Tracking an Agile Target

One of the most thoroughly studied applications of hybrid estimation arises in the synthesis of tracking algorithms for agile targets. These targets, sometimes intentionally and sometimes inadvertently, have motion paths that make them difficult to follow. One example is that of a piloted vehicle whose location must be tracked from a fixed sensor.

The operator of the vehicle exploits its maneuver capability to create a path that he hopes will cause the tracker to lose lock. Such paths have a familiar pattern, with nearly constant acceleration over intervals of unpredictable length followed by discrete maneuver mode changes. Even autonomous platforms can be designed to take such evasive maneuvers; for example, an antiship missile on approach to its objective may follow a preprogrammed jinking path. Such motions often have a constrained geometric structure. If the missile has limited speed control, it will focus its evasive efforts on turning motions, where the acceleration is perpendicular to the velocity.