Handoff between track-while-scan and image tracking

Abstract

The handoff between track-while-scan (TWS) mode and image based tracking raises some important questions for the systems designer. TWS is used for point targets and image tracking is used for resolved targets; during any given scenario there are times when both methods may work. An optimal point for handoff must be found. The target may oscillate between a state where TWS is optimal and a state where image based tracking is optimal; reacquisition of the target by one mode after breaklock in another is another problem that must be addressed. The limitations of both modes need to be considered: detection of a point target with 2D spatial algorithms is dependent on the apparent size of both the target and the filter. Performance of the image based tracker is also highly dependent on target size and shape. This paper will describe the detection algorithms used to detect point targets for a typical TWS mode, give a brief description of a typical image based tracker and show results for several different scenarios.