Research And Implementation Of Beidou Signal Capture Method Based On FPGA

With the sustaining development of Beidou satellite navigation system (BDS), it has been officially come in to use. BDS realizes receive type of position and passive way of position that offer the most accurate and reliable positioning, navigating and timing services. Therefore, it is of great significance to research and analyze the Beidou signals, which also push the development of satellite navigation industry of our country, especially.The core function of navigation receiver is to acquire Beidou signals. The thesis is to mainly research the acquisition algorithm for Beidou signals. At first, it gives an introduction on the geometric principle of satellite position and basic principles of signal acquisition algorithm. It also introduces three universal type of algorithm: serial capture algorithm, the parallel algorithm for maximum likelihood and the parallel algorithm based on FFT theory, analyzes and compares the characteristics among them as well. The traditional serial capture algorithm is being improved, which processes code phase to parallel research. The efficiency of signal capturing is highly increased.Then, we build the hardware system of Beidou receiver. It not only creates the basis for acquisition algorithm, but also provides hardware for researching Beidou receiver. Finally, the whole acquisition system is divided into carrier generator module, ranging code generator module, the data sampling module, Threshold judgment and initial phase calculation module, digital correlator and so on by function on the basis of chosen algorithm, according to the principle of modular design. We also design and simulated analyze each sub module separately. The system design and simulation is finished based on FPGA. The online test is processed for the whole system by analyzing the acquired Beidou satellite signal data, which proves the correctness and feasibility of algorithm.The acquisition system the thesis researched has the ability to capture Beidou signal in fast speed, which meets the requirement of project design.