GNSS Carrier Phase Anomaly Detection and Validation for Precise Land Vehicle Positioning

A carrier phase anomaly detection and validation method is proposed for precise vehicle positioning in dynamic environments. Given that carrier phase measurement is affected by satellite and user dynamics as well as unexpected anomalies, we propose four sequential processes to detect and identify an anomaly: 1) dynamics separation; 2) anomaly detection; 3) validation; and 4) position domain test. First, terms related to the satellite and user dynamics are estimated individually and removed from the carrier phase measurement to yield an error term, which possibly includes an anomaly and should be detected. The error term is examined with respect to a threshold level, and the measurement values are divided into anomaly candidates and normal candidates. Anomaly candidates are reexamined and validated one-by-one using a normal measurement set and the anomaly is determined. Finally, the position domain is evaluated so that position errors can be used as additional criteria for detecting the anomaly attributed to satellite deployment. The proposed algorithm is verified by simulation analyses and an experimental test. The proposed methods can be effective in detecting anomalies and increasing the reliability of precise vehicle positioning.