BackForwardInstrument:  GNSS-R 

Instrument details
Acronym GNSS-R
Full name GNSS Reflectometer
Purpose To observe ocean surface wind and soil moisture, inundation, permafrost freeze/thaw, and biomass
Short description A dual polarisation L-Band GNSS Receiver with sensitivity, in the range of 0.7-3.8 dB/10%. The core unit is a delay doppler mapping receiver.
Background A new development.
Scanning Technique Scanning provided by the changing relative position of the LEO and the GNSS satellites.
Resolution 2-7 km
Coverage / Cycle The revisit time of two HydroGNSS satellites over the globe using 0.25° × 0.25° cells is typically 3-4 days shorter over the poles and longer over equator.
Mass Power 41.5 W Data Rate


Providing Agency ESA
Instrument Maturity Flown on an R&D satellite
Utilization Period: 2024 to 2029
Last update: 2023-05-22
Detailed characteristics
Satellites this instrument is flying on

Note: a red tag indicates satellites no longer operational, a green tag indicates operational satellites, a blue tag indicates future satellites

Instrument classification
  • Other payload component
  • Positioning system
WIGOS Subcomponents
  • Subcomponent 2
  • GNSS reflectometry (GNSS-R) missions, passive MW, SAR
  • Constellation of GNSS receivers [for reflectometry]
Mission objectives
Primary mission objectives
  • Biomass
  • Permafrost
  • Soil moisture (in the roots region)
  • Wind speed (near surface)
Evaluation of Measurements

The following list indicates which measurements can typically be retrieved from this category of instrument. To see a full Gap Analysis by Variable, click on the respective variable.

Note: table can be sorted by clicking on the column headers
Note: * Primary mission objective.
VariableRelevance for measuring this variableOperational limitationsExplanation
Geoid4 - fairHighly indirect.Opportunity information from GNSS receiver used for precise orbit determination
Gravity field5 - marginalHighly indirect.Opportunity information from GNSS receiver used for precise orbit determination
Wind speed (near surface)*4 - fairOver sea only.GNSS receivers on a cluster of micro-satellites. Wind speed estimated from the intensity of signals from different incidence angles, reflected normally