Twice Acquisition Algorithm of BDS Signal Based on the Secondary Code

Due to the difficult to acquire weak BDS signals, a new algorithm was proposed which combined the hierarchical structure of main code with the secondary coding that adopted in BD. Firstly, a parallel capture was processed in the main code level, and then the secondary acquisition was practiced over the entire secondary coding cycle to wipe off the effect of the secondary coding on the integration time, and to improve the sensitivity of receiver. The experimental results show that the proposed method can improve the ability of signal acquiring and reduce the computational complexity.