Acoustic channel characterization in the Baltic Sea and in the North Sea

This paper reports results from the joint European project ldquoUUV covert acoustic communicationsrdquo (UCAC), which aims at the establishment of a covert communication link between an unmanned underwater vehicle (UUV) and a distant mother platform using acoustic telemetry. To this end, sea trials were carried out in 2006 and 2007 in two different areas in the Baltic and Norwegian North Sea. During the sea trials, acoustic and environmental data were obtained for the characterization of the acoustic channel - particularly the transmission loss and the channel impulse response - with the purpose of evaluating different (covert) acoustic communication schemes. A selection of these data is analyzed in the present paper.