Package org.orekit.propagation.analytical

Class FieldEcksteinHechlerPropagator<T extends RealFieldElement<T>>

java.lang.Object

org.orekit.propagation.FieldAbstractPropagator<T>

org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator<T>

org.orekit.propagation.analytical.FieldEcksteinHechlerPropagator<T>

All Implemented Interfaces:

FieldPropagator<T>, FieldPVCoordinatesProvider<T>

public class FieldEcksteinHechlerPropagator<T extends RealFieldElement<T>>
extends FieldAbstractAnalyticalPropagator<T>

This class propagates a FieldSpacecraftState using the analytical Eckstein-Hechler model.

The Eckstein-Hechler model is suited for near circular orbits (e < 0.1, with poor accuracy between 0.005 and 0.1) and inclination neither equatorial (direct or retrograde) nor critical (direct or retrograde).

Author:

Guylaine Prat

See Also:

FieldOrbit

Field Summary

Fields inherited from interface org.orekit.propagation.FieldPropagator

DEFAULT_LAW, DEFAULT_MASS, EPHEMERIS_GENERATION_MODE, MASTER_MODE, SLAVE_MODE

Constructor Summary

Constructors

Constructor	Description
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, double referenceRadius, double mu, double c20, double c30, double c40, double c50, double c60)	Build a propagator from FieldOrbit and potential.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, AttitudeProvider attitudeProv, double referenceRadius, double mu, double c20, double c30, double c40, double c50, double c60)	Build a propagator from FieldOrbit, attitude provider and potential.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, AttitudeProvider attitudeProv, UnnormalizedSphericalHarmonicsProvider provider)	Build a propagator from FieldOrbit, attitude provider and potential provider.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, AttitudeProvider attitudeProv, T mass, double referenceRadius, double mu, double c20, double c30, double c40, double c50, double c60)	Build a propagator from FieldOrbit, attitude provider, mass and potential.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, AttitudeProvider attitudeProv, T mass, UnnormalizedSphericalHarmonicsProvider provider)	Build a propagator from FieldOrbit, attitude provider, mass and potential provider.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, AttitudeProvider attitude, T mass, UnnormalizedSphericalHarmonicsProvider provider, UnnormalizedSphericalHarmonicsProvider.UnnormalizedSphericalHarmonics harmonics)	Private helper constructor.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, UnnormalizedSphericalHarmonicsProvider provider)	Build a propagator from FieldOrbit and potential provider.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, T mass, double referenceRadius, double mu, double c20, double c30, double c40, double c50, double c60)	Build a propagator from FieldOrbit, mass and potential.
FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit, T mass, UnnormalizedSphericalHarmonicsProvider provider)	Build a propagator from FieldOrbit, mass and potential provider.

Method Summary

Modifier and Type	Method	Description
protected T	getMass(FieldAbsoluteDate<T> date)	Get the mass.
static <T extends RealFieldElement<T>> T	normalizeAngle(T a, T center)	Normalize an angle in a 2π wide interval around a center value.
FieldCartesianOrbit<T>	propagateOrbit(FieldAbsoluteDate<T> date)	Extrapolate an orbit up to a specific target date.
void	resetInitialState(FieldSpacecraftState<T> state)	Reset the propagator initial state.
protected void	resetIntermediateState(FieldSpacecraftState<T> state, boolean forward)	Reset an intermediate state.

Methods inherited from class org.orekit.propagation.analytical.FieldAbstractAnalyticalPropagator

acceptStep, addEventDetector, basicPropagate, clearEventsDetectors, getEventsDetectors, getGeneratedEphemeris, getPvProvider, propagate

Methods inherited from class org.orekit.propagation.FieldAbstractPropagator

addAdditionalStateProvider, getAdditionalStateProviders, getAttitudeProvider, getField, getFixedStepSize, getFrame, getInitialState, getManagedAdditionalStates, getMode, getPVCoordinates, getStartDate, getStepHandler, isAdditionalStateManaged, propagate, setAttitudeProvider, setEphemerisMode, setMasterMode, setMasterMode, setSlaveMode, setStartDate, updateAdditionalStates

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      UnnormalizedSphericalHarmonicsProvider provider)
                               throws OrekitException

Build a propagator from FieldOrbit and potential provider.

Mass and attitude provider are set to unspecified non-null arbitrary values.

Parameters:

initialOrbit - initial FieldOrbit

provider - for un-normalized zonal coefficients

Throws:

OrekitException - if the zonal coefficients cannot be retrieved or if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      AttitudeProvider attitude,
                                      T mass,
                                      UnnormalizedSphericalHarmonicsProvider provider,
                                      UnnormalizedSphericalHarmonicsProvider.UnnormalizedSphericalHarmonics harmonics)
                               throws OrekitException

Private helper constructor.

Parameters:

initialOrbit - initial FieldOrbit

attitude - attitude provider

mass - spacecraft mass

provider - for un-normalized zonal coefficients

harmonics - provider.onDate(initialOrbit.getDate())

Throws:

OrekitException - if the zonal coefficients cannot be retrieved

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      double referenceRadius,
                                      double mu,
                                      double c20,
                                      double c30,
                                      double c40,
                                      double c50,
                                      double c60)
                               throws OrekitException

Build a propagator from FieldOrbit and potential.

Mass and attitude provider are set to unspecified non-null arbitrary values.

The C_n,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients C_n,0 and the J_n one as follows:

   Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½
                      Cn,0
   Cn,0 = -Jn
 

Parameters:

initialOrbit - initial FieldOrbit

referenceRadius - reference radius of the Earth for the potential model (m)

mu - central attraction coefficient (m³/s²)

c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)

c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)

c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)

c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)

c60 - un-normalized zonal coefficient (about -5.41e-7 for Earth)

Throws:

OrekitException - if the mean parameters cannot be computed

See Also:

Constants

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      T mass,
                                      UnnormalizedSphericalHarmonicsProvider provider)
                               throws OrekitException

Build a propagator from FieldOrbit, mass and potential provider.

Attitude law is set to an unspecified non-null arbitrary value.

Parameters:

initialOrbit - initial FieldOrbit

mass - spacecraft mass

provider - for un-normalized zonal coefficients

Throws:

OrekitException - if the zonal coefficients cannot be retrieved or if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      T mass,
                                      double referenceRadius,
                                      double mu,
                                      double c20,
                                      double c30,
                                      double c40,
                                      double c50,
                                      double c60)
                               throws OrekitException

Build a propagator from FieldOrbit, mass and potential.

Attitude law is set to an unspecified non-null arbitrary value.

The C_n,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients C_n,0 and the J_n one as follows:

   Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½
                      Cn,0
   Cn,0 = -Jn
 

Parameters:

initialOrbit - initial FieldOrbit

mass - spacecraft mass

referenceRadius - reference radius of the Earth for the potential model (m)

mu - central attraction coefficient (m³/s²)

c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)

c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)

c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)

c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)

c60 - un-normalized zonal coefficient (about -5.41e-7 for Earth)

Throws:

OrekitException - if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      AttitudeProvider attitudeProv,
                                      UnnormalizedSphericalHarmonicsProvider provider)
                               throws OrekitException

Build a propagator from FieldOrbit, attitude provider and potential provider.

Mass is set to an unspecified non-null arbitrary value.

Parameters:

initialOrbit - initial FieldOrbit

attitudeProv - attitude provider

provider - for un-normalized zonal coefficients

Throws:

OrekitException - if the zonal coefficients cannot be retrieved or if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      AttitudeProvider attitudeProv,
                                      double referenceRadius,
                                      double mu,
                                      double c20,
                                      double c30,
                                      double c40,
                                      double c50,
                                      double c60)
                               throws OrekitException

Build a propagator from FieldOrbit, attitude provider and potential.

Mass is set to an unspecified non-null arbitrary value.

The C_n,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients C_n,0 and the J_n one as follows:

   Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½
                     Cn,0
   Cn,0 = -Jn
 

Parameters:

initialOrbit - initial FieldOrbit

attitudeProv - attitude provider

referenceRadius - reference radius of the Earth for the potential model (m)

mu - central attraction coefficient (m³/s²)

c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)

c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)

c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)

c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)

c60 - un-normalized zonal coefficient (about -5.41e-7 for Earth)

Throws:

OrekitException - if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      AttitudeProvider attitudeProv,
                                      T mass,
                                      UnnormalizedSphericalHarmonicsProvider provider)
                               throws OrekitException

Build a propagator from FieldOrbit, attitude provider, mass and potential provider.

Parameters:

initialOrbit - initial FieldOrbit

attitudeProv - attitude provider

mass - spacecraft mass

provider - for un-normalized zonal coefficients

Throws:

OrekitException - if the zonal coefficients cannot be retrieved or if the mean parameters cannot be computed

FieldEcksteinHechlerPropagator

public FieldEcksteinHechlerPropagator(FieldOrbit<T> initialOrbit,
                                      AttitudeProvider attitudeProv,
                                      T mass,
                                      double referenceRadius,
                                      double mu,
                                      double c20,
                                      double c30,
                                      double c40,
                                      double c50,
                                      double c60)
                               throws OrekitException

Build a propagator from FieldOrbit, attitude provider, mass and potential.

The C_n,0 coefficients are the denormalized zonal coefficients, they are related to both the normalized coefficients C_n,0 and the J_n one as follows:

   Cn,0 = [(2-δ0,m)(2n+1)(n-m)!/(n+m)!]½
                      Cn,0
   Cn,0 = -Jn
 

Parameters:

initialOrbit - initial FieldOrbit

attitudeProv - attitude provider

mass - spacecraft mass

referenceRadius - reference radius of the Earth for the potential model (m)

mu - central attraction coefficient (m³/s²)

c20 - un-normalized zonal coefficient (about -1.08e-3 for Earth)

c30 - un-normalized zonal coefficient (about +2.53e-6 for Earth)

c40 - un-normalized zonal coefficient (about +1.62e-6 for Earth)

c50 - un-normalized zonal coefficient (about +2.28e-7 for Earth)

c60 - un-normalized zonal coefficient (about -5.41e-7 for Earth)

Throws:

OrekitException - if the mean parameters cannot be computed

Method Detail

resetInitialState

public void resetInitialState(FieldSpacecraftState<T> state)
                       throws OrekitException

Reset the propagator initial state.

Specified by:

resetInitialState in interface FieldPropagator<T extends RealFieldElement<T>>

Overrides:

resetInitialState in class FieldAbstractPropagator<T extends RealFieldElement<T>>

Parameters:

state - new initial state to consider

Throws:

OrekitException - if initial state cannot be reset

resetIntermediateState

protected void resetIntermediateState(FieldSpacecraftState<T> state,
                                      boolean forward)
                               throws OrekitException

Reset an intermediate state.

Specified by:

resetIntermediateState in class FieldAbstractAnalyticalPropagator<T extends RealFieldElement<T>>

Parameters:

state - new intermediate state to consider

forward - if true, the intermediate state is valid for propagations after itself

Throws:

OrekitException - if initial state cannot be reset

propagateOrbit

public FieldCartesianOrbit<T> propagateOrbit(FieldAbsoluteDate<T> date)
                                      throws OrekitException

Extrapolate an orbit up to a specific target date.

Specified by:

propagateOrbit in class FieldAbstractAnalyticalPropagator<T extends RealFieldElement<T>>

Parameters:

date - target date for the orbit

Returns:

extrapolated parameters

Throws:

OrekitException - if some parameters are out of bounds

getMass

protected T getMass(FieldAbsoluteDate<T> date)

Get the mass.

Specified by:

getMass in class FieldAbstractAnalyticalPropagator<T extends RealFieldElement<T>>

Parameters:

date - target date for the orbit

Returns:

mass mass

normalizeAngle

public static <T extends RealFieldElement<T>> T normalizeAngle(T a,
                                                               T center)

Normalize an angle in a 2π wide interval around a center value.

This method has three main uses:

• normalize an angle between 0 and 2π:
  a = MathUtils.normalizeAngle(a, FastMath.PI);
• normalize an angle between -π and +π
  a = MathUtils.normalizeAngle(a, 0.0);
• compute the angle between two defining angular positions:
  angle = MathUtils.normalizeAngle(end, start) - start;

Note that due to numerical accuracy and since π cannot be represented exactly, the result interval is closed, it cannot be half-closed as would be more satisfactory in a purely mathematical view.

Type Parameters:

T - the type of the field elements

Parameters:

a - angle to normalize

center - center of the desired 2π interval for the result

Returns:

a-2kπ with integer k and center-π <= a-2kπ <= center+π

Since:

1.2