An experiment on passive multi-sensor underwater surveillance

A sea trial has been performed in the Stockholm archipelago in August 2004. The performance of passive surveillance systems might be improved by fusion of data from acoustic and electromagnetic sensors. The aim of the trial was to collect data to investigate this prospect. Many targets have been measured for the purpose of detection, localization and classification studies. The sensors consisted of two passive arrays, one 32-element acoustic array and one long base-line electromagnetic array with 8 electrode pairs. In addition, a three-axis short base-line electrode system, also equipped with two magnetic field sensors, was used as a reference sensor. The targets consisted of smaller surface ships and of towed acoustic and electromagnetic sources. This report describes the sea trial and shows some results from a first, preliminary analysis of the data. Examples of acoustic beam-forming, electromagnetic tracking and acoustic and electric signatures are shown. Results from a more detailed analysis will be presented in the future.