Method and apparatus for making absolute range measurements

Patent · Fri Jan 01 00:00:00 EST 1999

OSTI ID:872349

Allison, Stephen W ^[1]; Cates, Michael R ^[2]; Key, William S ^[1]; Sanders, Alvin J ^[1]; Earl, Dennis D ^[1]

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1. Knoxville, TN
2. Oak Ridge, TN

This invention relates to a method and apparatus for making absolute distance or ranging measurements using Fresnel diffraction. The invention employs a source of electromagnetic radiation having a known wavelength or wavelength distribution, which sends a beam of electromagnetic radiation through an object which causes it to be split (hereinafter referred to as a "beamsplitter"), and then to a target. The beam is reflected from the target onto a screen containing an aperture spaced a known distance from the beamsplitter. The aperture is sized so as to produce a Fresnel diffraction pattern. A portion of the beam travels through the aperture to a detector, spaced a known distance from the screen. The detector detects the central intensity of the beam. The distance from the object which causes the beam to be split to the target can then be calculated based upon the known wavelength, aperture radius, beam intensity, and distance from the detector to the screen. Several apparatus embodiments are disclosed for practicing the method embodiments of the present invention.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• DOE Contract Number: AC05-96OR22464
• Assignee: University of Tennesee Research Corporation (Knoxville, TN); Lockheed Martin Energy Research Corporation (Oak Ridge, TN)
• Patent Number(s): US 5914785
• OSTI ID: 872349
• Country of Publication: United States
• Language: English

Related Subjects

method
apparatus
absolute
range
measurements
relates
distance
ranging
fresnel
diffraction
employs
source
electromagnetic
radiation
wavelength
distribution
sends
beam
causes
split
hereinafter
referred
beamsplitter
target
reflected
screen
containing
aperture
spaced
sized
produce
pattern
portion
travels
detector
detects
central
intensity
calculated
based
radius
embodiments
disclosed
practicing
beam intensity
electromagnetic radiation
detector detects
diffraction pattern
calculated based
beam travels
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