First Dual-Band Multiconstellation GNSS-R Scatterometry Experiment Over Boreal Forests From a Stratospheric Balloon

This work presents the first ever dual-frequency multiconstellation Reflectometry using Global Navigation Satellite Systems signals (GNSS-R) observations over boreal forests and lakes using GPS, GLONASS, and Galileo signals. The instrument used is the PYCARO reflectometer, which flew on-board a stratospheric balloon during the SNSB and ESA sponsored BEXUS 19 experiment. The coherent-to-incoherent scattering ratio over boreal forests is found to be as large as ~1.5, while over lakes, it is as high as 16.5. The scatterers' height fluctuations measured using the phase of the peak of the reflected complex waveforms ranges from ±10 m, to the submetric level. Finally, reflectivity maps using the different GNSS codes are presented using the conventional GNSS-R for the open-access codes, and the reconstructed GNSS-R for the encrypted ones. The coherence of the reflected signal is found to be high enough to allow the PYCARO instrument to reconstruct the P(Y) code.