Speaker
Mr
Luc Maisonobe
(CS SI)
Description
The Sentinel-2 mission is a component of the Copernicus program. It consists of two spacecrafts each carrying a
high resolution multispectral imager (13 bands) devoted to environmental, security, and agricultural applications.
One of the key feature of Sentinel-2 is the huge amount of imagery data that will be produced, as each spacecraft
produces 1.7TB of raw data daily. All data are transformed on ground at the Image Processing Facility to create the
various products levels.
One element of this processing chain is the Rugged library: an open-source library built on top of the open-source
Orekit space flight dynamics library. Rugged is used to compute very quickly and accurately the mapping between
ground points and on-board pixels, taking into account a Digital Elevation Model. Direct location computation is
used to identify which ground point is seen by a specified sensor pixel. Inverse location computation is used to
identify which sensor pixel will see a specified ground point. These methods are the basic elements for complete
processing algorithms. They are computationally intensive due to the very large number of pixels to manage (12
detectors, 13 bands, global coverage of land surfaces).
The geo-location methods are at the boundary between image processing and flight dynamics as they handle
accurate geometrical models. Rugged has therefore been designed as an intermediate level library, and it relies
on Orekit to compute the global geometry (spacecraft orbit and attitude, Earth precession nutation and proper
rotation including all IERS corrections, Earth mean ellipsoidal shape). The Rugged library adds on top of this the
Digital Elevation Model intersection computation.
The presentation will describe the overall Rugged technical architecture, the issues that were faced and how they
were solved in order to achieve a high performance level while not compromising accuracy. It will also present
the open-source strategy and the governance model of the library. The library is already operationally used,
some perspectives for it will be discussed.
| Applicant type | First author |
|---|
Primary author
Mr
Luc Maisonobe
(CS SI)
Co-authors
Mrs
Aude Espesset
(CS SI)
Mrs
Guylaine Prat
(CS SI)
