A lower bound on navigation error for marine robots guided by ocean circulation models

Abstract

This paper establishes the method of controlled Lagrangian particle tracking (CLPT) to analyse the offsets between physical positions of marine robots in the ocean and simulated positions of controlled particles in an ocean model. This offset (which we term CLPT error) has characteristics that are not previously seen in free-drifting ocean sampling platforms with no active control. CLPT error growth over time is exponential until it reaches a turning point that depends only on the resolution of the ocean model, after which the error growth is bounded by polynomial functions of time. In the ideal case, a theoretical lower bound on the steady-state CLPT error can be derived. These characteristics are proved theoretically for particles moving in a planar flow field. The method of CLPT may be applied to improve the accuracy of ocean circulation models and navigation performance of marine robots.