Underwater target motion analysis incorporating multipath arrivals using passive line array

Traditionally, underwater Target Motion Analysis (TMA) has assumed straight-line acoustic propagation, using only 2-D bearing information on the direct path. However, in the ocean environment, both targets and sensors exist in 3-D space, and acoustic signal propagation is affected by changes in sound speed, which lead to refraction, as well as by reflections from boundaries such as the sea surface and seafloor, resulting in multipath arrivals. Therefore, 2-D bearing-only approaches do not capture real-world conditions. This paper proposes a method for underwater TMA that incorporates multipath arrivals using a passive Horizontal Line Array sonar (HLA). The vertical arrival angles of multipath signals are modeled as functions of range and are incorporated into the filtering algorithm. The conical angles of multipath arrivals received via HLA are assigned using a Multi-Path Integrated Probabilistic Data Association (MP-IPDA) algorithm to account for multipath effects and enable accurate target tracking. The algorithm was validated through simulations, demonstrating its ability to estimate the specific multipath path from which each conical angle measurement originated. The results will be discussed during the presentation. Work supported by Korea Research Institute for defense Technology planning and advancement (KRIT)—Grant funded by Defense Acquisition Program Administration (DAPA), South Korea (KRIT-CT-23-026, Integrated Underwater Surveillance Research Center for Adapting Future Technologies, 2023–2029).