Instruments

Active Optical

Geometry

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:

PO_geometry

Biblos.COTS This is Biblos COTS package with installation script. Script installs libraries:- kissFFT- boost- netcdf- zlib- hdf5- eigen

Biblos.Geometry This is a module composed of Biblos.Orbit, Biblos.Attitude, Biblos.AocsInstrumentCoupling and Biblos.SceneInteraction blocks.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:o The LOS Simulator calculates the detector elements’ line-of-sight, and the misalignments in in instrument frame.o The Instrument Projection 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.

Biblos.Commons This is a package common for all the Blocks and Modules. Commons contain helper functions e.g. for reading NetCDF or parsing XML files as well as Blocks and Modules interfaces.

Tool: Tiff to NetCDF converter BIBLOS works with NetCDF format for the images. This is a tool to convert Tiff to NetCDF. It is external to BIBLOS, the user shall convert the image offline. THe package includes an executable, a README file (with instructions) and an example auxiliary file.

Biblos.Orbit In charge of the simulation of the nominal, real and estimated orbits. This block computes the nominal orbit from the input orbit parameters and disturbs this orbit with natural orbit perturbations. In addition, estimated orbit is calculated based on standard orbit determination methods.

Biblos.Attitude In charge of the simulation of the nominal, real and estimated platform attitude. This block computes the nominal attitude from the input mission configuration parameters and simulates the operation of attitude actuators, sensors and environmental torques.

Biblos.AOCSInstrumentCoupling This block is in charge of modelling the instrument LOS and detector projection coupling it with the platform AOCS and producing the final instrument viewing directions for image acquisition.Calculates the LOS (Line-Of-Sight) in instrument frame. The Instrument Projection calculates the LOS in ECEF frame. It is in charge of reproducing the scanning and pointing of the instrument LOS as function of time (cross-track, along-track, bidirectional, slowdown, limb…). In addition, this block couples the platform attitude with this scanning motion of the instrument.