A comparative evaluation of several bearings-only tracking filters

Eleven different filter configurations were studied in order to determine their nominal relative performance and stability when passively tracking an air target with ESM direction finding equipment. The characteristics of the various filters are: The composition of the state elements (Cartesian, polar with polar rates, polar with course and speed, or polar with Cartesian rates); the number of state elements (four or three); the type of estimation used (all but two being Kalman filters); and the type of target model assumed (all but one being constant velocity Cartesian). The filters were tested in a simulation against non-maneuvering targets assuming zero-mean uncorrelated measurement errors of known typical variance. Four filters were found to perform well and one other is possibly acceptable. A final choice would need to consider performance against a maneuvering target and performance with measurements from the actual sensor under consideration.