OverallStructure.md

Overall Structure of S2E

1. Overview

• This document explains the overall structure of the S2E.

2. Structure of S2E

• The following figure shows the structure of the S2E.

2.1. Simulation Case

• The highest layer of the structure of S2E is the Simulation Case, which is defined in the src/simulation/case/simulation_case.cpp.
• The Simulation Case always has Simulation Configuration and Global Environment.
  • Simulation Configuration has basic information on the interface of the simulation, such as log output and initialize input information.
  • Global Environment is defined as the common environment for the whole simulation case. It includes time, celestial information, star catalog, and GNSS satellite position.
• Users can make their Simulation Case by inheriting the Simulation Case base class and adding simulation target objects (e.g., spacecraft and ground station) for their demand.
• The defined simulation objects can use the information of Simulation Configuration and Global Environment.

2.2. Spacecraft

• An essential simulation object is the Spacecraft class.
• Spacecraft class has the following features to simulate the behavior of spacecraft in space.
  • Structure
    • This class handles the structure information of the spacecraft, such as the mass, the inertia tensor, surface information, and residual magnetic moment.
    • The information is used to calculate disturbance and propagate dynamics.
  • LocalEnvironment
    • This class handles space environment information around the spacecraft, such as air density, magnetic field, solar energy, and eclipse.
    • The information is used to calculate disturbance and emulate environment sensors.
  • Disturbance
    • This class handles disturbances forces(accelerations) and torques.
    • The information is used to propagate dynamics.
  • Dynamics
    • This class handles dynamics calculation for attitude, orbit, and thermal.
    • This is the core of the numerical simulation.
  • Components
    • This class emulates the behavior of components mounted on the spacecraft. The spacecraft can measure the physical quantities and generate control output by using the components.
    • This class is not defined in the Spacecraft base class, and users have to define it themselves.
• Users can add multiple spacecraft into their SimulationCase, and these spacecraft can communicate via communication components.

2.3. Ground Station

• TBW

2.4. Structure of initializing files

• The structure of the initializing files follows the above figure.
• simulation_base.ini sets the parameters for SimulationCase, and file paths to each simulation object.
• satellite.ini sets the parameters for Spacecraft and file paths to each component.

3. Structure of spacecraft components

Note: the structure of components is implemented now. So the following figure is just an idea, and it may be modified.

- Each component can communicate with other components. - All components have a power wire, and power control components control the switch.