This is the documentation for the ``skplatform`` package

*********
Platform
*********

.. autoclass:: skplatform.Platform
    :members:
    :special-members: __init__

..  toctree::
    :maxdepth: 2

    platforms_api/api_posn_techniques
    platforms_api/api_pointing_techniques
    platforms_api/api_roll_control


*****************
Satellite Classes
*****************
Satellite classes are used to locate the position of a platform for a variety of orbits. They are derived from class :class:`~.PlatformLocation`
which allows them to be used as ``platform locators`` in class :class:`~.Platform` when coupled with the :ref:`from_platform`
positioning technique.

Example::

    from skplatform import Platform

    def make_geometry():
        kepler = SatelliteKepler('2020-09-24T12:00:00.000000', period_from_altitude = 600000.0, inclination_radians= radians(97.0), longitude_of_ascending_node_degrees = 82.0, eccentricity= 0.05)
        platform = Platform(platform_locator=kepler)
        utc  = ['2020-09-24T12:15:36.123456', '2020-09-24T12:15:37.456123', '2020-09-24T12:15:38.654321', '2020-09-24T12:15:39.654321']
        pointing_values = [(35000, 10, 0), (27000, 5, 0), (24000, 0, 0), (21000, -5, 0)]
        platform.add_measurement_set(utc, ('from_platform',), ('tangent_altitude', 'limb', pointing_values))

The satellite classes can also be used as stand-alone classes in which case the user would execute the following steps.

#. Create a specific instance of a satellite.
#. Update the satellite position to a given instant in time, see :meth:`~.PlatformLocation.update_position`
#. Get the satellite position using one of the available methods, see :meth:`~.PlatformLocation.position`, :meth:`~.PlatformLocation.earth_location` or :meth:`~.PlatformLocation.lat_lon_height`
#. Repeat steps 2 and 3.

for example::

    dt = timedelta(minutes=1.0)                                         # step time of our simulation is one minute
    numtimes = 1440                                                     # Simulate for 1 day = 1440 * one minute
    platform_utc = datetime(2019,7,26, hour =20, minute=15, second=00)  # start time of our simulation
    sat = SatelliteSunSync(platform_utc,                                # Create the satellite
                           orbittype='sgp4',
                           period_from_altitude=600000.0,
                           localtime_of_ascending_node_hours=18.25)

    answers = np.zeros([3, numtimes])                                   # make an array to hold the latitude, longitude, altitude of each satellite at each simulation step
    times = np.zeros([numtimes], dtype='datetime64[us]')                # make an array to hold the UTC time of each simulation step.
    for i in range(numtimes):                                           # for each time step
        tnow = platform_utc + i * dt                                    # get the next time step
        times[i] = tnow                                                 # save the time of the step
        sat.update_position(tnow)                                       # Update the satellite position
        answers[:, i] = sat.lat_long_height                             # convert XYZ position and save

Users should be aware the satellite classes may internally implement numerical integration using Runge-Kutta algorithms and
should avoid large time steps (e.g. multiple orbits) as this may result in long execution times in the best case and
inaccuracy in the worst case.

..  toctree::
    :maxdepth: 2

    platforms_api/api_satellites

*****************
Internal Classes
*****************

..  toctree::
    :maxdepth: 2

    platforms_api/api_platform