Aerial view across the mountains of Crete
SPACE—CALIBEREarth observation · Calibration & validation
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Crete · GavdosReference infrastructure

Measuring Earth
to trust what we measure from space

How do we know
a satellite is right?

Satellite altimetry observations are independently calibrated and validated through reference infrastructure in Crete and Gavdos.

Explore our infrastructure
EO / CAL–VAL / 04Scroll to observe ↓
The measurement chain

From satellite observation to trusted data

01Satellite pass
02Radar altimetry
03Reference site
04Transponder / ground
05Reference measurement
06Calibration & validation
07Trusted data
ESA source image showing Crete, Gavdos and CDN1
Crete & Gavdos

Reference infrastructure

Visualized source map · no live status

CDN1Source-identified
GavdosReference area
Satellite altimetryIndependent referenceCal / Val
Stelios Mertikas beside field instrumentation
ESA documentary

Monitoring sea level change
from a mountain top

Watch film ▶

European Space Agency
Technical University of Crete / AORI Films
2018

Sentinel-6 satellite over Earth
Missions & Cal/Val

Engineering confidence
across missions

Ground reference for a new generation of ocean topography.

Explore missions
Research & publications

Science that builds
confidence

Schematic interface · not measured data
Selected researchCal / ValAltimetryGeodesyEarth observation
Data & resources

Open data.
Open knowledge.

Interface visualization · not an operational dataset

Access resources
Selected missions & Cal/Val activities

Reference infrastructure across missions

04SWOT Cal/Val

SWOT Ocean & Geodetic Calibration / Validation

Ground reference for a new generation of ocean topography.

Calibration and validation investigations use the permanent Crete and Gavdos satellite altimeter Cal/Val infrastructure to support SWOT oceanographic and geodetic products.

NASA / JPLSWOTCrete + Gavdos
SWOT · Ocean Cal/Val · Geodetic CalVal
Stelios MertikasProject Investigator · Technical University of Crete
Sentinel-6 satellite over Earth
04SWOT Cal/ValSatellite altimetry · Cal/Val reference
ESA films / field stories

Observation in context

Three films from the field and from orbit.

Capability framework

Satellite altimetryCalibration & validationCrete + GavdosReference infrastructureGeodesyReference systemsEarth observationScientific analysis
News & stories

Latest signals

Field notesReference infrastructure in practiceMission focusSatellite altimetry and Cal/ValResearchFrom observation to confidence
Earth at night from orbit
Collaborate

Build the next
reference, together.

Explore collaboration
Research & publications

Selected scientific work

Research supporting satellite altimetry, calibration and validation, geodesy and reference infrastructure in Crete and Gavdos.

AllAltimetryCal / ValGeodesyTransponders
012024Remote SensingCal / Val

The ESA Permanent Facility for Altimetry Calibration in Crete: Advanced Services and the Latest Cal/Val Results

Stelios P. Mertikas et al.

DOI10.3390/rs16020223View publication
022024Remote SensingGeodesy

Local Gravity and Geoid Improvements around the Gavdos Satellite Altimetry Cal/Val Site

Stelios P. Mertikas et al.

DOI10.3390/rs16173243View publication
032022Advances in Space ResearchTransponders / Cal / Val

Performance evaluation of the CDN1 altimetry Cal/Val transponder to internal and external constituents of uncertainty

Stelios P. Mertikas et al.

DOI10.1016/j.asr.2022.07.001View publication
042018Remote SensingSatellite Altimetry

Fifteen Years of Cal/Val Service to Reference Altimetry Missions: Calibration of Satellite Altimetry at the Permanent Facilities in Gavdos and Crete, Greece

Stelios P. Mertikas et al.

DOI10.3390/rs10101557View publication