Maximum PIW detection ranges of 0.5 to 0.7 nmi were achieved in 3 nmi mode when the radar was set up to provide high dynamic range images of the sea clutter. Similar performance was achieved in 1.5 nmi mode. Maximum radar sensitivity is required for the PIW to be detected on those scans when it is at a wave crest. Setting the radar for an uncluttered PPI was shown to be counterproductive when detecting such small targets as PIWs. Even with reduced radar sensitivity and a high detection threshold, a small life raft was solidly detected out to the maximum processed range of 1.3 nmi.
Much longer ranges are certainly possible even with the present simplified processing scheme.
Moving to an M of N track initiation criterion and higher scan rates will increase the detection range, which is presently limited by the slow 20 rpm radar scan rate precluding consecutive hits at longer ranges. Moving to integrated tracker motion compensation will increase the detection range, which is presently limited by the number of non-motion compensated tracks that must be tracked. The confidence with which we detect a PIW or other target will depend on at least its range, number of detections, track length and speed. The false track rate therefore depends on the criteria for declaring a detection. Slow tracks that are not PIWs but are too long to be considered sea clutter false alarms are also detected from time to time.