Geoid Measurements Made by Earth Observation Satellites

CEOS EO HANDBOOK – MEASUREMENT INSTRUMENTS

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Gravity, Magnetic and Geodynamic measurements >
Geoid

Measurement Definition*: Equipotential surface which would coincide exactly with the mean ocean surface of the Earth, if the oceans were in equilibrium, at rest, and extended through the continents (such as with very narrow channels) - Physical unit: [ cm ] - Accuracy unit: [ cm ].

Instrument	Status/ Accuracy	Instrument Description	Measurement Technology	Timeline
DORIS-NG Doppler Orbitography and Radio-positioning Integrated by Satellite-New Generation	Operational	Precise orbit determination; Real time onboard orbit determination (navigation).	n/a
POSEIDON-3B Altimeter Positioning Ocean Solid Earth Ice Dynamics Orbiting Navigator (Single frequency solid state radar altimeter)	Operational	Nadir viewing sounding radar for provision of real-time high precision sea surface topography, ocean circulation and wave height data.	Radar altimeter
Poseidon-4 Altimeter Poseidon-4 SAR Radar Altimeter	Operational	Nadir viewing sounding radar for provision of real-time high-precision sea surface topography, ocean circulation and wave height data.	Radar altimeter
SRAL SAR Radar Altimeter	Operational	Marine and land services.	Radar altimeter
LTI Laser Tracking Instrument	Approved	The aim of MAGIC is to obtain high-resolution measurements in space and time and include the capability to determine the variations in gravity field due to mass change in hydrology, cryosphere, oceanography, solid Earth and climate change signals so as to serve science and operational products including emergency services.	n/a
POSEIDON-3C Altimeter Positioning Ocean Solid Earth Ice Dynamics Orbiting Navigator (Single frequency solid state radar altimeter)	Approved	Nadir viewing sounding radar for provision of real-time high precision sea surface topography, ocean circulation and wave height data.	Radar altimeter

* Description adapted from WMO.