Geoffrey S. Edelson
Lockheed Sanders, Inc., MAN6-2000, P. O. Box 868, Nashua, NH 03061-0860
Donald W. Tufts
Univ. of Rhode Island, Kingston, RI 02881
Insights, simplified formulas, and figures are provided to aid in the design of unconventional towed array systems; specifically, for the case of a spatially referenced towed array (SPARTA). The SPARTA consists of two subarrays, one of which is moving and one of which is fixed in position. The estimated bearing of an acoustic source and the resolution in bearing of multiple acoustic sources can be improved if a SPARTA is used instead of a conventional towed array (CTA) or a fixed-position array (FPA). The CRLB provides a framework within which different array configurations can be compared in order to point the way toward better design possibilities. The capabilities attributable to the SPARTA are emphasized because of its overall potential to provide lower variance on bearing and bearing resolution than a FPA or CTA. A summary is given of the varying abilities of towed array configurations to estimate bearing, determine when the use of a SPARTA is desirable from the perspective of accurately estimating bearing, and help to build an understanding of design principles for passive towed line array systems. Important properties are derived, which characterize the ability of these configurations, with appropriate signal processing, to jointly estimate the bearing and frequency of each source.