Passive Sonar Ranging and Range-Doppler-Bearing Target Motion Analysis

In passive sonar, target motion analysis (TMA) provides an estimate of the trajectory of a moving source, generally based on bearing and Doppler measurements. When the source presents a low bearing rate, the problem is ill-conditioned and difficult to solve without observer maneuver. To address this issue, we propose to estimate the instantaneous range of the source from its measured spectrum, using a conventional radiated ship noise model and a sound absorption model in seawater. The introduction of this new measurement in what becomes a range-Doppler-bearing TMA algorithm, ensures the uniqueness of the trajectory. Compared with standard Doppler-bearing TMA, convergence is faster and stability is improved, especially at low bearing rates.