Real-Time Water Levels Using GNSS-IR: A Potential Tool for Flood Monitoring

Abstract

Global Navigation Satellite System Interferometric Reflectometry (GNSS-IR) using low-cost antennas is a practical solution for monitoring water levels from rivers, lakes and seas that does not require submerging any instruments in water. Here we present a novel method for obtaining real-time water levels using multiple low-cost antennas that we validate by comparing with measurements from a co-located pressure gauge at two sites with variable tides. Additionally, we use survey measurements to show that there is a site-dependant mean bias in GNSS-IR measurements up to a few centimeters, but this mean bias can be effectively removed by using a correction for the effect of tropospheric delay. We conclude that GNSS-IR water level sensors could be a powerful tool for real-time applications such as flood or storm surge monitoring and water resource management, as well as for improving the spatial coverage of sensors in remote regions.