Range gate pull off (RGPO): detection, observability and /spl alpha/-/spl beta/ target tracking

This paper considers the range gate pull off (RGPO) tracking problem, an electronic counter measure (ECM) which is included in the Benchmark 96 Target Tracking Problem. In RGPO, the target senses the radar pulse and repeats it with a control delay. The amplified, repeated/delayed pulse results in a false range measurement with signal-to-noise (S/N) ratio larger than the real target range measurement confusing the radar/target detection and tracking process. A false range measurement, r/sup ft//sub k/, appears along with the true range measurement, r/sub k/, and depending on the controlled delay motion causes range tracking bias, velocity and/or acceleration pull-off {r/sub po/, v/sub po/, a/sub po/} and eventually lost target track. Fundamental characteristics of the RGPO are considered from a target tracking viewpoint: the nature of the RGPO, the detection of true and false range measurements, the tracking observability, and the RGPO range /spl alpha/-/spl beta/ tracking. It is shown that it is impossible to track the true target using the false range measurement. Ironically, it is also shown that the RGPO false measurements intended to defeat target tracking contains information which can be used to improve the true target track. A practical RGPO /spl alpha/-/spl beta/ matrix tracking process is presented which tracks both true and false targets with improved performance.