Research On Sea Clutter Suppression And Direction Of Arrival Estimation Of Target For Shipborne High Frequency Surface Wave Radar

High Frequency Surface Wave Rader(HFSWR)is a kind of new system Radar that appears at the end of last century which has the over-the-horizon characteristics.The shipborne HFSWR has been widely used in military and civilian fields because of its flexibility compare to the shore-based HFSWR.The shipborne HFSWR will face the problem of first-order sea clutter submerging low-speed targets,and any radar system will be affected by array errors,resulting in inaccurate target DOA estimation results.Therefore,in order to make the shipborne HFSWR detect target accurately,clutter suppression and array error calibration are problems of great importance.Based on the measured data and the simulated data,researches on sea clutter suppression algorithm and the array error calibration algorithm of the shipborne HFSWR are carried out in this paper.The main work is as follows:Firstly,The signal processing method of shipborne HFSWR are studied.Also,formation reason and characteristics of sea clutter are studied.The space-time characteristics are studied emphatically.The three-degree-of-freedom swing of the shipbased platform was considered while simulating the sea clutter.Its validity is confirmed after it is compared with the measured data.Then research on the spatial suppression algorithm of sea clutter-Orthogonal Weighting and Oblique Projection algorithm,then use Doppler dimensional data-spacetime cascade clutter suppression algorithm-IOW,IOP algorithm are proposed.Among them,the OW-class algorithm always have the problem of a target gain loss while the target and the clutter are close to each other.The OP-class algorithm will solve this problem.Then the Space-time Adaptive Processing(STAP)algorithm for sea clutter suppression is studied.The use conditions of the algorithm are studied.Then the STAP method for dimensionality reduction-the Joint-Domain Localized(JDL)and the SpaceTime Multiple Beam(STMB)algorithm.These two methods have a better performance which is tested from measured data and simulated data.After clutter suppression,DOA algorithm under array errors are studied in order to get an accurate DOA of the target.Four kinds of array errors are studied and models are established.Also,their influence on the clutter suppression algorithm and the superresolution DOA algorithm-MUSIC is qualitatively studied.Then,the algorithm of using calibrated array elements and the self-calibration algorithm is studied: two algorithms based on the theory of blind estimation and the ESPRIT algorithm to realize the correction of amplitude and phase error are studied.Then the self-calibration algorithm for amplitude and phase error.