processor carries out position detertion algorithms, location updates and location corrections using the radio signals of the location system from the receiver of the location system. The system according to one or more of the preceding claims, characterized in that the transmission of the location signal is carried out in response to a request received by the telephony receiver and transmitted to the controller from the remote location during a telephone call. The system according to one or more of the preceding claims, characterized in that the telephony receiver further comprises: a reception channel coupled to the antenna system, for demodulating an input portion of the radio telephony signal and generating an intermediate signal of entry in response to it; a transmission channel, coupled to the antenna, for modulating an intermediate output signal and for generating an output portion of the radio telephony signal in response to it; and wherein the digital signal processor further comprises: means for encoding an output speech signal and generating the intermediate output signal; means for decoding the intermediate input signal and generating an input speech signal. The system according to one or more of the preceding claims, characterized in that it also comprises an interface circuit, between the digital signal processor and the reception and transmission channels, to carry out the error correction and the synchronization of the ti for intermediate input frequency signals and intermediate output frequency signals. The system according to one or more of the preceding claims, characterized in that the controller further carries out the processing of the message, the processing and the authentication of the call. The system according to one or more of the preceding claims, characterized in that the controller is coupled to the; we an oscillator in the telephony receiver and also controls the synchronization and frequency of the oscillator. The system according to one or more of the preceding claims, characterized in that the controller further comprises means for generating a deployment signal in response to the determination of the approximate location, - and wherein the system further comprises a deployment device coupled to the controller to display information in response to the display signal indicating the approximate location. The system according to claim 9, characterized in that it further comprises: a switch for selectively activating the deployment device in order to display the location information. SUMMARY OF THE INVENTION A cellular telephone system has an antenna for receiving a location system signal such as a GPS and a cellular signal, a location system receiver coupled to the antenna, a mobile radio telephone transceiver, such as a digital cellular , coupled to the antenna, and a processor coupled to the receiver of the global positioning system and the cellular telephone transceiver. The receiver of the global positioning system employs a GPS demodulator to demodulate a first position signal, a second position signal, and a third position signal from a first, second, third orbiting satellite. The cellular telephone transceiver employs a reception channel to demodulate an input portion of the cellular signal and generate an intermediate frequency input signal in response to it, and a transmission channel to modulate an intermediate frequency output signal and to generate an output portion of the cellular signal in response to it. In addition, the cellular telephone transceiver employs an interface circuit to convert the input intermediate frequency signal and to convert a digital output signal. The processor determines an approximate location of the cellular telephone system, encodes an output speech information signal, and decodes the input intermediate frequency signal,