An Novel Beidou Weak Signal Acquisition Method in Obstructed Environments

Signal acquisition is a critical step in the BeiDou satellite navigation system. In obstructed environments such as forest canopies or deep valleys, signals are often weakened due to multipath fading and shadowing effects, compounded by random noise. Traditional fixed-threshold detection methods struggle to achieve reliable acquisition under these conditions. To address this, a threshold-adaptive differential coherent accumulation algorithm is proposed in this paper. Firstly, based on the parallel phase acquisition algorithm, the proposed approach integrates a circular shifting algorithm and a differential coherent integration module. Furthermore, a noise power-based adaptive threshold detection method is introduced for decision making. MATLAB simulations and field tests in forest-obstructed environments demonstrate that the proposed algorithm significantly improves computational efficiency and signal acquisition probability compared to the parallel phase acquisition method.