Proceedings of the 2022 Mississippi Water Resources Conference

Year: 2022 Authors: Wolfe J.S., Chesser Jr. G.D., Lowe W., Moorhead J., Turnage G., Dash P., Moorhead R.

The need for real-time monitoring and management of water quality in inland and coastal marine environments is increasingly significant due to increases in land utilization which can negatively impact aquatic ecosystems from surface water runoff. Conventional water quality monitoring methodologies are laborious and expensive, requiring in situ monitoring stations and/or specialized manned vessel sampling missions at fixed locations and resultant laboratory analysis of water samples. These conventional methods are limited in their ability to gather high resolution spatio-temporal data. Multi-purpose autonomous surface vehicles (ASVs) provide a powered platform for sensors/instrumentation and serve as mobile sampling stations that enhance spatial and temporal data gathering capabilities. Solar powered ASVs provide long endurance continuous operations capabilities. However, commercially available solar powered ASVs are limited, and ASV autopilot navigational accuracy is affected by environmental forces (wind, current, and waves) that can alter trajectories and negatively affect spatio-temporal resolution of water quality data. The goal of this research was to evaluate the utility and navigational performance of a commercially available solar powered ASV (SeaTrac SP-48) equipped with a multi-sensor payload to operate autonomously under varying conditions of environmental forces. The specific objective was to evaluate the ability of the ASV to accurately and repeatedly maintain established A-B line transects under varying environmental conditions, where lateral deviation from a planned linear route was measured and expressed as cross-track error (XTE). Three testing scenarios by location (inland reservoir, riverine, and coastal) were considered to comprehensively evaluate the vessel under varying environmental conditions of wind, waves and current that could potentially alter trajectory and/or position. Results indicated mean XTE for A-B line transects tested across all scenarios of environmental conditions did not exceed 2.39 m. This work serves to provide a conceptual framework for development of spatial and temporal resolution limitations of ASVs for real-time monitoring campaigns and future development of station keeping and adaptive sampling technologies.