Laser sounding



Hydrographic surveying along the coastline must be done frequently because ocean bottom topography is under constant change. In a recent discussion in Naval Research News, M. B. White of the Office of Naval Research compared the traditional shipboard acoustic sounding method with the new Hydrographic Airborne Laser Sounder (HALS) being developed for the Navy and the National Ocean Survey. The shipboard system can be described by two words: slow, costly. According to a recent summary of White's discussion (Lasers & Applications, December 1982), the Defense Mapping Agency, which produces most civilian and military charts in the United States, now has a 200 ship-year backlog. The new HALS system will be 6 times less expensive to operate and 100 times faster. The questions remaining now are related to the type of airborne laser system that can perform the task, in a field of rapidly changing technology.