Airborne Radar Performance Evaluation And Target Detection In Sea Clutter

Airborne radar has the ability to detect air moving targets over the sea surface. The radar is inevitably affected by sea clutter when working. Therefore, the study of air moving targets detection and radar performance evaluation in the context of sea clutter is of great significance. To detect air moving targets in the context of sea clutter, we need to estimate the covariance matrix of the cell under test. This article puts forward a modified sample covariance matrix method to estimate the covariance matrix. The proposed method is helpful for improving the clutter suppression performance and radar detection performance. To study the radar performance evaluation method in the context of sea clutter, we need to simulate accurate sea clutter echo data firstly. This article proposes a fast sea clutter simulation algorithm. Simulation results demonstrate the effectiveness of the proposed method. The work of this thesis is outlined as follows:1. The research on the method of airborne radar performance evaluation in sea clutter background is carried out. First, the sea clutter model of airborne radar is given. Then, a fast sea clutter simulation algorithm which can be applied to radar performance evaluation is proposed. Finally, by the simulation of sea clutter echo data with the fast sea clutter simulation algorithm, the two-dimensional detection blind zone in range-velocity domain is obtained. With these results, the maximum detection range and minimum detectable velocity can be obtained, which give the resultant evaluation results. The proposed clutter simulation algorithm greatly raises the speed of airborne radar echo data simulation and significantly improves the efficiency of radar system performance evaluation.2. The study of air moving targets detection and adaptive clutter suppression for airborne radar in sea clutter background is developed. First, the fundamental principle and techniques of space-time adaptive processing are introduced, including full space-time adaptive processing and reduced-dimension space-time adaptive processing algorithms. Then, we introduce several conventional covariance matrix estimation methods in space-time adaptive processing, and we propose a modified sample covariance matrix estimation method. Finally, experiment results give a comparative analysis of detection performance with different covariance matrix estimation methods, which validates the effectiveness of the proposed method.3. Sea clutter characteristics of rotating antenna system in airborne radar are studied. First, the model of echo received by airborne rotating antennas is analyzed. Based on the model, a simulation analysis of sea clutter characteristics is carried out. Finally, a conclusion is obtained here that due to the presence of rotating motion, there will be a perturbation on the signal steering vector. Thus, the clutter component presents a serious spectral diffusion, which degrades the performance of clutter suppression and target detection in the conventional STAP.