Package org.orekit.bodies

Class Ellipse

java.lang.Object

org.orekit.bodies.Ellipse

public class Ellipse
extends Object

Model of a 2D ellipse in 3D space.

These ellipses are mainly created as plane sections of general 3D ellipsoids, but can be used for other purposes.

Instances of this class are guaranteed to be immutable.

Since:

7.0

Author:

Luc Maisonobe

See Also:

• Ellipsoid.getPlaneSection(Vector3D, Vector3D)

Constructor Summary

Constructors

Constructor	Description
Ellipse(Vector3D center, Vector3D u, Vector3D v, double a, double b, Frame frame)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
double	getA()	Get the semi major axis.
double	getB()	Get the semi minor axis.
Vector3D	getCenter()	Get the center of the 2D ellipse.
Vector2D	getCenterOfCurvature(Vector2D point)	Find the center of curvature (point on the evolute) at the nadir of a point.
Frame	getFrame()	Get the defining frame.
Vector3D	getU()	Get the unit vector along the major axis.
Vector3D	getV()	Get the unit vector along the minor axis.
Vector3D	pointAt(double theta)	Get a point of the 2D ellipse.
Vector2D	projectToEllipse(Vector2D p)	Find the closest ellipse point.
TimeStampedPVCoordinates	projectToEllipse(TimeStampedPVCoordinates pv)	Project position-velocity-acceleration on an ellipse.
Vector2D	toPlane(Vector3D p)	Project a point to the ellipse plane.
Vector3D	toSpace(Vector2D p)	Create a point from its ellipse-relative coordinates.

Methods inherited from class java.lang.Object

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

Constructor Details

Ellipse

public Ellipse(Vector3D center,
 Vector3D u,
 Vector3D v,
 double a,
 double b,
 Frame frame)

Simple constructor.

Parameters:

center - center of the 2D ellipse

u - unit vector along the major axis

v - unit vector along the minor axis

a - semi major axis

b - semi minor axis

frame - frame in which the ellipse is defined

Method Details

getCenter

public Vector3D getCenter()

Get the center of the 2D ellipse.

Returns:

center of the 2D ellipse

getU

public Vector3D getU()

Get the unit vector along the major axis.

Returns:

unit vector along the major axis

getV

public Vector3D getV()

Get the unit vector along the minor axis.

Returns:

unit vector along the minor axis

getA

public double getA()

Get the semi major axis.

Returns:

semi major axis

getB

public double getB()

Get the semi minor axis.

Returns:

semi minor axis

getFrame

public Frame getFrame()

Get the defining frame.

Returns:

defining frame

pointAt

public Vector3D pointAt(double theta)

Get a point of the 2D ellipse.

Parameters:

theta - angular parameter on the ellipse (really the eccentric anomaly)

Returns:

ellipse point at theta, in underlying ellipsoid frame

toSpace

public Vector3D toSpace(Vector2D p)

Create a point from its ellipse-relative coordinates.

Parameters:

p - point defined with respect to ellipse

Returns:

point defined with respect to 3D frame

See Also:

• toPlane(Vector3D)

toPlane

public Vector2D toPlane(Vector3D p)

Project a point to the ellipse plane.

Parameters:

p - point defined with respect to 3D frame

Returns:

point defined with respect to ellipse

See Also:

• toSpace(Vector2D)

projectToEllipse

public Vector2D projectToEllipse(Vector2D p)

Find the closest ellipse point.

Parameters:

p - point in the ellipse plane to project on the ellipse itself

Returns:

closest point belonging to 2D meridian ellipse

projectToEllipse

public TimeStampedPVCoordinates projectToEllipse(TimeStampedPVCoordinates pv)

Project position-velocity-acceleration on an ellipse.

Parameters:

pv - position-velocity-acceleration to project, in the reference frame

Returns:

projected position-velocity-acceleration

getCenterOfCurvature

public Vector2D getCenterOfCurvature(Vector2D point)

Find the center of curvature (point on the evolute) at the nadir of a point.

Parameters:

point - point in the ellipse plane

Returns:

center of curvature of the ellipse directly at point nadir

Since:

7.1