Study on airborne radar sea clutter suppression using deterministic space time model in post-Doppler domain

Abstract

When the airborne radar observes the land or the sea scene, the echoes will contain a large of clutter. Therefore, the target detection will be influenced and the clutter suppression is necessary. The time varying sea clutter makes the detection of sea targets more difficult. However, the airborne radar sea clutter suppression is rarely studied. In this paper, the sea clutter suppression for single channel and multi-channel are studied, respectively. The Doppler domain localization (DDL) method is used to suppress the real sea clutter data measured with a single channel. The results show that we can choose proper range cell number in the post Doppler domain to get better sea clutter suppression performance. For the multi-channel sea clutter, the clutter suppression is executed using sample matrix inverse (SMI), cross spectral metric (CSM) methods, subspace projection method and the proposed inverse sample covariance matrix (SCM) reconstruction method in the post-Doppler domain with joint three Doppler channels. It can be found that the sea clutter can be cancelled effectively by CSM and inverse SCM reconstruction methods. The residual sea clutter is relatively more for the subspace projection method due to the inaccuracy of the projection matrix. The moving targets can be detected with SMI, CSM and inverse SCM reconstruction methods, while they are submerged in the sea clutter for the subspace projection method. Meanwhile, the minimal detectable velocity (MDV) curves under different sea states show that the detection performance of the slow moving targets deteriorates with the increase of the sea state. The results can provide effective support for airborne sea clutter suppression and sea target detection.