Naval operations in the littoral have to deal with the threat of small sea-surface targets. These targets have a low radar cross-section and low velocity, which makes them hard to detect by radar in the presence of sea clutter. Typical threats include periscopes, jet skies, FIAC's, and speedboats. Search lidars on board naval vessels can provide detection capability for small sea-surface targets. Lidar measurements at the coast have shown a very good signal-to-clutter ratio with respect to buoys located up to 10 km from the shore were 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. The concept of a search lidar is presented and its performance is derived from system models. By using a high rep-rate laser and a variable beam divergence the search time can be limited. The design of a search lidar based on a commercially available high power and high rep-rate laser is shown.
展开▼
