On the detection of marine mammals with ship-borne polarimetric microwave radar

Collisions between ships and whales are not rare occurrences. Apart from constituting a major cause of death for whale species which frequent busy oceanic areas such as the North Atlantic, such collisions often result in damage to ships. Thus there is keen interest in finding reliable means of detection of whales at sufficient range to ensure successful collision avoidance. In this paper we present the results of experiments aimed at establishing the potential of polarimetric microwave radar to provide such a means. The key element in our approach is the construction of a polarimetric filter which enhances the contrast between the disturbed sea surface around the whale and the ambient sea. The results suggest that detection can be achieved under conditions where conventional uni-polar radars such as those normally found on merchant ships would fail.