org.orekit.attitudes

Class FieldAttitude<T extends CalculusFieldElement<T>>

java.lang.Object

org.orekit.attitudes.FieldAttitude<T>

All Implemented Interfaces:

FieldTimeInterpolable<FieldAttitude<T>,T>, FieldTimeShiftable<FieldAttitude<T>,T>, FieldTimeStamped<T>

public class FieldAttitude<T extends CalculusFieldElement<T>>
extends Object
implements FieldTimeStamped<T>, FieldTimeShiftable<FieldAttitude<T>,T>, FieldTimeInterpolable<FieldAttitude<T>,T>

This class handles attitude definition at a given date.

This class represents the rotation between a reference frame and the satellite frame, as well as the spin of the satellite (axis and rotation rate).

The state can be slightly shifted to close dates. This shift is based on a linear extrapolation for attitude taking the spin rate into account. It is not intended as a replacement for proper attitude propagation but should be sufficient for either small time shifts or coarse accuracy.

The instance Attitude is guaranteed to be immutable.

Author:

Véronique Pommier-Maurussane

See Also:

Orbit, AttitudeProvider

Constructor Summary

Constructors

Constructor and Description
FieldAttitude(Field<T> field, Attitude attitude) Builds an instance for a regular Attitude.
FieldAttitude(FieldAbsoluteDate<T> date, Frame referenceFrame, FieldAngularCoordinates<T> orientation) Creates a new instance.
FieldAttitude(FieldAbsoluteDate<T> date, Frame referenceFrame, FieldRotation<T> attitude, FieldVector3D<T> spin, FieldVector3D<T> acceleration) Creates a new instance.
FieldAttitude(FieldAbsoluteDate<T> date, Frame referenceFrame, Rotation attitude, Vector3D spin, Vector3D acceleration, Field<T> field) Creates a new instance.
FieldAttitude(Frame referenceFrame, TimeStampedFieldAngularCoordinates<T> orientation) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
FieldAbsoluteDate<T>	getDate() Get the date of attitude parameters.
TimeStampedFieldAngularCoordinates<T>	getOrientation() Get the complete orientation including spin.
Frame	getReferenceFrame() Get the reference frame.
FieldRotation<T>	getRotation() Get the attitude rotation.
FieldVector3D<T>	getRotationAcceleration() Get the satellite rotation acceleration.
FieldVector3D<T>	getSpin() Get the satellite spin.
FieldAttitude<T>	interpolate(FieldAbsoluteDate<T> interpolationDate, Stream<FieldAttitude<T>> sample) Get an interpolated instance.
FieldAttitude<T>	shiftedBy(double dt) Get a time-shifted attitude.
FieldAttitude<T>	shiftedBy(T dt) Get a time-shifted attitude.
Attitude	toAttitude() Converts to an Attitude instance.
FieldAttitude<T>	withReferenceFrame(Frame newReferenceFrame) Get a similar attitude with a specific reference frame.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.orekit.time.FieldTimeInterpolable

interpolate

Constructor Detail

FieldAttitude

public FieldAttitude(Frame referenceFrame,
                     TimeStampedFieldAngularCoordinates<T> orientation)

Creates a new instance.

Parameters:

referenceFrame - reference frame from which attitude is defined

orientation - complete orientation between reference frame and satellite frame, including rotation rate

FieldAttitude

public FieldAttitude(FieldAbsoluteDate<T> date,
                     Frame referenceFrame,
                     FieldAngularCoordinates<T> orientation)

Creates a new instance.

Parameters:

date - date at which attitude is defined

referenceFrame - reference frame from which attitude is defined

orientation - complete orientation between reference frame and satellite frame, including rotation rate

FieldAttitude

public FieldAttitude(FieldAbsoluteDate<T> date,
                     Frame referenceFrame,
                     FieldRotation<T> attitude,
                     FieldVector3D<T> spin,
                     FieldVector3D<T> acceleration)

Creates a new instance.

Parameters:

date - date at which attitude is defined

referenceFrame - reference frame from which attitude is defined

attitude - rotation between reference frame and satellite frame

spin - satellite spin (axis and velocity, in satellite frame)

acceleration - satellite rotation acceleration (in satellite frame)

FieldAttitude

public FieldAttitude(FieldAbsoluteDate<T> date,
                     Frame referenceFrame,
                     Rotation attitude,
                     Vector3D spin,
                     Vector3D acceleration,
                     Field<T> field)

Creates a new instance.

Parameters:

date - date at which attitude is defined

referenceFrame - reference frame from which attitude is defined

attitude - rotation between reference frame and satellite frame

spin - satellite spin (axis and velocity, in satellite frame)

acceleration - satellite rotation acceleration (in satellite frame)

field - field used by default

FieldAttitude

public FieldAttitude(Field<T> field,
                     Attitude attitude)

Builds an instance for a regular Attitude.

Parameters:

field - fields to which the elements belong

attitude - attitude to convert

Method Detail

shiftedBy

public FieldAttitude<T> shiftedBy(double dt)

Get a time-shifted attitude.

The state can be slightly shifted to close dates. This shift is based on a linear extrapolation for attitude taking the spin rate into account. It is not intended as a replacement for proper attitude propagation but should be sufficient for either small time shifts or coarse accuracy.

Specified by:

shiftedBy in interface FieldTimeShiftable<FieldAttitude<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

dt - time shift in seconds

Returns:

a new attitude, shifted with respect to the instance (which is immutable)

shiftedBy

public FieldAttitude<T> shiftedBy(T dt)

Get a time-shifted attitude.

The state can be slightly shifted to close dates. This shift is based on a linear extrapolation for attitude taking the spin rate into account. It is not intended as a replacement for proper attitude propagation but should be sufficient for either small time shifts or coarse accuracy.

Specified by:

shiftedBy in interface FieldTimeShiftable<FieldAttitude<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

dt - time shift in seconds

Returns:

a new attitude, shifted with respect to the instance (which is immutable)

withReferenceFrame

public FieldAttitude<T> withReferenceFrame(Frame newReferenceFrame)

Get a similar attitude with a specific reference frame.

If the instance reference frame is already the specified one, the instance itself is returned without any object creation. Otherwise, a new instance will be created with the specified reference frame. In this case, the required intermediate rotation and spin between the specified and the original reference frame will be inserted.

Parameters:

newReferenceFrame - desired reference frame for attitude

Returns:

an attitude that has the same orientation and motion as the instance, but guaranteed to have the specified reference frame

getDate

public FieldAbsoluteDate<T> getDate()

Get the date of attitude parameters.

Specified by:

getDate in interface FieldTimeStamped<T extends CalculusFieldElement<T>>

Returns:

date of the attitude parameters

getReferenceFrame

public Frame getReferenceFrame()

Get the reference frame.

Returns:

referenceFrame reference frame from which attitude is defined.

getOrientation

public TimeStampedFieldAngularCoordinates<T> getOrientation()

Get the complete orientation including spin.

Returns:

complete orientation including spin

See Also:

getRotation(), getSpin()

getRotation

public FieldRotation<T> getRotation()

Get the attitude rotation.

Returns:

attitude satellite rotation from reference frame.

See Also:

getOrientation(), getSpin()

getSpin

public FieldVector3D<T> getSpin()

Get the satellite spin.

The spin vector is defined in satellite frame.

Returns:

spin satellite spin (axis and velocity).

See Also:

getOrientation(), getRotation()

getRotationAcceleration

public FieldVector3D<T> getRotationAcceleration()

Get the satellite rotation acceleration.

The rotation acceleration. vector is defined in satellite frame.

Returns:

rotation acceleration

See Also:

getOrientation(), getRotation()

interpolate

public FieldAttitude<T> interpolate(FieldAbsoluteDate<T> interpolationDate,
                                    Stream<FieldAttitude<T>> sample)

Get an interpolated instance.

The interpolated instance is created by polynomial Hermite interpolation on Rodrigues vector ensuring rotation rate remains the exact derivative of rotation.

As this implementation of interpolation is polynomial, it should be used only with small samples (about 10-20 points) in order to avoid Runge's phenomenon and numerical problems (including NaN appearing).

Specified by:

interpolate in interface FieldTimeInterpolable<FieldAttitude<T extends CalculusFieldElement<T>>,T extends CalculusFieldElement<T>>

Parameters:

interpolationDate - interpolation date

sample - sample points on which interpolation should be done

Returns:

a new instance, interpolated at specified date

toAttitude

public Attitude toAttitude()

Converts to an Attitude instance.

Returns:

Attitude with same properties