Package org.orekit.forces.drag

Class DragForce

java.lang.Object

org.orekit.forces.drag.AbstractDragForceModel

org.orekit.forces.drag.DragForce

All Implemented Interfaces:

ForceModel, EventDetectorsProvider, ParameterDriversProvider

public class DragForce
extends AbstractDragForceModel

Atmospheric drag force model. The drag acceleration is computed as follows : γ = (1/2 * ρ * V² * S / Mass) * DragCoefVector With DragCoefVector = {C_x, C_y, C_z} and S given by the user through the interface DragSensitive

Author:

Édouard Delente, Fabien Maussion, Véronique Pommier-Maurussane, Pascal Parraud, Melina Vanel

Field Summary

Fields inherited from interface org.orekit.propagation.events.EventDetectorsProvider

DATATION_ACCURACY

Constructor Summary

Constructors

Constructor	Description
DragForce(Atmosphere atmosphere, DragSensitive spacecraft)	Constructor with default flag for finite differences.
DragForce(Atmosphere atmosphere, DragSensitive spacecraft, boolean useFiniteDifferencesOnDensityWrtPosition)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
<T extends CalculusFieldElement<T>> FieldVector3D<T>	acceleration(FieldSpacecraftState<T> s, T[] parameters)	Compute acceleration.
Vector3D	acceleration(SpacecraftState s, double[] parameters)	Compute acceleration.
boolean	dependsOnAttitudeRate()	Check if force model depends on attitude's rotation rate or acceleration at a given, fixed date.
List<ParameterDriver>	getParametersDrivers()	Get the drivers for parameters.
DragSensitive	getSpacecraft()	Get spacecraft that are sensitive to atmospheric drag forces.

Methods inherited from class org.orekit.forces.drag.AbstractDragForceModel

dependsOnPositionOnly, getAtmosphere, getDSDensityWrtState, getDSDensityWrtStateUsingFiniteDifferences, getFieldDensity, getGradientDensityWrtState, getGradientDensityWrtStateUsingFiniteDifferences, isDSStateDerivative, isGradientStateDerivative, isVariable, isVariable

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.propagation.events.EventDetectorsProvider

getDateDetector, getEventDetectors, getFieldDateDetector, getFieldEventDetectors

Methods inherited from interface org.orekit.forces.ForceModel

addContribution, addContribution, getEventDetectors, getFieldEventDetectors, init, init

Methods inherited from interface org.orekit.utils.ParameterDriversProvider

getNbParametersDriversValue, getParameterDriver, getParameters, getParameters, getParameters, getParameters, getParametersAllValues, getParametersAllValues, isSupported

Constructor Detail

DragForce

public DragForce(Atmosphere atmosphere,
                 DragSensitive spacecraft)

Constructor with default flag for finite differences.

Parameters:

atmosphere - atmospheric model

spacecraft - the object physical and geometrical information

DragForce

public DragForce(Atmosphere atmosphere,
                 DragSensitive spacecraft,
                 boolean useFiniteDifferencesOnDensityWrtPosition)

Simple constructor.

Parameters:

atmosphere - atmospheric model

spacecraft - the object physical and geometrical information

useFiniteDifferencesOnDensityWrtPosition - flag to use finite differences to compute density derivatives w.r.t. position (is less accurate but can be faster depending on model)

Since:

12.1

Method Detail

dependsOnAttitudeRate

public boolean dependsOnAttitudeRate()

Check if force model depends on attitude's rotation rate or acceleration at a given, fixed date. If false, it essentially means that at most the attitude's rotation is used when computing the acceleration vector. The default implementation returns false as common forces do not.

Returns:

true if force model depends on attitude derivatives

acceleration

public Vector3D acceleration(SpacecraftState s,
                             double[] parameters)

Compute acceleration.

Parameters:

s - current state information: date, kinematics, attitude

parameters - values of the force model parameters at state date, only 1 value for each parameterDriver

Returns:

acceleration in same frame as state

acceleration

public <T extends CalculusFieldElement<T>> FieldVector3D<T> acceleration(FieldSpacecraftState<T> s,
                                                                         T[] parameters)

Compute acceleration.

Type Parameters:

T - type of the elements

Parameters:

s - current state information: date, kinematics, attitude

parameters - values of the force model parameters at state date, only 1 value for each parameterDriver

Returns:

acceleration in same frame as state

getParametersDrivers

public List<ParameterDriver> getParametersDrivers()

Get the drivers for parameters.

Returns:

drivers for parameters

getSpacecraft

public DragSensitive getSpacecraft()

Get spacecraft that are sensitive to atmospheric drag forces.

Returns:

drag sensitive spacecraft model