Optical doppler radar system using a conically scanned laser beam

摘要

A homodyne laser of a first frequency is conically scanned on a surface from an elevated position and the beam is scattered by the surface. A return beam is formed from this scattered beam and is mixed with a single side band suppressed carrier laser beam at an offset frequency, producing an electrical signal whose frequency shifts from the offset frequency in proportion to the velocity relative to the surface. That shift is a function of the scan position and the direction of movement. Velocity components of the signal reflecting drift velocity and heading velocity are resolved from this signal by referencing it to the scan position at drift and heading positions. The signal component reflecting elevation velocity is resolved by removing those scan dependent components.