System for profiling objects on terrain forward and below an aircraft utilizing a cross-track laser altimeter

Abstract

A forward looking cross-track laser altimeter comprises: a first configuration of optical elements for guiding pulsed laser beams along a first optical path; a mirror element coupled to a scanner and disposed in the first optical path, the scanner operative to oscillate the mirror element to sweep the reflected laser beams back and forth across a line at a predetermined frequency; the scanner and mirror element configurable to reflect the pulsed laser beams along paths forward and downward at a predetermined angle to the flight path of the aircraft, wherein the pulsed laser beam paths are caused to be line swept across a ground track forward the aircraft; the mirror element for receiving returns of the pulsed laser beams from the terrain and objects on the terrain forward the aircraft and reflecting the returns along a second optical path to a light detector which produces a return signal in response thereto; a first circuit governed by the return signals for measuring times-of-flight of the returns and generating time-of-flight signals corresponding thereto; the scanner for generating a line sweep position signal; and a second circuit for generating for each return a data profile comprising range and line sweep position thereof based on the corresponding time-of-flight and position signals.