Semi-bit frequency compensation differential combining post-correlation processing for GNSS weak signal environment

Weak signal acquisition attracts global attention in GNSS research. Coherent losses caused by bit flipping lead to acquisition difficulty for traditional methods. An optimized semi-bit frequency compensated differential post-correlation processing is proposed through analyzing problems of the conventional differential post-correlation processing in this paper. The impact of data flipping is eliminated by the semi-bit time control logic, and the processing loss of carrier estimation error is improved by the carrier frequency compensation circuit. Theoretical analysis and simulation results show that the improved differential coherent accumulation technology can significantly improve the environment of weak signal detection probability of GNSS signals.