The Future of Maritime Target Detection Using HFSWRs: High-Resolution Approach

In recent years, maritime surveillance of sea targets at long distances has been a current topic, especially from a security point of view. For this purpose, High-Frequency Surface Wave Radars (HFSWRs) are often used because their detection range exceeds the over-the-horizon distance. This paper represents a comprehensive study of high-resolution (HR) primary signal processing in HFSWRs which is a critical task because the performance of such systems depends on it. The paper also proposes main principles of maritime target detection using HR approach, which differs from state-of-the art approaches. The proposed algorithms are based on a HR estimation of the Range–Doppler map, where target detection is performed, and then the azimuth estimation by a high-resolution MUSIC-type algorithm, that is executed for all detections founded in the range-Doppler map. The operation at one frequency, as well as bi-frequency operation mode are shown. The goal of the bi-frequency mode of operation is to improve the detectability of sea targets, which are affected by different Bragg-line interference patterns. The experimental study shows the effectiveness and efficiency of the newly developed algorithms in real conditions and promising performance that either matches or outperforms primary signal processing used by many existing radars. Probability of target detection, detection accuracy, matching with Automatic Identification System (AIS) and resolvability of targets are improved, which indicates that the proposed algorithms represent the future direction in HFSWR primary signal processing.