Study On Heterogeneous Clutter Suppression Method For Airborne Radar

Airborne radar has many advantages,such as small size and long visible distance,and its application fields are becoming more and more extensive.Since the echo signal received by the airborne radar contains clutter with severe space-time coupling characteristics,in order to be able to find and locate the target faster and more accurately,it is necessary to suppress the clutter.The optimal space-time adaptive processing is a classical clutter suppression algorithm,but its computation increases greatly with the increase of array size,and the clutter environment is assumed to be an ideal uniform clutter environment,but the performance of the algorithm is easily affected by factors such as actual terrain in actual engineering.Therefore,based on the airborne phased-array radar,this thesis focuses on the general model of heterogeneous clutter and the method of suppressing heterogeneous clutter.The main work of this thesis can be summarized as follows:1.The homogeneous clutter model of airborne phased-array radar is introduced and several STAP methods are studied.Firstly,the homogeneous clutter model is introduced based on the antenna array model.Then,the optimal STAP method and three classic suboptimal dimension-reduced STAP methods are studied.Simulation results show that the bending degree of the clutter power spectrum trajectory increases with the increase of yaw angle,and the spectrum broadening becomes more and more obvious with the increase of amplitudephase errors.At the same time,comparing the improvement factor curves of several methods,it is concluded that the performance of three dimensional-reduced STAP methods is close to the optimal STAP.2.A new heterogeneous clutter model of airborne phased-array radar is given to solve the actual problems such as terrain undulation,building height difference,etc.First of all,the different factors causing clutter heterogeneity are analyzed,and the definitions of azimuth heterogeneity and elevation heterogeneity are given,and the degrees of heterogeneity are quantified as azimuth heterogeneity factor and pitch dimension heterogeneity factor respectively.Then,the heterogeneous clutter model is designed according to the homogeneous clutter model.Next,it summarizes the detailed process of obtaining the airborne radar heterogeneous clutter echo data.Finally,the simulation results verify the correctness of the heterogeneous clutter model,and the performance of three dimension-reduced STAP methods decreases with the increase of the azimuth heterogeneity factor andelevation heterogeneity factor.3.The heterogeneous clutter suppression method of airborne phased-array radar is studied based on the proposed model in this thesis.Firstly,the two-dimensional pulse-to-pulse canceller(TDPC)method is studied by using priori information such as carrier speed and radar parameters.Secondly,a two-dimensional multi-pulse canceller(TDMC)method is given.Thirdly,a three-dimensional model of airborne radar heterogeneous clutter is established.And based on the model,a three-dimensional pulse-to-pulse canceller method is proposed.Finally,it is verified through simulation experiments that TDPC method,TDMC method and three-dimensional two-pulse canceller method can filter out most of the clutter,but the three-dimensional pulse-to-pulse canceller method has better performance in terms of clutter suppression,while the clutter suppression effect of the TDMC method is better than the TDPC method.