org.orekit.propagation.numerical.cr3bp

Class STMEquations

java.lang.Object

org.orekit.propagation.numerical.cr3bp.STMEquations

All Implemented Interfaces:

AdditionalDerivativesProvider, AdditionalEquations

public class STMEquations
extends Object
implements AdditionalDerivativesProvider, AdditionalEquations

Class calculating the state transition matrix coefficient for CR3BP Computation.

Since:

10.2

Author:

Vincent Mouraux

See Also:

"Dynamical systems, the three-body problem, and space mission design, Koon, Lo, Marsden, Ross"

Constructor Summary

Constructors

Constructor and Description
STMEquations(CR3BPSystem syst) Simple constructor.

Method Summary

Modifier and Type	Method and Description
CombinedDerivatives	combinedDerivatives(SpacecraftState s) Compute the derivatives related to the additional state (and optionally main state increments).
double[]	computeDerivatives(SpacecraftState s, double[] pDot) Compute the derivatives related to the additional state parameters.
double[]	derivatives(SpacecraftState state) Deprecated.
int	getDimension() Get the dimension of the generated derivative.
String	getName() Get the name of the additional derivatives (which will become state once integrated).
RealMatrix	getStateTransitionMatrix(SpacecraftState s) Method returning the State Transition Matrix.
void	init(SpacecraftState initialState, AbsoluteDate target) Initialize the generator at the start of propagation.
SpacecraftState	setInitialPhi(SpacecraftState s) Method adding the standard initial values of the additional state to the initial spacecraft state.

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.integration.AdditionalDerivativesProvider

yield

Constructor Detail

STMEquations

public STMEquations(CR3BPSystem syst)

Simple constructor.

Parameters:

syst - CR3BP System considered

Method Detail

setInitialPhi

public SpacecraftState setInitialPhi(SpacecraftState s)

Method adding the standard initial values of the additional state to the initial spacecraft state.

Parameters:

s - Initial state of the system

Returns:

s Initial augmented (with the additional equations) state

init

public void init(SpacecraftState initialState,
                 AbsoluteDate target)

Initialize the generator at the start of propagation.

Specified by:

init in interface AdditionalDerivativesProvider

Specified by:

init in interface AdditionalEquations

Parameters:

initialState - initial state information at the start of propagation

target - date of propagation

computeDerivatives

public double[] computeDerivatives(SpacecraftState s,
                                   double[] pDot)

Compute the derivatives related to the additional state parameters.

When this method is called, the spacecraft state contains the main state (orbit, attitude and mass), all the states provided through the additional state providers registered to the propagator, and the additional state integrated using this equation. It does not contains any other states to be integrated alongside during the same propagation.

Specified by:

computeDerivatives in interface AdditionalEquations

Parameters:

s - current state information: date, kinematics, attitude, and additional state

pDot - placeholder where the derivatives of the additional parameters should be put

Returns:

cumulative effect of the equations on the main state (may be null if equations do not change main state at all)

derivatives

@Deprecated
public double[] derivatives(SpacecraftState state)

Deprecated.

Compute the derivatives related to the additional state parameters.

Specified by:

derivatives in interface AdditionalDerivativesProvider

Parameters:

state - current state information: date, kinematics, attitude, and additional states this equations depend on (according to the yield method)

Returns:

computed derivatives

combinedDerivatives

public CombinedDerivatives combinedDerivatives(SpacecraftState s)

Compute the derivatives related to the additional state (and optionally main state increments).

As of 11.2, there is a default implementation that calls the deprecated AdditionalDerivativesProvider.derivatives(SpacecraftState) method. This has been done for backward compatibility only and will be removed in 12.0.

Specified by:

combinedDerivatives in interface AdditionalDerivativesProvider

Parameters:

s - current state information: date, kinematics, attitude, and additional states this equations depend on (according to the yield method)

Returns:

computed combined derivatives, which may include some incremental coupling effect to add to main state derivatives

getName

public String getName()

Get the name of the additional derivatives (which will become state once integrated).

Specified by:

getName in interface AdditionalDerivativesProvider

Specified by:

getName in interface AdditionalEquations

Returns:

name of the additional state (names containing "orekit" with any case are reserved for the library internal use)

getDimension

public int getDimension()

Get the dimension of the generated derivative.

Specified by:

getDimension in interface AdditionalDerivativesProvider

Returns:

dimension of the generated

getStateTransitionMatrix

public RealMatrix getStateTransitionMatrix(SpacecraftState s)

Method returning the State Transition Matrix.

Parameters:

s - SpacecraftState of the system

Returns:

phiM State Transition Matrix