Based Under-sampling Of The Low Signal To Noise Ratio And Ultra-wideband Linear Frequency Modulated Radar Signal Parameters Are Estimated

As a frequently used and important radar signal form, ultra-wideband LFM (linear frequency-modulated) signal has become a hot topic among many experts. And the research work focused on detection and reception of ultra-wideband LFM signal also becomes more and more important. However, Nyquist's theory points out that, the sampling frequency must be at least two times as the maxmum of signal frequency in order to re-display the signal without any distortion. Therefore, it's difficult for ultra-wideband LFM signal to live up to Nyquist's theory. Bandwidth and on-time processing becomes two problems of ultra-wideband signal processing. Sub-sampling is one good way to solve such problems however brings with it frequency distortion. How to give an excellent estimation of the initial-frequency and modulation ratio of low signal-to-noise rate LFM signal based on sub-sampling is the focus of the research work of this paper.Focused on the characteristics of the LFM signal, three different parameter estimation methods are given in this paper. Based on the old methods, some further developments are also given. And simulation results are presented. The results proved that the methods are efficient.Generally, a nice idea and method are proposed for radar signal processing. Meanwhile, there is still a lot of work worth further research with great effort.