Online reconstruction of drifting underwater ice topography: The 2D case

Abstract

An online estimation design for a drifting two dimensional ice topography is presented. Under the assumption that the topography can be accurately represented by a truncated Fourier series, and given a moving window of measurements along the topography, an observer design is proposed to estimate the parameters of the model. The chosen method ensures an online cutoff of higher wave numbers in the spectrum representing the topography such that sufficient data compression is achieved for transmitting the model parameters through a limited hydroacoustic communication channel. This allows online reconstruction of the underwater drifting ice topography at a remote operation center. The observer is shown to be uniformly globally exponentially stable under a persistency of excitation condition. For comparison, a design based on B-spline basis functions is also presented. The effectiveness of the estimation algorithm is verified on a set of real ice draft measurements taken from the underside of an ice sheet off the coast of Greenland.