Ship tracking by HF radar in coastal waters

Maritime domain awareness is important for coastal nations in terms of applications to coastal conservancy, security, fishery and stewardship of their exclusive economic zones (EEZs). Maritime situational awareness involves knowing the location, speed, course and identity of ships and boats in the EEZ. HF radar is a useful tool in providing ship information in real time. It is especially effective when combined with information from ship-borne AIS beacons. However, ship detection by AIS alone is limited to ships with AIS beacons broadcasting. HF radar does not have this limitation, but is hampered by false targets related to wave echoes, interference and the high variability of HF echoes from ships. We have developed a ship detection and tracking system that accepts Codar SeaSonde range file data as input and proceeds through a ship detection algorithm to produce a target file every time step (range, radial speed and azimuth for each ship-like target). A Kalman filter algorithm is applied to the time history of target files to produce ship tracks as well as to remove false alarms. We demonstrate this ship tracking system using radar data from the Pescadero CA station in the COCMP HF radar network along the California coast. Available AIS data are used to verify the target locations and ship tracks. Although improvements are needed, we can now demonstrate a working end-to-end HF radar system for tracking non-cooperating ships in coastal waters using standard, Codar-SeaSonde-HF-radar output and software developed by the authors.