Results from the search-lidar demonstrator project for detection of small sea-surface targets

Coastal surveillance and naval operations in the littoral both have to deal with the threat of small sea-surface targets. These targets have a low radar cross-section and a low velocity that makes them hard to detect by radar. Typical threats include jet skis, FIAC's, and speedboats. Previous lidar measurements at the coast of the Netherlands have shown a very good signal to clutter ratio with respect to buoys located up to 10 km from the shore where the lidar system was situated. The lidar clutter is much smaller than the radar clutter due to the smoothness of the sea surface for optical wavelengths, thus almost all laser light is scattered away from the receiver. These results show that due to the low clutter a search lidar is feasible that can detect small sea-surface targets. Based on these promising results a search-lidar demonstrator project has started end of year 2008. The system set-up of the search lidar demonstrator is presented and experimental results near the coast of Holland are presented. By using a high rep-rate laser the search time is limited in order to be useful in the operational context of coastal surveillance and naval surface surveillance. The realization of a search lidar based on a commercially available high power and high rep-rate laser is presented. This demonstrator is used to validate the system modeling, determine the critical issues, and demonstrate the feasibility.