Angle of Arrival Detection Through Analysis of Optical Fiber Intensity Patterns
Abstract
This thesis examined the feasibility of using optical fibers for angle of arrival (AOA) detection. Specifically, a uniform amplitude plane wave was transmitted through a 3mm diameter, multimode, step-index, plastic fiber. Fiber lengths of 1in, 2in, and 3in were investigated. The output intensity pattern from each optical fiber was detected by a 512 x 512 resolution, charge injection device (CID) camera. The data array from the camera was preprocessed with a median filter, and normalized to the peak intensity. A fast Fourier transform converted the data to the frequency domain where the fundamental and first three harmonic frequencies were extracted. These 49 numbers represented components of a feature vector representing the pattern related to a specific AOA. Twenty-six template vectors, each representing a 1 deg increment from 0 deg to 25 deg, were created. Test vectors were compared to template vectors using Euclidean distance. The minimum distance classified the test vector AOA. (kr)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1989
- Accession Number
- ADA215421
Entities
People
- John W. Welker
Organizations
- Air Force Institute of Technology