Research Effort in Atmospheric Propagation.
Abstract
This report presents work performed on: (1) The propagation of light through aircraft boundary layers; (2) The measurement and interpretation of refractive index spectra at high altitudes; and (3) The temporal spectra of angle-of-arrival fluctuations. A method of analyzing the data from the experiment on light beams propagating through aircraft boundary layers to obtain the boundary layer MTF was presented. Next a calculation of the effects of velocity and air mean free path on wire microthermal measurements was reported. The results were that the procedure of calibrating a microthermal sensor at zero velocity and making measurements at low altitude at Mach 1 can have up to 17% error. Further, flying at an altitude of 20 km where the air molecular mean free path is larger can increase the error another 4%. A discussion of refractive index spectra obtained from airborne microthermal measurements resulted in an empirical formula which could be made to fit the data. The formula involved the addition of two von Karman type of spatial spectra. The data showed outer scales between 300 to 1000 meters. Finally, results of an analysis on the temporal spectrum of angle-of-arrival fluctuations were presented. The model included a moving source, and a position proportional detector. The resulting curve showed a peak contribution from refractive index fluctuations of size equal to one fifth the source height.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1975
- Accession Number
- ADA014826
Entities
People
- D. D. Duncan
- S. A. Collins Jr.
- Y. J. Liu
Organizations
- Ohio State University