ASA 127th Meeting M.I.T. 1994 June 6-10

3aNS7. Software system for quantitative, observer-based analyses of aircraft noise.

N. H. Reddingius

M. D. Sneddon

J. S. Smyth

S. Fidell

BBN Systems and Technol., 21120 Vanowen St., Canoga Park, CA 91303

The National Park Service's Overflight Decision Support System (NODSS) now provides a functional capability for estimating airspace volumes above points and areas on the ground that should be avoided if aircraft are to remain unnoticed. Calculations of these volumes are sensitive to aircraft noise emissions, background noise levels at observers' positions, terrain shielding, atmospheric absorption, and geometric spreading. NODSS provides a complete and consistent framework for performing acoustic detectability-based calculations as well as more conventional aircraft emission-based analyses, and produces results that can be displayed in easily understood graphic form. The initial use intended for NODSS is to perform engineering analyses of airspace restrictions associated with restoration of natural quiet in Grand Canyon National Park, pursuant to Public Law 100-91. [Effort supported in part by U.S. National Park Service.]