A Compact GPS Surface Drifter with LoRa Telemetry and Self-Contained Tracking System

Abstract

AbstractShallow marine environments are characterized by complex and variable physical processes that have significance for biological and human communities. However, the global disparity in scientific resources limits examination of the coastal ocean in some regions, so the development of universal and accessible technologies is needed. We combined a compact, GPS-equipped drifter design with long-range (LoRa) radio telemetry and a receiver system housed on a research vessel to develop a low-cost, easily assembled system of drifters. LoRa transmission of real-time location data while deployed was used to increase recoverability, minimizing the initial and long-term costs of constructing and maintaining the operation of this drifter system. Bench and field testing confirmed the performance of the system, which was optimized for LoRa transmission, which is compromised when occurring near the sea surface. The swift currents, complex coastline, and varied sea states present in our study area provided a rigorous testing environment for the drifter system. We established the working limits of battery life and LoRa data transmission within our configuration of transmitters and receiver, evaluated the accuracy of the GPS receivers, and determined the most robust variant of the drifter body design. This study offers proof of concept for a radio-tracked drifter system that is ready for deployment to track nearshore surface currents. Both the drifter system and the data telemetry protocol can be adapted to other investigations of the marine environment by integrating new sensors, modifying the configuration or deployment procedure, or applying LoRa radios to transfer data from fixed sensing platforms.