A Preliminary Study of Ice-Relative Underwater Vehicle Navigation Beneath Moving Sea Ice

This paper addresses the problem of underwater robotic vehicle navigation relative to moving or stationary sea ice. A brief review of previously-reported under-ice navigation methods is given, as well as a brief motivation for the use of under-ice robotic vehicles with precision navigation capabilities. We then describe our proposed approach, which employs two or more satellite navigation beacons atop the sea ice along with other precision vehicle and ship mounted navigation sensors to estimate vehicle, ice, and ship states by means of an Extended Kalman Filter. Navigation results for a simulated 7.6 km under ice survey are presented for varying satellite beacon separation. Preliminary analysis suggests that for the simulated sensors, vehicle trajectory, and ice velocities, the proposed method can accurately estimate vehicle position up to 1.2 km from the deployment ship given sufficient satellite beacon separation. Decreased beacon separation results in divergence of the vehicle's position estimate at large standoff distances from the ship. We conclude with suggestions for future improvements.