Abstract
Global navigation satellite system reflectometry (GNSS-R) uses signals of opportunity in a bi-static configuration of L-band microwave radar to retrieve environmental variables such as water level. The line-of-sight signal and its coherent surface reflection signal are not separate observables in geodetic GNSS-R. The temporally constructive and destructive oscillations in the recorded signal-to-noise ratio (SNR) observations can be used to retrieve water-surface levels at intermediate spatial scales that are proportional to the height of the GNSS antenna above the water surface. In this contribution, SNR observations are used to retrieve water levels at the Vianden Pumped Storage Plant (VPSP) in Luxembourg, where the water-surface level abruptly changes up to 17 m every 4-8 h to generate a peak current when the energy demand increases. The GNSS-R water level retrievals are corrected for the vertical velocity and acceleration of the water surface. The vertical velocity and acceleration corrections are important corrections that mitigate systematic errors in the estimated water level, especially for VPSP with such large water-surface changes. The root mean square error (RMSE) between the 10-min multi-GNSS water level time series and water level gauge records is 7.0 cm for a one-year period, with a 0.999 correlation coefficient. Our results demonstrate that GNSS-R can be used as a new complementary approach to study hurricanes or storm surges that cause abnormal rises of water levels.
Highlights
Global navigation satellite systems (GNSS) signal have been used for unanticipated purposes, such as remote sensing of the environment [1]
Geodetic GNSS reflectometry (GNSS-R) uses near-surface or ground-based signals of opportunity at the L-band frequency to retrieve environmental variables such as snow depth, soil moisture, and water level at intermediate spatial scales that are proportional to the height of the antenna above the surface being observed (i.e., 1000 m2 for a GNSS antenna installed on 2-m-tall monument) [4,8,9,10,11,12]
The international workshop on sea-level measurements in hostile conditions that was held from 13 to 15 March 2018 and was cosponsored by the Intergovernmental Oceanographic Commission (IOC) of the United Nations Educational, Scientific and Cultural Organization (UNESCO) has recommended the investigation of GNSS reflectometry (GNSS-R) “if conditions are too difficult for conventional observing methods”; this was in addition to the general recommendation that “tide gauges should be connected to benchmarks and co-located with GNSS as Remote Sens. 2020, 12, x FOR PEER REVIEW
Summary
Global navigation satellite systems (GNSS) signal have been used for unanticipated purposes, such as remote sensing of the environment [1]. GNSS-R can retrieve absolute water levels by taking the vertical land motion into account. IItt ccaann bbee sseeeenn tthhaatt SSNNRR ffrriinnggeess aarree vveerryy cclleeaarr ffoorr aallll tthhee sseevveenn ssiiggnnaallss,, eessppeecciiaallllyy ffoorr llooww--eelleevvaattiioonn aannggllee oobbsseerrvvaattiioonnss,, ii..ee..,, oobbsseerrvvaattiioonnss bbeelloowwaa 2200◦° eelleevvaattiioonnaannggllee..
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
