Laser fresnel distance measuring system and method

US7446860B1 · kind B1 · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Jonathan Campbell · Harvest, US
• David L. Lehner · Huntsville, US
• Larry L. Smalley · Huntsville, US
• Alvin J. Sanders · Knoxville, US
• Dennis Duncan Earl · Knoxville, US
• Stephen W. Allison · Collierville, US
• Kelly Leigh Smith · Hebron, US

Key dates

• Filing date: Sep 18, 2006
• Grant date: Nov 4, 2008
• Expiry date: Oct 19, 2026

Classification

• Technology area (CPC G): Physics
• CPC primary: G01S17/02
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A method and system for determining range to a target are provided. A beam of electromagnetic energy is transmitted through an aperture in an opaque screen such that a portion of the beam passes through the aperture to generate a region of diffraction that varies as a function of distance from the aperture. An imaging system is focused on a target plane in the region of diffraction with the generated image being compared to known diffraction patterns. Each known diffraction pattern has a unique value associated therewith that is indicative of a distance from the aperture. A match between the generated image and at least one of the known diffraction patterns is indicative of a distance between the aperture and target plane.