Pre-correlation and post-correlation differential acquisition techniques for BDS B1I signal

Due to the fast data bit transitions for B1I signal in BeiDou Navigation Satellite System (BDS), pre-correlation and post-correlation differential acquisition techniques are studied. The techniques reduce the effect of data sign transition. The pre-correlation differential technique eliminates the effect of time-varying Doppler Frequency. In this paper, the technique is improved to reduce the hardware complexity and acquire faster Doppler Frequency. A post-correlation differential technique is analyzed, which has a shorter acquisition time. The simulation results are shown to verify the performance of the methods.