Ship surveillance by joint use of SAR and AIS

Abstract

The detectability of ships on synthetic aperture radar (SAR) images is validated by coastal (live) AIS and space AIS. The monitoring area chosen for surveillance is mainly the German coast and the Panama Canal. The detectability in respect to environmental parameters like wind field, sea state, currents and changing coastlines due to tidal effects is investigated. In the South Atlantic tracking of the German research vessel Polarstern has been performed. Issues of piracy in particular in respect to ships hijacked at the Somali coast are discussed. Possibilities and limitations of a near real time service are evaluated. As images from the SAR sensor do not only contain information on intensity, but as well on the phase of the returned signal, ship speed can be derived from Doppler effects. The ship wakes contain additional information on ship speed and type of ship. Some examples using the ESA satellites ERS and ENVISAT, that provide large coverage (up to 400 km) at moderate resolution (30 meters) are given together with high resolution images from TerraSAR-X.