Fault detection and exclusion of cycle slips for carrier-phase in GNSS positionning
Résumé
This paper presents an algorithm of a standalone GPS positioning system that uses both the C/A code and LI carrier-phase measurements. The algorithm is based on a dynamic state vector estimation using Information Filter (IF) and information theory metrics. The GPS carrier-phase measurements suffer from a common error source which is the cycle slips (CS). To solve such a problem, i.e. the detection and exclusion of CS from the positioning algorithm, in this work, we propose to integrate a Fault Detection and Exclusion (FOE) level into the data fusion procedure. The proposed methodology consists of four stages. The first one is the marginalization step that is suitable to add or eliminate an element of state vector. The second stage is the prediction step of the IF. The third stage uses the proposed FOE method to detect and exclude the CS and other errors. At the end comes the update stage (correction stage). Finally, the algorithm is tested using real data acquired with an experimental vehicle using low cost GNSS receivers in order to demonstrate the efficiency and validity of the proposed method.