Extended Applicability of Optical Wind Sensing Techniques.
Abstract
The objectives of this study were to extend the applicability of optical crosswind sensing techniques to allow operation in rain and to determine the feasibility of using the techniques to study water vapor induced fluctuations at millimeter wavelengths. Two field tests were conducted to determine the effects of rain on optical crosswind sensors. The results showed that, (a) temporal filtering of the rain induced noise could improve the optical sensor performance under light rain conditions, (b) a simple frequency measurement of the fluctuating signal yielded a good representation of the windspeed variations, and (c) an improved turbulent signal to rain signal ratio can be obtained by using a receiver array to form a spatial filter. Temporal filtering imposes an upper limit on the speed which can be measured, but spatial filters would not have this limitation. Wavelength scaling of intensity fluctuation observed at optical frequencies and at millimeter wave frequencies is used to obtain estimates of temperature and water vapor induced scintillations at millimeter and submillimeter wavelengths in the propagation windows. The estimated values are on the order of those observed in a 35 GHz propagation experiment. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 01, 1981
- Accession Number
- ADA098021
Entities
People
- Jack Smith
Organizations
- University of Texas at El Paso