Measurement of surface currents from a shipborne HFSWR

The spreading first-order sea echo spectrum in shipborne high-frequency surface wave radar (HFSWR) severely impacts the measurement of surface currents. Space-time processing techniques like space-time multiple signal classification (ST-MUSIC) algorithm, usually studied for two-dimensional high resolution radar imaging, are the effective methods for solving the problem. The rank of the sea echo covariance matrix is an important indicator of the severity of the sea echo scenario. With this knowledge, the sea echo can be accurately extracted from the complicated radar returns by using the ST-MUSIC algorithm. Furthermore, the least-squares method is introduced to estimate the uniform surface current vectors from a single shipborne HFSWR by fitting the adjacent radial current vectors. The simulation results have verified the validity of these algorithms.