org.orekit.propagation.analytical
Class J2DifferentialEffect

java.lang.Object
  org.orekit.propagation.analytical.J2DifferentialEffect

All Implemented Interfaces:

Serializable, AdapterPropagator.DifferentialEffect

public class J2DifferentialEffect
extends Object
implements AdapterPropagator.DifferentialEffect, Serializable

Analytical model for J2 effect.

This class computes the differential effect of J2 due to an initial orbit offset. A typical case is when an inclination maneuver changes an orbit inclination at time t₀. As ascending node drift rate depends on inclination, the change induces a time-dependent change in ascending node for later dates.

Author:

Luc Maisonobe

See Also:

SmallManeuverAnalyticalModel, Serialized Form

Constructor Summary

J2DifferentialEffect(Orbit orbit0, Orbit orbit1, boolean applyBefore, double referenceRadius, double mu, double j2)
Simple constructor.

J2DifferentialEffect(Orbit orbit0, Orbit orbit1, boolean applyBefore, PotentialCoefficientsProvider gravityField)
Simple constructor.

J2DifferentialEffect(SpacecraftState original, AdapterPropagator.DifferentialEffect directEffect, boolean applyBefore, double referenceRadius, double mu, double j2)
Simple constructor.

J2DifferentialEffect(SpacecraftState original, AdapterPropagator.DifferentialEffect directEffect, boolean applyBefore, PotentialCoefficientsProvider gravityField)
Simple constructor.

Method Summary

Orbit	apply(Orbit orbit1) Compute the effect of the maneuver on an orbit.
SpacecraftState	apply(SpacecraftState state1) Apply the effect to a spacecraft state.

Methods inherited from class java.lang.Object

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

Constructor Detail

J2DifferentialEffect

public J2DifferentialEffect(SpacecraftState original,
                            AdapterPropagator.DifferentialEffect directEffect,
                            boolean applyBefore,
                            PotentialCoefficientsProvider gravityField)
                     throws OrekitException

Simple constructor.

The applyBefore parameter is mainly used when the differential effect is associated with a maneuver. In this case, the parameter must be set to false.

Parameters:

original - original state at reference date

directEffect - direct effect changing the orbit

applyBefore - if true, effect is applied both before and after reference date, if false it is only applied after reference date

gravityField - gravity field to use

Throws:

OrekitException - if gravity field does not contain J2 coefficient

J2DifferentialEffect

public J2DifferentialEffect(Orbit orbit0,
                            Orbit orbit1,
                            boolean applyBefore,
                            PotentialCoefficientsProvider gravityField)
                     throws OrekitException

Simple constructor.

The applyBefore parameter is mainly used when the differential effect is associated with a maneuver. In this case, the parameter must be set to false.

Parameters:

orbit0 - original orbit at reference date

orbit1 - shifted orbit at reference date

applyBefore - if true, effect is applied both before and after reference date, if false it is only applied after reference date

gravityField - gravity field to use

Throws:

OrekitException - if gravity field does not contain J2 coefficient

J2DifferentialEffect

public J2DifferentialEffect(SpacecraftState original,
                            AdapterPropagator.DifferentialEffect directEffect,
                            boolean applyBefore,
                            double referenceRadius,
                            double mu,
                            double j2)
                     throws OrekitException

Simple constructor.

The applyBefore parameter is mainly used when the differential effect is associated with a maneuver. In this case, the parameter must be set to false.

Parameters:

original - original state at reference date

directEffect - direct effect changing the orbit

applyBefore - if true, effect is applied both before and after reference date, if false it is only applied after reference date

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

mu - central attraction coefficient (m³/s²)

j2 - un-normalized zonal coefficient (about +1.08e-3 for Earth)

Throws:

OrekitException - if direct effect cannot be applied

J2DifferentialEffect

public J2DifferentialEffect(Orbit orbit0,
                            Orbit orbit1,
                            boolean applyBefore,
                            double referenceRadius,
                            double mu,
                            double j2)

Simple constructor.

The applyBefore parameter is mainly used when the differential effect is associated with a maneuver. In this case, the parameter must be set to false.

Parameters:

orbit0 - original orbit at reference date

orbit1 - shifted orbit at reference date

applyBefore - if true, effect is applied both before and after reference date, if false it is only applied after reference date

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

mu - central attraction coefficient (m³/s²)

j2 - un-normalized zonal coefficient (about +1.08e-3 for Earth)

Method Detail

apply

public Orbit apply(Orbit orbit1)

Compute the effect of the maneuver on an orbit.

Parameters:

orbit1 - original orbit at t₁, without maneuver

Returns:

orbit at t₁, taking the maneuver into account if t₁ > t₀

See Also:

apply(SpacecraftState)

apply

public SpacecraftState apply(SpacecraftState state1)
                      throws OrekitException

Apply the effect to a spacecraft state.

Applying the effect may be a no-op in some cases. A typical example is maneuvers, for which the state is changed only for time after the maneuver occurrence.

Specified by:

apply in interface AdapterPropagator.DifferentialEffect

Parameters:

state1 - original state without the effect

Returns:

updated state at the same date, taking the effect into account if meaningful

Throws:

OrekitException - if effect cannot be computed