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. I.978-1-4244-5812-7/10/$26.00 ©2010 IEEE

A novel approach to high frequency radar ship tracking exploiting aspect diversity

“…Data collected from the WERA installations at Palmaria and San Rossore WERA have been processed separately using the 3D OS-CFAR detection algorithm described in [2].…”

“…The azimuth information is extracted via beamforming of the received data, using an Hamming window. Target detection was performed in the Fourier domain by a 3D (azimuth-range-Doppler) Ordered Statistics (OS) Constant False Alarm (CFAR) algorithm, developed at the Institute of Technology of the University of Hamburg [2]. Coherent processing intervals of 512 samples, with an overlap of 75% each (i.e.…”

“…Unfortunately, HFSW-radars suffer from poor azimuth resolution, high nonlinearity and significant false-alarm rate. These issues have been partially solved by a simple MTT algorithm, which uses a Nearest Neighbor (NN) data association rule [2].…”

“…The aspect diversity also allows the reduction of RCS variability due to the target orientation. Additional performance limiting factors related to single aspect HFSW systems are represented by shadowing effects, measurement noise, and reduced antenna gain due to non-uniform patterns [2].…”

Detection, tracking and fusion of multiple HFSW radars for ship traffic surveillance: Experimental performance assessment

“…AIS reports can be used as ground-truth information for ship detection and tracking assessment [5], stated some key assumptions. Ships equipped with AIS are assumed to be the only ones present in the surveyed region and their identifiers are unique.…”