Clutter Suppression Method Based On Sparse Representation

Radar is an electronic device that detects the spatial position of targets by radio.However,because the target is in a complex natural environment,the objects in the environment will scatter the electromagnetic waves emitted by the radar,so as to interfere with the search and detection of the target signals.It can be seen that it is very important for radar signal processing to establish radar clutter model correctly and adopt effective algorithm to suppress it.In recent years,with the rise of the sparse representation theory,a new idea and method for radar clutter cancellation is provided.For the sparse representation of radar signal,it is necessary to analyze the sparsity of the radar echo first.In general,the target is only distributed in a limited number of range units,and the clutter is distributed in a wide range,so the target signal is naturally sparse relative to the clutter component in the environment after the distance dimension compression processing,which satisfies the precondition of applying the sparse representation theory.In this dissertation,firstly,the working environment of radar is introduced,and the importance of clutter modeling,simulation and cancellation is pointed out.Secondly,the transmitting signal and echo signal of radar system and the classification of radar clutter are briefly introduced.Then,several kinds of common radar clutter amplitude distribution models and power spectrum models are analyzed in detail.On this basis,two types existing typical clutter simulation methods are introduced,and the ZMNL method is used to simulate the clutter model of Rayleigh distribution,Lognormal distribution,Weibull distribution and K-distribution.Then,on the premise that the clutter modeling is completed,the traditional clutter suppression technology of radar is introduced.The representative MTI technology,MTD technology and AMTI technology are selected.The principle,the realization of the block diagram and the filtering performance of three kinds of clutter suppression techniques are introduced in detail,and the improvement factor which is used to describe the performance index of the filter is discussed.The results of simulation clutter processing of the three kinds of filters are carried out in detail.Finally,the theory of Sparse Representation,the Variable Splitting method,the Augmented Lagrangian algorithm and its simple deformations are introduced in detail.On the basis of the previous theory,it can be known by analyzing the sparsity of radar echo that when there is clutter in radar echo,the sparsity of time-domain signal after pulse compression is destroyed.In order to detect the target better,the clutter should be filtered in advance to ensure the sparsity of the target.Based on the minimum power method and the time domain sparsity of target signal,the sparse representation theory is applied to the clutter suppression problem,and a new clutter suppression method based on sparse representation is proposed.The model solving process and experimental simulation results are given to verify the effectiveness of the method.