The Geometry Module is in charge of simulating the spacecraft orbit and attitude, the instrument line-of-sight, the observation area and the auxiliary geometrical data to feed the Scene Generator.
- The Orbit Block calculates the nominal, Satellite and Restituted orbit.
- The Attitude Block calculates the nominal, Satellite and Restituted attitude.
- The AOCS/Instrument Block simulates the detector line. It is composed by two sub-Blocks:
- The LOS Simulator Sub-Block calculates the detector elements’ line-of-sight, and the misalignments in in instrument frame.
- The Instrument Projection Sub-Block transforms the line-of-sight for the detector elements in ECEF frame.
- The Scene Interaction Geometry Block calculates the area of observation from the detector line-of-sight in the digital elevation model DEM. This Block also calculates a number of geometrical inputs needed for the Scene Generation Module like the Observation Zenith Angle, Sun Zenith Angle, etc. Ranging measurements for topography and canopy vertical description require detailed surface properties.
The Geometry Module, and the interaction between its Blocks, is shown in the following diagram: