Research On Step-Chirp Signal And Time Frequency Analysis

It is a new tendency of SAR (Synthetic Aperture Radar) to adopt ultra wideband signals to obtain high resolution. Moving Target Detection is one of the basic functions of modern radar. In order to maintain high imaging resolution and detect sensitively the moving targets and get their accurate position, signal processing is indispensable. It goes without saying that signal processing is the one of the most important subjects in the area of radar and is of great importance for the application of modern radars.This paper focuses on the application of time frequency analysis in the area of radar signal processing, introducing the basic theory and the lately development of time frequency analysis for the use of radar signal detection, filtering and parameters estimation by the way theoretical evolution and MATLAB simulation. From the difficulty encountered when using singular value decomposition (SVD) to separate random noise away from LFM (linear frequency modulation), this paper start a deep research on the application of time frequency analysis, ambiguity function and fractional Fourier transform in radar signal processing based on LFM.To sum up, there are some original and innovative points as follows:1. Analyze the influence of random phase error on pulse compressing of LFM and put forward a SVD and rotation of Ambiguity Function to remove the noise or better the compressing effect.2. Combine Radon-Ambiguity transform, Ambiguity Function and Hough transform to detect multi-component LFM and estimate its parameters with simulations. This method can be applied to movingtargets detection and imaging.3. Analyze in detail the application of fractional Fourier transform in the detection of LFM from strong background random noise and signal parameters estimation. At the end, simulations are presented to confirm the use of fractional Fourier transform in filtering and moving targets detection.