The Level-1A product is obtained by decompressing image data and developing a geometric model to locate any pixel in the image.

Figure 1: Level-1A Processing Overview

Level-1A processing includes:

• Level-1 viewing model initialisation
• Decompression
• Level-1A radiometric processing
• Level-1A compression

Level-1 Viewing Model Initialisation
This processing step computes the viewing model that will be used to initialize Level-1B processing. It uses the Precise Orbit Determination (POD) products generated by the Mission Performance Centre Coordinating Centre (MPC/CC).

Decompression
This processing step decompresses the ISPs.

Level-1A Radiometric Processing
This step includes the SWIR pixels arrangement.

Level-1A Compression
This processing step uses the JPEG2000 algorithm to compress the Level-1A imagery.