Array Gain of a Vertical Line Array in Shallow Water

The signal/noise performance of a vertical line array showing a horizontally directed main lobe in its angular response, and operating in a shallow channel of uniform depth, is discussed.The array gain is expressed as the product of the signal gain and the noise gain.Provided only a few modes contribute to the signal field the signal gain is on the order of N, where h is the number of hydrophones in the array.The noise gain depends on the anisotropy of the ambient noise field and in many cases can be expressed as a rational function of frequency with known coefficients. SUMMARY OF THE DISCUSJIONA large proportion of U.K. coastal waters lying over the Cont inental Shelf are on the order of 100m desp.The question addressed in this paper is the following: in a uniform channel of such a depth, and assuming a constant sound velocity depth profile in the water column, what is the array gain of a vertical line array showing a horizontally directed main lobe in its angular response pattern?1n the discussion the signal and noise fields are treated independently, and the array gain is expressed as the product of the signal gain and the noise gain.