Measurement for our planet
Measurement for our planet

As COP26 approaches, discover how NPL plays a key role in enabling climate action through the delivery of accurate, reliable data that supports decision making and enables low carbon innovation.


Satellite calibration

TRUTHS enables SI-traceable Earth Observation data from space

TRUTHS’ Cryogenic radiometer provides a primary reference for calibration

TRUTHS is the first satellite mission to calibrate its observations directly to an ultra-high accuracy reference standard in orbit, overcoming the usual uncertainties associated with drifts of sensor gain. The TRUTHS Cryogenic Solar Absolute Radiometer (CSAR) makes use of an electrical rather than an optical standard as the basis of its calibration and one which is a direct mimic of those used terrestrially.

Interactions of complex environmental factorsFor effective policy making and the development of global initiatives which will help address changes in the earth’s temperature there must be complete confidence in the data which underpins decision making. Satellite surveys are not only used for climate, but more readily to quantify the interactions of complex environmental factors, such as the atmosphere, the Sun, oceans, pollution, volcanoes, vegetation and deforestation.

The space-based reference provided by TRUTHS not only enable SI-traceable calibrations, but also improves synergies between satellite missions, by reducing measurement uncertainties due to different calibration biases. In this way, TRUTHS will also deliver cost reductions for future missions by reducing the demands for on-board calibration systems. These improvements are essential for strategies such as GEO, the EU Copernicus programme, and the Paris Agreement, to ensure that data from constellations of micro/nano-satellites can be integrated seamlessly into the emerging 'big data' analytical systems that will fuel the growth in services and information content.

Learn more about how TRUTHS works in the animation below:

Missions goals


Learn more about TRUTHS

Mission development

Lean more about earth observation and climate measurement at NPL

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