Clutter Suppression For Target Detection In Three-dimensional Radar

Three-dimensional radar is the sentinel of modern war.In the complex and changeable battlefield environment,how to conceal itself and find the enemy accurately and timely will affect the direction of war.As an important part of radar intelligence network,three-coordinate radar plays an irreplaceable role in target detection and intelligence analysis.Under the premise of maintaining high-precision measurement,it covers a wide range,and has strong anti-interference ability and fast maneuvering ability.However,in the complex geographical,meteorological and electromagnetic environment,the target signal will be submerged in clutter and interference,which makes target detection and tracking target difficult.Therefore,how to effectively suppress clutter is a key technology in radar signal processing.Based on the above analysis,the research of this paper is divided into three parts.Firstly,analyze the characteristics of clutter and target under the three-coordinate radar system.When studying the characteristics of the clutter,it is analyzed deeply from two aspects of time domain and spatial domain.The purpose is to combine the characteristics of clutter and suppress it pertinently when studying clutter suppression methods.At the same time,the characteristics of the target are analyzed.In order to analyze and verify the clutter suppression methods,the clutter simulation is also studied.Secondly,study the suppression methods that are optimized in different ways and aim at the time domain characteristics of clutter.Moving Target Indication(MTI)and Moving Target Detection(MTD)are two methods that are widely used in practical applications to suppress clutter.This article focuses on different filter design methods under different clutter characteristics in time domain.According to the characteristic of zero Doppler frequency of ground clutter,the MTI filter is realized by pulse cancellation,and for moving clutter whose Doppler frequency is not zero,the adaptive MTI filter is designed by feature vector method and zero allocation method,which has good effect.Then the MTD filter of pulse canceller cascaded FFT is studied,which can suppress clutter and improve the target detection ability.In order to improve the filter performance,two FIR filter,namely point optimal filter group and equal interval filter group,are used for optimization.Finally,combining the characteristics of clutter in the spatial domain,this paper proposes a knowledge-assisted adaptive filtering suppression method in the spatial domain.According to the coincidence information between different beams,the Minimum Variance Distortionless Response(MVDR)framework is used to process the signals in the beam domain to achieve the effect of clutter suppression.According to the correlation characteristics of clutter in range domain,the MVDR method based on range domain sampling is adopted,and according to the correlation characteristics of the clutter between different scans,the MVDR method based on cognitive sampling is adopted.In order to further improve the clutter suppression effect,the time domain method and the spatial domain method can be cascaded.