Study Of Ship Detection Method For High Frequency Radar

Over-the-Horizon (OTH) radar operates in high-frequency band and uses ionosphere refraction to detect targets at thousands of kilometers. HF-OTHR's detection range can be of 3000km or more. The ionosphere distortion contaminates Doppler spectrum,which made the detection of low ship targets very difficultly. Using signal processing techniques deal with ship detection under short coherent integration time is very significant. However, short CIT and the resulting low Doppler resolution cannot separate the low speed ship from the close powerful ocean clutter. To resolve this problem clutter cancellation algorithm can be adopted but it requires accurate estimation for clutter parameters.In this paper, several ship detection methods are investigated: the clutter cancellation proposed by Root, clutter cancellation based on FFT phase analysis and high resolution spectrum analysis algorithm proposed by Capon, finally a new clutter cancellation based on amplitude and phase estimation (APES) is proposed. Compared to the above mentioned methods, the algorithm proposed in this paper can obtain much higher estimation precision in ocean clutter parameter estimation, and achieve better clutter cancellation performance. As the result, the power and spreading of clutter residue are decreased significantly, that will benefit the ship targets visibility and detectability.