Measuring the depth of the sea. For this problem, a differential air-based lidar. The red wave is almost completely reflected the sea surface, whereas the green partially penetrate into the water, are scattered in it, and reflected from the seabed. Technology has not yet applied in civil hydrography due to high measurement error and a small range of measured depths.
Search the fish. Similar means can detect signs of shoals of fish in the surface layers of water. Specialists of the American State Laboratory ESRL argue that the search for fish light aircraft equipped with LIDAR, at least an order of magnitude cheaper than with vessels equipped with echo sounders.
Rescue at sea. In 1999, the U.S. Navy patented design of aircraft lidar applicable to search for people and human bodies on the sea surface, the principal novelty of this development - the application of optical masking of the reflected signal, which reduces interference.
Demining. Detection of mines is possible with lidar, directly immersed in water (eg, buoys, towed boat or helicopter), but has no special advantages in comparison with active acoustic systems (sonar). Are patented detection of mines in the surface layers of water using airborne LIDAR aircraft, the effectiveness of such lidars is not known.
Systems underwater view. At the root of underwater use lidar sea stood Corporation Kaman, patented technology operable in 1989. Intensive (as compared to air environment) light scattering in the water for a long time limited the effect of underwater lidar tens of meters. The laser pulse is able to "break" and long distances, but the useful echo signal is discernible on the background of spurious illumination. Kaman overcame this problem by means of electronic gates, which opened the way for optical CCD-receiver only for a short period of expected response. In addition, the very image of the target formed by "subtracting the shadows" which significantly improve the range of the system. Kaman uses the method of short time window and aviation systems in them at the opening of the optical channel is set altimeter aircraft carrier.
In subsequent years, Kaman developed the theme lidars in the direction of increasing range and reliability of pattern recognition, and part of the new applications. For example, in 1999 patented the use of LIDAR for establishing high-speed underwater communications with unmanned underwater vehicles (firebird) on the optical channel. In 1992 were offered individual lidar for divers and scuba divers. It is likely that a significant layer of naval development remains unknown to the public.