The first step of any software development is to define the architecture. The architecture for End-to-End Simulators depends primarily on the type of Instrument.
1.Basic concepts of BIBLOS: Instruments, Modules and Blocks
In Archeo the 4 most common types of Instruments for Earth Observation missions were identified: Passive Opticals, Active Microwaves, Passive Microwaves and Active Opticals [Ref.].
The high-level architecture units of the End-to-End Simulator are called Modules, in BIBLOS terminology. The software units that compose the Modules, and contain the algorithms are called Blocks.
2.The Reference Architecture
The Reference Architecture is the high-level architecture of any End-to-End Simulator. It contains the simulation of the acquisition of Instrument on board of the spacecraft (Geometry+Scene Generation+Instrument Modules), and the Ground Processor Prototypes (Level 1 and 2).
3. Type of Mission & Adapting the architecture for each Mission
Each mission has its own particularities. There might be several instruments on board, of the same or different type. This shall be taken into account to define the architecture and adapt the Reference Architecture.
4.Read more on the background of the project.
The BIBLOS project is an effort from ESA to reduce the effort in the development of E2ES. Additionally to the BIBLOS project, ESA has a number of activities, like OpenSF (a platform to execute different models) and the EO CFI library.