BackForwardInstrument:  RO 

Instrument details
Acronym RO
Full name Radio Occultation sounder
Purpose Atmospheric temperature/humidity sounding with highest vertical resolution. Ionospheric total electron profiles along occultation path.
Short description

Measuring the phase delay due to refraction during occultation between the navigation satellite (GPS, Galileo, BeiDou) and LEO.

Background

Follow-on of GRAS flown on MetOp A to C.

Scanning Technique

Limb scanning from 80 km (possibly 600 km) to close-to-surface by time sampling - Azimuth: 90° sectors fore- and aft-

Resolution About 300 km horizontal, 0.5 km vertical
Coverage / Cycle 3 constellations (GPS/Galileo/BeiDou) and 1500 soundings/day.
Mass 22 kg Power 30 W Data Rate 1 Mbps

 

Providing Agency ESA
Instrument Maturity Backed by strong heritage
Utilization Period: 2025 to 2048
Last update: 2024-02-26
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
  • Earth observation instrument
  • Active and radio-occultation sensor
  • GNSS radio-occultation
WIGOS Subcomponents
  • Subcomponent 1
  • GNSS radio occultation (basic constellation)
  • GNSS radio occultation sounder (basic constellation)
  • Subcomponent 2
  • Magnetospheric energetic particles and magnetometers
  • Ionospheric total electron content sensor [at LEO and cross magnetosphere]
  • Ionospheric electron density sensor [in LEO and cross magnetosphere]
Mission objectives
Primary mission objectives
  • Atmospheric temperature
  • Electron Density
  • Height of the top of PBL
  • Height of the tropopause
  • Ionospheric Total Electron Content (TEC)
  • Specific humidity
  • Temperature of the tropopause
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
Atmospheric temperature*2 - very highInaccurate in low troposphere.Two directional antennas, three GNSS system tracked, covering about 1500 soundings/day
Geoid4 - fairHighly indirect.Radio-occultation processing implies precise orbitography. Geoid derived from multi-temporal analysis
Gravity field5 - marginalHighly indirect.Radio-occultation processing implies precise orbitography. Gravity field derived from multi-temporal analysis
Height of the top of PBL*2 - very highNo specific limitation.Two directional antennas, three GNSS system tracked, about 1500 soundings/day. PBL top measured as discontinuity of the refraction index
Height of the tropopause*2 - very highNo specific limitation.Two directional antennas, three GNSS system tracked, about 1500 soundings/day. Tropopause height measured as discontinuity of the refraction index
Specific humidity*3 - highInaccurate in high troposphere.Two directional antennas, three GNSS system tracked, about 1500 soundings/day
Temperature of the tropopause*2 - very highNo specific limitation.Two directional antennas, three GNSS system tracked, about 1500 soundings/day
Atmospheric density1 - primaryNo specific limitation.Measuring atmospheric density
Electron Density*1 - primaryNo specific limitation.Two directional antennas, three GNSS system tracked, about 1500 soundings/day
Ionospheric Total Electron Content (TEC)*3 - highNo specific limitation.Two directional antennas, three GNSS system tracked, about 1500 soundings/day
Ionospheric Scintillation4 - fairNo specific limitation.Instrument type = GNSS radio-occultation sounder AND No. of tracked GNSS constellations >= 3 AND It has two directional antennas, looking fore- and aft- = TRUE AND It has ionospheric viewing capability = TRUE