Is accurate synoptic altimetry achievable by means of interferometric GNSS-R?

Fran Fabra*, Estel Cardellach, Serni Ribó, Weiqiang Li, Antonio Rius, Juan Carlos Arco-Fernández, Oleguer Nogués-Correig, Jaan Praks, Erkka Rouhe, Jaakko Seppänen, Manuel Martín-Neira

*Corresponding author for this work

Research output: Contribution to journalArticleScientificpeer-review

11 Citations (Scopus)
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This paper evaluates the capability of interferometric global navigation satellite system reflectometry (GNSS-R) to perform sea surface altimetry in a synoptic scenario. Such purpose, which requires the combination of the results from different GNSS signals, constitutes a unique characteristic of this approach. Interferometric GNSS-R group delay altimetry has been proven to be more precise than conventional GNSS-R. However, the self-consistency and accuracy of their synoptic solutions (simultaneous multi-static results) have never been proved before. In our work, we analyze a dataset of GNSS signals reflected off the Baltic Sea acquired during an airborne campaign using a receiver that was developed for such a purpose. Among other features, it enables beamformer capability in post-processing to get multiple and simultaneous GNSS signals under the interferometric approach's restrictions. In particular, the signals from two GPS and two Galileo satellites, at two frequency bands (L1 and L5), covering an elevation range between 28° and 83°, are processed to retrieve sea surface height estimations. The results obtained are self-consistent among the different GNSS signals and data tracks, with discrepancies between 0.01 and 0.26 m. Overall, they agree with ancillary information at 0.40 m level, following a characteristic height gradient present at the experimental site.

Original languageEnglish
Article number505
Number of pages19
JournalRemote Sensing
Issue number5
Publication statusPublished - 1 Mar 2019
MoE publication typeA1 Journal article-refereed


  • Altimetry
  • Galileo
  • GNSS-R
  • GPS
  • Interferometry
  • Radar
  • Sea level


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