Browse Prior Art Database

Laser Doppler Radar

IP.com Disclosure Number: IPCOM000097282D
Original Publication Date: 1962-Aug-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Werhultz, LM: AUTHOR [+2]

Abstract

A coherent beam of light 10 generated by laser 11 is directed toward a target, the velocity of which it is desired to determine. The beam passes through half silvered mirror 12 where it is split into a reflected beam 13 and a transmitted interrogation beam 14. On reflection from the target, the interrogation beam is received by a second mirror 15 for redirection along path 16 substantially parallel to that of beam 13. These two beams, under the control of shutters 17 and 18, pass through diffraction grating 19 to display respective interference patterns 20 and 21 on a special sensing surface 22. The latter has a plurality of photosensitive devices arranged longitudinally with respect to the spectral patterns.

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Laser Doppler Radar

A coherent beam of light 10 generated by laser 11 is directed toward a target, the velocity of which it is desired to determine. The beam passes through half silvered mirror 12 where it is split into a reflected beam 13 and a transmitted interrogation beam 14. On reflection from the target, the interrogation beam is received by a second mirror 15 for redirection along path 16 substantially parallel to that of beam 13. These two beams, under the control of shutters 17 and 18, pass through diffraction grating 19 to display respective interference patterns 20 and 21 on a special sensing surface 22. The latter has a plurality of photosensitive devices arranged longitudinally with respect to the spectral patterns.

The output signals of surface 22 are fed into a servo control system 23. This drives motor generator 24 effecting movement of the diffraction grating in such direction as to bring the brightest line of a given interference pattern to the zero position. Also, at this time position transducer 25 indicates the magnitude of this movement to zero, which movement is a measure of the relative velocity magnitude. By means of a second servo control 26 and motor generator 27, the entire apparatus is aimed in a direction indicative of the relative velocity vector direction. Several of these arrangements can be commonly located to detect velocity components in various directions for the purpose of more accurately determining relative velocity magnitu...