Research On Target Detection By Group Strategy In Sea Clutter

Target detection algorithm by group strategy in sea clutter is addressed in this thesis.The target detection in sea clutter is not only the most important branch of radar target detection,but also the most complex part of radar signal processing.The target detection in sea clutter is of great significance in both military and civil fields.The partial homogeneity of sea clutter and the unavoidable false targets lead to a large error when the covariance matrix of sea clutter is estimated by the traditional estimators.Aiming at this question,a grouped weighted covariance matrix estimator in partially homogeneous sea clutter is proposed,and its performance is compared with the counterparts by using IPIX radar data in the simulation experiments.Due to partially homogeneous clutter which satisfies a different statistical property in adjacent range cells,a knowledge-aided group GLRT for range distributed target detection is proposed,and its performance is compared by using IPIX radar data in a simulated experiment.Three parts are mainly included in the thesis:1)There is a summary of sea clutter statistical characteristics and the basic model.At first,the statistical characteristics of sea clutter are introduced,and then the common models of sea clutter are exhibited and contrasted.2)Research on a grouped weighted covariance matrix estimator in partially homogeneous sea clutter.Firstly,the secondary data of sea clutter are grouped,the maximum posteriori estimation of texture is used as a weighted coefficient in each group,and a grouped weighted sample covariance matrix estimator is proposed.Due to the existing false targets,a consistent factor measuring the difference between covariance matrices is proposed.The group where interference lies in is identified by the proposed parameter,and the interference is eliminated at last.The experimental results of the real data show that the proposed grouped covariance matrix estimator not only eliminates false targets effectively,but also outperforms the estimator without grouping about 3dB in the partially homogeneous sea clutter.3)Research on a knowledge-aided group GLRT for range distributed target detection in partially homogeneous sea clutter.The group generalized likelihood ratio test(G-GLRT)developed here concerns the cells group effects on deducing the GLRT.Considering a knowledge-aided(KA)model that taking into account the partially homogeneous training samples,we develop a KA-G-GLRT for range-spread target detection and verify the constant false alarm rate(CFAR)with respect to the estimated covariance matrix of speckle.Experimental results are presented to illustrate the performance and effectiveness of the KA-G-GLRT in real clutter data.