Topcon Positioning Systems, Inc.

Daniel Milyutin

Ivan Giovanni Di Federico

Raymond M O'Connor

Andrey Valerievich Plenkin

Sergey Vladislavovich Averin

Mark Isaakovich Zhodzishsky

Victor Andreevich Prasolov

Alexey Stanislavovich Lebedinsky

A global navigation system includes a first navigation receiver located in a rover and a second navigation receiver located in a base station. Single differences of measurements of satellite signals received at the two receivers are calculated and compared to single differences derived from an observation model. Anomalous measurements are detected and removed prior to performing computations for determining the output position of the rover and resolving integer ambiguities. Detection criteria are based on the residuals between the calculated and the derived single differences. For resolving integer ambiguities, computations based on Cholesky information Kalman filters and Householder transformations are advantageously applied. Changes in the state of the satellite constellation from one epoch to another are included in the computations.

Detection and correction of anomalous measurements and ambiguity resolution in a global navigation satellite system receiver

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

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.

Selection of a subset of global navigation satellite system measurements based on prediction of accuracy of target parameters

The present invention proposes a digital system and method of measuring (estimating) non-energy parameters of the signal (phase, frequency and frequency rate) received in additive mixture with Gaussian noise. The first embodiment of the measuring system consists of a PLL system tracking variable signal frequency, a block of NCO full phase computation (OFPC), a block of signal phase primary estimation (SPPE) and a first type adaptive filter filtering the signal from the output of SPPE. The second embodiment of the invention has no block SPPE, and NCO full phase is fed to the input of a second type adaptive filter. The present invention can be used in receivers of various navigation systems, such as GPS, GLONASS and GALILEO, which provide precise measurements of signal phase at different rates of frequency change, as well as systems using digital PLLs for speed measurements.

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Moscow, Russia

Daniel Milyutin