Abstract: A non-GPS satellite-based system enables correction of a local clock in a user device to facilitate GPS-based location determination.

Abstract: In an apparatus of correcting a clock drift error, a receiver unit receives a first GNSS signal from a satellite. A Doppler correction unit obtains a first predicted frequency. A tracking unit can obtain a first tracked frequency. The satellite-positioning unit determines a clock offset based on a position fix. A computation unit calculates a first difference between the first predicted and tracked frequencies. When the receiver unit is turned off and then on for receiving a second GNSS signal from the satellite, the Doppler correction unit obtains a second predicted frequency, the tracking unit obtains a second tracked frequency, and the computation unit calculates a second difference between the second predicted and tracked frequencies. An error correction unit computes an estimated clock offset according to the clock offset, the first difference, and the second difference.

Abstract: Provided is an apparatus and method for generating a satellite navigation signal, the method including: extracting, navigation data that is a parameter required to generate a navigation message; verifying visible satellites at a current position of a receiver based on a position of the receiver and positions of satellites calculated based on navigation data; calculating a pseudo distance from each visible satellite and a Doppler of each visible satellite; calculating, as a Doppler period, a duration of time corresponding to a Doppler displacement capable of being processed at the receiver; generating a navigation message frame to generate a satellite navigation signal, based on navigation data and a TOW; and generating a satellite navigation signal of a digitized IF for each visible satellite based on the navigation message frame, the pseudo distance for each visible satellite, and the Doppler for each visible satellite during the Doppler period.

Abstract: Systems and methods for calibrating real time clock are provided. A representative receiver includes a GPS device comprising a real time clock (RTC) circuitry that generates RTC clock signals and a temperature compensated crystal oscillator (TCXO) that generates TCXO clock signals. A ratio counter circuitry receives both the RTC clock signals and the TCXO clock signals and determines a frequency ratio by comparing the RTC clock signals and the TCXO clock signals. A computing device receives the frequency ratio and estimates a current RTC frequency based on the received frequency ratio. The computing device is configured to calibrate an estimated RTC time being maintained at the RTC circuitry based on an estimated RTC frequency from a prior estimation, the current RTC frequency and an elapsed time of the RTC circuitry.

Abstract: A method and a terminal for acquiring a frequency difference are disclosed. The method includes acquiring a difference T1 between clock timing before dormancy and clock timing of a base station, recording a dormancy period T between dormancy start and dormancy end, acquiring a difference T2 between clock timing after dormancy and clock timing of the base station, and computing a frequency difference between a low speed clock and a base station clock according to normalization frequencies, T1, T, and T2.

Abstract: In the field of active phase-control antennas, a method is provided for calibrating the phase centre of an active antenna comprising a plurality of sub-elements able to receive a useful signal emitted by a satellite, said calibration being defined as a function of the reception characteristics of a reference signal at the level of each sub-element, said reference signal being emitted by the same satellite on a frequency band substantially equal to the frequency band of the useful signal and whose theoretical reception characteristics are known.

Abstract: Navigation system receiver, and test circuits and methods for determining drift profile of a receiver clock in the navigation system receiver are disclosed. In an embodiment, the navigation system receiver includes a clock source configured to generate a receiver clock for the navigation system receiver and a test circuit. The test circuit is configured to facilitate determination of a drift profile associated with the receiver clock based on detection and tracking of a test signal received by the test circuit, where the test signal comprises at least one continuous wave (CW) signal.

Abstract: A frequency calibration method and a satellite positioning system utilizing the frequency calibration method are disclosed. The frequency calibration method includes the following steps: detecting a plurality of chip state parameters; and determining a frequency drift and a frequency variation of a target signal according to the detected chip state parameters.

Abstract: A low-cost GPS/GNSS receiver receives a satellite signal at an RF frequency (fRF). The GPS/GNSS receiver includes a front end section for receiving the satellite signal and generating a digital complex signal having a first bandwidth, the received satellite signal being converted into a complex signal before digitizing, a signal capturing section for searching for and acquiring the satellite signal, the signal capturing section including a capture memory, a baseband processor for tracking the acquired satellite signal, and a signal splitter coupled to the front end section. The signal splitter splits the digital complex signal into two bandwidths, by generating a narrowband digital complex signal having a second bandwidth substantially smaller than the first bandwidth. The signal splitter provides the narrowband digital signal to the capture memory and the wider first bandwidth digital complex signal to the baseband processor.

Abstract: The present invention relates to a system, and a method for time synchronization with low power consumption and high accuracy. The system comprises a plurality of devices for time synchronization. Each device comprises a GPS receiver, a microprocessor, and an oscillator. The microprocessor generates a drift per second according to the difference between the PPS signal and the clock signal, and calibrates the clock signal constantly according to drift per second. The GPS receiver is turned off when the drift per second is obtained, and then is turned on after a pre-determined time period for updating the drift per second.

Abstract: The invention relates to a method for calibrating an antenna of a receiver of signals (s1, . . . , sN) originating from a plurality of sources, said receiver comprising a plurality of sensors (c1, . . . , cM), characterized in that it comprises the following steps: measurement of a phase shift (dm,n measure) for each of the sensors (c1, . . . , cM) on each of the signals (s1, . . . , sN), determination of at least one attitude value of the antenna, said attitude being defined by a set of coordinates, calculation, for each of the sensors on each of the signals, of a theoretical phase shift (dm,n theoretical) as a function of the attitude of the antenna, from the directions of arrival of the signals, calculation of a bias (?1 sensor m) for each of the sensors from the measured phase shifts (dm,n measure) and from the theoretical phase shifts (dm,n theoretical) of the sensor.

Abstract: A satellite navigation system receiver that includes a counter and a controlling unit is described. The counter may be driven by a reference clock signal having a reference clock frequency. The controlling unit can calculate a correction value indicative of a corrected reference clock frequency by comparing an increment of the counter values during a time period with an increment of the navigation system times during the time period. The controlling unit can generate a calculated navigation system time according to the correction value.

Abstract: Methods and apparatuses are provided for use with mode switchable navigation radios and the like. The methods and apparatuses may be implemented to selectively switch between certain operating modes based, at least in part, a mode-switching test that takes into consideration one or more non-timed test conditions to determine if mode-switching may be enabled.

Abstract: An advanced multiple-beam GPS receiving system is achieved that is capable of simultaneously tracking multiple GPS satellites independently, detecting multiple interference signals individually, and suppressing directional gain in the antenna pattern of each beam in the interference directions. The GPS receiving system can be used for both planar and non-planar receiving arrays, including arrays that are conformally applied to the surface of a platform such as an aircraft. The GPS receiver combines spatial filtering and acquisition code correlation for enhanced rejection of interfering sources. Enhanced gain in the direction of GPS satellites and the ability to shape the beam patterns to suppress gain in the direction of interfering sources make the GPS receiving system largely insensitive to interfering and jamming signals that plague conventional GPS receivers.

Abstract: A non-GPS satellite-based system enables correction of a local clock in a user device to facilitate GPS-based location determination.

Abstract: Methods and systems for stabilizing a GNSS clock by reducing interference are disclosed and may include stabilizing a frequency of a temperature compensated crystal oscillator (TCXO) on a chip in a GNSS device. A clock signal may be generated for the device by temporarily configuring circuitry adjacent to the TCXO at a constant power level. Temperature and electromagnetic interference of the TCXO may be stabilized by the constant power level of the adjacent circuitry, which may be on the chip or external to the chip. The frequency of the TCXO may be stabilized by temporarily disabling the adjacent circuitry. A GNSS clock signal may be stabilized by the configuring of the constant power level while a GNSS location may be calibrated. A GNSS location of a fixed wireless device, such as a wireless access point, may be calibrated utilizing the configured constant power level and shared with other wireless devices.

Abstract: A system comprises a first clock module configured to generate a first clock reference that is not corrected using automatic frequency correction (AFC). A global position system (GPS) module is configured to receive the first clock reference. An integrated circuit for a cellular transceiver includes a system phase lock loop configured to receive the first clock reference, to perform AFC, and to generate a second clock reference that is AFC corrected.

Abstract: A method, device and system for determining a receiver location using weak signal satellite transmissions. The invention involves a sequence of exchanges between an aiding source and a receiver that serve to provide aiding information to the receiver so that the receiver's location may be determined in the presence of weak satellite transmissions. With the aiding information, the novel receiver detects, acquires and tracks weak satellite signals and computes position solutions from calculated pseudo ranges despite the inability to extract time synchronization date from the weak satellite signals. The invention includes as features, methods and apparatus for the calibration of a local oscillator, the cancellation of cross correlations, a Doppler location scheme, an ensemble averaging scheme, the calculation of almanac aiding from a table of orbit coefficients, absolute time determination, and a modified search engine.

Abstract: Dynamic inter-channel bias calibration of a navigational receiver is provided. A reference signal is propagated through front-end circuitry of the receiver. A delay caused by the propagation of the reference signal through the front-end circuitry is measured. The inter-channel bias of the navigational receiver is reduced using the measured delay associated with the front-end circuitry of the receiver.

Abstract: A global navigation satellite system (GNSS) enabled mobile device comprising a crystal oscillator and an automatic frequency correction (AFC) circuit may be operable to share the crystal oscillator between processing of cellular radio signals and processing of GNSS data messages. The GNSS enabled mobile device may be operable to enforce an AFC correction when the crystal oscillator drifts beyond a specific frequency error. The AFC correction may be allowed during time intervals corresponding to GNSS words at which decoding of these words is not required. The GNSS enabled mobile device may be operable to disable the AFC correction during time intervals associated with decoding of words while the crystal oscillator may drift within the specific frequency error range. After the decoding of one or more of words is completed, the AFC correction may be allowed during the time intervals corresponding to these words.

Abstract: Method and apparatus for processing satellite signals from a first satellite navigation system and a second satellite navigation system is described. In one example, at least one first pseudorange between a satellite signal receiver and at least one satellite of the first satellite navigation system is measured. At least one second pseudorange between the satellite signal receiver and at least one satellite of the second satellite navigation system is measured. A difference between a first time reference frame of the first satellite navigation system and a second time reference frame of the second satellite navigation system is obtained. The at least one first pseudorange and the at least one second pseudorange are combined using the difference in time references.

Abstract: A system comprises a Global Navigation Satellite System (GNSS) receiver configured to acquire and track a unique radio frequency (RF) signal for each of a plurality of channels, wherein the GNSS receiver is configured to provide one or more system state measurements based on the unique RF signals; processing functionality configured to calculate a respective code delay error for each of the plurality of channels based on the respective unique RF signal; and micro jump detection functionality configured to calculate an average code delay error across all of the plurality of channels based on the plurality of calculated code delay errors, wherein the micro jump detection functionality is further configured to compare the calculated average code delay error to an error threshold to detect a micro jump event when the calculated average code delay error exceeds the error threshold.

Abstract: A method for determining a Doppler shift of a first signal is provided. First, a plurality of Doppler frequency hypotheses is combined to obtain a joint Doppler signal. The first signal is the correlated according to the joint Doppler signal and a plurality of code signals with phases corresponding to a series of code phase hypotheses to obtain a series of correlation results which are then examined to determine whether the Doppler shift does lie in the Doppler hypotheses. A fine Doppler search is then performed to determine the Doppler shift when the Doppler shift lies in the Doppler hypotheses.

Abstract: A high accuracy satellite signal receiving controller and associated method is provided. The high accuracy satellite signal receiving controller includes a frequency synthesizer, and an analog-to-digital converter (ADC), a Global Positioning System (GPS) receiving module and a control unit. The frequency synthesizer, coupled to an external non-temperature-compensated crystal oscillator (non-TXCO), generates an oscillating frequency signal to the GPS receiving module. The ADC converts an analog temperature signal into a digital temperature signal. The control unit, coupled to the ADC, adaptively updates temperature/frequency offset data.

Abstract: A GNSS receiver design is tested, which design includes software for generating position/time related data (DPT) based on raw digital data (dRAW) when the software is executed in a processing unit of the receiver. GNSS signals (SRF) are received via a radio frequency input device while moving the radio frequency input device along a route trajectory. The received GNSS signals (SRF) are fed to a radio-frequency front end of a representative example of a receiver unit built according to the design to be tested. The radio-frequency front end produces raw digital data (dRAW) representing the received GNSS signals (SRF), and the raw digital data (dRAW) are stored in a primary data storage as a source file (Fsc). The source file (Fsc) is read from the primary data storage, and the source file (Fsc) is processed by means of the software to generate at least one set of position/time related data (DPT).

Abstract: A wireless device including a transceiver that utilizes a power supply is described. The wireless device includes a Global Positioning System (“GPS”) section having a plurality of GPS subsystems and a power controller in signal communication with the power supply and GPS section, wherein the power controller is configured to selectively power each GPS subsystem from the plurality of GPS subsystems.

Abstract: The wireless communication device includes a wireless communication transceiver to generate an oscillator control signal and an activation signal, a positioning-system receiver (e.g. a GPS receiver) to process received positioning signals, and a shared oscillator (e.g. a temperature compensated and voltage controlled crystal oscillator TCVCXO) responsive to the oscillator control signal and to generate a reference frequency signal for the wireless communication transceiver and the positioning-system receiver. The positioning-system receiver may control processing of the received positioning signals based upon the activation signal to reduce a noise contribution (e.g. phase noise) due to frequency control of the shared oscillator based upon the oscillator control signal. The activation signal may indicate that the oscillator control signal is being varied to provide frequency control or adjustment of the shared oscillator.

Abstract: Global Navigation Satellite System (GNSS) pseudorange measurements must be compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications. The problem of pseudorange measurement errors resulting from directionally dependent group delays is not an issue in Fixed Reception Pattern Antenna (FRPA) GNSS sensors. However, for the complex case of a GNSS receiver employing a controlled reception pattern antenna (CRPA) and dynamic beam steering, the multiplicity of combinations of antenna element outputs makes compensation of directionally dependent antenna induced errors more difficult, as the simple subtraction that might be used for FRPA compensation does not work with a CRPA. Example embodiments provide for frequency domain correction of GNSS pseudorange measurements in CRPA receivers.

Abstract: A global navigation satellite system (GNSS) enabled mobile device comprising a crystal oscillator and an automatic frequency correction (AFC) circuit may be operable to share the crystal oscillator between processing of cellular radio signals and processing of GNSS data messages. The GNSS enabled mobile device may be operable to enforce an AFC correction when the crystal oscillator drifts beyond a specific frequency error. The AFC correction may be allowed during time intervals corresponding to GNSS words at which decoding of these words is not required. The GNSS enabled mobile device may be operable to disable the AFC correction during time intervals associated with decoding of words while the crystal oscillator may drift within the specific frequency error range. After the decoding of one or more of words is completed, the AFC correction may be allowed during the time intervals corresponding to these words.

Abstract: Methods and apparatuses are provided for use with mode switchable navigation radios and the like. The methods and apparatuses may be implemented to selectively switch between certain operating modes based, at least in part, a mode-switching test that takes into consideration one or more non-timed test conditions to determine if mode-switching may be enabled.

Abstract: This invention discloses a method for enhancing a Global Navigation Satellite System (GNSS), such as Global Positioning System (GPS), location calculation by supplying carrier phase corrections within a GNSS receiver used with a multiple element Controlled Reception Pattern Antenna (CRPA) receiver. GNSS carrier phase measurements should be compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications. One technique successfully employed in Fixed Reception Pattern Antenna (FRPA) GPS sensors applies a simple directionally dependent set of correction factors to the measurement outputs. For the complex case of a GNSS receiver employing a CRPA and dynamic beam steering, however, the multiplicity of combinations of antenna element outputs makes the FRPA compensation technique impractical. Compensation of carrier phase measurements is a problem not addressed in previous GPS CRPA beam steering sensors.

Abstract: An advanced multiple-beam GPS receiving system is achieved that is capable of simultaneously tracking multiple GPS satellites independently, detecting multiple interference signals individually, and suppressing directional gain in the antenna pattern of each beam in the interference directions. The GPS receiving system can be used for both planar and non-planar receiving arrays, including arrays that are conformally applied to the surface of a platform such as an aircraft. The GPS receiver combines spatial filtering and acquisition code correlation for enhanced rejection of interfering sources. Enhanced gain in the direction of GPS satellites and the ability to shape the beam patterns to suppress gain in the direction of interfering sources make the GPS receiving system largely insensitive to interfering and jamming signals that plague conventional GPS receivers.

Abstract: Embodiments of the invention provide a method of adjusting a bandwidth of receivers. A plurality of outputs from a correlator engine are combined. User dynamics are sensed. Bandwidth of one or more receivers are adjusted. By detecting when the user is stationary, the Doppler frequency estimation can be corrected or the SNR can be boosted more both of which lead to improved performance. The embodiments allow a receiver to process signals in when the signal level would otherwise be too low—for example indoors. The embodiments can improve performance when one or more satellites are temporarily blocked but one or more satellites are still being tracked.

Abstract: A method and apparatus for faster global positioning system (GPS) location using pre-computed spatial location data are described. In one embodiment, a method includes acquiring a pre-computed spatial location of a mobile platform device (MPD) that is computed when a GPS receiver is disabled due to the spatial location of the MPD. In one embodiment, the pre-computed spatial location is determined by a non-GPS based spatial location technology when a receiver is disabled due to the spatial location of the MPD. During the periodic computation of spatial location data, the GPS receiver may be monitored. In one embodiment, in response to activation of the GPS receiver, the pre-computed spatial location data is provided to the GPS receiver for identification and lock onto a predetermined number of visible satellites to reduce a time to first fix (TTFF) a current spatial location of the MPD. Other embodiments are described and claimed.

Abstract: A GNSS enabled handset receives signals from different resources comprising GNSS satellites and/or from a wireless network. The GNSS enabled handset acquires location information comprising various positioning resource data comprising GPS data and/or WiFi data from the received signals. The GNSS enabled handset calculates a plurality of possible position fixes based on the acquired location information using various positioning approaches. A current position fix associated with the GNSS enabled handset is determined based on the plurality of calculated possible position fixes via running a location-based service (“LBS”) client on the GNSS enabled handset. The LBS client determines the plurality of possible position fixes using various positioning approaches in a particular or determined order. Confidence levels for each of the calculated plurality of possible positions are determined and used to refine the current position fix.

Abstract: A method and apparatus for obtaining Global navigation Satellite System (GNSS) time in a GNSS receiver are provided. The following steps are included: obtaining a time relationship between a first clock signal and the received GNSS time; obtaining a first clock value of a second clock signal and an first associated clock value of the first clock signal at a first time point; calculating a first GNSS time corresponding to the first clock value of the second clock signal according to the first associated clock value and the time relationship; obtaining a second clock value of the second clock signal and an second associated clock value of the first clock signal at a second time point; and calculating a second GNSS time corresponding to the second associated clock value, according to the first GNSS time, the first clock value and the second clock value of the second clock signal.

Abstract: A rapidly deployable HF surface wave radar phased array antenna system is provided, including a plurality of separate antenna elements that are relatively movable to desired spaced apart positions, each antenna element including a respective receiver for receiving HF radio signals, wherein, in order to determine and control properties of the radar system, each element includes a GPS receiver for determining the location of each element and for timing and frequency synchronization.

Abstract: Methods and apparatus are presented for improved productivity in determining static position of an antenna of a GNSS rover, such as in stop-and-go surveying. Computer-implemented methods and apparatus provide for determining a static position of an antenna of a GNSS rover from observations of GNSS signals collected at the antenna over multiple epochs and from correction data for at least one of the epochs.

Abstract: Methods and systems are provided for accessing GPS signals in faded environments. Means are provided for predicting the nonlinear phase induced by the receiver's own clock, when there is at least one GPS satellite link strong enough to calculate a phase profile. In an embodiment, GPS signals are accessed in faded environments by increasing the sensitivity of a GPS receiver by increasing the processing gain of received GPS signals through increased integration time. Matching a near-baseband signal requires removing a nonlinear part of the phase which may arise from several sources, including: the phase drift of the GPS satellite's atomic clock, the phase drift due to the motion of the GPS receiver, the phase drift due to the motion of the GPS satellite, and the phase drift due to the GPS receiver's clock.

Abstract: Methods and apparatus are provided for processing a set of GNSS signal data derived from signals of a first set of satellites having at least three carriers and signals of a second set of satellites having two carriers. A geometry filter uses a geometry filter combination to obtain an array of geometry-filter ambiguity estimates for the geometry filter combination and associated statistical information. Ionosphere filters use a two-frequency ionospheric combination to obtain an array of ionosphere-filter ambiguity estimates for the two-frequency ionospheric combinations and associated statistical information. Each two-frequency ionospheric combination comprises a geometry-free two-frequency ionospheric residual carrier-phase combination of observations of a first frequency and observations of a second frequency.

Abstract: An active GPS tracking system and method includes a user setting interface for receiving a reporting distance, a distance trigger module, a GPS module and a wireless communication module. The distance trigger module calculates a moving distance of the active GPS tracking system, and generates and sends an interrupt signals to the GPS module to make it enter a working mode when the moving distance is greater than or equal to the reporting distance. Then, the GPS module determines a current position of the active GPS tracking system and determines whether an actual displacement is greater than or equal to the reporting distance to determine if reporting the current position. If the actual displacement is greater than or equal to the reporting distance, the wireless communication module receives the current position from the GPS module, and reports to a monitor center.

Abstract: A portable user device may provide Global Positioning System (GPS) services. The device may include a GPS receiver. The GPS receiver may provide accurate information about the current location of the device. A user may use the device to perform tasks. Certain tasks may generate excess heat or de-generate heat that causes the GPS receiver to perform unsatisfactorily. Methods are provided that can test GPS receiver performance during acquisition mode and during tracking mode. During testing, the GPS receiver may be given a predetermined amount of time to acquire a GPS fix. The GPS receiver may be tested repeatedly to acquire successive GPS fixes. After a desired number of tests are performed, a success rate may be calculated. If the success rate is satisfactory, the GPS receiver satisfies design criteria. If the success rate is not satisfactory, the GPS receiver may be reconfigured with new settings.

Abstract: A method is provided for determining the validity of a signal received by a GPS receiver. A signal that is unfiltered, either mathematically or electronically, is monitored to determine the variability of different occurrences of the signal. These occurrences, which may be sequential, are compared to each other in order to detect whether or not variation exists between one occurrence of the signal and a subsequent occurrence of the signal. If no variation exists, it is determined that the signal is invalid and that a loss of fix of the satellite signal has occurred. If sufficient variability exists in the signal, between successive occurrences, the signal is deemed to be valid and suitable for use to control a vehicle such as a marine vessel.

Abstract: Embodiments provided herein recite methods and systems for position determination based on hybrid pseudorange solution data. In one embodiment, navigation satellite system (NSS) pseudorange data is received for high yield pseudoranges. In addition, NSS pseudorange data is received for high accuracy pseudoranges. The high accuracy pseudoranges and selected ones of the high yield pseudoranges utilized by a hybrid PVT processor to determine a hybrid NSS-based location solution.

Abstract: Global Navigation Satellite System (GNSS) pseudorange measurements are compensated for receiver hardware and directionally dependent antenna errors to obtain desired accuracies for high precision GNSS positioning applications using a multiple element controlled reception pattern antenna (CRPA). Pseudorange errors are calibrated and stored in a sky map by azimuth, elevation, radio frequency (RF) channel, and frequency. Corrections are applied in real time to each pseudorange measurement by applying a combination of the stored errors. The coefficients of the errors in the combination are computed as a function of steering vectors and CRPA filter weights. This implements a generalized pseudorange correction able to compensate a GNSS CRPA sensor for channel dependent errors such as group delay for both the case of uniform weights for all frequencies and the more complex case of frequency-dependent weights.

Abstract: A method for testing GPS receivers may read GPS files with data for a plurality of GPS satellites, and two or more GPS satellites may be selected from that data. The method may receive parameters for a GPS receiver to be tested. The method may generate two or more GPS signals for the two or more selected GPS satellites. The method may operate on the two or more GPS signals using the received parameters for the GPS receiver to generate two or more calculated GPS signals. These two or more calculated GPS signals may be re-sampled to a common rate. The two or more re-sampled GPS signals may be added together to create a composite GPS signal. The composite GPS signal may be generated using a hardware signal generator, where the composite GPS signal used to test the GPS receiver.

Abstract: Dynamic inter-channel bias calibration of a navigational receiver is provided. A reference signal is propagated through front end circuitry of the receiver. A delay caused by the propagation of the reference signal through the front end circuitry is measured. The inter-channel bias of the navigational receiver is reduced using the measured delay associated with the front end circuitry of the receiver.

Abstract: A system and method of providing a clock signal to a navigation satellite receiver in a device is disclosed. A clock signal generated by a voltage controlled temperature compensated crystal oscillator (VCTCXO) in a cellular engine of the same device is appropriated to clock a numerically controlled oscillator (NCO) programmed to generate an adjusted clock signal suitable for use in receiving signals from navigation satellites and to heterodyne them down to baseband or an intermediate frequency for processing. Preferably, if the cellular engine has an automatic frequency control (AFC) module for adjusting the voltage control input to the VCTCXO to compensate for a change in the operating environment of the cellular engine, the AFC module modifies the control word in the NCO to counteract such adjustment so that the adjusted clock signal provided to the navigation satellite receiver is not unduly impacted.

Abstract: Methods and systems for stabilizing a GNSS clock by reducing interference are disclosed and may include stabilizing a frequency of a temperature compensated crystal oscillator (TCXO) on a chip in a GNSS device. A clock signal may be generated for the device by temporarily configuring circuitry adjacent to the TCXO at a constant power level. Temperature and electromagnetic interference of the TCXO may be stabilized by the constant power level of the adjacent circuitry, which may be on the chip or external to the chip. The frequency of the TCXO may be stabilized by temporarily disabling the adjacent circuitry. A GNSS clock signal may be stabilized by the configuring of the constant power level while a GNSS location may be calibrated. A GNSS location of a fixed wireless device, such as a wireless access point, may be calibrated utilizing the configured constant power level and shared with other wireless devices.

Abstract: A GPS data recording apparatus includes a storage device and a processing circuit coupled to the storage device. The processing circuit comprises: a sampling module, for sampling a GPS data; and a packet processor, for packetizing the sampled GPS data to generate a data packet to be stored in the storage device, and for unpacketizing the stored data packet from the storage device if necessary. According to present invention, GPS data can be recorded and be replayed as necessary.