| US 7,446,860 B1 | ||
| Laser fresnel distance measuring system and method | ||
| Jonathan W. Campbell, Madison, Ala. (US); David L. Lehner, Huntsville, Ala. (US); Larry L. Smalley, Huntsville, Ala. (US); Kelly L. Smith, deceased, late of Madison, Ala. (US), by Molly C. Smith, legal representative, ; Alvin J. Sanders, Knoxville, Tenn. (US); Dennis Duncan Earl, Knoxville, Tenn. (US); and Stephen W. Allison, Knoxville, Tenn. (US) | ||
| Assigned to The United States of America as represented by the Administrator of the National Aeronautics and Space Administration, Washington, D.C. (US) | ||
| Filed on Sep. 18, 2006, as Appl. No. 11/527,648. | ||
| Int. Cl. G01C 3/08 (2006.01) | ||
| U.S. Cl. 356—4.03 | 29 Claims |
| 1. A method of determining range to a target, comprising the steps of:
transmitting a beam of electromagnetic energy through an aperture in an opaque screen such that a portion of said beam passes
through said aperture to generate a region of diffraction that varies as a function of distance from said aperture;
focusing an imaging system on a target plane in said region of diffraction wherein an image of said target plane is generated;
and
comparing said image with a plurality of known diffraction patterns with each of said known diffraction patterns having a
unique value associated therewith that is indicative of a distance from said aperture, wherein a match between said image
and at least one of said known diffraction patterns is indicative of a distance between said aperture and said target plane.
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