Target tracking with bearings - Only measurements

The estimation of target position and velocity is attempted on the basis of angular measurements only. This topic is of interest for: airborne radar and sonar in passive listening mode, and electronic warfare systems; in these cases the target radiates either an electro-magnetic (e.m.) or an acoustic wave. The measurements are affected by white Gaussian noise; the presence of outliers is also considered. Two types of tracking filters are presented: (i) one processes a batch of data, (ii) the other recursively processes the data. The estimation of the target kinematic co-ordinates in the filter (i) is obtained by minimising a suitable quadratic cost function of measurement error. The closed form expression of the Cramer-Rao lower bound of the estimate is evaluated in a number of operational cases of practical interest; comparison with Monte Carlo simulation results is also shown. The filter (ii) is determined on the basis of the so-called modified polar co-ordinates. Monte Carlo simulation demonstrates the performance of this filter for straight line and accelerating moving targets. (C) 1999 Elsevier Science B.V. All rights reserved.