HF radar performance analysis based on AIS ship information

Abstract

High-Frequency (HF) radars are operated in the 3–30 MHz frequency band. For oceanographic applications low transmit power HF radar systems have been developed, which use surface electromagnetic wave propagation along the salty ocean surface. The WERA HF radar system transmits a power of 30 watts but achieves detection ranges up to 200 km, which are far beyond the conventional microwave radar coverage. Hence the radar system can be used for coastal monitoring. Due to external noise, radio frequency interference, and sea clutter the radar detection capability is limited. Real measured radar data from the WERA system were recorded for a 12-hour period. The measured radar data were correlated with simultaneously available Automatic Identification System (AIS) information, which shows current ship position, speed, course and type. This paper presents statistical analysis of maximum detectable range and target reflectivity to estimate the radar performance in case of different cargo ship sizes. Based on the order-statistic constant false alarm rate (OS-CFAR) detection rule the potentially detectable target range and aspect angle of different ship categories were analyzed.