Spatial positioning and measurement system

• US 5,110,202 A
• Filed: 12/31/1990
• Issued: 05/05/1992
• Est. Priority Date: 08/17/1990
• Status: Expired due to Term

• Current Assignee: Nikon Metrology NV (Nikon Corporation)
• Original Assignee: Spatial Positioning Systems, Inc.
• Inventors: Dornbusch, Andrew W., Pratt, Timothy, Lundberg, Eric J., Beliveau, Yvan J.
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US07/636,459
• Time in Patent Office: 491 Days
• Field of Search: 356/1, 356/4, 356/141, 356/152, 172/4.5
• US Class Current: 356/3.12
• CPC Class Codes: G01C 15/002 Active optical surveying means optical plumbing G01C15/105
• CPC Class Codes: G01S 5/16 using electromagnetic waves other than radio waves

Abstract

A spatial positioning and measurement system provides three-dimensional position and/or measurement information of an object using one or more fixed referent station systems, and one or more portable position sensor systems. Each fixed station produces at least one primary laser beam which is rotated at a constant angular velocity about a vertical axis. The primary laser beam has a predetermined angle of divergence or angle of spread which is inclined at a predetermined angle from the vertical axis. Each fixed station also preferably includes at least one reflective surface for generating a secondary laser beam.

The portable position sensor includes a light sensitive detector, computer, and a display. The light sensitive detector can be formed of at least one "axicon" which directs incoming light to a photosensitive detector. The photosensitive detector generates an electrical pulse when struck by crossing laser beam and sends this pulse to the computer. The computer time labels each received pulse, which corresponds to the time of a laser beam crossing the axicon.

For any point which is crossed by the two laser beams, a horizontal angle can be determined from the time difference between the time of crossing of the primary and reflected laser beam. Once these horizontal angles are known for three fixed referent stations, the point of intersection of three planes, and thus the three dimensional position of the point, is determined. Q A C

Claims

1. A spatial positioning and measurement system for determining the instantaneous x-y-z position of an object in a three-dimensional Cartesian coordinate system, comprising:

at least one fixed reference station, each said station emitting a primary laser beam having an angle of divergence φ and

being about an axis at an angle of inclination β

, each said station including at least one reflective surface for generating a secondary laser beam having said angle of divergence φ and

being rotated in an opposite direction from said primary beam about said axis at said angle of inclination β

;

a portable position sensor located at said object, said sensor including detector means for detecting said primary and reflected laser beams, said detector means emitting a signal indicating detection of a laser beam, said sensor also including at least one axicon for directing incoming light to said detector means; and

a determination means for determining the position of the object based on the signals emitted from said detector means.

2. A system as claimed in claim 1, wherein three fixed reference stations are used.

3. A system as claimed in claim 2, wherein said determination means includes a computer which time-labels the detection of each primary and reflected laser beam detected by the detector and stores each said time-label in memory

4. A system as claimed in claim 3, wherein said determination means calculates the three-dimensional position of the sensor according to the following formulae:

##EQU3##

5. A system as claimed in claim 1, wherein said reflector is curved.

6. A system as claimed in claim 1, wherein each said reference stations emits two primary laser beams.

7. A system as claimed in claim 6, wherein two such reference stations are used, and said determination means includes a computer which time-labels the detection of each primary and reflected laser beam detected by the detector and stores each said time-label in memory, wherein said computer calculates the three-dimensional position of the sensor according to the following formulae:

##EQU4##

8. A system as claimed in claim 6, wherein one such reference station is used, and said sensor includes three axicons for directed incoming light to three corresponding detectors means.

9. A method of determining relative spatial positioning in a three-dimensional Cartesian coordinate system, comprising:

emitting a divergent primary laser beam and rotating said primary laser beam about an axis at an angle of inclination β

;

generating a divergent reflected laser beam and rotating said reflected laser beam in an opposite direction from said primary beam about said axis at said angle of inclination β

;

directing incoming light from said primary and reflected laser beams to at least one photodetector via an axicon lens;

emitting a signal from said at least one detector corresponding to the detection of each of said laser beams;

time-labelling each detection of said laser beams at said at least one detector; and

calculating the relative spatial positioning based on the signals emitted from said at least one detector.

10. A spatial positioning and measurement system for determining the instantaneous x-y-z position of an object in a three-dimensional Cartesian coordinate system, comprising:

at least one fixed reference station, each said reference station emitting at least one primary radiation beam having an angle of divergence and being rotated about an axis at an angle of inclination β

, said reference station also emitting at least one secondary radiation beam having said angle of divergence

and being rotated about said axis in an opposite direction from said primary beam at said angle of inclination β

;

a portable position sensor located at said object, said sensor including detector means for detecting said primary and secondary beams and emitting a signal each time one of said beams is detected; and

determination means for determining the position of the object based on the signals emitted from said detectors means.

11. A system as in claim 10, wherein said sensor includes at laest one axicon for directing incoming light to said detector means.

12. A system as in claim 10, wherein two primary beams and two secondary beams are emitted.

13. A system as in claim 10, wherein said station includes at least one reflective surface for generating said at least one secondary beam.

14. A system as in claim 13, wherein said surface is curved.