Study Of Advanced Adaptive Processing Approach For Airborne Radar

We request array antennae which has vast antennae to sending and incepting signals for detecting the far targets. But this does a great problem to process the signal in real time .So we research Space Time Adaptive Processing (STAP) to process the data with reduced- rank.This thesis first analyzes radars'non-stationary clutter characteristics, and then explains basic theory of Space Time Adaptive Processing(STAP).After the knowledge of the clutter characteristics is got ,two common methods are discussed. Theoretical analysis and simulation experiments validate the advantages and disadvantages of each method. A large array up to hundreds of thousands of elements, limited to the cost and difficulty of the realization of the project, can not be in all-digital adaptive beamforming way, and it is necessary to carry out Reduced-Rank STAP to deal with. In this paper, the performance of three methods to synthesis the larger array is discussed from the following aspects: IF, two-dimension response spectrum, and Rang-Doppler spectrum.A method to Digital BeamForming(DBF) of the Sampling Matrix Inverse(SMI) algorithm based on array antenna to lower the height of the side beam is proposed .There are two problems: the performance degradation caused by the existence of errors in covariance, and the appearance of high side beam with the increase of small eigenvalues of clutter. A method to effectively control the height of side beam through amending the estimated covariance of clutter is proposed, after the analysis of the reason of beam-aberrance. The simulation results validate the effectiveness of the proposed method to suppress the beam height in adaptive pattern without influences on the nulling depth of the interference when the iteration times are proper.