WO2005019855A2 - Dispositif recepteur et procede consistant a utiliser un ensemble de circuits a bande de base gps pour recuperer a la fois des signaux de bande de base gps et des signaux de bande de base sans fil local - Google Patents

Dispositif recepteur et procede consistant a utiliser un ensemble de circuits a bande de base gps pour recuperer a la fois des signaux de bande de base gps et des signaux de bande de base sans fil local Download PDF

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Publication number
WO2005019855A2
WO2005019855A2 PCT/US2004/023389 US2004023389W WO2005019855A2 WO 2005019855 A2 WO2005019855 A2 WO 2005019855A2 US 2004023389 W US2004023389 W US 2004023389W WO 2005019855 A2 WO2005019855 A2 WO 2005019855A2
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WIPO (PCT)
Prior art keywords
gps
signal
baseband
circuit
common
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Application number
PCT/US2004/023389
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English (en)
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WO2005019855A3 (fr
Inventor
Steve Wozniak
Dimitri Rubin
Original Assignee
Wheels Of Zeus, Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US10/703,348 external-priority patent/US20050101346A1/en
Application filed by Wheels Of Zeus, Inc. filed Critical Wheels Of Zeus, Inc.
Publication of WO2005019855A2 publication Critical patent/WO2005019855A2/fr
Publication of WO2005019855A3 publication Critical patent/WO2005019855A3/fr

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S19/00—Satellite radio beacon positioning systems; Determining position, velocity or attitude using signals transmitted by such systems
    • G01S19/01—Satellite radio beacon positioning systems transmitting time-stamped messages, e.g. GPS [Global Positioning System], GLONASS [Global Orbiting Navigation Satellite System] or GALILEO
    • G01S19/13—Receivers
    • G01S19/35—Constructional details or hardware or software details of the signal processing chain
    • G01S19/36—Constructional details or hardware or software details of the signal processing chain relating to the receiver frond end

Definitions

  • Embodiments of trie-present invention relate to the field of wireless communication- More specifically, embodiments of the present invention relate to a receiver circuit for receiving both global positioning system (GPS) data and local wireless data.
  • GPS global positioning system
  • GPS devices communicate with orbiting satellites (and/or terrestrial based reference systems) to determine a global location of the device. Position information can be obtained in this manner, in part, by measuring timing differences in the communication signals made between various' satellites (and/or terrestrial systems) and the device using wireless communication links. A GPS device using such a location system may be hand-held. GPS data communicated over wireless links uses a technique called direct sequence spread spectrum in order to accurately broadcast a weak signal over a long distance.
  • GPS uses a Code Division Multiple Access (CDMA) Direct Sequence Spread Spectrum (DSSS) technique.
  • the GPS signal is Information bits spread by orthogonal binary 1023 bit code, often called “gold code”. In the current generation of GPS. the same information bit is repeated 20 times and up converted to the "L1" frequency which is 1.57542 Ghz.
  • the wireless communication link becomes very resistant to noise and can be broadcast over vast distances, as is well known.
  • the 1.57542 GHz GPS signal is received, it is fed to an RF front- end circuit which is down converts it to a digital baseband signal.
  • a GPS baseband circuit receives this diyilal baseband signal, despreads and demodulates the signal to recover the GPS data. Correlator cirouKs of the GPS baseband circuit are used to perform the despreading function according to well known methods.
  • GPS devices also may communicate wirelessly with other GPS devices or local devices to perform various functions, such as locating a device using another device. GPS devices use radio or RF signals when communicating in this fashion. This Is called local wireless communication and refers to GPS devices communicating with other local devices.
  • Prior an GPS devices utilize two separate receiver subsystems f ⁇ i receiving GPS and local wireless information.
  • a 1.57542 GH ⁇ receiver i ⁇ used for receiving and recovering GPS data
  • a separate radio receiver is used for receiving and recovering local wireless data.
  • the receivers are typically maintained as separate because of the different frequencies and communication protocols involved between GPS and local wireless data. This is true for devices capable of both GPS and cellular communication, GPS and radio communication and GPS and pager communication.
  • Unfortunately, by using two separate receiver systems the cost and complexity of these GPS devices increases and this poses problems for developers of low cost GPS devices. It would be advantageous to provide a very inexpensive device having boih GPS and local wireless communication. Such device could, for example, be placed on objects for the tracking thereof.
  • embodiments of the present invention provide a GPS and local wireless data receiver that share components in common thereby reducing the cost and complexity of the overall receiver unit.
  • the GPS baseband circuit of the present invention can be used for recovering local wireless data as well as recovering GPS data.
  • an embodiment of the present invention makes use of a very low cost RF receiver circuit for the local wireless path thereby allowing a low cost GPS/local wireless receiver solution.
  • the present invention provides a very inexpensive device, e.g., "tag device,” having both GPS and local wireless communication. Such device could, for example, be placed on objects for the tracking thereof.
  • the Inexpensive receiver system could also be implemented within a "finder device” as described further below, for communicating with and locating tag devices.
  • Embodiments of the present invention are directed to a method and system using a GPS baseband circuit for despreading both GPS data and local wireless data.
  • an RF signal local wireless
  • a GPS signal is also received at the second frequency and a digital baseband signal is produced therefrom.
  • Both baseband signals are provided to a single GPS baseband circuit for data recovery.
  • GPS data is recovered from the baseband signal by despreading and demodulation.
  • the GPS baseband circuit is programmed to despread and ⁇ recover local wireless data.
  • the GPS data and the local wireless data can be stored in a data buffer for downstream processing.
  • the local wireless baseband signal is produced by up conversion of the local wireless RF signal and then processing though a common RF front-end circuit that is also used by the received GPS signal.
  • a receiver device contains a receiver circuit for coupling with an antenna and for producing an global positioning system (GPS) signal therefrom having a first frequency.
  • the receiver device also contains a radio frequency (RF) front-end circuit for receiving the analog GPS signal and for producing a GP5 baseband signal therefrom.
  • the receiver device also contains a low cost receiver circuit for coupling with an antenna and for producing a first analog local wireless (LW) signal therefrom having a second frequency.
  • the receiver device also contains a frequency converter circuit coupled to the low cost receiver circuit and for converting the first analog LW signal to a second analog LW signal having the first frequency, wherein the RF front-end circuit also receives the second analog LW signal and produces an LW baseband signal therefrom.
  • the receiver device also contains a baseband circuit for receiving both the GPS and the LW baseband signals and recovering therefrom GPS and LW data.
  • the first frequency is substantially 1.57542 GHz and the second • frequency is substantially 900 MH*.
  • the baseband circuit is operable in a first mode wherein correlator circuitry of the baseband circuit despreads the LW baseband signal and the baseband circuit Is also operable in a second mode wherein the correlator circuitry despreads the GPS baseband signal.
  • An RF switch coupled to receive the analog GPS signal and the second analog LW signal, may be used for passing through the second analog LW signal to the RF front-end circuit during the first mode and for passing through the analog GPS signal to the RF front-end circuit during the second mode.
  • a receiver device in another embodiment, contains a first radio frequency (RF) front-end circuit for producing a GPS baseband signal from a received wireless analog GPS signal.
  • the receiver device also contains a second RF front-end circuit tor producing a local wireless (LW) baseband signal from a received wirclcoa analog LW signal.
  • the receiver device al3o contains a common baseband circuit for receiving both the GPS and the LW baseband signals and for recovering therefrom GPS and LW digital data.
  • the received GPS signal is substantially 1.57542 GHz in frequency and the received wireless analog LW signal has a frequency of substantially 900 MHz.
  • the common baseband circuit comprises common correlator circuitry that is used for despreading both the GPS the LW baseband signals for recovering digital data therefrom and farther the common baseband circuit is operable in a first mode wherein the common correlator circuitry despreads the LW baseband signal and Is operable in a second mode wherein - the common correlator circuitry despreads the GPS baseband signal.
  • the receiver device also contains a switch coupled to receive signals from the first and second Rl ⁇ front-end circuits and coupled to supply signals to the common baseband circuit, the switch for passing through the LW baseband signal during the first mode and for passing through the GPS baseband signal during the second mode.
  • Embodiments of the present invention also include methods of operating the receivers as described above.
  • FIG. 1 Illustrates a system in which receiver embodiments of the present invention may be employed In a finder unit and/or in a tag unit for receiving both GPS wireless dala and local wirel ss data.
  • FIG. 2 is a circuit diagram of a GPS/Local Wireless receiver unit In accordance with one embodiment of the present Invention employing local wireless RF signal upconversion and common RF front-end and baseband circuits.
  • FIG. 3A is a circuit diagram of a GPS/Local Wireless receiver unit in accordance with another embodiment of the present invention employing two RF front-end circuits for producing two baseband digital signals.
  • FIG. 3B is a circuit diagram of a GPS/Local Wireless receiver unit in accordance with another embodiment of the present invention employing a single RF front-end circuit that is frequency tunable and a common baseband circuit.
  • FIG. 4 is a block diagram of a baseband circuit in accordance with an embodiment of the present invention employing a shared correlator circuit for recovering both GPS data and local wireless data.
  • Figure 5 is a block diagram of a correlator circuit in accidence with an embodiment of the present Invention for performing despreading to recover both ⁇ GPS data and local wireless data.
  • Figure 6 is an exemplary flow diagram of a process In accordance with one embodiment of the present invention for up converting a local wirolooo RF signal so that a GPS baseband circuit can be used for recovery of local wireless data therefrom in accordance with the receiver circuit of Figure 2.
  • FIG 7 is an exemplary flow diagram of a process in accordance with another embodiment of the present invention for the correlator circuit of a single baseband circuit for recovery of both GPS and local wireless data in accordance with the receiver circuits of Figure 2 and Figure 3A.
  • FIG. 1 illustrates an exemplary communication system 30 in which embodiments of the present Invention may be practiced. It is appreciated that embodiments of the present Invention are directed to a receiver device capable of receiving global positioning system (GPS) wireless signals and local wireless signals. Such a receiver device can be used in any communication system configuration having need for these signals. Exemplary system 30 Is but one example of such a system and is shown for purposes of illustration and discussion only.
  • GPS global positioning system
  • device 15 Is a handheld electronic device, but could be a stationary or otherwise desktop device.
  • GPS wireless link 27 may be of a number of well known types using a number of different well known GPS communication protocols and frequencies.
  • GPS communication protocols utilize direct sequence spread spectrum techniques for data spreading and further may utilize other forms of modulation, all of which are very well known in the art. These techniques allow a relatively weak signal and low power signal to be broadcast over long distances and offer excellent noise suppression and accurate recovery.
  • GPS wireless communication link 27 utilizes a standard frequency of 1.57542-GHz, but could be any acceptable and used GPS frequency.
  • the locator or finder device 15 also may communicate over a radio frequency (RF) wireless link 17 to another GPS device 20, called herein the "tag device.”
  • RF radio frequency
  • This comrtiunicatlon link 17 is referred to herein as the local wireless (LW) communication fink 17 and may be bi-directional.
  • This communication link 17 can be of any frequency, but in one embodiment, It is an RF frequency, e.g., 000 MHz. Any of a number of different RF frequencies can be used as the RF frequency, e.g., 400 MHz, 868 MHz, 2400 MHz, 27 MHz, etc., and 900 MHz is merely exemplary.
  • the tag devices 20 may be placed on objects for tracking their locations.
  • the finder device 15 may communicate requests to the tag 20, over LW link 17, such as "where are you?"
  • the tag 20, in response, may communicate its location to the finder 15 over LW link 17, or may communicate a signal that It Is lost, for Instance.
  • the tag 20 may also communicate a signal to the finder 15, over LW link 1 , in response to some event that it has detected or computed, such as, It was moved outside a prescribed boundary, or that it is moving at a predetermined speed or direction, etc.
  • the tag 20 may receive a signal from the GPS based systems 25 using a GPS wireless link 22, similar to link 27, to obtain ite location information.
  • the finder device 15 and the tag device 20 each contain receiver circuitry for receiving both a GPS based wireless communication (e.g., links 27 and 22) and a local wireless (LW) communication, e.g., link 17. Digital data may be broadcast over these communication links. While the GPS wireless communications adhere to well known and standardized communication protocols and frequencies, the local wireless communications links may be of any suitable frequency or communication protocol.
  • embodiments of the present Invention are directed to a low cost receiver circuit for receiving signals from both GPS and LW communication links.
  • This so called GPS/LW receiver circuit may be utilized in the finder device 15 and/or the tag device 20, for Instance.
  • inexpensive and low power tag devices 20 may be provided.
  • FIG. 2 Illustrates a GPS/LW receiver circuit 100
  • Circuit 100 as doscribod furthor bolow, advantageously utilizes correlator circuits within a baseband circuit 110 for despreading both GPS and LW communication, thereby significantly reducing the cost of the receiver subsystem required to receive LW communication.
  • the circuitry normally used to merely receive and recover GPS Information is advantageously used for also receiving and recovering LW information, in accordance with embodiments of the present invention.
  • the LW receiver path of circuit 100 is now described. As shown in Figure 2, an RF antenna 150 is connected to an optional saw filter circuit 145 using connection 222 and switch 190.
  • any well known RF antenna design can be used for receiving RF signals, e.g., over LW communication link 17 ( Figure 1).
  • the saw filter circuit 145 of Figure 2 performs signal filtering allowing only specified signals through.
  • the received LW analog signal is 900 MHz, but could be of any RF frequency.
  • a -1.5 dB filter is used for circuit 145.
  • the saw filter circuit 145 is connected to a low cost LW receiver circuit, which in the exemplary embodiment shown in Figure 2, is a low noise amplifier (LNA) circuit 140.
  • LNA low noise amplifier
  • this connection is made through a transmit/receive switch 190, which in this description may be assumed to be set in the receive mode thus connecting the RF Input 222 to the filter 145 and bypassing transmitter circuit 155.
  • LNA low noise amplifier
  • Any of a number of well known, low cost LNA circuits may he used, but in one particular implementation, an LNA circuit having a Gmax of 18 dB and an NF of 2.0 dB may be used.
  • the LNA circuit 140 is not generally a full receiver circuit in the traditional description, but rather a low cost receiver circuit for boosting the LW signal in the 900 MHz range.
  • the LNA circuit 140 amplifies an analog LW signal at a frequency of 900 MHz, which optionally may be fed to a filter 135 to eliminate unwanted frequencies, as needed.
  • Circuit 130, 160, and 165 in combination upconverts the analog LW signal to the frequency of the GPS communication link.
  • VCO voltage controlled oscillator
  • PLL phase locked loop
  • Mixer circuit 130, 160 and 165 function together to provide a ⁇ 00 MHz signal (at 1G2) that is mixed with the analog LW signal provided by LNA circuit 1 0 (and optionally filtered by 135).
  • circuits 130, 160 and 165 operate together, in a well known manner, to upconvert the analog LW signal to 1.57542 GHz, which is the GPS frequency as described herein.
  • these circuits 160 and 165 may also be used by transmitter circuitry 155.
  • mixer 130 has a Gmax of 8 dB and an NF of 10 dB in one example.
  • Circuits 130, 160 and 165 function as a frequency converter and produce an LW analog signal at 210 having 1.57542 GHz frequency. It is appreciated that, in accordance with this embodiment, the particular frequency produced at 210 may be any frequency that matohes that of the GPS communication froquoncy. In the illustrated embodiment, this happens to be 1.57542 GHz, for discussion.
  • the I W analog signal at 210 is then provided to an input leg of an analog switch 195 which switches between the LW receiver path and the GPS receiver path.
  • 900 MHz is but one LW frequency that can be used and is discussed herein as an exemplary frequency.
  • the up conversion discussed above may actually be a down conversion, e.g., cases in which the LW frequency is actually - higher than the GPS frequency.
  • a GPS antenna 180 is connected to an optional saw filter circuit 175 using connection 212, Any well known antenna design can be used for receiving GPS signals, ⁇ .g., over GPS communication links 22 and 27 ( Figure 1 ).
  • the GPS saw filter circuit 175 of Figure 2 performs signal cleaning allowing only specified signals through.
  • the received GPS0 analog signal is 1.57542 GHz, but could be of any acceptable GPS standardized frequency.
  • a -1.5 dB filter Is used as circuit 175.
  • the aw filter circuit, 75 Is connected to a GPS low noise amplifier (LNA) circuit 170.
  • LNA GPS low noise amplifier
  • LNA circuit 170 produces a GPS analog signal of 1.57542 GHz at line 215 and is coupled to the other input leg of switch 195.
  • Switch 195 has an output leg that is coupled to an optional gain stage0 circuit 125.
  • Switch 195 Is controlled by a signal over line 350 that toggles between "LW receive mode" and "GPS receive mode:"
  • GPS receive mode the GPS analog signal of 215 is supplied to circuit 125 and in LW receive mode, the LW analog signal of 210 is supplied to circuit 125.
  • the output of circuit 125 is coupled to another GPS saw filter 120 (e.g., -1.5 dB) which provides a filtered analog signal (GPS or LW) to the input of an Rf- front- end unit 115.
  • GPS and LW analog signals of 1.57G42 MHz are time multiplexed over line 230 under control of switch 195 depending on the type of information desired.
  • RF front-end unit 115 in this embodiment, is shared by the GPS and LW receive paths and produces a baseband signal over lines 235 to a baseband unit 1 0.
  • the baseband signal over lines 235 Is the GPS baseband signal and is generally digital.
  • the baseband signal over lines 235 is the LW baseband signal and is generally digital.
  • FIG. 9 illustrates baseband circuit 110 controlling the state of switch control line 350, e.g., via a controller or processor. It appreciated that any type of control circuit can control the mode signal over line 350 and the embodiment shown in Figure 2 is merely exemplary.
  • Baseband circuit 110 provides recovered digital GPS data and recovered LW digital data over line 240 for downstream processing. Alternatively, this digital data may be consumed by processors and logic within the baseband circuit 110.
  • the baseband circuit 110 operates according to well known standard GPS baseband functionality for despreading and demodulating the GPS baseband signal according to well known and standard GPS communication protocols, which include decoding signals thai are encoded using direct sequence spread spectrum techniques, for Instance. ⁇ s Is well known, correlator circuits are used to recover GPS data from a GPS baseband signal of lines 235.
  • baseband circuit 110 When in the LW mode of operation, baseband circuit 110 advantageously shares the correlator circuits to also recover LW data that may be encoded using direct sequence spread spectrum techniques. By spreading the LW data in this fashion at the transmitter, the present invention is able to provide an RF signal (carrying LW information) that can be received over long distances, uses relatively little power and provides excellent noise suppression and channel sharing capabilities.
  • standard GPS communication protocol can he used for encoding (and recovering) the LW data thereby requiring little, of any, changes in conventional GPS baseband circuits for the recovery of the LW data.
  • the communication protocol for LW data may be altered in an optimization which eliminates much of the GPS overhead that may not be required to communicate LW data.
  • standard GPS communication techniques it is common to repeat (e.g. " 20 repetitions) the same symbol spread with a 1023 bit sequence (or gold code) to represent a single information bit, 1 or 0.
  • This technique can be eliminated or significantly reduced when communicating LW data.
  • an LW bit can be encoded using direct sequence spread spectrum techniques, but only a single transmission of its" "gold code” (or inverse) Is used to transmit the bit when in LW mode.
  • this alternative requires slight modifications to the standard GPS baseband data recovery programming and represents an optimization for LW communication.
  • the correlator circuits of the baseband circuit 110 are advantageously used for data recovery of LW digital data and also for GPS digital data.
  • receiver circuit' 100 of the present invention Is sensitive to LW RF signals of approximately -135 dB while using a very low oost, low power, LW receiver circuit and little, if any, required changes of the GPS baseband circuit
  • FIG. 3A illustrates another embodiment 200 of the GPS/LW receiver circuit irr accordance with the present invention.
  • This embodiment does not perform frequency upconversion of the LW analog signal, but rather utilizes a separate RF front-end circuit (or off the self transceiver) for separately generating the LW baseband signal.
  • a common baseband circuit then receives a signal that is time multiplexed between the LW baseband signal and the GPS baseband signal.
  • the GPS receiver path of circuit 200 is analogous to that of circuit 100 and includes GPS antenna 180, GPS saw filter 175 and GPS LNA circuit 170.
  • the output of the RF front-end circuit 115 is a GPS baseband signal of lines 340.
  • the LW receiver path of circuit 200 includes its own RF front-end circuit 325 which generates an LW baseband signal over lines 330.
  • the LW baseband signal may be produced from a commercially available RF transceiver circuit.
  • RF antenna 150 Is coupled to saw filter 145 which Is then coupled to a standard RF receiver circuit 320, as is well known In the art.
  • Receiver circuit 320 provides a 900 MHz analog LW signal to the RF front-end circuit 325.
  • Multiplexer circuit 345 receives the LW baseband signal over lines 330 at one input and also receives the GPS baseband signal over lines 340 at another input.
  • the output lines 235 of the multiplexer 345 are coupled to a common baseband circuit 110.
  • the select input of the multiplexer 345 is controlled by line 350 which toggles between GPS mode and LW mode.
  • GPS mode GPS baseband signal of lines 340 is supplied to circuit 110.
  • LW mode LW baseband signal of lines 330 is supplied to circuit 110.
  • Baseband circuit 110 operates In an analogous fashion to the baseband circuit of receiver 100 and recovers GPS data when in GPS mode and recovers LW data when in LW mode. This digital data can be provided over line 240 to downstream circuitry or used internally.
  • Figure 3B illustrates another embodiment 200' of a GPS/LW receiver circuit in accordance with the present invention.
  • the gain from the signals received directly from the GPS antenna 180 and from the RF antenna 150 can be sufficient to directly feed Into a single RF front end circuit 115. Therefore, the LNA and saw filter circuits 392a and 392b are optional on each of the GPS and LW legs of the circuit 200'.
  • a switoh circuit 396 controlled by a switoh 3 * ⁇ g ⁇ l 394 controls the selection of either the GPS or LW legs
  • the single RF front end circuit 115 can be programmed to tune either GPS or LW frequency according to a tuner signal 390.
  • the single RF front end circuit supplies a time multiplexed baseband signal to the baseband circuit 110 which recovers GPS digital and LW digital signals which are time multiplexed according to the tuner signal 390.
  • This information may be stored in memory.
  • Figure 4 Illustrates " relevant portions of the baseband circuit 110 In accordance with the embodiments of the present invention as shown in Figure 2 and Figure 3A and Figure 3B.
  • Inputs 235 carry time multiplexed baseband signals. During GPS mode, inpute 235 are GPS baseband signals and during LW mode they are LW baseband signals.
  • the baseband signals are supplied to correlator circuits 425 which are controlled by a processor or controller 430. A microprocessor may be used.
  • Microprocessor 430 generates the GPS/LW mode signal over line 350, In one embodiment. It is appreciated that microprocessor 430 may also be located external to circuit 110. Microprocessor 430 controls the operation of the correlators, loads them, resets them, causes them to sequence and checks the results of their counters to despread the baseband signal and recover therefrom the GPS or LW digital data. It is appreciated that the correlator circuitry 425 is shared between the GPS receiver path and the LW receiver path in accordance with embodiments of the present invention.
  • Memory 435 contains firmware code A 435a and firmware code B 435b In accordance with one embodiment.
  • Firmware code A ' is used during GPS mode to control processor 430 and correlator circuits 425 to recover GPS digital data from the GPS- baseband signal using conventional GPS communication protocols.
  • Firmware code B is used during LW mode to control processor 430 and correlator circuits 425 to recover LW digital data from the LW baseband signal using LW communication protocols.
  • LW communication protocols In one embodiment may be analogous to GPS recovery techniques. In another embodiment, LW communication may eliminate much of the GPS protocol overhead that Is otherwise not required for LW data communication and may also reduce the amount of signal repetition used by GPS communication In an effort to optimize LW data communication.
  • Figure 4 also illustrates an exemplary data buffer 440 for storing recovered LW digital data 440a and recovered GPS digital data 440b. This Information may be consumed directly by the microprocessor 430 or provided to optional downstream circuits 410 via bus 240.
  • FIG. 5 illustrates components of the correlator circuitry 425 in more detail.
  • correlator circuits contain multiple commonly clocked shift registers, e.g., register 0510 through register 1612 that are used for despreading. These shift registers are loaded with a locally generated replica of a gold code (e.g., a multi-bit binary number) that matches the gold code of the transmitter.
  • the microprocessor 430 controls the loading of the shift registers.
  • Each shift register presents bits of this gold code in a slightly time shifted manner to a separate XOR circuit, e.g., XOR 0520 through XOR 1522.
  • the XOR circuits also commonly receive the digital baseband signal as input 235 and therefore compare this baseband signal against the time shifted outputs of the shift registers as each locally generated bit is clocked but from the shift register.
  • the XOR circuit responds to differences and generates an output when the two digital signals are not equal.
  • Each output increases the count of a corresponding counter circuit, e.g., counters 530 and 532, which can be read by the microprocessor 430.
  • the microprocessor 430 may also perform demodulation as it may be required for the GPS or LW communication protocols.
  • igure 6 illustrates a flow diagram of a process 600 of receiving GPS
  • the analog RF signal of the local wireless communication path is upconverted so that it can be fed into shared RF front-end and baseband circuitry that are traditionally used only by the GPS receiver path.
  • an RF analog signal is received al a first frequency ⁇ e.g., 900 MHz, and represents LW data.
  • the RF signal is received using an inexpensive, low power, LNA circuit.
  • the LW data may represent wireless communication between two finder devices, between a finder device and a tag, or between two tags, for Instance.
  • this first analog LW signal may be filtered and may be amplified as required.
  • the first analog LW signal Is upconverted to a second frequency.
  • the upconverted signal is a second analog LW signal. In one embodiment, this second frequency matches the frequency used by GPS systems for wireless communication. In one embodiment, this second frequency is 1.57542 GHz. It is appreciated that in cases when the LW frequency is actually higher than the GPS frequency, the up conversion step 620 actually performs a down conversion function.
  • the upconverted or second analog LW signal is then converted to a baseband signal, e.g., by being processed by an RF front end circuit.
  • the baseband signal generated by step 625 is then processed by a GPS baseband circuit which recovers LW digital data therefrom.
  • the GPS baseband circuit may also be used by a GPS receiver path for recovering GPS digital data from a GPS baseband signal that may be time multiplexed with the LW baseband signal (which was generated at step 625).
  • the recovered LW digital data Is stored in a - memory buffer.
  • FIG. 7 illustrates a flow diagram of a process 700 of recovering GPS and LW wireless data In accordance with GPS/LW receiver 100 and GPS/LW receiver 200.
  • process 700 it is assumed that two baseband signals are available, a GPS baseband signal and an LW baseband signal. They can be of the same frequency, e.g., 1.57542 GHz.
  • a common baseband circuit receives a GPS baseband signal in response to a mode signal indicating that the receiver is to recover GPS digital data.
  • the common baseband circuit executes processor instructions, e.g., firmware, in accordance with a well known GPS communication protocol to despread and demodulate the GPS baseband 3lgnal. GPS digital data is then recovered and stored in a buffer memory at step 720.
  • processor instructions e.g., firmware
  • the common baseband circuit receives an LW baseband signal in response to a mode signal indicating that the receiver is to recover LW digital data.
  • the common baseband circuit executes processor instructions, e.g., firmware, in accordance with a communication protocol to despread the LW baseband signal. These instructions may be different from the instructions used to recover the GPS digital data. LW digital data Is then recovered and stored In a buffer memory at step 735.
  • the firmware used at step 7 5 may be the same as the firmware used in step 730 because the recovery of LW digital data follow the GPS communication protocol.
  • the LW transmitter merely encodes the LW data according to the GPS protocol.
  • an optimized communication protocol can be used which eliminates GPS protocol overhead and signal bit repetitions. In such a case, different firmware may be used between step 715 and step 730. The mode signal may switch between these firmware.
  • the GPS signal-recovery programming of the baseband circuit may bo used to reoover looal wireless data from the LW signal.
  • the local wireless data is encoded using substantially the same data encoding format as is used by GPS systems. Therefore, the GPS recovery programming operates sufficiently to recover both GPS data, e.g., from the GPS signal and local wireless data, e.g., from the LW signal. In such case, there is no need to reprogram the signal recovery functions of the baseband circuit between GPS and LW modes.
  • the GPS programmed correlator circuits are used to recover LW data which is encoded using substantially a GPS data format.

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  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
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  • Computer Networks & Wireless Communication (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Position Fixing By Use Of Radio Waves (AREA)

Abstract

La présente invention concerne un procédé et un système permettant d'utiliser un ensemble de circuits de corrélation pour désétaler à la fois de données GPS et des données sans fil local. Dans un mode de réalisation, un signal RF (sans fil local) est reçu à une première fréquence et un signal de bande de base numérique est produit à une seconde fréquence. Un signal GPS est également reçu à la seconde fréquence et un signal de bande de base numérique est produit. Les deux signaux de bande de base sont envoyés à un circuit à bande de base GPS pour permettre la récupération de données. Dans un mode GPS, les données GPS sont récupérées à partir du signal de bande de base par désétalement et démodulation. Dans un mode sans fil local, le circuit à bande de base GPS est programmé pour désétaler et récupérer les données sans fil local. Les données GPS et les données sans fil local peuvent être stockées dans une mémoire tampon en vue d'un traitement en aval. Le partage des circuits de corrélation dans le circuit à bande de base GPS à la fois pour la récupération des données GPS et des données sans fil local permet d'obtenir une unité récepteur bon marché. Dans un mode de réalisation, le signal de bande de base sans fil local est produit par conversion du signal RF sans fil local, puis traitement à travers un circuit frontal RF qui est également utilisé par le signal GPS reçu.
PCT/US2004/023389 2003-07-21 2004-07-19 Dispositif recepteur et procede consistant a utiliser un ensemble de circuits a bande de base gps pour recuperer a la fois des signaux de bande de base gps et des signaux de bande de base sans fil local WO2005019855A2 (fr)

Applications Claiming Priority (4)

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US48913103P 2003-07-21 2003-07-21
US60/489,131 2003-07-21
US10/703,348 US20050101346A1 (en) 2003-11-07 2003-11-07 Receiver device and method using GPS baseband correlator circuitry for despreading both GPS and local wireless baseband signals
US10/703,348 2003-11-07

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WO2005019855A3 WO2005019855A3 (fr) 2005-06-02

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WO2009132252A1 (fr) * 2008-04-24 2009-10-29 Axonn, L.L.C. Réception de données au moyen d’un récepteur gps
EP2878974A3 (fr) * 2013-11-12 2015-10-07 BlackBerry Limited Procédé et système permettant de mettre en oeuvre un récepteur des pseudolites GNSS/M-LMS bibande bimode
US9507010B2 (en) 2013-12-20 2016-11-29 Blackberry Limited Method for improving clock accuracy in a wide area positioning pseudolite receiver system architecture
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WO2024055722A1 (fr) * 2022-09-16 2024-03-21 华为技术有限公司 Équipement terminal

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US9521508B2 (en) 2013-06-19 2016-12-13 Blackberry Limited Architecture and method to 4G-mobile positioning
EP2878974A3 (fr) * 2013-11-12 2015-10-07 BlackBerry Limited Procédé et système permettant de mettre en oeuvre un récepteur des pseudolites GNSS/M-LMS bibande bimode
US9507010B2 (en) 2013-12-20 2016-11-29 Blackberry Limited Method for improving clock accuracy in a wide area positioning pseudolite receiver system architecture
WO2024055722A1 (fr) * 2022-09-16 2024-03-21 华为技术有限公司 Équipement terminal

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