Bounds on Optimal Revisit Times in Persistent Monitoring Missions with a Distinct \& Remote Service Station

TL;DR

This paper addresses the challenge of minimizing revisit times in persistent UAV monitoring missions with a remote service station, proposing algorithms and bounds to achieve near-optimal solutions efficiently.

Contribution

It introduces a novel algorithm for near-optimal UAV routing in remote station scenarios and provides tight lower bounds on revisit times, demonstrating high solution accuracy.

Findings

Constructed solutions are within 0.01% of the optimal revisit time.

The algorithm is efficient for UAV fuel capacities above a certain threshold.

Lower bounds effectively estimate the minimum possible revisit times.

Abstract

Persistent monitoring missions require an up-to-date knowledge of the changing state of the underlying environment. UAVs can be gainfully employed to continually visit a set of targets representing tasks (and locations) in the environment and collect data therein for long time periods. The enduring nature of these missions requires the UAV to be regularly recharged at a service station. In this paper, we consider the case in which the service station is not co-located with any of the targets. An efficient monitoring requires the revisit time, defined as the maximum of the time elapsed between successive revisits to targets, to be minimized. Here, we consider the problem of determining UAV routes that lead to the minimum revisit time. The problem is NP-hard, and its computational difficulty increases with the fuel capacity of the UAV. We develop an algorithm to construct near-optimal solutions to the problem quickly, when the fuel capacity exceeds a threshold. We also develop lower bounds to the optimal revisit time and use these bounds to demonstrate (through numerical simulations) that the constructed solutions are, on an average, at most 0.01% away from the optimum.