Differential arrival time accuracy using ships of opportunity
Kay L. Gemba, Jit Sarkar, Bruce D. Cornuelle, Nicholas C. Durofchalk, Karim G. Sabra, William S. Hodgkiss, W. A. Kuperman · The Journal of the Acoustical Society of America · 2017
Previously, we demonstrated using the Noise-09 data set that it is possible to estimate the relative channel impulse responses (CIR) over a 1.5 km transect independently at 3 vertical line arrays (VLAs). This vessel provided sufficient SNR and bandwidth for the uncertainty of the direct arrival time to reach 5 microseconds. The time evolution of the CIRs as the ship passed by was subsequently used to determine VLA hydrophone positions relative to a reference hydrophone with accuracy on the order of centimeters. An experiment was performed in the Santa Barbara Channel using four VLAs placed between the sea lanes of in- and outgoing shipping traffic. Ship tracks were obtained from the Automatic Identification System (AIS). We extend the previous processing to this data set and discuss the uncertainties of relative multi-path arrival-times and differential travel times between VLAs.