//! Function to create a gravity field model.
boost::shared_ptr< gravitation::GravityFieldModel > createGravityFieldModel(
const boost::shared_ptr< GravityFieldSettings > gravityFieldSettings,
const std::string& body,
const NamedBodyMap& bodyMap,
const std::vector< boost::shared_ptr< GravityFieldVariationSettings > >& gravityFieldVariationSettings )
{
using namespace tudat::gravitation;
// Declare return object.
boost::shared_ptr< GravityFieldModel > gravityFieldModel;
// Check which type of gravity field model is to be created.
switch( gravityFieldSettings->getGravityFieldType( ) )
{
case central:
{
// Check whether settings for point mass gravity field model are consistent with its type.
boost::shared_ptr< CentralGravityFieldSettings > centralFieldSettings =
boost::dynamic_pointer_cast< CentralGravityFieldSettings >( gravityFieldSettings );
if( centralFieldSettings == NULL )
{
throw std::runtime_error(
"Error, expected central field settings when making gravity field model for body " +
body);
}
else if( gravityFieldVariationSettings.size( ) != 0 )
{
std::cerr<<"Error, requested central gravity field, but field variations settings are not empty."<<std::endl;
}
else
{
// Create and initialize point mass gravity field model.
gravityFieldModel = boost::make_shared< GravityFieldModel >(
centralFieldSettings->getGravitationalParameter( ) );
}
break;
}
#if USE_CSPICE
case central_spice:
{
if( gravityFieldVariationSettings.size( ) != 0 )
{
std::cerr<<"Error, requested central gravity field, but field variations settings are not empty."<<std::endl;
}
else
{
// Create and initialize point mass gravity field model from Spice.
gravityFieldModel = boost::make_shared< GravityFieldModel >(
spice_interface::getBodyGravitationalParameter( body ) );
}
break;
}
#endif
case spherical_harmonic:
{
// Check whether settings for spherical harmonic gravity field model are consistent with
// its type.
boost::shared_ptr< SphericalHarmonicsGravityFieldSettings > sphericalHarmonicFieldSettings =
boost::dynamic_pointer_cast< SphericalHarmonicsGravityFieldSettings >(
gravityFieldSettings );
if( sphericalHarmonicFieldSettings == NULL )
{
throw std::runtime_error(
"Error, expected spherical harmonic field settings when making gravity field model of "
+ body );
}
else
{
// Check consistency of cosine and sine coefficients.
if( ( sphericalHarmonicFieldSettings->getCosineCoefficients( ).rows( ) !=
sphericalHarmonicFieldSettings->getSineCoefficients( ).rows( ) ) ||
( sphericalHarmonicFieldSettings->getCosineCoefficients( ).cols( ) !=
sphericalHarmonicFieldSettings->getSineCoefficients( ).cols( ) ) )
{
throw std::runtime_error(
std::string( "Error when making spherical harmonic field, sine and " ) +
std::string( "cosine matrix sizes are not equal for body " ) + body );
}
else
{
if( gravityFieldVariationSettings.size( ) == 0 &&
sphericalHarmonicFieldSettings->getCreateTimeDependentField( ) == 0 )
{
// Create and initialize spherical harmonic gravity field model.
gravityFieldModel = boost::make_shared< SphericalHarmonicsGravityField >(
sphericalHarmonicFieldSettings->getGravitationalParameter( ),
sphericalHarmonicFieldSettings->getReferenceRadius( ),
sphericalHarmonicFieldSettings->getCosineCoefficients( ),
sphericalHarmonicFieldSettings->getSineCoefficients( ),
sphericalHarmonicFieldSettings->getAssociatedReferenceFrame( ) );
}
else
{
if( bodyMap.at( body )->getGravityFieldModel( ) != NULL )
{
std::cerr<<"Warning when making time-dependent gravity field model for body "<<body<<" existing gravity field "
<<" is not empty but overwritten in Body! "<<std::endl;
}
// Create preliminary TimeDependentSphericalHarmonicsGravityField, without actual variation settings.
gravityFieldModel = boost::make_shared< TimeDependentSphericalHarmonicsGravityField >(
sphericalHarmonicFieldSettings->getGravitationalParameter( ),
sphericalHarmonicFieldSettings->getReferenceRadius( ),
sphericalHarmonicFieldSettings->getCosineCoefficients( ),
sphericalHarmonicFieldSettings->getSineCoefficients( ),
sphericalHarmonicFieldSettings->getAssociatedReferenceFrame( ) );
}
}
}
break;
}
default:
throw std::runtime_error(
"Error, did not recognize gravity field model settings type " +
boost::lexical_cast< std::string >(
gravityFieldSettings->getGravityFieldType( ) ) );
}
return gravityFieldModel;
}
Eigen::Matrix< StateScalarType, 6, 1 > propagateForwardBackwards( const int integratorCase )
{
//Load spice kernels.
spice_interface::loadStandardSpiceKernels( );
// Define bodies in simulation.
std::vector< std::string > bodyNames;
bodyNames.push_back( "Earth" );
bodyNames.push_back( "Moon" );
bodyNames.push_back( "Sun" );
bodyNames.push_back( "Mars" );
bodyNames.push_back( "Venus" );
// Specify initial time
double initialEphemerisTime = 1.0E7;
double finalEphemerisTime = initialEphemerisTime + 86400.0;
double buffer = 3600.0;
// Create bodies needed in simulation
std::map< std::string, boost::shared_ptr< BodySettings > > bodySettings =
getDefaultBodySettings( bodyNames, initialEphemerisTime - 2.0 * buffer, finalEphemerisTime + 2.0 * buffer );
boost::dynamic_pointer_cast< InterpolatedSpiceEphemerisSettings >( bodySettings[ "Moon" ]->ephemerisSettings )->
resetFrameOrigin( "Earth" );
NamedBodyMap bodyMap = createBodies( bodySettings );
setGlobalFrameBodyEphemerides( bodyMap, "Earth", "ECLIPJ2000" );
// Set accelerations between bodies that are to be taken into account.
SelectedAccelerationMap accelerationMap;
std::map< std::string, std::vector< boost::shared_ptr< AccelerationSettings > > > accelerationsOfMoon;
accelerationsOfMoon[ "Earth" ].push_back( boost::make_shared< AccelerationSettings >( central_gravity ) );
accelerationsOfMoon[ "Sun" ].push_back( boost::make_shared< AccelerationSettings >( central_gravity ) );
accelerationMap[ "Moon" ] = accelerationsOfMoon;
// Propagate the moon only
std::vector< std::string > bodiesToIntegrate;
bodiesToIntegrate.push_back( "Moon" );
std::vector< std::string > centralBodies;
centralBodies.push_back( "Earth" );
// Define settings for numerical integrator.
boost::shared_ptr< IntegratorSettings< TimeType > > integratorSettings = getIntegrationSettings< TimeType >(
integratorCase, initialEphemerisTime, true );
// Propagate forwards
{
// Create acceleration models and propagation settings.
Eigen::Matrix< StateScalarType, 6, 1 > systemInitialState =
spice_interface::getBodyCartesianStateAtEpoch(
bodiesToIntegrate[ 0 ], centralBodies[ 0 ], "ECLIPJ2000", "NONE", initialEphemerisTime ).
template cast< StateScalarType >( );
AccelerationMap accelerationModelMap = createAccelerationModelsMap(
bodyMap, accelerationMap, bodiesToIntegrate, centralBodies );
boost::shared_ptr< TranslationalStatePropagatorSettings< StateScalarType > > propagatorSettings =
boost::make_shared< TranslationalStatePropagatorSettings< StateScalarType > >
( centralBodies, accelerationModelMap, bodiesToIntegrate, systemInitialState, finalEphemerisTime + buffer );
// Create dynamics simulation object.
SingleArcDynamicsSimulator< StateScalarType, TimeType > dynamicsSimulator(
bodyMap, integratorSettings, propagatorSettings, true, true, true );
}
double testTime = initialEphemerisTime + ( finalEphemerisTime - initialEphemerisTime ) / 2.0;
Eigen::Vector6d forwardState = bodyMap.at( "Moon" )->getEphemeris( )->getCartesianState( testTime );
// Re-define settings for numerical integrator.
integratorSettings = getIntegrationSettings< TimeType >( integratorCase, finalEphemerisTime, false );
// Propagate backwards
{
// Create acceleration models and propagation settings.
Eigen::Matrix< StateScalarType, 6, 1 > systemInitialState =
spice_interface::getBodyCartesianStateAtEpoch(
bodiesToIntegrate[ 0 ], centralBodies[ 0 ], "ECLIPJ2000", "NONE", finalEphemerisTime ).
template cast< StateScalarType >( );
AccelerationMap accelerationModelMap = createAccelerationModelsMap(
bodyMap, accelerationMap, bodiesToIntegrate, centralBodies );
boost::shared_ptr< TranslationalStatePropagatorSettings< StateScalarType > > propagatorSettings =
boost::make_shared< TranslationalStatePropagatorSettings< StateScalarType > >
( centralBodies, accelerationModelMap, bodiesToIntegrate, systemInitialState, initialEphemerisTime - buffer );
// Create dynamics simulation object.
SingleArcDynamicsSimulator< StateScalarType, TimeType > dynamicsSimulator(
bodyMap, integratorSettings, propagatorSettings, true, true, true );
}
Eigen::Vector6d backwardState = bodyMap.at( "Moon" )->getEphemeris( )->getCartesianState( testTime );
return forwardState - backwardState;
}
