The Theoretical Signal Response of a Passive Vertical Array in Shallow Water.
Abstract
The performance of an array of hydrophones is determined by its response to the signal and noise fields in which it operates. This paper investigates the theoretical response of a vertical line array to the signal field in shallow water, taking the noise field as isotropic. A normal-mode propagation model was used to provide the incident field. Two methods of combining hydrophone signals have been studied: a broadside beamforming approach and a mode-matching method. In the first, limitations to the gain of the array are found due to the particular propagation properties of the shallow water environment. The maximum gain is achieved with an array of length 15 lambda to 20 lambda. Longer arrays have degraded performance. The second, mode-matching, method involves applying amplitude and phase weightings to the array in order to enhance its response to a selected propagation mode; provided the most powerful mode is chosen, this gives some gain improvements. The effects of the relevant parameters, e.g. range, frequency, bottom conditions, sound-speed profile, etc., on array performance and its variation with array length have been investigated and general conclusions drawn. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1979
- Accession Number
- ADA082010
Entities
People
- Rachel M. Hamson
Organizations
- SACLANT ASW Research Centre