RSS-based underwater acoustic distance measurement with multiple frequencies

Among various underwater ranging techniques, received signal strength (RSS)-based ranging method enjoys great popularity because of its accessibility and low cost. However, this effective method encounters great performance challenges due to multipath phenomenon. In this paper, to accurately map RSS values to distance in the multipath environment, ray tracing method based on image sources is introduced into the Urick propagation model. In this way, we can better obtain the relationship between RSS and parameters containing distance in the new transmission model. However, since these parameters cannot be derived with only one RSS measurement, we utilize multiple RSS measurements at different frequencies to calculate them. Moreover, since the mapping problem between RSS and distance is ill-conditioned, we construct additional inequalities based on prior information of the scene, and then present an algorithm named interior-point, to solve the problem. We analyze the proposed scheme to derive the lower bound, and numerical simulation shows ranging error is minor and almost falls on the top of CRLB. The results in next simulations and experiment show the localization performance is close to the state-of-art method based on compressed sensing and ranging accuracy improves up to 2 times when compared to the conventional method.