.. _state_propagation:

******************
State Propagation
******************

In this section, the different stages and options of a typical simulation setup for a numerical state propagation are described.
Tudat is organized as shown in the figure below.


.. figure:: _static/tudatpy_high_level.png
   :width: 600

Inputs
=======

There are two distinct input types necessary to create a simulation:

- :ref:`environment_setup`: physical modeling of environment and system properties (for both celestial and artificial bodies)
- :ref:`propagation_setup`: formulation of the differential equations representing the problem, and the method to solve them

.. toctree::
   :titlesonly:
   :hidden:
   :maxdepth: 1

   state-propagation/environment-setup
   state-propagation/propagation-setup


Simulation & Output
===================

Once all the settings are in place, the numerical solution to the equations of motion can be generated. All the details
about this part, including the interpretation and availability of outputs, are explained in the following pages:

- :ref:`propagating_dynamics`: For simulations in which only the dynamics are propagated
- :ref:`propagating_variational_simulation` For simulations in which the dynamics and associated variational equations are propagated


.. toctree::
   :titlesonly:
   :hidden:
   :maxdepth: 1

   state-propagation/propagating-dynamics
   state-propagation/propagating-variational-simulation