1. Aker BP ASA, Trondheim, Norway. (corresponding author)
2. Aker BP ASA, Trondheim, Norway.
3. Norwegian University of Science and Technology, Department of Electronic Systems, Trondheim, Norway.
4. Alcatel Submarine Networks Norway AS, Tiller, Norway.
5. Tampnet AS, Stavanger, Norway and Simula MET, Oslo, Norway.
6. Shearwater GeoServices, Bergen, Norway.