Environmental research applications of Global Navigation Satellite Systems (GNSS) and Synthetic Aperture Radar (SAR): water resources and hydrology approach

Abstract

This review explores the synergistic application of Global Navigation Satellite Systems (GNSS) and Synthetic Aperture Radar (SAR) in environmental research. By leveraging GNSS's precise positioning and SAR's high-resolution, all-weather imaging capabilities, the combined approach significantly enhances accuracy, spatial coverage, and temporal resolution in ecological and climate monitoring. The integrated use of these technologies is pivotal for monitoring atmospheric water vapor, vegetation health, hydrological changes, and tectonic plate movements. Case studies using SAR imagery to delineate lake and river flood boundaries, along with manually determined water level measurements, demonstrate the effectiveness of the approach for environmental monitoring. Looking ahead, incorporating GNSS-based techniques such as GNSS Reflectometry for near-real-time water level monitoring upstream could enhance flood prediction models, with SAR imagery subsequently validating and refining flood extent estimates. The review also discusses challenges such as integrating heterogeneous datasets and the computational requirements for processing the data. It suggests that future research might explore more refined data fusion methods and additional applications, for example in climate.