A Physical Approach to Dynamic Modeling of Detection Performance Using Performed Beams in a Multitarget Environment.
Annual rept. 1 May 71-30 Apr 72,
BOLT BERANEK AND NEWMAN INC ARLINGTON VA
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Methods are developed for realistically analyzing the detection performance of preformed beam sonars operating in multitarget or multiship environments. A key technique allows assessment of the performance of operators using two-dimensional modulated displays such as bearing-time recorders, which are subject to uneven background marking spoking. A systematic method is also developed for calculating the aggregate received signal power produced by a multiship formation. The method accounts for the radiational directivity of each source, the transmission medium, and the directional response of the array-beamformer combination of the receiving sonar. The calculation is executed by a digital program that generates a polar plot which shows the aggregate response as a function of the bearing of the sonar platform. To serve as a framework for organizing complete analyses, a modified sonar equation is derived which separates the array-beamformer operations on signal and noise fields. This permits the composite noise field representation to be synthesized from basic components associated with specific types of generating sources. Another analysis derives the quantitative dependence of the detection differential on the characteristics of the receiver input filter and on the shapes of the spectral density functions of signal and noise. Finally, an alternative characterization of the sound-reflecting properties of targets is discussed which would form the basis for more valid assessment of the tactical performance of active sonars. Author
- Acoustic Detection and Detectors