Gnss Satellite Positioning Signal Processing Technology Research

Global Navigation Satellite System (GNSS) has found broad applications in both military and civil domain, and brought invaluable military, economic and social merit.At first, this thesis introduces the development of the GNSS systems and the principles of the GNSS positioning. Secondly, the signal acquisition technology is studied in the thesis. An improved algorithm is proposed based on the traditional Short Time Matched Filter (SMTF) and Fast Fourier Transform (FFT). The improved algorithm has higher frequency acquisition accuracy with a few more resources. Simulation results show that this algorithm gets better frequency acquisiton accuracy than the tranditional algorithm. Thirdly, the signal tracking technology is presented in the thesis. In the research of code tracking loop and carrier tracking loop, a signal tacking loop is designed and simulated using Matlab. The simulation results show that the designed tracking loop meets with the design requirements. Finally, the narrowband interference suppression technology is studied, and an improved algorithm based on frequency-domain Least Mean Square (LMS) algorithm is proposed in the thesis. By using the weight leakage factor, the method can reduce the loss of the desired signal in filter process. Meanwhile, with the judgment of the weight coefficient stability, the method can effectively suppress variable frequency narrowband interference. Simulation results show that the effectiveness of the proposed algorithm in suppressing the narrowband interferences of both fixed and variable frequency.