Three and five axis laser tracking systems
First Claim
1. A laser tracking system, comprising:
- a laser light source (27) for producing a beam (42) of coherent light having first and second beam components of different wavelengths;
a target point (A) and a tracking point (B) having a separation therebetween;
first optical means associated with said tracking point for reflecting said first beam component and transmitting said second beam component from said tracking point to said target point;
second optical means associated with said target point for transmitting a first portion of said second beam component and reflecting a second portion of said second beam component toward said first optical means, said first optical means including means for reflecting said second portion of said second beam component toward said second optical means, and said second optical means including means for transmitting a first part of said second portion and reflecting a second part of said second portion;
control means (30) for controlling said first optical means to direct said second beam component to said target point and for controlling said second optical means to reflect said second portion resultant from said second beam component back to said tracking point, said control means controlling said first and second optical means in at least two degrees of freedom;
angular measuring means for measuring said at least two degrees of freedom; and
means associated with one of said tracking and target points for measuring said separation from said first beam component and at least part of said second portion of said second beam component.
1 Assignment
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Reexaminations
Accused Products
Abstract
A tracking system for measuring at least the spatial coordinates of a target and possibly the angular orientation of the target. A collimated beam is directed to the target and a mirror attached to the target reflects this beam back to a tracking point. Photosensors attached to the tracking or target point provide error signals to a servo system which controls optics at the tracking or target points to provide the direction necessary to accomplish the coincidence of the beams. An interferometer interferes the source beam with the beam that has travelled twice between the tracking and target points in order to measure the separation. By measuring the directions of the beams relative to structure attached to the tracking and target points, the target point can be located in spatial coordinates and additionally the orientation of the target structure can be determined.
339 Citations
16 Claims
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1. A laser tracking system, comprising:
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a laser light source (27) for producing a beam (42) of coherent light having first and second beam components of different wavelengths; a target point (A) and a tracking point (B) having a separation therebetween; first optical means associated with said tracking point for reflecting said first beam component and transmitting said second beam component from said tracking point to said target point; second optical means associated with said target point for transmitting a first portion of said second beam component and reflecting a second portion of said second beam component toward said first optical means, said first optical means including means for reflecting said second portion of said second beam component toward said second optical means, and said second optical means including means for transmitting a first part of said second portion and reflecting a second part of said second portion; control means (30) for controlling said first optical means to direct said second beam component to said target point and for controlling said second optical means to reflect said second portion resultant from said second beam component back to said tracking point, said control means controlling said first and second optical means in at least two degrees of freedom; angular measuring means for measuring said at least two degrees of freedom; and means associated with one of said tracking and target points for measuring said separation from said first beam component and at least part of said second portion of said second beam component. - View Dependent Claims (2, 3)
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4. A laser tracking system, comprising:
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a laser light source associated with a tracking point for producing a beam of coherent light; a first rotatable planar reflector (28) associated with said tracking point for reflecting said beam from said laser light source into a first beam; a second rotatable planar reflector (20) associated with a target point for reflecting a beam incident thereupon into a second beam, said tracking point and said target point being separated by a separation; control means for controlling said first and second reflectors to direct said first beam to said target point and to direct said second beam resultant from said first beam to said tracking point, said control means including first and second detecting means and being responsive to respective outputs thereof for respectively controlling said first and second reflectors to each rotate about at least two substantially orthogonal axes; and interferometric means (44,48) associated with said tracking point for measuring said separation by interfering said light beam from said laser light source before it is reflected by said first reflector with light from said second beam, wherein said laser system further comprises a partially reflecting mirror (74) coupled to said second planar reflector, said first detecting means receiving a portion of said first beam reflected by said partially reflecting mirror and said second detecting means receiving a portion of said first beam transmitted by said partially reflecting mirror. - View Dependent Claims (5, 6)
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7. A laser tracking system, comprising:
a laser light source associated with a tracking point (A) for producing a beam of coherent light;
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8. a first rotatable planar reflector (28) associated with said tracking point for reflecting said beam from said laser light source into a first beam;
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a retroreflector (120) associated with a target point (B) for reflecting a beam incident thereupon into a second beam anti-parallel to said incident beam, said tracking point and said target point being separated by a separation; control means for controlling said first reflector to direct said first beam to said retroreflector at said target point, said control means controlling said first reflector to rotate in at least two degrees of freedom, said control means including means (128) associated with said tracking point for determining the planar position of a light beam falling thereupon and receiving said second beam; angular measuring means for measuring said at least two degrees of freedom; and interferometric means (124,48) associated with said tracking point for measuring said separation by interfering said light beam from said laser light source before it is reflected by said first reflector.
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9. A laser tracking system, comprising:
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a laser light source for producing an initial beam comprising two orthogonally polarized components; a first beamsplitter receiving said initial beam on a first face thereof; a fringe counter disposed to receive light from a second face of said first beamsplitter; a first polarizing beamsplitter disposed to receive light on a first face thereof from a third face of said first beamsplitter; two reflectors disposed on opposing second and third faces of said first polarizing beamsplitter; a tracking mirror, rotatable in two directions, disposed to receive light from a fourth face of said first polarizing beamsplitter; first means for rotating said tracking mirror in two directions; a quarter-wave retardation plate disposed between said tracking mirror and said first polarizing beamsplitter; a partially transmitting mirror, disposed at a target point, receiving a light beam from said tracking mirror on a first principal face; a second polarizing beamsplitter having a first face facing a second principal face of said partially transmitting mirror; a quarter-wave retardation plate disposed between said partially transmitting mirror and second polarizing beamsplitter; two dual-axis linear photosensors receiving light from a second face opposing said first face and from a third face of said second polarizing beamsplitter; second means for rotating together in two directions said partially transmitting mirror, said second polarizing beamsplitter and said two photosensors; and means for controlling said first and second rotating means responsive to said photosensors to direct a first beam a light incident upon said tracking mirror from said first polarizing beamsplitter toward said partially reflecting mirror and to direct a second beam resultant from a reflection of said first beam from said partially reflecting mirror to said tracking mirror. - View Dependent Claims (11)
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10. A method of tracking a target point, comprising:
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variationally directing an initial beam of coherent light from a tracking point to said target point in a collimated incident first beam; specularly reflecting a first portion of said first incident beam from said target point back to said tracking point in a collimated reflected second beam and transmitting a second portion of said first beam; specularly reflecting said second beam from said tracking point to said target point in a collimated reflected third beam; specularly reflecting a first portion of said third beam from said target point back to said tracking point in a collimated reflected fourth beam and transmitting a second portion of said third beam; angularly controlling said directing and reflecting at said tracking and target points in at least two degrees of freedom; measuring said degrees of freedom from said second portion of said first beam and said second portion of said third beam; interfering said initial beam with said fourth beam; and measuring a separation of said target point from said tracking point by measuring an interference pattern of said interfering.
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12. A laser tracking system, comprising:
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a laser light source associated with a tracking point (A) for producing a beam of coherent light; interferometric means associated with said target point for reflecting a first portion of said beam from said laser light source and for transmitting a second portion of said beam from said laser light source, said first portion of said beam comprising a first beam and said second portion of said beam comprising a second beam, said interferometric means being rotatable in at least a first two degrees of freedom; a planar reflector (20) associated with a target point (B) for receiving said second beam and reflecting it into a third beam, said tracking point and said target point being separated by a separation, said planar reflector being rotatable in at least a second two degrees of freedom; control means for controlling said interferometric means to direct said second beam to said target point and said third beam to said tracking point, said control means including first and second detecting means and being responsive to respective outputs thereof for respectively controlling said interferometric means and said planar reflector in said first and second two degrees of freedom; and counter means associated with said tracking point for measuring said separation by interfering said first beam with light from said third beam. - View Dependent Claims (14)
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13. A laser tracking system, comprising:
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a laser light source for producing an initial beam comprising first and second beams which are orthogonally polarized components of said initial beam; an interferometer associated with a target point and including a beamsplitter for receiving said initial beam and reflecting said first beam and transmitting said second beam; first means for rotating said interferometer in two directions; a partially transmitting target mirror disposed at said target point for receiving said second beam from said interferometer on a first principal face thereof; first and second photosensors receiving light transmitted by said target mirror; second means for rotating together in two directions said target mirror and said first and second photosensors; and means for controlling said first and second rotating means responsive to said first and second photosensors to direct said second beam transmitted by said beamsplitter toward said target mirror and to direct a third beam resultant from a reflection of said first beam from said target mirror to said beamsplitter in said interferometer.
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15. A laser tracking system, comprising:
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a laser light source associated with a tracking point for producing a beam of coherent light; a first rotatable planar reflector associated with said tracking point for reflecting said beam from said laser light source into a first beam; a second rotatable planar reflector associated with a target point for reflecting a beam incident thereupon into a second beam, said tracking point and said target point being separated by a separation; control means for controlling said first and second reflectors to direct said first beam to said target point and to direct said second beam resultant from said first beam to said tracking point, said control means controlling said first and second reflectors to rotate about at least two axes; and interferometric means associated with said tracking point for measuring said separation by interfering said light beam from said laser light source before it is reflected by said first reflector with light from said second beam, wherein said laser system further comprises a motor for causing one of said first and second reflectors to rotate and a drive circuit for driving said motor, said control system further comprises at least two photodetectors for detecting a position of a beam incident thereon, and wherein said control means includes a proportional-integral-differential controller receiving signals from at least one of said photosensors and providing error signals to said drive circuit.
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16. A laser tracking system, comprising:
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a laser light source associated with a tracking point for producing a beam of coherent light; a first rotatable planar reflector associated with said tracking point for reflecting said beam from said laser light source into a first beam; a second rotatable planar reflector associated with a target point for reflecting a beam incident thereupon into a second beam, said tracking point and said target point being separated by a separation; control means for controlling said first and second reflectors to direct said first beam to said target point and to direct said second beam resultant from said first beam to said tracking point, said control means controlling said first and second reflectors to rotate about at least two axes; and interferometric means associated with said tracking point for measuring said separation by interfering said light beam from said laser light source before it is reflected by said first reflector with light from said second beam, wherein said laser system further comprises a stepping motor for causing one of said first and second reflectors to rotate.
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Specification