Persistent Monitoring of Large Environments with Robot Deployment Scheduling in between Remote Sensing Cycles

This paper proposes a novel decision-making framework for planning "when" and "where" to deploy robots based on prior data with the goal of persistently monitoring a spatio-temporal phenomenon in an environment. We specifically focus on large lake monitoring, where remote sensors, such as satellites, can provide a snapshot of the target phenomenon at regular cycles. Between these cycles, Autonomous Surface Vehicles (ASVs) can be deployed to maintain an up-to-date model of the phenomenon. However, deploying ASVs has a significant logistical overhead in terms of time and cost. It requires a team of people to go on site and spend typically a day to monitor the deployment. It is vital to not only be intentional about where to sample in the environment on a given day, but also determine the worth of deploying the ASVs that day at all. Therefore, we propose a persistent monitoring strategy that provides the days and locations of when and where to sample with the robots by leveraging Gaussian Process model estimates of future trends based on collected remote sensing and point measurement data. Our approach minimizes the number of days and locations for sampling, while preserving the quality of estimates. Through simulation experiments using realistic spatio-temporal datasets, we demonstrate the benefits of our approach over traditional deployment strategies, including significant savings on the effort and operational cost of deploying the ASVs.