Study on Code Multipath Mitigation Technology for BDS-3 B2a Signal

The construction and development of BDS is divided into three phases: BDS-1, BDS-2, and BDS-3 in sequence. In December 2017, China Satellite Navigation Office published the open service signal B2a transmitted from the BDS space segment to the BDS user segment. The B2a signal is transmitted by the Medium Earth Orbit (MEO) satellites and the Inclined Geosynchronous Satellite Orbit (IGSO) satellites of BDS-3, and provides open services. When the signal is transmitted to the ground, it can be reflected or scattered into the receiver through the ground object. This phenomenon is called multipath. The multipath signal will be attached to the direct signal, and that causes the autocorrelation function to be distorted which causes the error of measuring at the end. This paper introduces the characteristics of B2a signal briefly at first, and then analyzes the Narrow Correlator Spacing Technique, the Early/Late Slope Technique (ELS), the Double-Delta Correlator Technique, and the Code Correlation Reference Waveform Technique (CCRW) for B2a signal. The simulation results show that the W4 waveform of CCRW is the best for the multipath mitigation for B2a signal, and the multipath error envelope is reduced by 67.31% compared with the Narrow Correlator Technique with the infinite bandwidth.