Focused laser doppler velocimeter

US3984686A · kind A · utility

Inventors

• James C. Administrator of the National Aeronautics and Space Fletcher
• James W. Bilbro · Huntsville, US
• Werner K. Dahm · Huntsville, US
• Ronald B. Campbell, Jr. · Natick, US
• Robert M. Huffaker · Huntsville, US
• Harold B. Jeffreys · Decatur, US
• Albert V. Jelalian · Bedford, US
• Wayne H. Keene · Medfield, US
• Michael C. Krause · Huntsville, US
• Thomas R. Lawrence · Seattle, US
• Charles M. Sonnenschein · Natick, US
• David J. Wilson · Saint Peters, US
• James A. L. Thomson · Berkeley, US

Key dates

• Filing date: Dec 3, 1975
• Grant date: Oct 5, 1976
• Expiry date: Dec 3, 1995

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02A90/10
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

A system for remotely measuring velocities present in discrete volumes of air in which a CO.sub.2 laser beam is focused by a telescope at such a volume, a focal volume, and within the focusable range, near field, of the telescope. The back scatter, or reflected light, principally from the focal volume, passes back through the telescope and is frequency compared with the original frequency of the laser, and the difference frequency or frequencies represent particle velocities in that focal volume.