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Instrument details
Acronym
TGRS (COSMIC-2)
Full name
TriG (Tri-GNSS) GNSS Radio Occultation 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 constellations possible to track, only 2 actually tracked. About 5000 soundings/day (with 6 satellites) - Average spacing 320 km - Global coverage (300 km spacing) in 24 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:
2021-10-02
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 sounder (basic constellation) Subcomponent 2 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 Height of the top of PBL Height of the tropopause Specific humidity Temperature of the tropopause
Secondary mission objectives Atmospheric density Electron Density Ionospheric Scintillation Ionospheric Vertical Total Electron Content (VTEC) Opportunity objectives Show all Show fewer
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
Variable Relevance for measuring this variable Operational limitations Explanation
Atmospheric temperature 1 - primary Inaccurate in low troposphere. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Geoid 4 - fair Highly indirect. Radio-occultation processing implies precise orbitography. Geoid derived from multi-temporal analysis
Gravity field 5 - marginal Highly indirect. Radio-occultation processing implies precise orbitography. Gravity field derived from multi-temporal analysis
Height of the top of PBL 1 - primary No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite. PBL top measured as discontinuity of the refraction index
Height of the tropopause 1 - primary No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite. Tropopause height measured as discontinuity of the refraction index
Specific humidity 2 - very high Inaccurate in high troposphere. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Temperature of the tropopause 1 - primary No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Atmospheric density 1 - primary No specific limitation. Measuring atmospheric density
Electron Density 1 - primary No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Ionospheric Vertical Total Electron Content (VTEC) 2 - very high No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Ionospheric Scintillation 4 - fair No specific limitation. Flown in a satellite cluster. Two directional antennas, one GNSS system tracked, about 500 soundings/day per satellite
Instrument: TGRS (COSMIC-2)