A Study On Clutter Suppression Methods For Non-side Looking Airborne Radar

For lacking of enough training samples that are independently and identically distributed(IID)to estimate covariance matrix,the traditional and statistical space-time adaptive processing(STAP)algorithms' performance are declined sharply for the non side-looking array.Especially,in order to avoid the speed of fuzzy and increase the rate of signal acquisition,airborne radar usually adopts the middle or high pulse repetition frequency,which leads to range ambiguities.Under this environment,the short-range clutter and fuzzy clutter mixed together,the performance of the STAP algorithms is further degraded.Therefore,the STAP technique for non side-looking array airborne radar with or without range ambiguities is studied in this thesis.In order to solve the non side-looking range-dependence problem,an improved DBU method based on the tangent value of the pitch is proposed,which has better performance and more stable than DBU method.To deal with the non-side looking range-dependence problem under range ambiguities environment,a clutter compensation method based on maximum detection range is proposed firstly,which compensates range dependence of all training cells and the detected cell to the most remote cell.It can significantly reduce the influence of the range ambiguity and is not influenced by the target location.Then,in order to reduce the amount of calculation and speed up the computing speed,a clutter compensation method based on least squares algorithm is put forward.It classes the range cells into near rang cells and remote rang cells,and the compensation is carried out only for heterogeneous clutter of near rang cells.All above methods are guaranteed their validities by computer simulation.