Characterization and identification of trajectories using a leg by leg approach of bearings only target motion analysis

The problem of bearings-only target motion analysis consists in estimating the position and kinematics parameters of a target, traveling on straight lines at constant velocity from a collection of noisy bearing measurements delivered by passive sensor. The resulting dynamic process is inherently non linear and exhibits unusual observability properties. We propose a new approach which consists in estimating the always observable variables of the process, and identifying the parameter family of solutions when the observer\´s motion is confined to a constant velocity segment termed "leg\´, The unique solution of the TMA problem is obtained via a leg by leg approach in the typical case of observer maneuver, with a geometric interpretation of the observability level depending of the observer maneuver strategy. In addition, this approach permits to identify the target trajectory on any leg of the observer in the case of target maneuver. The leg by leg approach is described in the three considered situations and justified by satisfactory results obtained on realistic simulation data.