A STEP CYCLE SLIP DETECTION AND REPAIR METHOD BASED ON DOUBLE-CONSTRAINT OF EPHEMERIS AND SMOOTHED PSEUDORANGE

摘要

Most cycle slip (CS) processing methods are based on the linear combinations of pseudorange and phase observation, and the gross error on pseudorange can lead to mistakes on the results. From this perspective, a novel method is proposed relying on satellite orbit and smoothed pseudorange, which is divided into two steps: rough and detailed process. During the first process, we calculate and compare the TD (Time Difference) model difference between satellite-to-receiver distance and phase observation to get the systematic error. We use the difference between the predicted and calculated to detect and fix the massive mistake. During the second process, we add -3 to +3 cycles on phase observation which is used to smooth pseudorange by an eliminating ionospheric method, then we search the unique error by validating the ambiguity of WL-MW, L1 and L2, and the difference of smoothed pseudorange and phase observation. Besides, the detectors constructed by ionospheric information of previous epochs are used to test the estimation by LS (least square). The first process can correctly detect and repair the integer error for high sampling rate datasets while limiting it in a small range for low sampling rate datasets. The datasets from IGS (International GNSS Service) with low and high sampling rate are used to verify the proposed method. High sampling rate datasets experiment shows there are only 4 among 640.778 observations from GODN is failed to repair the error when testing 9 stations. Low sampling rate datasets experiment shows that the average success rate of all stations is about 99.56 %. The lowest success rate of L1 and L2 frequency reaches 99.20 % and 99.21 %, respectively of DYNG station, while the highest reaches 99.83 % of both L1 and L2 of HRAO station.