BackForwardInstrument:  TGRS (COSMIC-2) 

Instrument details
Acronym TGRS (COSMIC-2)
Full name Triple G (GPS, Galileo, GLONASS) Global Navigation Satellite System (GNSS) Radio Occultation (RO) Receiver System
Purpose Temperature/humidity sounding with highest vertical resolution, space weather
Short description Measuring the phase delay due to refraction during occultation between GPS and LEO
Background New development
Scanning Technique Limb scanning from 800 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 GNSS constellation tracked. About 6600 soundings/day (with 6 satellites) - Average spacing 280 km - Global coverage (300 km spacing) in 18 h. Complex of two constellations: 9 h
Mass 6 kg Power 50 W Data Rate 40 kbps

 

Providing Agency NASA
Instrument Maturity Backed by strong heritage
Utilization Period: TBD
Last update: 2017-03-30
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
Mission objectives
Primary mission objectives
  • Atmospheric temperature
  • Height of the top of PBL
  • Height of the tropopause
  • Specific humidity
  • Temperature of the tropopause
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Tentative 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
VariableRelevance for measuring this variableOperational limitationsExplanation
Atmospheric temperature1 - primaryInaccurate in low troposphere.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite
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 PBL1 - primaryNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite. PBL top measured as discontinuity of the refraction index
Height of the tropopause1 - primaryNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite. Tropopause height measured as discontinuity of the refraction index
Specific humidity3 - highInaccurate in high troposphere.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite
Temperature of the tropopause1 - primaryNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite
Electron Density1 - primaryNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite
Ionospheric Vertical Total Electron Content (VTEC)2 - very highNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite
Ionospheric Scintillation2 - very highNo specific limitation.Flown in a satellite cluster. Two directional antennas, three GNSS systems tracked, about 1500 soundings/day per satellite