Tracking Loop Distortion of BDS-3 B1C Signal in Spoofing Scenarios: An Experimental Analysis

Abstract

An experimental analysis method for the correlation peak distortion of the BeiDou-3 satellite navigation system (BDS-3) B1C signal is proposed to address the gaps in existing research—lack of experimental validation and insufficient insights into tracking loop distortion mechanisms under spoofing. First, the autocorrelation characteristics of the B1C signal under narrow band (NB) and wide band (WB) tracking modes were analysed based on its modulation characteristics. A feeder-based BDS spoofing experimental platform was constructed to accurately simulate real-world spoofing scenarios and collect high-fidelity intermediate frequency (IF) data. Multi-correlator tracking outputs were utilised to quantify the distortion effects of spoofing types and tracking modes on the B1C tracking loop. Experimental results revealed three key findings: (1) during spoofing takeover, the combined correlation peak oscillates at high frequency (spoofing as reference, residual true signal as amplitude); (2) under position spoofing, correlation peak pulling direction/rate vary by satellite; under time spoofing, the pulling is consistent across satellites; (3) WB tracking offers higher ranging accuracy than NB tracking but is more susceptible to spoofing-induced pulling and exhibits a more complex correlation peak distortion. These results provide a theoretical and experimental basis for the design of BDS-3 anti-spoofing algorithms and equipment optimisation.