Aspects of Cardioid Processing
Abstract
It is well known that conventional active towed arrays suffer from 'The Ambiguity Problem' in which it is impossible to distinguish returns from port or starboard. Although operational methods for overcoming this problem exist they are time-consuming and cannot be used for a single ping. One proposed method of coping with these difficulties is to use a triplet array in which the direction of arrival of a signal can be ascertained on a single ping. This report details a broadband algorithm which has been developed and is currently being used at the Saclant Undersea Research Centre. The algorithm was specifically designed to be used on a delay-type beamformer in which shading cannot be applied at the beamlevel. A second algorithm employing the full-flexibility of a 3d beamformer is also described and the two algorithms are compared for their performance in terms of left-right suppression and SNR for which analytical expressions are computed. It is shown that both of the algorithms have desirable but different features. The algorithms are applied to data taken from the trial BACCHUS'98 and the results obtained are used to help validate the theoretical results and to give an indication of the performance which is achievable for the triplet system. We show that for the Centre algorithm a typical achievable left-right suppression is greater than 15dB.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 2000
- Accession Number
- ADA389975
Entities
People
- D. T. Hughes
Organizations
- SACLANT ASW Research Centre