In order to continuously improve our data products, we are releasing an updated version of our SAR processor that will produce calibrated SAR imagery products. The data produced by this new version of the SAR processor will include the following new features.
First Order Calibration
Both radiometric calibration and geometric calibration have been improved to ensure that Capella radar system data can be precisely related to physical quantities and targets on the scene.
As result of the calibration activity, the pixel values of sigma_nought for GEO and beta_nought for SLC is refined (radiometric calibration), as well as the pixel displacement in the scene has improved accuracy (geometric calibration).
This improvement is the result of the acquisition and analysis of numerous collects over calibration targets, such as corner reflectors (e.g. special devises used for the calibration of SAR sensors that have known properties) and distributed targets (e.g. rain forest). In particular, the rain forest collects have been used to compensate for the antenna pattern differences in both range and azimuth direction.
Improved focusing in mountainous region
The processor algorithm has been updated to better handle the focusing in images acquired over mountains regions. The example shows how the processor 2.0 allows an improvement in the focusing for a GEO product collected new Pangong Lake, Tibet.
Breaking changes and reprocessing
These changes were required to improve our data quality, however they can cause breaking changes in downstream processing pipeline. For instance, when a pair of images is analyzed, the desire is to have both images produced by the new processor version.
To ensure compatibility, we are conducting a reprocessing campaign of our archive catalog made of the following collections:
- "capella-open-data"
- "capella-slc"
- "capella-geo"
The reprocessing activity will start from May 31st. We will provide an addition communication on the duration of the reprocessing activity and how this would impact users.