Real-time cycle slip detection and repair for BDS-3 triple-frequency and quad-frequency B1C/B1I/B3I/B2a signals

Abstract

This paper presents a real-time cycle slip detection and repair strategy for the BDS-3 triple-frequency and quad-frequency phase observations. For the triple-frequency phase observations, two EWL code-phase combinations and one GF-phase combination are jointly employed to detect and repair cycle slips. Based on the different performances in the success of cycle slip detection and repair, this paper uses GF-phase combinations to detect and repair cycle slip individually. Specifically, the GF-phase combination with a large MTIV value is applied to detect cycle slip possessing the stronger ability to resist ionospheric delay. Besides, the GF-phase combination with a higher success rate of cycle slip repair is selected to repair cycle slip, and the classic LAMBDA method and Ratio test are implemented to fix the cycle slip solution and evaluate reliability separately. For the quad-frequency phase observations, we employ a supernumerary EWL combination based on the triple-frequency, which can directly determine the cycle slip value of the 4th frequency. The results show that the cycle slip estimation value still can detect and repair all real and artificially added cycle slips even under harsh conditions. Moreover, the overall cycle slip repair success rate is greater than 99.99 %.