Abstract
In this paper, we present a method of detecting abnormal measurement data due to cycle slips and multipath in GNSS (global navigation satellite system) for RTK-PPP (real time kinematic - precise point positioning), based on GR (GNSS Regressive) models. After detecting the received signals with cycle slips and multipath from the GNSS satellites, we exclude psuedoranges data for multipath and re-estimate the integer ambiguity included in L1 or L2 carrier phase for cycle slips, for maintaining the accuracy of GNSS positioning. We present two methods of detecting cycle slips. The first method is based on statistical testing of the innovation process and the second method is using difference between successive-time estimates of integer ambiguities, with applying the Kalman filter. Finally we present the experimental results using real GPS observables in the automobile and show the feasibility of detecting cycle slips and multipath by our method proposed in this paper.
