Ocean depth sounder using laser beam

摘要

The depth sounder uses two laser beams (1,2) with differing wave lengths, one of which is displaced laterally to-and-fro, the other remaining static to detect the water surface. Two separate receivers are used for the two reflected beams and the measured distances indicated by the two reflection signals are subtracted to provide the ocean depth. The first beam (1) is moved in the direction of the aircraft trajectory and has a wavelength lying in the green range of the spectrum, the other beam (2) having a wavelength in the IR range of the spectrum. Pref. the amplifier gain for the reflected first beam (1) is reduced when the signal is received to optimise detection of the seabed, the signal sampled over a given period.