fr.cnes.sirius.patrius.forces.gravity.grid

Class GridGravityModel

java.lang.Object

fr.cnes.sirius.patrius.forces.gravity.AbstractGravityModel

fr.cnes.sirius.patrius.forces.gravity.grid.GridGravityModel

All Implemented Interfaces:

GravityModel, Serializable

public class GridGravityModel
extends AbstractGravityModel

Computation of central body attraction with a grid attraction model: attraction acceleration is given by GridAttractionProvider which provides for a set of coordinates the value of acceleration. Interpolation is performed within grid points using a TrivariateGridInterpolator. Computed acceleration excludes the central attraction force like the other AbstractGravityModel. If requested point is out of grid boundaries, a 2nd model (back-up model) is used for computing attraction force.

Potential is also available using method #computePotential(SpacecraftState).

Partial derivatives are not available.

Since:

4.7

Author:

Emmanuel Bignon

See Also:

Serialized Form

Field Summary

Fields inherited from class fr.cnes.sirius.patrius.forces.gravity.AbstractGravityModel

bodyFrame, centralTermContribution, MU, paramMu

Constructor Summary

Constructors

Constructor and Description
GridGravityModel(GridAttractionProvider attractionProvider, TrivariateGridInterpolator interpolator, GravityModel backupModel, Frame bodyFrame) Constructor.
GridGravityModel(GridAttractionProvider attractionProvider, TrivariateGridInterpolator interpolator, GravityModel backupModel, Frame bodyFrame, boolean centralTermContributionIn) Constructor.

Method Summary

Modifier and Type	Method and Description
void	checkData(AbsoluteDate start, AbsoluteDate end) This methods throws an exception if the user did not provide all the required data to perform model call on provided range [start; end].
Vector3D	computeAcceleration(Vector3D pos, Frame frame, AbsoluteDate date) Compute the acceleration due to the gravitational attraction.
double[][]	computeDAccDPos(Vector3D pos, Frame frame, AbsoluteDate date) Compute acceleration derivatives with respect to the position of the spacecraft.
double	computePotential(Vector3D pos, Frame frame, AbsoluteDate date) Compute the potential due to the body attraction.
double	getMu() Get the central attraction coefficient.
void	setMu(double muIn) Set the central attraction coefficient.

Methods inherited from class fr.cnes.sirius.patrius.forces.gravity.AbstractGravityModel

getBodyFrame

Methods inherited from class java.lang.Object

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

Constructor Detail

GridGravityModel

public GridGravityModel(GridAttractionProvider attractionProvider,
                        TrivariateGridInterpolator interpolator,
                        GravityModel backupModel,
                        Frame bodyFrame)

Constructor.

Parameters:

attractionProvider - attraction data provider

interpolator - 3D interpolator using for interpolating acceleration and potential

backupModel - back-up model used if requested point out of boundaries. Beware that this model should not include multiplicative coefficient

bodyFrame - body-centered frame in which grid and accelerations are expressed. Frame shall be centered on body center of mass, not on grid system

GridGravityModel

public GridGravityModel(GridAttractionProvider attractionProvider,
                        TrivariateGridInterpolator interpolator,
                        GravityModel backupModel,
                        Frame bodyFrame,
                        boolean centralTermContributionIn)

Constructor.

Parameters:

attractionProvider - attraction data provider

interpolator - 3D interpolator using for interpolating acceleration and potential

backupModel - back-up model used if requested point out of boundaries. Beware that this model should not include multiplicative coefficient

bodyFrame - body-centered frame in which grid and accelerations are expressed.

centralTermContributionIn - true if central term contribution should be considered (by default), false if not Frame shall be centered on body center of mass, not on grid system

Method Detail

computeAcceleration

public Vector3D computeAcceleration(Vector3D pos,
                                    Frame frame,
                                    AbsoluteDate date)
                             throws PatriusException

Compute the acceleration due to the gravitational attraction.

Parameters:

pos - position of the spacecraft

frame - frame in which the acceleration is computed

date - date

Returns:

the acceleration in the given frame

Throws:

PatriusException - if some specific error occurs

computePotential

public double computePotential(Vector3D pos,
                               Frame frame,
                               AbsoluteDate date)
                        throws PatriusException

Compute the potential due to the body attraction.

If state position is out of grid boundaries, potential is approximated to central body potential.

Parameters:

pos - position of the spacecraft

frame - frame in which the position of the spacecraft is given

date - date

Returns:

the potential due to the body attraction

Throws:

PatriusException - thrown if position is out of grid boundaries

computeDAccDPos

public final double[][] computeDAccDPos(Vector3D pos,
                                        Frame frame,
                                        AbsoluteDate date)
                                 throws PatriusException

Compute acceleration derivatives with respect to the position of the spacecraft..

Parameters:

pos - position of the spacecraft

frame - frame in which the acceleration derivatives are computed

date - date

Returns:

acceleration derivatives with respect to the position of the spacecraft

Throws:

PatriusException - if derivatives cannot be computed

checkData

public void checkData(AbsoluteDate start,
                      AbsoluteDate end)
               throws PatriusException

This methods throws an exception if the user did not provide all the required data to perform model call on provided range [start; end]. It is the responsibility of the model implementation to properly throw exceptions.

Parameters:

start - range start date

end - range end date

Throws:

PatriusException - thrown if some data is missing

getMu

public double getMu()

Get the central attraction coefficient..

Specified by:

getMu in interface GravityModel

Overrides:

getMu in class AbstractGravityModel

Returns:

central attraction coefficient (m³/s²)

setMu

public void setMu(double muIn)

Set the central attraction coefficient..

Specified by:

setMu in interface GravityModel

Overrides:

setMu in class AbstractGravityModel

Parameters:

muIn - the central attraction coefficient.