WAVES (Waterlevel Accessible Via Economical Satellite)

Status: Inactive

Dates: 2023

Building on previous work at Georgia Tech by Dr. Russ Clark and the Smart Sea Level Sensor (SSLS) project, WAVES aimed to extend the range of feasible locations for low-cost water level monitoring by replacing existing internet-dependent backhaul with low-cost satellite modems. While the SSLS project achieved early success providing real-time flood safety information to Savannah residents and measuring long-term sea level change, its sensors rely on existing internet infrastructure to upload data — making deployments in remote locations like Sapelo Island impossible, despite their importance for monitoring. Funded by the Georgia Tech Center for the Development and Applications of the Internet of Things Technologies (CDAIT), I led a team of undergraduate and graduate students in developing a water level monitoring system capable of automatically uploading data from anywhere, regardless of existing connectivity infrastructure.

We acquired Swarm modems at approximately $100 each and integrated them as a replacement for the existing LoRa backhaul. At $5 per month per device for 750 packets of 192 bytes each, the constrained data budget presented significant engineering challenges. Our key areas of focus were:

• Data efficiency — bundling and compressing sensor readings to fit within tight packet size limits
• Transmission scheduling — optimising when to transmit given a sparse, transient satellite constellation
• Connectivity characterisation — identifying robust deployment locations accounting for tree cover and other environmental factors affecting RF propagation
• Power management — reducing energy consumption and exploring harvesting strategies for extended battery-operated deployments
• Ruggedisation — hardening the enclosure for long-term field deployments in coastal environments

We planned to conduct field tests in Atlanta and Savannah before expanding to other locations where automatic data collection had previously been infeasible. Unfortunately, after Swarm was acquired by Starlink they discontinued modem sales and later ended network access entirely. We hope to resume this project if and when Starlink releases a low-cost, low-power IoT modem.