def __init__(self,
tudatpy_bodies,
custom_bodies=None,
frame_origin=None,
frame_orientation=None,
start_epoch=None,
end_epoch=None,
epoch_margin=300.0):
"""
Parameters
----------
tudatpy_bodies : list[str]
List of bodies to be added to the environment that are part
of the available bodies cataloged in the tudatBundle.
custom_bodies : list[str]
List of user-defined bodies to be added to the environment
which are not part of the available bodies in the tudatBundle.
frame_origin : str
Frame origin for simulation output results.
frame_orientation : str
Frame orientation for simulation output results.
Examples
--------
"""
# Sets as [] if tudatpy_bodies is None.
self._tudatpy_bodies = [] or tudatpy_bodies
# Sets as [] if custom_bodies is None.
self._custom_bodies = [] or custom_bodies
# Warns ands sets default origin.
self._frame_origin = frame_origin or self._default_origin()
# Warns and sets default orientation.
self._frame_orientation = frame_orientation or self._default_orient()
self._start_epoch = start_epoch
self._end_epoch = end_epoch
self._epoch_margin = abs(epoch_margin)
self._body_settings = None
self._environment_finalized = False
if self._start_epoch and self._end_epoch:
# Get default body settings for cataloged bodies in tudatpy.
self._body_settings = simulation_setup.get_default_body_settings(
self._tudatpy_bodies, self._start_epoch - self._epoch_margin,
self._end_epoch + self._epoch_margin)
else:
# Get default body settings for cataloged bodies in tudatpy.
self._body_settings = simulation_setup.get_default_body_settings(
self._tudatpy_bodies)
# Reset all bodies ephemeris and rotation model orientation frame.
for body in self._tudatpy_bodies:
self._body_settings[
body].ephemeris_settings.reset_frame_orientation(
self._frame_orientation)
self._body_settings[
body].rotation_model_settings.reset_original_frame(
self._frame_orientation)
# Create cataloged bodies.
self._bodies = simulation_setup.create_bodies(self._body_settings)
# Create all custom bodies.
for body in self._custom_bodies:
self._bodies[body] = simulation_setup.Body()
def main():
# Load spice kernels.
spice_interface.load_standard_spice_kernels()
# Set simulation start epoch.
simulation_start_epoch = 0.0
# Set numerical integration fixed step size.
fixed_step_size = 10.0
# Set simulation end epoch.
simulation_end_epoch = constants.JULIAN_DAY
###########################################################################
# CREATE ENVIRONMENT ######################################################
###########################################################################
# Create body objects.
bodies_to_create = ["Earth"]
body_settings = simulation_setup.get_default_body_settings(
bodies_to_create)
body_settings[
"Earth"].ephemeris_settings = simulation_setup.ConstantEphemerisSettings(
np.zeros(6))
body_settings["Earth"].rotation_model_settings.reset_original_frame(
"ECLIPJ2000")
# Create Earth Object.
bodies = simulation_setup.create_bodies(body_settings)
###########################################################################
# CREATE VEHICLE ##########################################################
###########################################################################
# Create vehicle objects.
bodies["Delfi-C3"] = simulation_setup.Body()
###########################################################################
# FINALIZE BODIES #########################################################
###########################################################################
simulation_setup.set_global_frame_body_ephemerides(bodies, "SSB",
"ECLIPJ2000")
###########################################################################
# CREATE ACCELERATIONS ####################################################
###########################################################################
# Define bodies that are propagated.
bodies_to_propagate = ["Delfi-C3"]
# Define central bodies.
central_bodies = ["Earth"]
# Define accelerations acting on Delfi-C3.
accelerations_of_delfi_c3 = dict(
Earth=[simulation_setup.Acceleration.point_mass_gravity()])
# Create global accelerations dictionary.
accelerations = {"Delfi-C3": accelerations_of_delfi_c3}
# Create acceleration models.
acceleration_models = simulation_setup.create_acceleration_models_dict(
bodies, accelerations, bodies_to_propagate, central_bodies)
###########################################################################
# CREATE PROPAGATION SETTINGS #############################################
###########################################################################
# Set initial conditions for the Asterix satellite that will be
# propagated in this simulation. The initial conditions are given in
# Keplerian elements and later on converted to Cartesian elements.
# Set Keplerian elements for Delfi-C3
earth_gravitational_parameter = bodies[
"Earth"].gravity_field_model.get_gravitational_parameter()
# LEGACY DESIGN.
# KEI = orbital_element_conversions.KeplerianElementIndices
# asterix_initial_state_in_keplerian_elements = np.zeros(6)
# kep_state = asterix_initial_state_in_keplerian_elements
# kep_state[int(KEI.semi_major_axis_index)] = 7500.0E3
# kep_state[int(KEI.eccentricity_index)] = 0.1
# kep_state[int(KEI.inclination_index)] = np.deg2rad(85.3)
# kep_state[int(KEI.argument_of_periapsis_index)] = np.deg2rad(235.7)
# kep_state[int(KEI.longitude_of_ascending_node_index)] = np.deg2rad(23.4)
# kep_state[int(KEI.true_anomaly_index)] = np.deg2rad(139.87)
# system_initial_state = corbital_element_conversions.onvert_keplerian_to_cartesian_elements(
# kep_state, earth_gravitational_parameter)
# REVISED CONTEMPORARY DESIGN.
system_initial_state = elements.keplerian2cartesian(
mu=earth_gravitational_parameter,
a=7500.0E3,
ecc=0.1,
inc=np.deg2rad(85.3),
raan=np.deg2rad(23.4),
argp=np.deg2rad(235.7),
nu=np.deg2rad(139.87))
# Create propagation settings.
propagator_settings = propagators.TranslationalStatePropagatorSettings(
central_bodies, acceleration_models, bodies_to_propagate,
system_initial_state, simulation_end_epoch)
# Create numerical integrator settings.
integrator_settings = numerical_integrators.IntegratorSettings(
numerical_integrators.AvailableIntegrators.rungeKutta4,
simulation_start_epoch, fixed_step_size)
###########################################################################
# PROPAGATE ORBIT #########################################################
###########################################################################
t0 = time.time()
# Create simulation object and propagate dynamics.
dynamics_simulator = propagators.SingleArcDynamicsSimulator(
bodies, integrator_settings, propagator_settings, True)
result = dynamics_simulator.get_equations_of_motion_numerical_solution()
###########################################################################
# PRINT INITIAL AND FINAL STATES ##########################################
###########################################################################
print(f"""
Single Earth-Orbiting Satellite Example.
The initial position vector of Delfi-C3 is [km]: \n{
result[simulation_start_epoch][:3] / 1E3}
The initial velocity vector of Delfi-C3 is [km]: \n{
result[simulation_start_epoch][3:] / 1E3}
After {simulation_end_epoch} seconds the position vector of Delfi-C3 is [km]: \n{
result[simulation_end_epoch][:3] / 1E3}
And the velocity vector of Delfi-C3 is [km]: \n{
result[simulation_start_epoch][3:] / 1E3}
""")
###########################################################################
# SAVE RESULTS ############################################################
###########################################################################
#
# io.save2txt(
# solution=result,
# filename="singleSatellitePropagationHistory.dat",
# directory="./tutorial_1",
# )
# Final statement (not required, though good practice in a __main__).
return 0
#
if __name__ == "__main__":
spice_interface.load_standard_spice_kernels()
env = Environment(tudatpy_bodies=["Earth"],
custom_bodies=["Delfi"],
frame_origin="SSB",
frame_orientation="ECLIPJ2000",
start_epoch=None,
end_epoch=None,
epoch_margin=300.0)
# After environment has been finalized, then member functions can be called.
env.finalize_environment()
# Method 1 of retrieving bodies.
state = env["Delfi"].get_state()
# Alternative way of retrieving bodies.
state = env.Delfi.get_state()
# Method 2 of setting custom bodies.
env["DWelfi_n3xt"] = simulation_setup.Body()
env.Delfi_one = simulation_setup.Body()
# print(env)
def main():
# Load spice kernels.
spice_interface.load_standard_spice_kernels()
# Set simulation start epoch.
simulation_start_epoch = 0.0
# Set numerical integration fixed step size.
fixed_step_size = 0.5
# Set simulation end epoch.
simulation_end_epoch = constants.JULIAN_DAY
###########################################################################
# CREATE ENVIRONMENT ######################################################
###########################################################################
# Create body objects.
bodies_to_create = ["Sun", "Earth", "Moon", "Mars", "Venus"]
body_settings = simulation_setup.get_default_body_settings(
bodies_to_create, simulation_start_epoch - 300.0,
simulation_end_epoch + 300.0, fixed_step_size)
for body in bodies_to_create:
body_settings[body].ephemeris_settings.reset_frame_orientation("J2000")
body_settings[body].rotation_model_settings.reset_original_frame(
"J2000")
bodies = simulation_setup.create_bodies(body_settings)
###########################################################################
# CREATE VEHICLE ##########################################################
###########################################################################
# Create vehicle objects.
bodies["Delfi-C3"] = simulation_setup.Body()
bodies["Delfi-C3"].set_constant_body_mass(400.0)
###########################################################################
# CREATE VEHICLE - ENVIRONMENT INTERFACE ##################################
###########################################################################
# Create aerodynamic coefficient interface settings
reference_area = 4.0
aerodynamic_coefficient = 1.2
aero_c_settings = simulation_setup.ConstantAerodynamicCoefficientSettings(
reference_area,
aerodynamic_coefficient * np.ones(3),
are_coefficients_in_aerodynamic_frame=True,
are_coefficients_in_negative_axis_direction=True)
# Create and set aerodynamic coefficients object
bodies["Delfi-C3"].set_aerodynamic_coefficient_interface(
simulation_setup.create_aerodynamic_coefficient_interface(
aero_c_settings, "Delfi-C3"))
# TODO: Simplify (post 1.0.0 work)
# Create radiation pressure settings
reference_area_radiation = 4.0
radiation_pressure_coefficient = 1.2
occulting_bodies = ["Earth"]
rad_press_settings = simulation_setup.CannonBallRadiationPressureInterfaceSettings(
"Sun", reference_area_radiation, radiation_pressure_coefficient,
occulting_bodies)
# Create and set radiation pressure settings
bodies["Delfi-C3"].set_radiation_pressure_interface(
"Sun",
simulation_setup.create_radiation_pressure_interface(
rad_press_settings, "Delfi-C3", bodies))
# TODO: Simplify (post 1.0.0 work)
###########################################################################
# FINALIZE BODIES #########################################################
###########################################################################
# Finalize body creation.
simulation_setup.set_global_frame_body_ephemerides(bodies, "SSB", "J2000")
###########################################################################
# CREATE ACCELERATIONS ####################################################
###########################################################################
# Define bodies that are propagated.
bodies_to_propagate = ["Delfi-C3"]
# Define central bodies.
central_bodies = ["Earth"]
# Define unique (Sun, Earth) accelerations acting on Delfi-C3.
accelerations_of_delfi_c3 = dict(
Sun=[
simulation_setup.Acceleration.canon_ball_radiation_pressure()
# AccelerationSettings(AvailableAcceleration.cannon_ball_radiation_pressure) # LEGACY DESIGN.
],
Earth=[
simulation_setup.Acceleration.spherical_harmonic_gravity(5, 5),
# SphericalHarmonicAccelerationSettings(5, 5), # LEGACY DESIGN.
simulation_setup.Acceleration.aerodynamic()
# AccelerationSettings(AvailableAcceleration.aerodynamic) # LEGACY DESIGN.
])
# Define other point mass accelerations acting on Delfi-C3.
for other in set(bodies_to_create).difference({"Sun", "Earth"}):
accelerations_of_delfi_c3[other] = [
simulation_setup.Acceleration.point_mass_gravity()
]
# Create global accelerations dictionary.
acceleration_dict = {"Delfi-C3": accelerations_of_delfi_c3}
# Create acceleration models.
acceleration_models = simulation_setup.create_acceleration_models_dict(
bodies, acceleration_dict, bodies_to_propagate, central_bodies)
###########################################################################
# CREATE PROPAGATION SETTINGS #############################################
###########################################################################
# Set initial conditions for the Asterix satellite that will be
# propagated in this simulation. The initial conditions are given in
# Keplerian elements and later on converted to Cartesian elements.
# Set Keplerian elements for Delfi-C3
earth_gravitational_parameter = bodies[
"Earth"].gravity_field_model.get_gravitational_parameter()
# LEGACY DESIGN.
# KEI = orbital_element_conversions.KeplerianElementIndices
# asterix_initial_state_in_keplerian_elements = np.zeros(6)
# kep_state = asterix_initial_state_in_keplerian_elements
# kep_state[int(KEI.semi_major_axis_index)] = 7500.0E3
# kep_state[int(KEI.eccentricity_index)] = 0.1
# kep_state[int(KEI.inclination_index)] = np.deg2rad(85.3)
# kep_state[int(KEI.argument_of_periapsis_index)] = np.deg2rad(235.7)
# kep_state[int(KEI.longitude_of_ascending_node_index)] = np.deg2rad(23.4)
# kep_state[int(KEI.true_anomaly_index)] = np.deg2rad(139.87)
# system_initial_state = corbital_element_conversions.onvert_keplerian_to_cartesian_elements(
# kep_state, earth_gravitational_parameter)
# REVISED CONTEMPORARY DESIGN.
system_initial_state = elements.keplerian2cartesian(
mu=earth_gravitational_parameter,
a=7500.0E3,
ecc=0.1,
inc=np.deg2rad(85.3),
raan=np.deg2rad(23.4),
argp=np.deg2rad(235.7),
nu=np.deg2rad(139.87))
# Create propagation settings.
propagator_settings = propagators.TranslationalStatePropagatorSettings(
central_bodies, acceleration_models, bodies_to_propagate,
system_initial_state, simulation_end_epoch)
# Create numerical integrator settings.
integrator_settings = numerical_integrators.IntegratorSettings(
numerical_integrators.AvailableIntegrators.rungeKutta4,
simulation_start_epoch, fixed_step_size)
###########################################################################
# PROPAGATE ORBIT #########################################################
###########################################################################
# Create simulation object and propagate dynamics.
dynamics_simulator = propagators.SingleArcDynamicsSimulator(
bodies, integrator_settings, propagator_settings, True)
result = dynamics_simulator.get_equations_of_motion_numerical_solution()
###########################################################################
# PRINT INITIAL AND FINAL STATES ##########################################
###########################################################################
print(f"""
Single Earth-Orbiting Satellite Example.
The initial position vector of Delfi-C3 is [km]: \n{
result[simulation_start_epoch][:3] / 1E3}
The initial velocity vector of Delfi-C3 is [km/s]: \n{
result[simulation_start_epoch][3:] / 1E3}
After {simulation_end_epoch} seconds the position vector of Delfi-C3 is [km]: \n{
result[simulation_end_epoch][:3] / 1E3}
And the velocity vector of Delfi-C3 is [km/s]: \n{
result[simulation_end_epoch][3:] / 1E3}
""")
###########################################################################
# SAVE RESULTS ############################################################
###########################################################################
io.save2txt(
solution=result,
filename="singlePerturbedSatellitePropagationHistory.dat",
directory="./tutorial_2",
)
# Final statement (not required, though good practice in a __main__).
return 0