Analytic Approximation to Randomly Oriented Spheroid Extinction
Abstract
The present and future electro-optic capabilities of fire control systems require full spectrum obscurants as an effective countermeasure. It is well known that spherical particles can obscure efficiently only in the visible region of the spectrum. In the near and far infrared as well as in the microwave region of the spectrum the use of non-spherical particles is mandatory. Imaging through ocean waters and dusty environments both require knowledge of the extinction by non-spherical particles. Communications, remote sensing, surveillance and radar propagation frequently encounter scenarios involving non- spherical particles. The estimation of electromagnetic extinction through dust or other non-spherical atmospheric aerosols and hydrosols is an essential first step in the evaluation of the performance of all electro-optic systems. To date, the theoretical exploration of the effect of these types of particles on the performance of obscurants has been either extremely restrictive prohibitively expensive. This work partially overcomes these severe restrictions and will aid in the design and performance analysis of potential new obscurants. For instance, a factor greater than ten thousand in computational speed has been achieved with minimal loss in accuracy. Furthermore, the present approach is much more flexible in the sense that extremely elongated or flattened particles can now be modeled. Elongated particles are through to be good millimeter wave obscurants and flattened or flake-like particles are known to be good infrared obscurants. The immediate objective of this work is to significantly reduce the computational burden in calculating the extinction from non-spherical particles. This allows for the exploration of the effects of non-spherical particles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1993
- Accession Number
- ADA274195
Entities
People
- B. T. Evans
- G. R. Fournier