Patent ID: 7400386

Claim:
Laser-based apparatus for generating signals for use in determining both altitude and ground velocity of an aircraft, said apparatus comprising: a laser source for emitting pulsed laser beams substantially at a predetermined wavelength over a first optical path; a plurality of first optical elements for directing said laser beams from said first optical path to a second optical path which exits said first optical elements; a plurality of second optical elements configured to form a telescope with a predetermined field of view, said second optical path and telescope field of view being fixedly co-aligned; said telescope for receiving Doppler wavelength shifted reflections of said pulsed laser beams within the field of view thereof and directing said received reflections substantially over a third optical path; an optical filter element disposed in said third optical path for separating the reflections of said third optical path into first and second portions that are dependent on the Doppler wavelength shift of said reflections; and at least one light detector configured to receive said first and second portions and operative to generate first and second signals representative of said first and second portions, respectively.