Study Of Target Detection In Sea Clutter Based On Over-The-Horizon Radar

Over-the-horizon radar (OTHR) has far detection range and large covering area. With advantages of anti-low-altitude penetration, anti-stealth aircraft and anti-ARM, OTHR is mainly applied to early strategic warning and remote tactical alert. Since the strong sea clutter has an effect on the signal and the signal received is non-stationary, the thesis studies the target detection methods in sea clutter background based on the principle and characteristic of OTHR.First of all, the thesis analyzes a spectrum simulation model based on the clutter generation principle, and describes four kinds of data models including Rayleigh distribution, lognormal distribution, Weibull distribution and K-distribution according to the sea clutter statistical characteristic. Secondly, the thesis discusses the clutter suppression method based on matrix eigen-decomposition and AR model spectrum estimation method. Simulation results show that the two methods can detect the target signal buried in strong sea clutter. However, OTHR uses long coherent integration time to improve Doppler resolution, thus detection ability can be enhanced in external electromagnetic and strong sea clutter environment. Then, long time integration target detection method based on Hough transform is discussed. Finally, considering the long observation time, the Gaussian white noise background, and the low SNR, this thesis studies the method using short-time Fourier transform, thresholding, morphological filtering in slow maneuvering target detection, the result proves the feasibility of the method above.