Iceberg detection capabilities of RADARSAT synthetic aperture radar

Though iceberg detection capability has increased considerably over the past several decades, surveillance and detection limitations still present an obstacle to the safety and efficiency of marine operations. Transatlantic shipping incurs significant southerly detours during the ice season and offshore oil production facilities and procedures must be specially designed for operation in iceberg-frequented waters, including additional ships dedicated to iceberg "management". As a result, considerable effort has been expended in the development of various remote sensing tools for reliable, all-weather detection of icebergs. The RADARSAT-1 synthetic aperture radar (SAR) satellite provides the opportunity to substantially increase iceberg detection frequency and accuracy. This paper presents some of the results of the validation study for the iceberg detection capabilities of RADARSAT-1 that was conducted during 2000 on the East Coast of Canada. Wide 2, Wide 3 and ScanSAR Narrow B scenes were acquired at various near-shore and offshore locations in Newfoundland during the months of May and June. Ground-truth data on icebergs, mainly using scaled aerial photography, were collected coincident with RADARSAT-1 acquisitions. The ground-truth iceberg positions were correlated to the locations of targets in the RADARSAT-1 imagery, and the characteristics of the iceberg signatures within the SAR images were documented. Constant False Alarm Rate (CFAR) techniques were used in the empirical determination of the probability of iceberg detection as a junction of iceberg size, wind speed and radar incidence angle. For SAR incidence angles greater than around 35 degrees, icebergs with sizes on the order of the resolution of the particular SAR mode can generally be detected. Larger icebergs will be detected more consistently, and even during rough sea states.