Trajectory Planning for Navigation Aiding of Autonomous Underwater Vehicles

Oystein Sture,Petter Norgren,Martin Ludvigsen

doi:10.1109/access.2020.3004439

Abstract

Autonomous underwater vehicles can perform seabed surveys with a higher resolution and quality than from equivalent ship-mounted sensors. Although high-grade inertial navigation systems aided by Doppler velocity logs can operate without external position references for extended durations, this may still be required to meet survey specifications. This paper presents a trajectory planning algorithm for an autonomous surface vessel with the purpose of aiding the navigation of one or multiple underwater vehicles using ultra-short baseline acoustic positioning. The trajectory planning problem is formulated as a nonlinear program for the single-vehicle tracking scenario and mixed-integer nonlinear program for tracking of multiple vehicles. In the absence of external acoustic positioning, the horizontal uncertainties of all targets increase as functions of time and heading. The optimal placement of the surface vessel is calculated by considering the propagated acoustic measurement uncertainty, which varies according to the range and direction towards the target. The trajectories are generated by minimizing the uncertainty of all targets, while also considering penalties on the control inputs and obeying vessel kinematics. The approach is demonstrated through a series of simulations.

Highlights

Autonomous underwater vehicles (AUVs) are untethered sensor carrying platforms capable of performing surveys in high proximity to the seabed
In this work we focus on the ultra-short baseline (USBL) acoustic measurement principle, where a measured range and direction is used to estimate the position
The path planning problem for a surface vessel following one or more underwater vehicles is presented in the form of a non-linear program (NLP)

Summary

Introduction

Autonomous underwater vehicles (AUVs) are untethered sensor carrying platforms capable of performing surveys in high proximity to the seabed. Moving the sensor carrying platform closer to the seabed can increase the resolution of the collected data significantly This may be a requirement for certain applications, such as geomorphological studies where small-scale features of interest are not resolved in sufficient detail by hull-mounted instruments on ships. Examples of such applications may be the study of erosive processes over time, submarine landslides, hydrothermal vents, mid-ocean ridges, mud volcanoes and cold-water coral mounds [1]. Microwaves are absorbed rapidly in water, and a large caveat with data collection on underwater vehicles is the loss of global navigation satellite systems (GNSS) for positioning.

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