The Research of the High-Altitude BDS Weak Signal Acquisition

Aiming at the application for High-Earth orbit spaceflight navigation, the paper is about the weak BDS signal acquisition on High-Earth orbit. First, this paper achieves the receiving power and Doppler-shift of the High-Earth orbit receiver by simulating the navigation signal characteristic which based on the STK (Satellite Tool Kit). In order to solve the problem of the secondary code witch modulated on BDS B1I and improve the acquisition sensibility, this paper analyses the autocorrelation characteristic of the data which modulated with the NH code, comes up with the resolution of using the alternate half-bit method by combining the coherent integration with the non-coherent integration. The result indicates that it can successfully acquire the -178 dBW BDS B1I signal under the mentioned method.