In Situ Shape Estimation of Triangular Moored Hydrophone Arrays Using Ambient Signals

In this paper, a method is presented for correcting relative errors in the locations of individual sensors in a three-element bottom-moored array, using ambient signal arrivals recorded by the array. It has the benefit that knowledge of absolute source positions is not required to determine the relative shape of the array. The procedure is demonstrated using episodic ambient signal arrivals recorded by the southern array of the Wake Island hydrophone station, which is a component of the Comprehensive Nuclear-Test Ban Treaty Organization's (CTBTO) International Monitoring System (IMS). The original coordinates of sensors 2 and 3 were adjusted by 75 and 115 m, respectively, removing approximately 4 $^{\circ}$ of error in estimating the arrival angles of signals. The estimated coordinates compared favorably with the results of a position revision by the CTBTO a year after the triad installation.