Package org.orekit.propagation.relative.clohessywiltshire

Class ClohessyWiltshireProvider

java.lang.Object

org.orekit.propagation.relative.AbstractRelativeProvider

org.orekit.propagation.relative.clohessywiltshire.ClohessyWiltshireProvider

All Implemented Interfaces:

AdditionalDataProvider<double[]>, RelativeProvider

public class ClohessyWiltshireProvider
extends AbstractRelativeProvider

This additional state provider implements the Clohessy-Wiltshire equations of relative motion to propagate the relative orbit of a chaser spacecraft around the target spacecraft whose orbit is being propagated.

Note 1: the Clohessy-Wiltshire equations consider the target to be in a perfectly circular orbit around a central potential.

Note 2: the additional state returned is a PV of the chaser at the given time expressed in the target's QSW local orbital frame.

The actual orbit of a chaser around the target will be different when considering a small eccentricity, or other perturbations. It is however a good and analytical (very fast) way to approximate the relative motion of two spacecraft.

The class ClohessyWiltshireRendezVous allows the analytical computation of 2-maneuver rendez-vous transfers.

Since:

14.0

Author:

Jérôme Tabeaud, Romain Cuvillon

Field Summary

Fields

Modifier and Type	Field	Description
static final String	DEFAULT_ADDITIONAL_EQUATIONS_NAME	Default additional equations name.
static final LOFType	LOF_TYPE	Local Orbital Frame.

Constructor Summary

Constructors

Constructor	Description
ClohessyWiltshireProvider(Orbit targetOrbit)	Builds a new ClohessyWiltshireProvider object from the target orbit and an all-zero PVT for the chaser.
ClohessyWiltshireProvider(Orbit targetOrbit, TimeStampedPVCoordinates initialChaserPVTLof)	Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser.
ClohessyWiltshireProvider(Orbit targetOrbit, TimeStampedPVCoordinates initialChaserPVTLof, String additionalEquationsName)	Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser.
ClohessyWiltshireProvider(Orbit targetOrbit, TimeStampedPVCoordinates initialChaserPVT, Frame inputPVTFrame)	Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser expressed in the given input frame.
ClohessyWiltshireProvider(Orbit targetOrbit, TimeStampedPVCoordinates initialChaserPVT, Frame inputPVTFrame, String additionalEquationsName)	Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser expressed in the given input frame.

Method Summary

Modifier and Type	Method	Description
TimeStampedPVCoordinates	extractChaserPVT(SpacecraftState targetState)	Extracts the chaser's PVT in the target LOF from the given target SpacecraftState.

Methods inherited from class org.orekit.propagation.relative.AbstractRelativeProvider

getInitialChaserPVTLof, getLof, getName, getTargetOrbit, setInitialChaserPVTLof, setTargetOrbit

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.AdditionalDataProvider

init, update, yields

Methods inherited from interface org.orekit.propagation.relative.RelativeProvider

extractChaserPVT, getAdditionalData, setTargetTrueAnomaly

Field Details

DEFAULT_ADDITIONAL_EQUATIONS_NAME

public static final String DEFAULT_ADDITIONAL_EQUATIONS_NAME

Default additional equations name.

See Also:

• Constant Field Values

LOF_TYPE

public static final LOFType LOF_TYPE

Local Orbital Frame. Clohessy-Wiltshire equations are defined in the QSW local orbital frame of the target, so this provider is hardcoded to use this LOF.

Constructor Details

ClohessyWiltshireProvider

@DefaultDataContext
public ClohessyWiltshireProvider(Orbit targetOrbit)

Builds a new ClohessyWiltshireProvider object from the target orbit and an all-zero PVT for the chaser.

Parameters:

targetOrbit - Target orbit. Should be circular for better results

ClohessyWiltshireProvider

public ClohessyWiltshireProvider(Orbit targetOrbit,
 TimeStampedPVCoordinates initialChaserPVTLof)

Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser.

Parameters:

targetOrbit - Target orbit. Should be circular for better results

initialChaserPVTLof - Chaser PVT in the target's QSW local orbital frame

ClohessyWiltshireProvider

public ClohessyWiltshireProvider(Orbit targetOrbit,
 TimeStampedPVCoordinates initialChaserPVTLof,
 String additionalEquationsName)

Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser.

Parameters:

targetOrbit - Target orbit. Should be circular for better results

initialChaserPVTLof - Chaser PVT in the target's QSW local orbital frame

additionalEquationsName - Additional equations name

ClohessyWiltshireProvider

public ClohessyWiltshireProvider(Orbit targetOrbit,
 TimeStampedPVCoordinates initialChaserPVT,
 Frame inputPVTFrame)

Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser expressed in the given input frame.

Parameters:

targetOrbit - Target orbit. Should be circular for better results

initialChaserPVT - Chaser PVT in the input frame

inputPVTFrame - Input frame for the initial chaser PVT

ClohessyWiltshireProvider

public ClohessyWiltshireProvider(Orbit targetOrbit,
 TimeStampedPVCoordinates initialChaserPVT,
 Frame inputPVTFrame,
 String additionalEquationsName)

Builds a new ClohessyWiltshireProvider object from the target orbit and an initial PVT of the chaser expressed in the given input frame.

Parameters:

targetOrbit - Target orbit. Should be circular for better results

initialChaserPVT - Chaser PVT in the input Frame

inputPVTFrame - Input frame for the initial chaser PVT

additionalEquationsName - Additional equations name

Method Details

extractChaserPVT

public TimeStampedPVCoordinates extractChaserPVT(SpacecraftState targetState)

Extracts the chaser's PVT in the target LOF from the given target SpacecraftState..

Get the chaser state relative to a target, in target's QSW LOF.

Parameters:

targetState - target SpacecraftState

Returns:

chaser's TimeStampedPVCoordinates in target's LOF