Research on the Performance of Cross-Frequency Doppler-aided Beidou MEO B2b Signal Demodulation

The high message broadcast rate of the BDS-3 MEO satellite B2b signal leads to poor carrier phase tracking performance, limiting its navigation message demodulation capability. In contrast, the Beidou B1C and B2a signals incorporate pilot components free from navigation message modulation, resulting in superior tracking performance. This paper proposes a cross-frequency Doppler-aided method to improve B2b signal demodulation by leveraging pilot signals from other frequencies. After applying cross-frequency Doppler aiding, the carrier phase tracking threshold for the B2b signal is reduced, and tracking accuracy is enhanced, thereby improving demodulation performance. Simulation and field measurements demonstrate a 1 dB improvement in B2b signal demodulation performance when aided by pilot signals.