LeGNSS-Based Cycle Slip Detection Method for High-Precision PPP

Low earth orbit (LEO)-enhanced global navigation satellite systems (GNSSs) (LeGNSSs) have emerged as a promising paradigm for next-generation precise point positioning (PPP). However, the highly dynamic nature of LEO satellites results in significant ionospheric variations with more frequent cycle slips. Thus, identifying fractional cycle slips and evaluating false alarms present significant challenges. In this paper, we propose an ionospheric preprocessing generalized combination (IPGC) method to improve the reliability of cycle slip detection. The ionospheric delay in the carrier phase is mitigated using the NeQuick model. Additionally, a set of specifically designed coefficients is used to combine LEO and GNSS observations, which increases the sensitivity of cycle slip detection. The simulation results indicate that the proposed method can effectively eliminate ionospheric interference of up to 4 cycles in LEO satellite cycle slip detection and can accurately detect all combinations of cycle slips with a maximum deviation of 0.14 cycles. Compared with solutions without cycle slip repair, this method accelerates the positioning convergence time by 0.96/0.89/1.2 min on the north/east/up (NEU) components, and the reconvergence efficiency is increased by factors of 10, 5.5, and 2, respectively. Even with an elevated cutoff angle of 40∘, the system achieves centimeter-level positioning accuracy (0.38/1.08/1.86 cm). These results confirm the effectiveness of the proposed method in LEO satellite cycle slip detection, providing key algorithmic guidance for the practical implementation of PPP in hybrid constellation systems.