US 4,736,247 AGranted

Range and range rate system

AssigneeThe United States of America as represented by the Administrator of the National Aeronautics and Space Administration

InventorsOlin L. Graham, Jim K. Russell, Walter L. Epperly

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Abstract

A video controlled solid state range finding system includes an opto-electric camera and a helium neon laser. The laser applies coherent light to a beam splitter which applies a reference beam to the camera and an outgoing beam to a first angularly variable reflector which directs the outgoing beam to the object. An incoming beam from the object is reflected to a second angularly variable reflector and thus to the camera via the beam splitter. The first and second reflectors are configured with respect to the beam splitter so that the distance D travelled by the outgoing beam is the same as the distance travelled by the incoming beam from the second reflector to the beam splitter. The reference beam produces a reference signal and the incoming beam produces an object signal at the camera. The difference between the reference and object signals is used to vary the angle A between the outgoing beam and the reference line (31), and the angle B between the incoming beam and the reference line. The angles A and B are maintained essentially equal. The difference between the reference signal is used to provide an input to a rotator driven circuit to vary the angles of the first and second reflectors until the reference signal and object signal are coincident. Range R is then determined as R=D tan A.

Claims11

Dependent claims

A system for determining the range of a distant object comprising,

source means for producing a source beam of coherent light,
opto-electric means having a photo-responsive surface for generating one or more signals indicative of the position at which one or more beams of coherent light strike said surface,
beam splitter means stationarily disposed with respect to said opto-electric means and said source means for splitting said source beam into a reference beam and an outgoing beam, said reference beam being directed to said opto-electric means for generating a reference signal,
first angularly variable reflecting means for redirecting said outgoing beam to a point on said distant object, said outgoing beam being reflected as an incoming beam from said object,
second angularly variable reflecting means responsive to said incoming beam for reflecting said incoming beam to said beam splitter means, said beam splitter means directing said incoming beam to said surface of said opto-electric means for generating an object signal,
said first angularly variable reflecting means being placed from said beam splitter means such that said outgoing beam travels a distance D between said beam splitter means and said first angularly variable reflecting means,
said second angularly variable reflecting means being placed from said beam splitter means such that said incoming beam travels a distance D between said beam splitter means and said second angularly variable reflecting means,
means for generating an angle signal .alpha. proportional to the angle between said outgoing beam and a reference line between beam reflecting points of said first and second reflecting means,
means for maintaining said angle .alpha. between said outgoing beam and said reference line substantially equal to an angle .beta. between said incoming beam and said reference line, and
computer means responsive to said angle signal .alpha. when said object signal and said reference signals are coincident for generating a range signal R according to the relation, R=D tan .alpha..

7 more elements

A system for determining the range of a distant object comprising,

source means for producing a source beam of coherent light,
opto-electric means having a photo-responsive surface for generating one or more signals indicative of the position at which one or more beams of coherent light strike said surface,
beam splitter means stationarily disposed with respect to said opto-electric means and said source means for splitting said source beam into a reference beam and an outgoing beam, said reference beam being directed to said opto-electric means for generating a reference signal,
first reflecting means for redirecting said outgoing beam to a point on said distant object, said outgoing beam being reflected as an incoming beam,
second reflecting means responsive to said incoming beam for reflecting said incoming beam to said beam splitter means, said beam splitter means directing said incoming beam to said surface of said opto-electric means for generating an object signal,
said first reflecting means being placed from said beam splitter means such that said outgoing beam travels a distance D between said beam splitter means and said first reflecting means, said outgoing beam forming an angle .alpha. with respect to a reference line between beam reflecting points of said first and second reflecting means,
said second reflecting means being placed from said beam splitter means such that said incoming beam travels a distance D between said beam splitter means and said second reflecting means, said incoming beam forming an angle .alpha. with respect to a reference line between beam reflecting points of said first and second reflecting means,
means for detecting the difference between said reference signal and said object signal to produce a difference signal between said object signal and said reference signal,
computer storage means for storing data corresponding to the range of said distance object as a function of said difference signal, and
computer means responsive to said difference signal for accessing said computer storage means and generating a distance signal corresponding to said difference signal.

7 more elements

Dependencies are inferred from the claim text.