Work

Multi-Band, Multi-GNSS Polarimetric GNSS-R Observations From SCOMAG Airborne Campaign

Year: 2026

Type: article

Abstract: Global navigation satellite system reflectometry (GNSS-R) has demonstrated strong potential for retrieving geophysical parameters related to surface properties, as confirmed by numerous in situ, airborne, and satellite experiments. In particular, the recently launched ESA HydroGNSS mission aims to exploit GNSS-R observations for the monitoring of soil moisture, inland water bodies, and vegetation parameters at the global scale. In this context, this article introduces a modified version of the French airborne GNSS-R instrument global navigation satellite system reflectometry instrument (GLORI), originally proposed in 2015. While the first GLORI instrument provided polarimetric measurements limited to the GPS L1 frequency band, the modified-GLORI extends these capabilities to multiple GNSS configurations, including GPS L1 and L5 as well as Galileo E1 and E5 frequency bands, fully aligned with the frequency bands used by HydroGNSS. Following a series of laboratory qualification tests, an airborne measurement campaign was conducted in June 2024, encompassing a total of five flights over southwestern France. The campaign covered a variety of land cover types, including agricultural landscapes and forested aereas, but only data acquired over agricultural plots are used for band intercomparison. These flights were conducted in parallel to in situ ground-truth measurements over more than ten agricultural test fields. This article presents the instrument design, calibration strategy, reflectivity statistics, and band-to-band consistency analysis of the M-GLORI instrument. Preliminary analysis of the collected data indicates that the M-GLORI instrument operates within its specified performance parameters. An analysis of the performance of each configuration (frequency band, polarization) for GPS and Galileo acquisitions is presented. An intercomparison of measurements of all proposed bands, after normalization to one incidence angle and inter-calibration, is discussed. These results highlight the strong potential of combining GPS L1 and L5 bands and Galileo E1 and E5 bands for the accurate retrieval of land surface geophysical parameters.

Source: IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing

DOI: 10.1109/jstars.2026.3698506