Study Of Space-Time Adaptive Processing For Airborne Radar

The key task of airborne early warning (AEW) radar is to find and track targets in a complicated background, so the suppression of interference and clutter in radar system is of great importance. If the radar works in a relatively flat and low scattering area, the clutter is weak and the Conventional processing is enough; however, for most cases, the clutter is quite strong. In addition, due to the motion of the airborne platform, the ground clutter spectra for airborne phased array radar are distributed in the space-time domain, therefore, the space-time adaptive processing (STAP) is adopted to suppress clutter and interference. The optimum full rank STAP has not found any application in the projects for its great implementation complexity and its huge computation load. So it gives birth to the Reduced-rank (R-R) STAP, which will lead STAP into practical projects.Firstly, the basic concept and principle of phase antenna and technique of beam shaping are discussed and then the effect of the variation of main beam direction on the clutter is analyzed. Based on these analyses, the basic characteristics of ground clutter are studied. Secondly, the fundamental principle of STAP is presented in detail, and on that basis, the reduced-rank processing methods in both space domain and time domain are researched. In the space domain, the methods of subarray division by regular, by irregular and by overlapped-subarray means are mainly discussed. In the time domain Extended Factored Approach (EFA or mDT) is discussed in detail. Finally, the noise model, the clutter-noise model, the jam-noise model and the jam-clutter-noise model are discussed. The simulation results prove that the clutter and interference can be suppressed well.