Range finder wherein distance between target and source is determined by measuring scan time across a retroreflective target
First Claim
1. A target determining apparatus comprising in combination;
- a light source at a first location;
means at said first location for scanning a beam from said light source along a scanning path at a known rate of angular velocity;
a retroreflector and a non-retroreflector adapted to be at a second location in said scanning path to reflect said light beam from said retroreflector back toward said scanning means;
one of said retroreflector and said nonretroreflector being a target having leading and trailing edges;
said light source beam being narrow in the direction of said scanning path and narrower than the scanned width of said target;
one of the target scan width and target distance being known;
a photoreceptor positioned at said first location to be responsive to any reflected light beam from said retroreflector; and
target determining means to determine the other of said target scan width and distance with distance related inversely, and the target scan width related directly, to the length of time between the light beam scan from the target leading edge across the target to the trailing edge.
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Accused Products
Abstract
A target has leading and trailing edges which are boundaries between a retroreflector and a non-retroreflector. The target is used in target determining apparatus for distance, width, azimuth, gauging, profiling, object detection, and particular target identification. A laser light source scans along a scanning path across the target. The retroreflector reflects light back toward the scanning means where it is received in a photoreceptor to determine the angles of the target edges. The distance to the target and the width are inversely proportional to the length of time that the light beam scans across the target. The laser light also scans across a reference point and the length of time between this reference point and the reflection from the target is directly proportional to the azimuthal position of the target relative to the reference. Further, the target may include a plurality of reflective and non-reflective strips transverse to the scanning path to establish binary indicia on the target. This results in a series of pulses from the photoreceptor as the beam scans the width of the target. This information is then decoded to determine the binary indicia and hence identify that particular target. The foregoing abstract is merely a resume of one general application, is not a complete discussion of all principles of operation or applications, and is not to be construed as a limitation on the scope of the claimed subject matter.
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Citations
30 Claims
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1. A target determining apparatus comprising in combination;
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a light source at a first location;
means at said first location for scanning a beam from said light source along a scanning path at a known rate of angular velocity;a retroreflector and a non-retroreflector adapted to be at a second location in said scanning path to reflect said light beam from said retroreflector back toward said scanning means; one of said retroreflector and said nonretroreflector being a target having leading and trailing edges; said light source beam being narrow in the direction of said scanning path and narrower than the scanned width of said target; one of the target scan width and target distance being known; a photoreceptor positioned at said first location to be responsive to any reflected light beam from said retroreflector; and target determining means to determine the other of said target scan width and distance with distance related inversely, and the target scan width related directly, to the length of time between the light beam scan from the target leading edge across the target to the trailing edge. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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13. A target determining apparatus comprising in combination:
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a light source; means for scanning a base from said light source along a scanned path; a target mounted on an object adapted to be in said scanning path to reflect said light beam back toward said scanning means; a photoreceptor positioned to be responsive to any reflected light beam from said target reflector; a plurality of retroreflective and nonreflective strips transverse to said scanning path constituting said target to establish binary indicia on said target; means connected to said photoreceptor to read the binary indicia on said target; and means to compensate for differing effective scan times of said strip in accordance with variations in distance to said target. - View Dependent Claims (14, 15, 16)
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27. A target determining apparatus comprising in combination:
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a light source at a first location;
means at said first location for scanning a beam from said light source along a scanning path at a known rate of angular velocity;a retroreflector and a non-retroreflector adapted to be at a second location in said scanning path to reflect said light beam from said retroreflector back toward said scanning means; said non-retroreflector being a target having leading and trailing edges; said light source beam being narrow in the direction of said scanning path and narrower than the scanned width of said target; a photoreceptor positioned at said first location to be responsive to any reflected light beam from said retroreflector; and target determining means to determine the presence of a target in the scan of said light beam including means to measure the angle between the light beam scan from the target leading edge across the target to the trailing edge. - View Dependent Claims (28, 29, 30)
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Specification