Research On The Key Algorithms Of The Base Band Signal Of The Bei Dou Receiver

BeiDou satellite navigation system, which is developed independently by our country, will have the ability to cover the whole world in 2020. However, with the rapid development of China’s aerospace industry, we must realize that our own BeiDou navigation receiver is still in its infancy. For many of the technical difficulties, we have not made a breakthrough, which in a large extent affects the BeiDou navigation satellite applications in various fields. Therefore, we must pay close attention to the design of the user receiver.User receiver design includes many aspects. This paper studies some of the key algorithm of the BeiDou receiver base band signal: Digital Down Converter, Capture and Track. DDC is a basic module of capture and tracking. However, its design has a direct impact on the results of the receiver signal processing. In this paper we introduce its principle, simulation, and the specific implementation of the project. There are many ways to realize the Digital Down Conversion. In this paper, we use the CORDIC algorithm to do the simulation analysis and engineering implementation. To determine the BeiDou navigation satellite signal and the parameters need to be done by the BeiDou satellite signal capture. Predecessors have developed many methods. Based on the analysis of these basic algorithms, this paper uses the method of matched filter and the detection of Tang to realize the capture of the BeiDou satellite signal. This method is simple, of less computation, and of less time. It can not only meet the requirements of the user of the receiver time, but also reduce a lot of hardware and software resources. Capture is only a rough estimate of the BeiDou navigation satellite signal. To obtain more detailed satellite signal parameters, we must pass the tracking loop. Predecessors also introduced a lot of ways of the tracking loop design. In order to cater for the conditions of high dynamic and accurate tracking satellite signals, in this paper we use 3-step FLL and 4-step PLL in carrier tracking loop and 2-step DLL in code tracking loop to tracke Beidou navigation satellite signals.All designs of this paper are based on the study of the theory of MATLAB. They reached the expected purpose through verification. I expecte to provide a good foundation of reference for BeiDou satellite navigation receiver.