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

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.