Estimation of the Under-Ice Acoustic Field in AUV Communication Networks

Autonomous underwater vehicles (AUVs) are the platform of choice for ocean exploration and surveillance in the ice-covered regions. Due to the large attenuation of radio signals in water, acoustic communications have been the major technique for underwater wireless information transfer. In the under-ice environment, the acoustic propagation is largely determined by a stratified sound speed profile (SSP) and the ice-reflection characteristics. Based on the ray theory, this work develops an inversion algorithm to estimate the SSP and the ice reflection coefficient via an iterative method. The acoustic measurements collected during data transmission within the AUV network, including the propagation delay and the amplitude of the received signal along each eigen path, are used for the inversion. With the estimated SSP and the ice-reflection coefficient, the under-ice acoustic field can then be constructed to guide future acoustic communications among the AUVs. The proposed algorithm is evaluated via Bellhop synthesized data and achieves decent accuracy in the SSP and the ice-reflection coefficient estimation.