International effort helps users get ready for Sentinel-1
Those who need satellite data for a wide range of applications, from mapping sea ice and tracking maritime traffic to monitoring geohazards over land, are eagerly awaiting the launch of Sentinel-1. ESA is helping users get ahead of the game by offering test data and simulated images.
To be launched later this year, Sentinel-1 is the first of five satellite missions dedicated to supplying a stream of data for Europe’s Global Monitoring for Environment and Security ‘Copernicus’ programme.
This particular satellite will provide timely high-quality radar images of our planet’s surface to support European operational services that use Earth observation data in areas such as emergency response, marine and land monitoring, civil security and climate studies.
Getting ready for using Sentinel data is a complex task. The new data format and information structure, the increased data volume, the expected data quality and sensor characteristics all mean that users have to develop or update processing facilities before the launch.
An important step forward in this respect is the availability of simulated products and documentation to users. ESA is responding to these needs in two ways.
Firstly, ESA has just released a sample of Sentinel-1 simulated user products and associated format and product definition documents to GMES users. In addition, the Agency is planning a further distribution to all potential users in the coming weeks.
This first release contains a set of simulated radar intensity ‘Level-1’ products, covering all four Sentinel-1 imaging modes and different product types. An example is shown by way of the image of the Netherlands on the right.
Notably, these products were generated by a preliminary version of Sentinel-1’s operational Instrument Processing Facility.
Though they are not intended to reflect the final characteristics of the user products, the format and contents are representative of what the mission will offer.
This will evolve with new versions of the facility and may be slightly tuned following system qualification and inflight commissioning.
Joel Dorandeu from MyOcean said, “We very much welcome the efforts being made to help service providers such as us prepare for the new data from Sentinel-1.
“Considering the volumes of data we expect from Sentinel-1 along with its method of acquisition we have the challenge of developing new processing chains.
“We are now eager to start simulating our products."
To complement this initial release of test data, ESA is, in parallel, simulating Sentinel-1 acquisitions from space using Canada’s Radarsat-2 satellite.
This initiative is now starting to bear fruit following the first full simulation of a Sentinel-1 radar image as shown in picture at the top and here on the left.
Thanks to MacDonald, Dettwiler and Associates Ltd. (MDA), Radarsat-2 was carefully reprogrammed to match the way Sentinel-1 will be operated. A remarkable achievement is the fact that Radarsat was able to emulate the way Sentinel-1 images Earth’s surface using a method called TOPS, thus providing a quality of image almost exactly the same as Sentinel-1.
The very first results are promising, as can be seen in the images acquired over Vancouver harbour on the west coast of Canada. The city is clearly visible, as are the ships docked in the harbour, the coastline and the nearby mountain ranges.
The acquisition of more images over specific test sites are planned to demonstrate the suitability of Sentinel-1 for classifying sea-ice, for applications using ocean winds and waves, and for detecting ships, thereby preparing users for the uptake of data.
Dedicated acquisitions of image pairs and data stacks suitable for measuring surface movements such as glacier dynamics and subsidence are also planned to take place in the coming months.
As for the current set of test data, the Radarsat-2 simulated images will also be processed and formatted using the Sentinel-1 Instrument Processing Facility and made available to users shortly.