Research On The Key Techniques Of BDS Software Receiver

Beidou navigation satellite system, which can be shorted for Beidou system,or BDS. BDS is a global positioning and communication system that isself-developed by our country. The system can provide accurate and reliablepositioning, navigation and timing services for kinds of users, moreover, itexclusively has the function of short message communication. the merit ofsoftware receiver are incomparable, it can give full play to the role of flexibility,lay the foundations for advancing research to navigation algorithm and acceleratethe pace of the BDS development.In this paper, the main attention is payed on the key techniques of the B1band signal include acquisition and tracking system and the subsequent decodingand demodulation algorithm. In the part of acquisition and tracking, variousacquisition algorithms are comparatively analyzed. First, the real BDS signaliscaptured by combining FFT based on parallel detecting technique and fineacquisition technique. Then the fundamentals of signal tracking are introduced，and the parameters of signal tracking are optimized for better tracking the realBDS signal. In the part of demodulation and decoding, NH code demodulationand BCH checking are conducted, and two checking methods are presented. Onthe basis of ensuring the correctness of the navigation message,the positioningresult is obtained by extracting the content of sub-frames and analyzing theephemeris parameters.Comparing the positioning result and the real position, theerror is in the permissible bounds, which demonstrates the effectiveness of theproposed algorithm.