Study Of The First Order Sea Clutter Suppression Method For Shipborne High Frequency Surface Wave Radar

In shipborne high frequency surface wave radar(HFSWR)system,the first order sea clutter is an important factor which influence the slow target detection.To achieve effective target detection,it is necessary to analyze the method to suppress the first order sea clutter.In this paper,we study the space-time distribution of the first order sea clutter in the shipborne HFSWR system,and use the effective space-time adaptive processing(STAP)method to suppress the first order sea clutter.Firstly,the space-time distribution of shipborne HFSWR first order sea clutter is studied.The movement of the shipboard platform can be divided into two categories: ship's maneuvering forward motion and the ship's six degrees of freedom movement caused by the interaction between the two power systems of the waves and the ship.In this paper,the influence of the two categories of motion on the echo signal and the space-time distribution of the first order sea clutter are analyzed theoretically.The results of theoretical analysis are proved by simulation experiments.The analysis of the first order sea clutter space-time distribution provides a theoretical basis for the application of the next STAP method.Secondly,this paper studies the STAP method based on sparse recovery(SR-STAP)and applies it to the first order sea clutter suppression of shipborne HFSWR.First,this paper studies the sparseness and sparsity of the first order sea clutter of shipborne HFSWR.Then,we use three typical sparse recovery algorithms to deal with the simulated shipboard HFSWR echo data.The processing performance of the algorithms is analyzed.Then,this paper proposes a super complete dictionary preprocessing method based on prior knowledge,which improves the processing performance of SR-STAP and greatly reduces the computational complexity of the system and the memory usage in the system processing.Finally,this paper presents a STAP method based on parametric covariance matrix estimation(PCE-STAP).This method can achieve more effective clutter suppression under small training samples,while protecting the target's power and enabling effective target detection.Since the radar studied in this paper works in the high frequency band,which leads to the low resolution of the radar system and the insufficient training samples with independent identical distribution.Therefore,it is very important to study the effective STAP method under the condition of small training samples.Then,we study the compensation method of the six degrees of freedom motion of the ship by modifying the space-time vector in the covariance matrix estimation procedure.