Research And Implementation On Non-stationary Communication Jamming Patterns To GPS

Global Positioning System (GPS) plays an important role in modern local warfare. It is of great interest to find effective ways to jam the system. At the same time, as the time-frequency distribution theory has laid a solid foundation for non-stationary signal analysis and generation, this thesis studies on the simulation and implementation of time-frequency distribution based jamming patterns to GPS.Based on the analysis of system architecture, principles and characteristics of synchronous capturing methods in GPS system, this thesis puts emphases on the non-stationary jamming patterns based on Chirplet signal. The main research of this thesis consists of the following three aspects:1. The characteristics of various detection methods for direct sequence spectrum spread communications are analyzed and compared. The synchronous capturing methods in GPS system are studied and the anti-jamming performance of FFT-based approach for PN code fast acquisition is analyzed. The simulation and comparision of the anti-jamming characteristics of this method are given.2. According to GPS signal generating process, on the MATLAB simulation platform of GPS jamming system, a high efficient non-stationary jamming pattern based Chirplet signal is designed, which is of high randomness in time-frequency domain, high peak power, low occupancy and low average power.3. Based on the new jamming pattern, the FPGA implementation is undertaken, thus the base band processing module is improved. The field test is taken to verify the performance of the jamming pattern.