Package org.orekit.forces

Class PointingPanel

java.lang.Object

org.orekit.forces.Panel

org.orekit.forces.PointingPanel

public class PointingPanel
extends Panel

Class representing one panel of a satellite, roughly pointing towards some target.

It is mainly used to represent a rotating solar array that points towards the Sun.

The panel rotation with respect to satellite body is the best pointing orientation achievable when the rotation axix is fixed by body attitude. Target is therefore always exactly in meridian plane defined by rotation axis and panel normal vector.

These panels are considered to be always double-sided.

Since:

3.0

Author:

Luc Maisonobe

Constructor Summary

Constructors

Constructor	Description
PointingPanel(Vector3D rotationAxis, ExtendedPositionProvider target, double area, double drag, double liftRatio, double absorption, double reflection)	Simple constructor.

Method Summary

Modifier and Type	Method	Description
<T extends CalculusFieldElement<T>> FieldVector3D<T>	getNormal(FieldSpacecraftState<T> state)	Get panel normal in spacecraft frame.
Vector3D	getNormal(SpacecraftState state)	Get panel normal in spacecraft frame.

Methods inherited from class org.orekit.forces.Panel

getAbsorption, getArea, getDrag, getLiftRatio, getReflection, isDoubleSided

Methods inherited from class java.lang.Object

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

Constructor Detail

PointingPanel

public PointingPanel(Vector3D rotationAxis,
                     ExtendedPositionProvider target,
                     double area,
                     double drag,
                     double liftRatio,
                     double absorption,
                     double reflection)

Simple constructor.

As the sum of absorption coefficient, specular reflection coefficient and diffuse reflection coefficient is exactly 1, only the first two coefficients are needed here, the third one is deduced from the other ones.

The panel is considered to rotate about one axis in order to make its normal point as close as possible to the target. It means the target will always be in the plane defined by the rotation axis and the panel normal.

Parameters:

rotationAxis - rotation axis of the panel

target - target towards which the panel will point (the Sun for a solar array)

area - panel area in m²

drag - drag coefficient

liftRatio - drag lift ratio (proportion between 0 and 1 of atmosphere modecules that will experience specular reflection when hitting spacecraft instead of experiencing diffuse reflection, hence producing lift)

absorption - radiation pressure absorption coefficient (between 0 and 1)

reflection - radiation pressure specular reflection coefficient (between 0 and 1)

Method Detail

getNormal

public Vector3D getNormal(SpacecraftState state)

Get panel normal in spacecraft frame.

Specified by:

getNormal in class Panel

Parameters:

state - current spacecraft state

Returns:

panel normal in spacecraft frame

getNormal

public <T extends CalculusFieldElement<T>> FieldVector3D<T> getNormal(FieldSpacecraftState<T> state)

Get panel normal in spacecraft frame.

Specified by:

getNormal in class Panel

Type Parameters:

T - type of the field elements

Parameters:

state - current spacecraft state

Returns:

panel normal in spacecraft frame