LASER SPOT TRACKING WITH OFF-AXIS ANGLE DETECTION
1 Assignment
0 Petitions
Accused Products
Abstract
A laser spot tracker comprising a quadrant detector. A portion of a spot of laser light reflected from an object being illuminated (OBI) may be defocused to occupy a significant portion such as one-third of the field of view, while another portion remains focused, therefore allowing for quick calculation of the spot centroid. With such a “composite spot”, multiple target (OBI) positions may simultaneously be defined in elevation and azimuth with respect to null by analyzing the energy in each quadrant. The X and Y angle information (off null) for multiple targets (OBIs), and their codes may be displayed. For a large, defocused spot, two segmented multi-element detectors may be used, one in front of and the other behind the focal plane to reduce the effects of hot spots in a spot of laser light collected from an object being illuminated.
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Citations
26 Claims
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1. (canceled)
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6. Method of locating at least one object being illuminated by a laser designator comprising:
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providing a tracker having a quadrant detector in a field of view; receiving laser light scattered by the at least one object being illuminated; causing the received laser light to impinge as a corresponding at least one spot on the quadrant detector; for each of the spots of received laser light impinging on the detector, determining an angle of the spot of the received laser light relative to a center of the field of view; and increasing a spot size for a defocused portion of the received laser light, a remaining focused portion of the received laser light impinging as a relatively small spot on the detector. - View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 19, 20, 21, 22, 23, 24, 25, 26)
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10. Method of locating at least one object being illuminated by a laser designator comprising:
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providing a tracker having a quadrant detector in a field of view; receiving laser light scattered by the at least one object being illuminated; causing the received laser light to impinge as a corresponding at least one spot on the quadrant detector; for each of the spots of received laser light impinging on the detector, determining an angle of the spot of the received laser light relative to a center of the field of view; calculating azimuth and elevation angular co-ordinates for centroids of the spots by measuring energy of the received laser light in each quadrant of the detector; and adding signals from the quadrants on each side of an axis of interest, and deriving a ratio of these quadrants such that that the ratio varies as the spot traverses the quadrants across the axis of interest. - View Dependent Claims (18)
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11. Method of locating multiple objects being illuminated by at least one laser designator comprising:
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providing a tracker having a quadrant detector in a field of view; receiving laser light scattered by the multiple objects being illuminated; causing the received laser light to impinge as corresponding multiple spots on the quadrant detector; for each of the spots of received laser light impinging on the detector, determining an angle of the spot of the received laser light relative to a center of the field of view; and wherein the quadrant detector comprises two quadrant detectors, and further comprising; disposing a first of the two detectors effectively in front of a focal plane; disposing a second of the two detectors effectively behind the focal plane; and combining outputs of the two detectors to reduce inconsistencies of amplitude within the spots.
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12-15. -15. (canceled)
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16-17. -17. (canceled)
Specification