Topcon Positioning Systems, Inc.

Sergey Vladislavovich Averin

Andrey Valerievich Plenkin

Roman Anatolyevich Nevzorov

Mark Isaakovich Zhodzishsky

Ivan Giovanni Di Federico

Raymond M O'Connor

Viktor Abramovich Veitsel

Daniel Milyutin

Vladimir Viktorovich Beloglazov

Mikhail Yurievich Vorobiev

Vyacheslav Viktorovich Lanovets

Danila Svyatoslavovich Milyutin

Alexey Vasilievich Bashaev

Konstantin Viktorovich Ebauer

Andrey Valeryevich Plenkin

Mikhail Arkadievich Mironov

Andrey Andreevich Trofimov

Amir Salikhovich Bakeev

Vladimir Ivanovich Zubinsky

Method for detecting motion of an object using GNSS signals, including (i) measuring distances between a GNSS antenna and GNSS satellites with carrier phases at a first time; (ii) computing distances between known positions of antenna and satellites at first time; (iii) for each satellite, calculating first set of residuals=distances in (i)−distances in (ii); (iv) measuring distances between antenna and satellites with carrier phases at a second time; (v) computing distances between known positions of antenna and satellites at second time; (vi) for each satellite, calculating second set of residuals=distances in (iv)−distances in (v); (vii) differencing first and second sets of residuals; (viii) computing a metric based on set of differences in (vii); (ix) comparing metric to a threshold; (x) based on comparison in (ix), determining if object moved or possibly moved between first time and second time.

Method and apparatus for GNSS-based motion detection

An apparatus for detecting global navigation satellite system (GNSS) spoofing, including a GNSS receiver that includes a first radio-frequency front-end (RF1) connected to antenna 1; a second radio-frequency front-end (RF2) connected to antenna 2; a digital section connected to both RF1 and RF2 and controlled with a single frequency oscillator. The digital section generates a first set of GNSS raw measurements based on signals received from antenna 1; generates a second set of GNSS raw measurements based on signals received from antenna 2; computes single differences between simultaneous raw measurements, generated with the signals received from the antenna 1 and the antenna 2 for the same GNSS satellite; compares the single differences with a threshold; and issues a spoofing alert when more than one of the single differences is below a threshold.

Method and apparatus for detecting GNSS spoofing

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.

Method and apparatus for improving the quality of position determination using GNSS data

A high performance attitude determination system, including a global navigation satellite system (GNSS) receiver, the receiver including a first radio-frequency front-end (RF1) connected to a main antenna; a second radio-frequency front-end (RF2) connected to an auxiliary antenna; and a digital section connected to both RF1 and RF2. The digital section (i) generates a first set of GNSS raw measurements based on signals received from RF1; (ii) generates a second set of GNSS raw measurements based on signals received from RF2; (iii) computes a spatial attitude of a baseline between main and auxiliary antennas, using the first and the second sets of GNSS raw measurements, and based on carrier phase integer ambiguity resolution; (iv) continues updating the spatial attitude using the first and the second sets of GNSS raw measurements without carrier phase integer ambiguity resolution, and using fractional carrier phases. Optionally, RF1 and RF2 use a common clock.

High performance positioning system based on GNSS receiver with multiple front ends

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.

Reducing time and increasing reliability of ambiguity resolution in GNSS

A scintillation caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements is detected. A first input GNSS measurement corresponding to a navigation satellite and corresponding to a first carrier frequency and a second GNSS measurement corresponding to the navigation satellite and corresponding to a second carrier frequency, in which the second carrier frequency is different from the first carrier frequency, are received. A geometry-free combination (GFC) parameter based at least in part on the first input GNSS measurement, the second input GNSS measurement, the first carrier frequency, and the second carrier frequency is calculated. The occurrence of a scintillation caused by an ionospheric irregularity is determined based at least in part on the GFC parameter. In an embodiment of the invention, the dispersion of the GFC parameter over a specified time interval is determined. A scintillation is detected if the dispersion exceeds a specified threshold value.

Detection of scintillations in signals of global navigation satellite systems caused by ionospheric irregularities

An optimum measurement subset with a specified number of elements is generated from a set of input global navigation satellite system (GNSS) measurements. A design matrix and a weight matrix are generated. Values of a set of coefficients corresponding to the set of input GNSS measurements are calculated. The value of a specific coefficient is calculated as the ratio of the change in value of the at least one target parameter resulting from the change in value of the specific input GNSS measurement to the change in value of the sum of squared residuals resulting from the change in value of the specific input GNSS measurement. The optimum measurement subset is selected based at least in part on the values of the set of coefficients.

Selection of a subset of global navigation satellite system measurements based on relation between shifts in target parameters and sum of residuals

Scintillations caused by ionospheric irregularities during Global Navigation Satellite System (GNSS) measurements are detected and mitigated. Detection is based at least in part on statistical properties of geometry-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Mitigation is based at least in part on ionosphere-free combination parameters calculated from input GNSS measurements corresponding to the same navigation satellite and different carrier frequencies. Depending on the number of satellites with detected scintillations, different algorithms are used to calculate values of target parameters from a set of ionosphere-free combination parameters or from a set of ionosphere-free combination parameters and the remaining input GNSS measurements. Different algorithms accommodate stand-alone mode code phase measurements, stand-alone mode carrier phase measurements, differential navigation mode code phase measurements, and differential navigation mode carrier phase measurements.

Mitigation of scintillations in signals of global navigation satellite systems caused by ionospheric irregularities

An optimum measurement subset with a specified number n of elements is generated from a set of N&#x3e;n weighted input global navigation satellite system (GNSS) measurements. A group of trial measurement subsets is generated by removing a different individual weighted input GNSS measurement from the set. A value of accuracy criterion for a target parameter is calculated for each trial measurement subset, and the trial measurement subset with the minimum value of accuracy criterion is selected. A new group of trial measurement subsets is generated by removing a different individual weighted GNSS measurement from the previously selected trial measurement subset. A value of accuracy criterion is calculated for each new trial measurement subset, and a new trial measurement subset with the new minimum value of accuracy criterion is selected. The process is repeated until the selected trial measurement subset has the specified number n of elements.

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Obninsk, Russia

Sergey Vladislavovich Averin