An efficient, reliable approach for hydroacoustical bearings only target motion analysis

The hydroacoustical bearings only target motion analysis (TMA) problem is that of determining target location, heading and velocity from target bearings. It must be solved using noisy data. Also, the hydroacoustical bearing trackers used for the measurements produce poor quality data because of the nature of the ocean medium. Since bearings only TMA is used on submarines for fire control, the performance of the TMA subsystems must be accurate, reliable, and computationally efficient. Historically, this problem has been most effectively solved using plotting boards and extended Kalman filters. Recent work has established the performance superiority of batch estimation techniques. The work presented here is a batch maximum likelihood estimation technique which solves the computational problems associated with batch estimation of the past. In addition, the reliability of the approach given here is appropriate for "hands-off" application in a real time subsystem. The problem is solved using state of the art computational and statistical estimation techniques and a coordinate system differing slightly from those used in the past. The formulation of the technique is a response to the hydroacoustical, computational, and mathematical aspects of the TMA problem, within the constraints of performance requirements and real time implementation considerations. Simulation results are presented which show the performance of the maximum likelihood TMA estimator to be superior to a Kalman TMA estimator.