Vertical Spatial Correlation of Reverberation in Shallow Water - Mode Enhancement Techniques (METS) as a Means to Improve Echo Detection.
Abstract
A vertical array of transducers, amplitude shaded with uniform and cosine weightings, and two of its individual elements were used to produce reverberation at 1700 Hz under iso-sound speed conditions in waters 30 m deep. Eleven of the vertical array elements spaced 1 m apart were than used to receive and record the reverberation levels as a function of range (time). The vertical correlation values of reverberation as a function of hydrophone spacing for the transmitting configurations were obtained using a clipper correlator. Although the uniform and cosine configurations produced higher correlation values than did the single transducers, they fell below 0.5 for spacings greater than 2 m. By assuming echoes that consist primarily of mode 1 or mode 2 and applying Mode Enhancement Techniques (METS) to a receiving array of six elements uniformly spaced 2 m apart, we see that the array gain is computed to be 3.0 and 7.8 dB, repsectively. The example of METS indicates that appreciable array gains can be achieved with vertical arrays operating in shallow water. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 24, 1978
- Accession Number
- ADA056615
Entities
People
- Louis A. King
- Ralph W. Carone
- Wolfgang Bachor
Organizations
- Naval Underwater Systems Center