2016 Volume 29 Issue 1 Pages 18-28
In this paper, we propose methods of detecting Doppler outliers which cause positioning errors at Doppler-aided GNSS (Global Navigation Satellite System) positioning, and correcting the errors. We apply the existing detection method based on the innovation process in Kalman filtering to Doppler outlier problems, and we propose a novel detection method based on the measurements by the difference between C/A code pseudoranges and Doppler shift range-rates. Both methods are based on chi-squared tests. We apply two correction methods which are Doppler bias exclusion,or the estimation for detected anomalies. The efficient detection of anomalous observables can be developed to RAIM (Receiver Autonomous Integrity Monitoring), and useful to achieve higher accuracy positioning for increasing satellite signals by multi-frequencies and multi-GNSSs. Doppler shift observables are utilized on a priority basis even in urban areas because of immunity to cycleslip and continuous availability, however unexpected Doppler outliers prone to cause positioning errors. The experimental results of positioning by using real receiver data show the feasibility of the proposed detection and correction methods.