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Proceedings Paper

Wind Satellite (WINDSAT) Experiment
Author(s): John S. Osmundson
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Paper Abstract

WINDSAT is a proposed future space-based global wind measuring system. A Shuttleborne experiment is proposed as a proof-of-principle demonstration before development of a full operational system. WINDSAT goals are to measure wind speed and direction to ± 1 m/s and ± 10 deg accuracy, respectively, over the entire earth from 0- to 20-km altitude with 1-km altitude resolution. The wind measuring instrument is a coherent lidar incorporating a pulsed CO2 TEA laser transmitter and a continuously scanning 1.25-m-diameter optical system. The laser fires at an 8-Hz prf and the optics performs a conical scan at 60° to nadir every 7 seconds. Each laser pulse is backscattered by aerosols in the earth's atmosphere. The original transmitted laser frequency is Doppler shifted since the aerosols are moving with the wind. The wind speed is measured by heterodyne detecting the backscattered return laser radiation and measuring the frequency shift. Each wind speed measurement must be repeated at a different look angle in order to determine wind direction. A special feature of combining a continuously rotating optical system with heterodyne detection is the requirement for active alignment or image motion compensation of the return radiation. Short-term pointing stability of 2 μrad and long-term pointing accuracy of 100 μrad is required for efficient detection and accurate wind mapping. A separate WINDSAT attitude determination and control system is required to meet these accuracies.

Paper Details

Date Published: 3 April 1981
PDF: 4 pages
Proc. SPIE 0265, Shuttle Pointing of Electro-Optical Experiments, (3 April 1981); doi: 10.1117/12.959886
Show Author Affiliations
John S. Osmundson, Lockheed Palo Alto Research Laboratory (United States)

Published in SPIE Proceedings Vol. 0265:
Shuttle Pointing of Electro-Optical Experiments
William Jerkovsky, Editor(s)

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