Method and apparatus for making absolute range measurements

Patent · Tue Jun 22 04:00:00 EDT 1999

OSTI ID:6158742

Allison, S W; Cates, M R; Key, W S; Sanders, A J; Earl, D D

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 beam splitter''), and then to a target. The beam is reflected from the target onto a screen containing an aperture spaced a known distance from the beam splitter. 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. 9 figs.

• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC05-96OR22464
• Assignee: Univ. of Tennessee Research Corp., Knoxville, TN (United States); Lockheed Martin Energy Research Corp., Oak Ridge, TN (United States)
• Patent Number(s): US 5914785; A
• Application Number: PPN: US 9-018502
• OSTI ID: 6158742
• Country of Publication: United States
• Language: English

Related Subjects

440800* -- Miscellaneous Instrumentation-- (1990-)
47 OTHER INSTRUMENTATION
BEAM SPLITTING
DESIGN
MEASURING INSTRUMENTS
MEASURING METHODS
OPTICAL SYSTEMS
RANGE FINDERS