OPTICAL DEVICE FOR SIMULTANEOUSLY MEASURING THE DISTANCE AND SPEED OF A MOVING OBJECT WITH RESPECT TO A REFERENCE

• US 3,765,768 A
• Filed: 03/11/1971
• Issued: 10/16/1973
• Est. Priority Date: 03/16/1970
• Status: Expired due to Term

• Current Assignee: Georges Roger, Jean-Pierre Budin
• Original Assignee: Georges Roger, Jean-Pierre Budin
• Inventors: Budin, Jean-Pierre, Roger, Georges
• Primary Examiner(s): Borchelt, Benjamin A.
• Assistant Examiner(s): Buczinski, S. C.
• Application Number:
  US05/123,288
• Time in Patent Office: 950 Days
• Field of Search: 356/28,4,5,16R,16RL
• US Class Current: 356/28
• CPC Class Codes: G01S 17/14 wherein a voltage or current pulse is initiated and terminated in accordance with the pulse transmission and echo reception respectively, e.g. using counters
• CPC Class Codes: G01S 17/50 Systems of measurement based on relative movement of target
• CPC Class Codes: G01S 17/58 Velocity or trajectory determination systems; Sense-of-movement determination systems

Abstract

An optical device making it possible to simultaneously measure the distance and radial speed of a moving object with respect to a fixed reference. The device includes at least one laser generator intended to emit at least one light pulse in the direction of said moving object, means to measure the propagation time of said pulse reflected by said moving object, and means for measuring the '"'"''"'"''"'"''"'"'Doppler'"'"''"'"''"'"''"'"' frequency of said reflected pulse. These spectral analysis means are made up of an acoustic-optical tank arranged in a parallel and monochromatic light beam.

Claims

1. Device for the simultaneous measurement of the distance d and the radial speed v of a moving object, comprsing a laser source capable of transmitting at least one light pulse with frequency gamma 1 in the direction of said moving object, detector means for detecting a light pulse reflected from said moving object at freqnecy gamma 2, the freqeuency gamma a 1- gamma 2 being proportional to v, means for counting the time Delta t separating the instant of transmission of said pulse at frequency gamma 1 and the instant of detection of said pulse at frequency gamma 2, d being proportional to Delta t, a laser source for transmitting a reference light beam at frequency gamma , optical means for diverting, in a common direction, a portion of said pulse at frequency gamma 1, a portion of said pulse at frequency gamma 2, and a portion of the beam at frequency gamma , detection means, arranged in said common direction, for transmitting signals at freqency gamma 1 - gamma and gamma 2 - gamma , the output of said detection means being connected to the input of a device for the spectral analysis of signals at frequency gamma 1 - gamma and gamma 2 - gamma , said device for the spectral analysis comprising a transducer, an acousticoptical tank and means for illuminating said tank with a light beam.

2. Device according to claim 1, wherein said source capable of transmitting at least one light pulse, includes a light modulator positioned in a path to receive a portion of said beam at frequency gamma .

3. Device according to claim 1, wherein said light beam illuminating said tank is inclined with respect to the said tank by an angle equal one half of the Bragg angle relative to the average frequency transmitted by said transducer.

4. Device according to claim 1, further including a plurality of transducers with different pass bands, and a plurality of acoustic-optical tanks, each of said transducers being connected to an acoustic-optical tank arranged in the path of said beam, each of said tanks being inclined upon said light beam by an angle equal to one half the Bragg angle relative to the central frequency of the pass band of the transducer which is associated with it.