Sentinel-1C demonstrates power to map land deformation

Launched just two months ago and still in the process of being commissioned for service, the Copernicus Sentinel-1C satellite is, remarkably, already showing how its radar data can be used to map the shape of Earth’s land surface with extreme precision.

These first cross-satellite ‘interferometry’ results assure its ability to monitor subsidence, uplift, glacier flow, and disasters such as landslides and earthquakes.

Sentinel-1C, like its predecessors, it is equipped with a C-band Synthetic Aperture Radar (SAR) instrument. Since the launch of Sentinel-1A in 2014, this cutting-edge technology has continually set new standards for spaceborne radar for Earth observation.

The mission delivers high-resolution imagery of Earth, no matter the weather or if it is day or night, for a wide range of Copernicus services and applications, including Arctic sea-ice monitoring, iceberg tracking, routine sea-ice mapping and glacier ice flow.

It also plays a vital role in marine surveillance, such as oil-spill detection, ship tracking for maritime security and for monitoring illegal fishing activities.

Additionally, it is widely used for observing ground deformation caused by subsidence, uplift, landslides, earthquakes and volcanic activity. The mission is crucial in supporting humanitarian aid and responding to natural disasters worldwide.

Using the Sentinel-1 mission to monitor the changing shape of Earth’s land surface with millimetre precision relies on a complex data processing method called SAR interferometry (InSAR).

Put simply, this involves the radar signal transmitted from the satellite bouncing off the Earth’s surface being recorded as an image containing both amplitude and phase information. Two or more images of the same location, but taken at different times, can then be combined to generate an interferogram that reveals surface displacement.

This information is key to understanding how the land surface may have shifted after an earthquake, for example.

Sentinel-1A–Sentinel-1C cross-satellite interferogram, Atacama Desert

The interferogram above, a cross-satellite interferogram, is of the Atacama Desert plateau in northern Chile and was generated using images acquired  just one day apart, by Sentinel-1A on 19 January and Sentinel-1C on 20 January.

The interferogram below of the Antofagasta area, also in northern Chile, however, uses only Sentinel-1C data. It combines acquisitions from 20 January and 1 February, which is representative of the satellite’s 12-day orbital repeat interval.

The ‘grey-scale amplitude’ radar images next to both interferograms are for reference.

ESA’s Sentinel-1 System Manager, Dirk Geudtner, explained, “While both images are vibrantly coloured, they do not particularly depict any surface deformation, but show the topography of the dry desert and some contributions from the atmosphere. In fact, we use this area to calibrate the Sentinel-1C radar.

“More importantly, these interferograms demonstrate that data from Sentinel-1C and Sentinel-1A can be combined for cross-satellite interferometric analysis, demonstrating the highly accurate timing synchronisation and stability of the radar instruments on both satellites.

Sentinel-1C interferogram, Antofagasta, Chile

“We are extremely happy with these first results and thank the Sentinel-1 calibration team at the DLR German Aerospace Center Microwaves & Radar Institute for their analysis.

“The whole process of this analysis is very complex and practically we have to ensure that the satellites’ radar scans are properly synchronised, but the results speak for themselves.

“We can state with confidence that the new Sentinel-1C satellite will be able to continue the mission’s important task of monitoring ground deformation, which is essential for disaster response.”

ESA’s Sentinel-1 Project Manager, Ramón Torres, added, “Indeed we are thrilled with these first interferograms and the functioning of the Sentinel-1C satellite at this early stage in its mission. Quality is never an accident; it is always the result of high intention, sincere effort, intelligent direction and skillful execution; it represents the wise choice from many alternatives.”

Nuno Miranda, ESA’s Sentinel-1 Mission Manager responsible for the Sentinel-1 satellites in operations, emphasised, “The cross-satellite interferogram marks a significant step in restoring the constellation’s full capacity, particularly for services and applications focused on surface deformation monitoring.”

A preliminary Sentinel-1C dataset is now available, allowing users to begin preparing for their needs. This dataset will soon be complemented with data from the Sentinel-1C pair used to create the interferogram shown here.

Source:

European Space Agency (ESA). (2025, February 13). Sentinel-1C demonstrates power to map land deformation. Observing the Earth.