Abstract:  Cycle slip detection and repair is an essential part of onboard Global Positioning System (GPS) data preprocessing. In this contribution, the effectiveness of TurboEdit algorithm is firstly analyzed using onboard GPS data observed by Swarm satellite. After that, an improved method is proposed, considering that TurboEdit algorithm can not detect small cycle slips when the observation noise is large. This new method uses carrier phase to smooth combined pseudorange observations and therefore reduces the impact observation noise laid on wide lane ambiguity and improves the capability of cycle slip detection. The method is tested and results show that it can effectively detect and repair small cycle slip.