Study Of Dimension-reduced STAP For Airborne Phased Array Radar

The space-time adaptive processing (STAP) is an important technique for improving moving target detection performance for airborne radar systems in strong clutter and interference environments. But the computation load and the implementation complexity of optimum full rank STAP are so large that can not be accepted.These two problems have motivated the development of suboptimal dimension-reduced STAP algorithms. In the past three decades,there have produced largely developed in STAP, particularly in suboptimal dimension-reduced STAP algorithms. Radar operators apply themselves to implement STAP in engineering, and the main purpose of this dissertation is this.The main work can be summarized as follows:1. In chapter 2, the principles of the 3DT and F$A dimension-reduced STAP algorithms are firstly described. In post-Doppler processing methods of space time adaptive processing available, when window function is not used, Doppler channels are orthogonal, even when window function is used, the correlation between channels is not high. A new post-Doppler processing STAP method is proposed. This method improves the correlation between channel of interest and auxiliary channels, reduces the degree of freedom of clutter and lightens the burden of spatial adaptive processing, by reducing their space. Its validity is illustrated through experiment utilizing raw data of airborne dual-channel radar system.2. In angular and Doppler domain, clutter spectrum from short ranges for airborne forward-looking radar varies sharply and widen with range bins, thus leading to wide and low clutter notch, and achieving the undisirable performance of ground moving target indication(GMTI) in space-time adaptive processing(STAP). In chapter 3, we present a method of steering vector matrix fitting via the least square principle. The clutter subspace on the range under test can be approximated by transforming the training data via a series of fitting matrixs.These matrixs can be obtained by converting steering vector of the trainning ranges into the range under test. Results from experiments show that the proposed method can mitigate the range-dependence effectively.3. Compared with common radar, bistatic radar has advantages in anti-jamming , anti-interception and so on. Clutter suppression becomes very hard, because of its clutter characteristics of range dependent and multimainlobe. In chapter 4 firstly introduces the bistatic sidelooking radar principium briefly. Clutter power spectrum is compensated by using Doppler warping method.Dimension-reduced Space Time Adaptive Processing is applied to process the clutter data that has been compensated. References are given to the engineering practice and system optimizing by simulations that have done. Several typical reduced-rank STAP methods are simulated from signal to interference plus noise ratio, space time response and error robustness.