Cho Chomgun, Song H C, Hursky P, Jesus S M
Scripps Institution of Oceanography, La Jolla, California 92093-0238, USA.
Heat, Light, and Sound Research, Incorporated, San Diego, California 92130, USA.
J Acoust Soc Am. 2017 Jul;142(1):55. doi: 10.1121/1.4990670.
The array invariant theory was generalized by incorporating the waveguide invariant β, referred to as the generalized array invariant. In this paper, the generalized array invariant is extended to mildly range-dependent environments with a sloping bottom where the waveguide invariant is variable in range. Assuming knowledge of the bottom slope, the array invariant can be applied iteratively to estimate the source range starting with β = 1 (i.e., range-independent), which converges toward the correct source range by updating β at the previously estimated range. The iterative array invariant approach is demonstrated using a short-aperture vertical array (2.8-m) in a sloping-bottom shallow-water waveguide from the Random Array of Drifting Acoustic Receivers 2007 experiment, where a high-frequency source (2-3.5 kHz) close to the surface (6-m) was towed between 0.5 and 5 km in range with the water depth varying from 80 to 50 m.
通过纳入被称为广义阵列不变量的波导不变量β，对阵列不变量理论进行了推广。在本文中，广义阵列不变量被扩展到具有倾斜海底的轻度距离依赖环境，其中波导不变量在距离上是可变的。假设已知海底坡度，则可以从β = 1（即与距离无关）开始迭代应用阵列不变量来估计源距离，通过在先前估计的距离处更新β，使其收敛到正确的源距离。使用来自2007年随机漂移声学接收器阵列实验的倾斜海底浅水波导中的短孔径垂直阵列（2.8米），演示了迭代阵列不变量方法，其中一个靠近水面（6米）的高频源（2 - 3.5千赫）在0.5至5千米的范围内被拖曳，水深从80米变化到50米。
