A Novel Fine Doppler Frequency Acquisition Algorithm For Bds-3 B1c Signal Based On An Adaptive Filter

Fine Doppler frequency estimation has an important role in accelerating the convergence of the tracking loop in a global navigation satellite system (GNSS) receiver to achieve short time to first fix. BDS-3 started broadcasting a civil B1C signal to provide open services for global users, which is beneficial for GNSS-based applications. Therefore, a fine Doppler frequency acquisition algorithm based on an adaptive filter is proposed, whose purpose is to acquire the BDS-3 B1C signal Doppler frequency accurately after the completion of coarse acquisition. The proposed algorithm is based on a first-order complex-coefficients adaptive filter. The adaptive filter depends on the proposed adaptation algorithm to track the input BDS-3 B1C signal. An accurate Doppler frequency estimate is extracted. Simulation results show the proposed algorithm has high acquisition sensitivity, high acquisition accuracy, short acquisition time, and few hardware resources consumption, and also works well under many different coarse acquisition strategies. Overall, the proposed algorithm is better than the generic second-order frequency locked loop. Consequently, the proposed algorithm has high practical value.