Acquisition And Tracking Technique Research Of Beidou 2nd Nagivation Receiver

Beidou Navigation Satellite System is the global satellite navigation system, researched, developed, and operated by our country. Its goal is to provide the location, navigation, and timing services of high quality. The phase deviation and Doppler frequency offset caused by the relative movement between the satellite and the navigation receiver can influence the navigation location and the timing service accuracy. In order to decrease the effect caused by the relative movement, the navigation receiver can adopt the capture and tracking technology. Therefore, it has a vital practical significance to the capture and tracking technology to the BD2 Satellite Navigation System.According to the above problem, this paper based on Beidou satellite navigation system of ICD files, transceiver simulation model was built based on Simulink. In order to get the better performance and the lower complexity capture and tracking algorithms of BD2 baseband signal have been studied and improved. Finally, by considering the performance and realizability, this paper implement the relevant algorithms on FPGA. The main work and innovations are follows:1. Based on Simulink platform to build BD2 navigation system transceiver.According to the ICD file of Beidou satellite navigation system, this paper introduced the BD2 navigation signal structure, and analysis transceiver and channel for BD2 navigation system, at the same time the corresponding software platform is established, which correct SNR and laid the foundation for subsequent research algorithm.2. Comparative and analysis the baseband capture, tracking algorithm of BD2 navigation system.The acquisition algorithm of BD2 navigation system include the serial search capture based on time, two parallel capture algorithm based on FFT, and the parallel capture algorithm based on PMF-FFT. The PMF-FFT parallel search acquisition algorithm is improved based on the complexity of the algorithm. Finally the above algorithm completes simulation comparison on the software platform.Tracking algorithm of the BD2 navigation system investigate the code phase tracking and carrier tracking algorithm. Firstly, this paper analysis the original algorithm, for carrier frequency tracking algorithm is improved as follows: 1) eliminate the burr, 2) extend the limit of frequency tracking. For two-quadrant arctangent phase tracking algorithm is improved as follows: 1) the loop built-in structure can be converted to the outer structure, 2) a new tracking algorithm namely vector tracing is proposed on the basis of phase tracking. Finally, the tracking algorithm completes on simulation software platform verifying the correctness and superiority of improved algorithm.3. Choose an acquisition, tracking algorithm design the hardware implementation, and FPGA implementation.According to the simulation results, capture choose PMF-FFT, code phase tracking select DLL, carrier frequency tracking use improved FLL+PLL algorithm and design the hardware implementation architecture. This paper presents the implementation of capture and tracking by using Xilinx XC7K70 T chip.The hardware simulation results were compared with the software simulation results verifying the feasibility and correctness of the implementation.