RCM Polarimetric SAR for Enhanced Ship Detection and Classification

The RADARSAT Constellation Mission (RCM), which involves three small synthetic aperture radar (SAR) satellites flying in a constellation configuration, will be equipped with fully polarimetric (FP) capabilities in addition to single-polarization (HH, HV, VV), conventional (HH-HV, VV-VH, and HH-VV), and hybrid (i.e., compact) dual polarization. In this article, the added value of polarimetric SAR information for enhanced ship detection is demonstrated using polarimetric RADARSAT-2 (RS2) data collected over vessels (validated with Automatic Identification System (AIS) data) in the Strait of Georgia, near Vancouver, Canada. It is shown that the excursion (Delta p) of the degree of polarization (DoP) provides a significant increase in ship-sea contrast in comparison with conventional (i.e., scalar) single-channel polarizations (HH, HV, VV) and compact. Delta p, which is a measure of the variation of the DoP with transmit antenna polarization, performs better than compact intensities and degree of depolarization (DoD) promoted recently for ship detection. The unique potential of FP for ship classification is also demonstrated using polarimetric Convair-580 SAR data collected off Cape Race, Newfoundland, Canada. An efficient combination of successive wide-swath ScanSAR and FP, which exploits the RCM rapid-revisit capability at high latitudes, is considered for operational ship detection and classification.