Analysis and Application of Secondary Code in BDS

The Chinese Bei Dou Navigation Satellite System Signal (BDS) [1] and the modernized GNSS take along a feature of the new modulations is the presence of two channels which is consist of the data and pilot components. The specific structure promoted by secondary codes and the presence of data/pilot channels. However, thanks to the new tiered code, it limits the coherent integration time for acquisition, in order to extend the coherent integration time, relative signs between subsequent portions of the incoming signal have to be estimated and used to remove the effect of sign transitions. To solve the problem the traditional algorithm like tree-based acquire technique suffers a high computational complexity. The paper demonstrates a new algorithm to acquire the BDS signal with a low complexity. The proposed algorithms are simulated in terms of the performance of a software defined receiver.