Abstract:We propose a new method for cycle slip real-time detection and repair using un-differenced dual-frequency GNSS carrier phase observations, based on Melbourne-Wübbena linear combination and Geometry-Free combination. In M-W combination, the combination of weighted according the satellite elevation and moving window averaging is recursively used to calculate the wide-lane ambiguity. Then, the second-order time-difference phase ionospheric residual is used in phase ionospheric residual method. This reduces the influence of ionospheric variations to enable the detection of cycle slips. When the cycle slips are detected, the search method is used to repair cycle slips. The proposed method is tested using static data and dynamic data, the sampling rates are 30 seconds and 1 second recursively. Further, we add some simulated cycle slips in these data, which include big cycle slip and small cycle slip. The results indicate that this method is effective for cycle slip real-time detection and repairing.