Atmospheric Transmission Measurement 1
Abstract
A novel method for improving the performance of laser communication links through a turbulent atmosphere, called 'fast tracking,' has been demonstrated experimentally in the laboratory to be both theoretically sound and practicable. Also, a design has been prepared for an atmospheric transmission measurement (ATM) system suitable for use at field sites for evaluation of atmospheric turbulence effects on ground-to-space laser communication links. The ATM system makes use of a fast-response (1 msec) star tracker and image intensity sensor; it is relatively simple and economical to use because neither flight hardware nor flight operations is involved, and it is capable of day or night operation. A field measurement plan is presented that is designed to aid in the selection of laser transmitter sites and to indicate the performance of ground-to-space links using those sites. Because the concept of optical antenna gain reciprocity is central to both the fast-tracking technique and to the ATM system, an initial experimental objective of the program was to test this theory. The key test was conducted over a 450-ft outdoor path using two laser- transmitter/pinhole-receiver units directed toward one another. To provide quantitative criteria for the design of the experiments, the reciprocity theory was reviewed in detail and was extended to cover the quasicoherent pinhole- detector receiver using a pinhole of finite size. Boresight requirements also were derived for a fast-tracking transmitter.
Document Details
- Document Type
- Technical Report
- Publication Date
- Aug 01, 1973
- Accession Number
- AD0913977
Entities
People
- B. Grabois
- H. V. Hance
Organizations
- Lockheed Martin Missiles and Space