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Performance Bounds on Atmospheric Acoustic Sensor Arrays Operating in a Turbulent Medium. 1. Plane-Wave Analysis
Performance Bounds on Atmospheric Acoustic Sensor Arrays Operating in a Turbulent Medium 1 PlaneWave Analysis Author:Sandra L. Collier, D. K. Wilson This is a ARMY RESEARCH LAB ADELPHI MD COMPUTATIONAL AND INFORMATION SCIENCES DIRECTORATE report procured by the Pentagon and made available for public release. It has been reproduced in the best form available to the Pentagon. It is not spiral-bound, but rather assembled with Velobinding in a soft, white linen cover. The Storming Media report n... more »umber is A042304. The abstract provided by the Pentagon follows: The performance bounds of an atmospheric acoustic array operating in a turbulent medium with fluctuations described by a von Karman spectrum are investigated. This treatment considers a single monochromatic source and a line- of-sight propagation path. The primary interests are in calculating the Cramer- Rao lower bounds (CRLBs) of the azimuthal and zenith angles of arrival (AOAs) and in observing how these bounds change with the introduction of additional unknowns, such as the normalized propagation distance (to wavelength), turbulence parameters, and signal-to-noise ratio (SNR). In both two and three dimensions, the CRLBs of the AOAs increase significantly for large values of the index-of-refraction variance and normalized propagation distance. For small values of the index-of-refraction variance and normalized propagation distance, the SNR is the limiting factor. For the two-dimensional treatment, the estimate of the AOA will decouple from the estimates of the other parameters with the appropriate choice of array geometry. In three dimensions, again with an appropriate choice of array geometry, the estimates of the azimuth and zenith will decouple from the estimates of the other parameters, but because of the constraints of the turbulence model, they will remain coupled to one another.« less