LPI Noise Radar Signal Generator

Now. the radar is an indispensably approach to collect information in modern war. It is facing the menace of survival in the environment of electronics countermeasures. The radar with low probability of intercept (LPI) is a new radar system for improving vitality in battlefield. Noise radar is typical LPI radar which has good electronic counter-countermeasure (ECCM) capability and excellent performance of target-detection. So it can be used in many applications, such as surveillance, collision warning. In these applications, it is of paramount importance to generate the noise signal, as its performance has the very tremendous influence on the practical application. This dissertation will discuss the generation of the random signals and noise-FM signal of noise radar by using the high performance digital technique.Firstly, the method for generating the random signal is discussed. Linear feedback shift register and Cellular Automata are used to generate the uniform distribution random signal, and the accumulating method based on central limit theorem is used to generate the Gaussian random signal. Then the performance of the generated signals is analyzed, including the distributing test, autocorrelation function and power spectrum. A conclusion that the peak-to-sidelobe ratio is concerned with the correlation length but not the variance is proved. And then the generation of noise-FM and linear-FM signals by using direct digital synthesis method is studied. Theoretical analysis and simulation results show that noise-FM signal can improve the peak-to-sidelobe ratio by increasing the variance. The randomness of noise-FM signal brings it better LPI performance. Finally, the analog waves from the D/A converter are displayed. The waves prove that the method of noise signal generation is feasible.