Navigation Receiver Transform Domain Interference Suppression Technology

Recent years, with the rapid development of global satellite position systems, navigation receivers are widely used in various fields all over the world. However, signals of navigation satellite are usually too weak and vulnerable to interference. In this paper, the interference suppression technology of satellite navigation system are studied.The key tasks of this paper are as follows:1. Establish the model of navigation signal and interference signal, and discuss the interference suppression ability of spread spectrum system.2. Analyze the interference suppression ability of navigation receiver with generalized stationary interference and non-stationary interference, and study the relationship between ADC's sampling precision/ quantification SNR and the interference suppression ability of navigation receiver.3. Study the suppression algorithm of non-stationary interference in transform domain. Mainly analyze the algorithm based on the Discrete Fourier Transform. And make corresponding solutions to problems about window-function SNR and fixed capture threshold. Finally, study the feasibility of the method by computer simulation.4. Study the suppression algorithm of non-stationary interference in transform domain. Establish the mathematical model of chirp signal. Study the suppression algorithm of chirp interference based on Short Time Fourier Transform and Fractional Fourier Transform, using time-frequency analysis theory. Finally, study the feasibility of the method by computer simulation.5. According to the analysis of suppression algorithms, the deployment of interference suppression system on FPGA hardware is discussed, which is mainly based on FFT algorithm. Provide the detail structure of the interference suppression system, the input and output signal standard, the interface specification and the composition of every sub-module. Then the specific algorithms and the design processes of each sub-module are discussed in detail, such as FFT/IFFT, windowing, SNR compensation, interference suppression, scaling and digital AGC etc, and make computer simulations to some key modules.6. Make comprehensive tests on the interference suppression system of the anti-jamming receiver in the anechoic chamber. The results show that the interference suppression system can effectively suppress narrowband interference and chirp interference, and its performance meets the design requirements so well.