Parameter considerations for the retrieval of surface soil moisture from spaceborne GNSS-R

J. F. Munoz-Martin, R. Onrubia, D. Pascual, H. Park, A. Camps, C. Rüdiger, J. P. Walker, A. Monerris

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther


The Microwave Interferometric Reflectometer (MIR) is an airborne GNSS-R instrument developed by Universitat Politècnica de Catalunya. In 2018, it was flown twice over the agricultural Yanco area, New South Wales, Australia, once after a very dry period, and a further time the day after a strong rain event. This rain event resulted in many crop fields being entirely flooded, producing a saturation in the GNSS-R reflectivity value. In this work, the received data set is processed to identify the optimum integration time with the goal to minimize pixel blurring. This issue is assessed for airborne conditions, and then extra-polated to the spaceborne case. The presented results show that the blurring of the GNSS waveform is produced even from an airborne sensor with short integration times. Following the determination of an optimal integration time for the platform in use, the surface roughness term in the reflectivity equation can be isolated due to the signal saturation during very wet surface conditions. The final results from the two channels (L1 C/A and L5) are subsequently presented. In this case, it is shown that most reflectivity variations in GNSS-R measurements are linked to surface roughness and Speckle noise fluctuations rather than soil moisture changes.

Original languageEnglish
Title of host publication2021 IEEE International Geoscience and Remote Sensing Symposium IGARSS
PublisherIEEE, Institute of Electrical and Electronics Engineers
Number of pages4
Publication statusPublished - 2021
EventIEEE International Geoscience and Remote Sensing Symposium 2021 - Brussels, Belgium
Duration: 12 Jul 202116 Jul 2021 (Proceedings)


ConferenceIEEE International Geoscience and Remote Sensing Symposium 2021
Abbreviated titleIGARSS 2021
Internet address


  • GNSS-R
  • roughness
  • soil moisture

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