Abstract: GNSS receiver which includes RF front end, connected to GNSS antenna, an ADC converting the satellite signals into digitized signals, a digital section, including a processor receiving the digitized signals, forming raw measurements with pseudoranges measured between the antenna and satellites, and estimating target parameters, including receiver position and receiver time offset by (i) extrapolating the target parameters from previous epoch to current epoch using a dynamic model; (ii) computing a quasi-measurement for each satellite based on extrapolated target parameters and GNSS satellite positions; (iii) detecting and rejecting raw measurements with anomalous errors by testing differences between the raw measurements and respective quasi-measurements against predefined thresholds; (iv) substituting quasi-measurements for rejected raw measurements; (v) estimating target parameters using unrejected raw measurements and substituted quasi-measurements; (vi) outputting estimated target parameters.

Abstract: GNSS receiver which includes RF front end, connected to GNSS antenna, an ADC converting the satellite signals into digitized signals, a digital section, including a processor receiving the digitized signals, forming raw measurements with pseudoranges measured between the antenna and satellites, and estimating target parameters, including receiver position and receiver time offset by (i) extrapolating the target parameters from previous epoch to current epoch using a dynamic model; (ii) computing a quasi-measurement for each satellite based on extrapolated target parameters and GNSS satellite positions; (iii) detecting and rejecting raw measurements with anomalous errors by testing differences between the raw measurements and respective quasi-measurements against predefined thresholds; (iv) substituting quasi-measurements for rejected raw measurements; (v) estimating target parameters using unrejected raw measurements and substituted quasi-measurements; (vi) outputting estimated target parameters.

Abstract: A method and apparatus are provided for processing navigation signals with improved stability in a multi-frequency, multi-system environment. Satellite signals, which are transmitted by a plurality of satellites from a plurality of different global navigation satellite systems, are received on a common radio path and processed in separate digital satellite channels, with each of the separate digital satellite channels corresponding to a respective satellite signal. A common quartz-locked-loop (QLL) discriminator signal is generated based on correlation signals from each of the separate digital satellite channels. Based on the common QLL discriminator signal, guiding signals are generated, with each of the guiding signals corresponding to a respective one of the separate digital satellite channels, for reducing phase-related tracking errors in the respective satellite signal processed in its corresponding digital satellite channel.

Abstract: A method and system are provided for estimating the g-sensitivity of a quartz oscillator, which includes rotating the quartz oscillator successively around each of a plurality of axes constituting a full-rank system, measuring a frequency of the quartz oscillator at a predetermined rate as a function of time during rotation, and estimating an integral g-sensitivity vector while the quartz oscillator is rotated. Estimation can be performed utilizing a data fitting and estimation model, e.g., a Least Square Method (LSM) in one example, using the frequency measurements obtained while the quartz oscillator is in rotation around the axes. The method and system are especially useful for measuring g-sensitivity of quartz oscillators that are incorporated in high-precision systems, such as navigation receivers, which operate in environments that are subjected to vibrational effects and other mechanical forces.

Abstract: A method and system are provided for estimating the g-sensitivity of a quartz oscillator, which includes rotating the quartz oscillator successively around each of a plurality of axes constituting a full-rank system, measuring a frequency of the quartz oscillator at a predetermined rate as a function of time during rotation, and estimating an integral g-sensitivity vector while the quartz oscillator is rotated. Estimation can be performed utilizing a data fitting and estimation model, e.g., a Least Square Method (LSM) in one example, using the frequency measurements obtained while the quartz oscillator is in rotation around the axes. The method and system are especially useful for measuring g-sensitivity of quartz oscillators that are incorporated in high-precision systems, such as navigation receivers, which operate in environments that are subjected to vibrational effects and other mechanical forces.

Abstract: System for estimating carrier phases, including a receiver that receives radio signals from satellites; the radio signals are converted into digital signals; a plurality of channels, each including a correlator receives digital signals and outputs (I, Q) components for one satellite; a reset accumulator that receives (I, Q) components, accumulates them over multiple cycles of a pseudorandom code and outputs accumulated (Is, Qs); a discriminator that generates a tracking error signal; a CCLF (common controlled loop filter) receives the tracking error signal and outputs a frequency control signal and a phase control signal; NCO receives the frequency and phase control signals, and outputs a reference signal. CCLF also receives correction signals based on the radio signals due to shock, vibration or acceleration. NCO control signals depend on the correction signals due to a change in an effective bandwidth of the CCLF to reduce coordinate measurement dynamic distortions.

Abstract: A method and a receiver apparatus allows obtaining accurate estimates of motion parameters of a mobile receiver, including smoothed estimates of total coordinates increments relative to its initial position, projections of velocity vector and acceleration vector. High estimation accuracy is achieved by filtering the biased or unbiased estimates of total coordinate increments relative to the receiver's initial position using smoothing tracking filters of a 2-nd or 3-rd order.

Abstract: System for estimating carrier phases, including a receiver that receives radio signals from satellites; the radio signals are converted into digital signals; a plurality of channels, each including a correlator receives digital signals and outputs (I, Q) components for one satellite; a reset accumulator that receives (I, Q) components, accumulates them over multiple cycles of a pseudorandom code and outputs accumulated (Is, Qs); a discriminator that generates a tracking error signal; a CCLF (common controlled loop filter) receives the tracking error signal and outputs a frequency control signal and a phase control signal; NCO receives the frequency and phase control signals, and outputs a reference signal. CCLF also receives correction signals based on the radio signals due to shock, vibration or acceleration. NCO control signals depend on the correction signals due to a change in an effective bandwidth of the CCLF to reduce coordinate measurement dynamic distortions.

Abstract: A system for estimating carrier phases of radio signals in a satellite navigation system receiver for coordinate determination includes a complex of reference signals (CRS), wherein, in each jth satellite channel, a digital reference signal RefSigj, represents an output phase and frequency-controlled oscillation of a corresponding numerically-controlled oscillator (NCOj) for each jth satellite channel, the phase of the oscillation of the NCOj tracking a carrier signal received from the jth satellite; and an adaptation complex (AC) that, in response to vibration or movement of the receiver, changes (expands or reduces) an effective bandpass of the CRS, producing control signals that determine phase and frequency changes in the corresponding NCOj for reducing dynamic distortions in coordinate measurements.

Abstract: A method and a receiver apparatus allows obtaining accurate estimates of motion parameters of a mobile receiver, including smoothed estimates of total coordinates increments relative to its initial position, projections of velocity vector and acceleration vector. High estimation accuracy is achieved by filtering the biased or unbiased estimates of total coordinate increments relative to the receiver's initial position using smoothing tracking filters of a 2-nd or 3-rd order.

Abstract: A first plurality of differences (first differences or second differences) of carrier phase measurements of global navigation satellite system (GNSS) signals corresponding to a first measurement epoch is received. A plurality of differences of carrier phase ambiguities of the first plurality of differences of carrier phase measurements is resolved. A first fixed position of the rover is computed. A first plurality of sub-corrections is computed based at least in part on the first fixed position of the rover, a position of the base, a position of each specific GNSS satellite, and the first plurality of differences of carrier phase measurements. The first plurality of sub-corrections is then used to reduce the processing time for ambiguity resolution of carrier phase measurements in subsequent measurement epochs. The sub-corrections can be smoothed, aged, or smoothed and aged.

Abstract: A system for estimating carrier phases of radio signals in a satellite navigation system receiver for coordinate determination includes a complex of reference signals (CRS), wherein, in each jth satellite channel, a digital reference signal RefSigj, represents an output phase and frequency-controlled oscillation of a corresponding numerically-controlled oscillator (NCOj) for each jth satellite channel, the phase of the oscillation of the NCOj tracking a carrier signal received from the jth satellite; and an adaptation complex (AC) that, in response to vibration or movement of the receiver, changes (expands or reduces) an effective bandpass of the CRS, producing control signals that determine phase and frequency changes in the corresponding NCOj for reducing dynamic distortions in coordinate measurements

Abstract: A first plurality of differences (first differences or second differences) of carrier phase measurements of global navigation satellite system (GNSS) signals corresponding to a first measurement epoch is received. A plurality of differences of carrier phase ambiguities of the first plurality of differences of carrier phase measurements is resolved. A first fixed position of the rover is computed. A first plurality of sub-corrections is computed based at least in part on the first fixed position of the rover, a position of the base, a position of each specific GNSS satellite, and the first plurality of differences of carrier phase measurements. The first plurality of sub-corrections is then used to reduce the processing time for ambiguity resolution of carrier phase measurements in subsequent measurement epochs. The sub-corrections can be smoothed, aged, or smoothed and aged.

Abstract: A navigation receiver operating in a differential navigation mode can change from one solution type to another. At each epoch, primary estimates of coordinates and the solution type are received. Each solution type has a corresponding accuracy. To improve the positioning quality when the solution type changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. Two conditions are evaluated. If both conditions are satisfied, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases. If at least one of the conditions is not satisfied, updated smoothed estimates of coordinates are generated based on the sum of the current-epoch extended estimates of coordinates and a correction signal.

Abstract: A navigation receiver operably coupled to an antenna can determine location by receiving and processing radiofrequency navigation signals from global navigation satellites. The navigation receiver includes a quartz crystal oscillator that serves as a reference frequency source for a local oscillator signal that is mixed with the radiofrequency navigation signals to generate intermediate signals at intermediate frequencies lower than the radiofrequencies. In particular applications, the quartz crystal oscillator and the antenna are subjected to vibration and shock. A shift in the frequency or phase of the intermediate signals can result, and performance of phase-lock loops can degrade. Performance is improved with a phase-lock loop that processes a combination of individual channel control signals and common control signals.

Abstract: A navigation receiver operating in a differential navigation mode transmits primary estimates of coordinates with an accuracy estimate that can vary during operation. To improve the positioning quality when the accuracy estimate changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. The current-epoch accuracy estimate is compared to a current-epoch value of threshold accuracy. Upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases.

Abstract: A navigation receiver operably coupled to an antenna can determine location by receiving and processing radiofrequency navigation signals from global navigation satellites. The navigation receiver includes a quartz crystal oscillator that serves as a reference frequency source for a local oscillator signal that is mixed with the radiofrequency navigation signals to generate intermediate signals at intermediate frequencies lower than the radiofrequencies. In particular applications, the quartz crystal oscillator and the antenna are subjected to vibration and shock. A shift in the frequency or phase of the intermediate signals can result, and performance of phase-lock loops can degrade. Performance is improved with a phase-lock loop that processes a combination of individual channel control signals and common control signals.

Abstract: A navigation receiver operating in a differential navigation mode transmits primary estimates of coordinates with an accuracy estimate that can vary during operation. To improve the positioning quality when the accuracy estimate changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. The current-epoch accuracy estimate is compared to a current-epoch value of threshold accuracy. Upon determining that the current-epoch accuracy estimate is greater than or equal to the current-epoch value of threshold accuracy, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases.

Abstract: A navigation receiver operating in a differential navigation mode can change from one solution type to another. At each epoch, primary estimates of coordinates and the solution type are received. Each solution type has a corresponding accuracy. To improve the positioning quality when the solution type changes, smoothed estimates of coordinates are generated according to a two-branch algorithm. Two conditions are evaluated. If both conditions are satisfied, the current-epoch smoothed estimates of coordinates are set equal to the current-epoch extended estimates of coordinates calculated from the sum of the previous smoothed estimates of coordinates and coordinate increments calculated from carrier phases. If at least one of the conditions is not satisfied, updated smoothed estimates of coordinates are generated based on the sum of the current-epoch extended estimates of coordinates and a correction signal.

Abstract: The energy potential of a receiver receiving signals from a navigation satellite is calculated according to an algorithm which is a function of an estimate of the mean and an estimate of the variance of a correlation signal. Improving the accuracy of measuring the energy potential may be achieved by improving the variance estimate. The variance estimate may be determined from measurements of the correlation signal over long time intervals during operation of the receiver. The variance estimate may also be determined during a calibration procedure, or by mathematical modeling of the receiver.