An improved triple‐frequency cycle slip detection and repair method based on wavelet packet transform and adaptive threshold for BeiDou System satellite

Abstract

Cycle slip detection and repair is one of the key factors of Global Navigation Satellite System carrier phase high precision positioning. Although various methods have been proposed to detect and repair the cycle slip, they are still limited by kinds of factors and the effect is not ideal, especially in real-time triple-frequency high precise positioning applications for BeiDou Systems (BDSs). Traditional methods only improve the algorithm from the detection level, but the observation level and the threshold of detection always be ignored. Research indicates that the noise of observation seriously affects the success rate of cycle slip detection, and the threshold of detection largely depends on the satellite type and data sampling rate. A new triple-frequency cycle slip detection and repair method, based on wavelet packet transform and adaptive threshold strategy, is proposed to detect and repair the cycle slip for real-time BDS triple-frequency positioning applications. The key idea of the proposed method is the use of both the wavelet packet transform and elevation model to mitigate random noise and the satellite-induced code bias from the observation level, and the adaptive threshold strategy to adjust the threshold of detection based on satellite type and data sampling rate in the detection level. Real datasets are collected to evaluate the performance of the proposed method. Experimental results indicated that the proposed method can effectively detect and repair all types of cycle slips, such as single-frequency small cycle slip, large cycle slip, and particular cycle slip, improve the success rate and reliability, and lay a solid foundation for BDS high-precision positioning.