Underwater Source Localization Using TDOA and FDOA Measurements with Unknown Propagation Speed and Sensor Parameter Errors

TL;DR

This paper introduces an efficient underwater source localization method using TDOA and FDOA measurements that handles unknown propagation speed and sensor errors, effectively mitigating Doppler effects and achieving near-optimal accuracy.

Contribution

The paper presents a novel localization approach that copes with unknown propagation speed and sensor errors, providing a low-complexity solution close to theoretical bounds.

Findings

Method outperforms existing approaches in accuracy.

Performance approaches the Cramer-Rao lower bounds under small noise.

Effectively mitigates Doppler effects in underwater localization.

Abstract

Underwater source localization problems are complicated and challenging: a) the sound propagation speed is often unknown and the unpredictable ocean current might lead to the uncertainties of sensor parameters (i.e. position and velocity); b) the underwater acoustic signal travels much slower than the radio one in terrestrial environments, thus resulting in a significantly severe Doppler effect; c) energy-efficient techniques are urgently required and hence in favour of the design with a low computational complexity. Considering these issues, we propose a simple and efficient underwater source localization approach based on time difference of arrival (TDOA) and frequency difference of arrival (FDOA) measurements, which copes with unknown propagation speed and sensor parameter errors. The proposed method mitigates the impact of the Doppler effect for accurately inferring the source parameters (i.e. position and velocity). The Cramer-Rao lower bounds (CRLBs) for this kind of localization are derived and, moreover, the analytical study shows that our method can yield the performance that is very close to the CRLB, particularly under small noise. The numerical results not only confirm the above conclusions but also show that our method outperforms other competing approaches.