A Geometric Analysis-Based Safety Assessment Framework for MASS Route Decision-Making in Restricted Waters

TL;DR

This paper introduces GARSA, a geometric analysis-based framework that assesses route safety for Maritime Autonomous Surface Ships in restricted waters, improving safety and decision-making through dynamic safety indices and path adjustments.

Contribution

The paper presents a novel geometric analysis framework for route safety assessment that incorporates dynamic safety indices and ship kinematic constraints for autonomous MASS navigation.

Findings

GARSA effectively identifies safe routes in simulated environments.

The framework balances global safety and local risk in route planning.

Path modifications improve navigation safety in narrow waterways.

Abstract

To enhance the safety of Maritime Autonomous Surface Ships (MASS) navigating in restricted waters, this paper aims to develop a geometric analysis-based route safety assessment (GARSA) framework, specifically designed for their route decision-making in irregularly shaped waterways. Utilizing line and point geometric elements to define waterway boundaries, the framework enables to construct a dynamic width characterization function to quantify spatial safety along intricate waterways. An iterative method is developed to calculate this function, enabling an abstracted spatial property representation of the waterways. Based on this, we introduce a navigational safety index that balances global navigational safety and local risk to determine the safest route. To accommodate ship kinematic constraints, path modifications are applied using a dynamic window approach. A case study in a simulated Port of Hamburg environment shows that GARSA effectively identifies safe routes and avoids the risk of entering narrow waterways in an autonomous manner, thereby prioritizing safety in route decision-making for MASS in confined waters.