Total electron content (TEC) Measurements Made by Earth Observation Satellites

CEOS EO HANDBOOK – MEASUREMENT INSTRUMENTS

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Total electron content (TEC)

Measurement Definition*: Number of electrons in between two points. Observed under more viewing angles so as to generate profiles by tomography - Physical unit: [ electrons/m2 ]; practical unit: TECU = 1016 electrons/m2 - Accuracy unit: [ % ].

Instrument	Status/ Accuracy	Instrument Description	Measurement Technology	Timeline
m-NLP multi-Needle Langmuir Probe	Operational	m-NLP measures the plasma around the Earth at a higher resolution than other Langmuir probe instruments that have been flown in space.	n/a
RF Beacon Radio Frequency Beacon	Operational	Transmitter that enables ground-based measurement of ionospheric scintillation and ionospheric total electron content (TEC). Critical to understanding the impacts of space weather on satellite communication systems and GPS.	n/a
SSULI Special Sensor Ultraviolet Limb Imager	Operational	Measures vertical profiles of the natural airglow radiation from atoms, molecules and ions in the upper atmosphere and ionosphere.	n/a
SWS/SEM/HEPD Space Weather Suite / Space Environment Monitor/ High Energy Particle Detector	Operational	Energetic particle spectrometer: Spectrometer for electrons (0.25-2.0 MeV), protons (6.4-38 MeV) and alpha-particles (15-60 MeV)	n/a
SWS/SEM/IMS Space Weather Suite / Space Environment Monitor / Ionosphere Measurement Sensor	Operational	To measure ionospheric electron temperature and density, and platform charge and dose. Specially arranged Langmuir Probe for electron temperature (0-1 eV) and density in the 10- 10^6 e/cm3 range	n/a
TGRS TriG (Tri-GNSS) GNSS Radio-occultation System	Operational	TGRS is the radio occultation receiver, which will receive signals from GPS, Galileo, and Glonass.	GNSS radio-occultation receiver

* Description adapted from WMO.