agi.foundation.stk

Class StkAttitudeFile.AttitudeTimeQuaternions

java.lang.Object

agi.foundation.stk.StkAttitudeFile.Attitude

agi.foundation.stk.StkAttitudeFile.AttitudeTimeQuaternions

Direct Known Subclasses:

StkAttitudeFile.AttitudeTimeQuatAngVels, StkAttitudeFile.AttitudeTimeQuatScalarFirst

Enclosing class:

StkAttitudeFile

public static class StkAttitudeFile.AttitudeTimeQuaternions
extends StkAttitudeFile.Attitude

A class that holds the data in the attitude file when the attitude file is in the "AttitudeTimeQuaternions" or "AttitudeTimeQuatScalarFirst" format.

Constructor Summary

Constructors

Constructor and Description
AttitudeTimeQuaternions()

Method Summary

Modifier and Type	Method and Description
static DateMotionCollection2<UnitQuaternion,Cartesian>	convertFromStkAttitudeConvention(DateMotionCollection2<UnitQuaternion,Cartesian> data) Converts raw attitude data from the STK Desktop convention used by AttitudeData (get / set) to use the DME Component Libraries convention for representing attitude, which expresses the derivatives in the body frame instead of the frame in which the body is defined.
static DateMotionCollection2<UnitQuaternion,Cartesian>	convertToStkAttitudeConvention(DateMotionCollection2<UnitQuaternion,Cartesian> data) Converts raw attitude data from the DME Component Libraries convention to use the STK Desktop convention used by AttitudeData (get / set), which expresses the derivatives in the body frame instead of the frame in which the body is defined.
Axes	createAxes() Creates an Axes whose time-varying orientation is computed by interpolating over the attitude data held by this instance.
DateMotionCollection2<UnitQuaternion,Cartesian>	getAttitudeData() Gets the attitude data relative to CoordinateAxes (get / set).
Axes	getCoordinateAxes() Gets the axes in which the data is defined.
RotationalMotionInterpolator	getInterpolator() Gets the interpolator to use to interpolate this attitude data.
String	getName() Gets the name of this attitude format.
List<JulianDate>	getTimes() Gets the times of the data points.
void	setAttitudeData(DateMotionCollection2<UnitQuaternion,Cartesian> value) Sets the attitude data relative to CoordinateAxes (get / set).
void	setCoordinateAxes(Axes value) Sets the axes in which the data is defined.
void	setInterpolator(RotationalMotionInterpolator value) Sets the interpolator to use to interpolate this attitude data.

Methods inherited from class java.lang.Object

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

Constructor Detail

AttitudeTimeQuaternions

public AttitudeTimeQuaternions()

Method Detail

getName

public String getName()

Gets the name of this attitude format.

Specified by:

getName in class StkAttitudeFile.Attitude

getTimes

public List<JulianDate> getTimes()

Gets the times of the data points.

Specified by:

getTimes in class StkAttitudeFile.Attitude

getAttitudeData

public final DateMotionCollection2<UnitQuaternion,Cartesian> getAttitudeData()

Gets the attitude data relative to CoordinateAxes (get / set). Note that the convention here is not the usual convention elsewhere in DME Component Libraries, and instead represents the convention used in the STK Attitude Files themselves. See the remarks for more information or use StkAttitudeFile.AttitudeTimeQuaternions.convertToStkAttitudeConvention(agi.foundation.DateMotionCollection2<agi.foundation.coordinates.UnitQuaternion, agi.foundation.coordinates.Cartesian>).

The following example indicates how to convert rotational motion using the DME Component Libraries convention to the STK attitude file convention.

// Get some rotational motion which uses the DME Component Libraries convention of rates expressed
// with respect to the originating axes and in radians.
Motion2<UnitQuaternion, Cartesian> componentsMotion = getMotion();

// Convert the motion to use the STK attitude file convention of rates expressed with respect
// to the destination axes and in degrees.
UnitQuaternion rotation = componentsMotion.getValue();
Cartesian temp = componentsMotion.getFirstDerivative().rotate(rotation);
Cartesian rotationalVelocity = new Cartesian(Trig.radiansToDegrees(temp.getX()), Trig.radiansToDegrees(temp.getY()), Trig.radiansToDegrees(temp.getZ()));
temp = componentsMotion.getSecondDerivative().rotate(rotation);
Cartesian rotationalAcceleration = new Cartesian(Trig.radiansToDegrees(temp.getX()), Trig.radiansToDegrees(temp.getY()), Trig.radiansToDegrees(temp.getZ()));
Motion2<UnitQuaternion, Cartesian> stkAttitudeFileMotion = new Motion2<>(rotation, rotationalVelocity, rotationalAcceleration);

The convention used by STK attitude files for representing rotational motion is different than the convention used in DME Component Libraries. Specifically, the derivative information is expressed in radians in DME Component Libraries and in degrees in the STK attitude file, and is expressed with respect to the originating axes in DME Component Libraries and with respect to the destination axes in the STK attitude file. For example, if the UnitQuaternion represents the transformation from axes "A" to axes "B", then the rotational velocities and accelerations should be expressed with respect to axes "A" for DME Component Libraries and should be expressed with respect to axes "B" for STK attitude files.

setAttitudeData

public final void setAttitudeData(DateMotionCollection2<UnitQuaternion,Cartesian> value)

Sets the attitude data relative to CoordinateAxes (get / set). Note that the convention here is not the usual convention elsewhere in DME Component Libraries, and instead represents the convention used in the STK Attitude Files themselves. See the remarks for more information or use StkAttitudeFile.AttitudeTimeQuaternions.convertToStkAttitudeConvention(agi.foundation.DateMotionCollection2<agi.foundation.coordinates.UnitQuaternion, agi.foundation.coordinates.Cartesian>).

The following example indicates how to convert rotational motion using the DME Component Libraries convention to the STK attitude file convention.

// Get some rotational motion which uses the DME Component Libraries convention of rates expressed
// with respect to the originating axes and in radians.
Motion2<UnitQuaternion, Cartesian> componentsMotion = getMotion();

// Convert the motion to use the STK attitude file convention of rates expressed with respect
// to the destination axes and in degrees.
UnitQuaternion rotation = componentsMotion.getValue();
Cartesian temp = componentsMotion.getFirstDerivative().rotate(rotation);
Cartesian rotationalVelocity = new Cartesian(Trig.radiansToDegrees(temp.getX()), Trig.radiansToDegrees(temp.getY()), Trig.radiansToDegrees(temp.getZ()));
temp = componentsMotion.getSecondDerivative().rotate(rotation);
Cartesian rotationalAcceleration = new Cartesian(Trig.radiansToDegrees(temp.getX()), Trig.radiansToDegrees(temp.getY()), Trig.radiansToDegrees(temp.getZ()));
Motion2<UnitQuaternion, Cartesian> stkAttitudeFileMotion = new Motion2<>(rotation, rotationalVelocity, rotationalAcceleration);

The convention used by STK attitude files for representing rotational motion is different than the convention used in DME Component Libraries. Specifically, the derivative information is expressed in radians in DME Component Libraries and in degrees in the STK attitude file, and is expressed with respect to the originating axes in DME Component Libraries and with respect to the destination axes in the STK attitude file. For example, if the UnitQuaternion represents the transformation from axes "A" to axes "B", then the rotational velocities and accelerations should be expressed with respect to axes "A" for DME Component Libraries and should be expressed with respect to axes "B" for STK attitude files.

convertToStkAttitudeConvention

@Nonnull
public static DateMotionCollection2<UnitQuaternion,Cartesian> convertToStkAttitudeConvention(@Nonnull
                                                                                                       DateMotionCollection2<UnitQuaternion,Cartesian> data)

Converts raw attitude data from the DME Component Libraries convention to use the STK Desktop convention used by AttitudeData (get / set), which expresses the derivatives in the body frame instead of the frame in which the body is defined.

Parameters:

data - The attitude data in the DME Component Libraries convention.

Returns:

The attitude data in the STK Desktop convention.

Throws:

ArgumentNullException - Thrown when data is null.

convertFromStkAttitudeConvention

@Nonnull
public static DateMotionCollection2<UnitQuaternion,Cartesian> convertFromStkAttitudeConvention(@Nonnull
                                                                                                         DateMotionCollection2<UnitQuaternion,Cartesian> data)

Converts raw attitude data from the STK Desktop convention used by AttitudeData (get / set) to use the DME Component Libraries convention for representing attitude, which expresses the derivatives in the body frame instead of the frame in which the body is defined.

Parameters:

data - The attitude data in the STK Desktop convention.

Returns:

The attitude data in the DME Component Libraries convention.

Throws:

ArgumentNullException - Thrown when data is null.

getCoordinateAxes

public final Axes getCoordinateAxes()

Gets the axes in which the data is defined.

When reading an attitude file, this property may be null if the "CoordinateAxes" property did not exist in the file or if it could not be automatically mapped to an Axes instance. In the latter case, the original string representation of the name of the reference frame can be found in the Properties (get) collection.

When writing an attitude file, and this property is non-null, it overrides "CoordinateAxes" in Properties (get). However, if this property is null, the value in Properties (get) is used.

setCoordinateAxes

public final void setCoordinateAxes(Axes value)

Sets the axes in which the data is defined.

When reading an attitude file, this property may be null if the "CoordinateAxes" property did not exist in the file or if it could not be automatically mapped to an Axes instance. In the latter case, the original string representation of the name of the reference frame can be found in the Properties (get) collection.

When writing an attitude file, and this property is non-null, it overrides "CoordinateAxes" in Properties (get). However, if this property is null, the value in Properties (get) is used.

getInterpolator

public RotationalMotionInterpolator getInterpolator()

Description copied from class: StkAttitudeFile.Attitude

Gets the interpolator to use to interpolate this attitude data.

When reading an attitude file, this property may be null if the "InterpolationMethod" property did not exist in the file or if it could not be automatically mapped to an RotationalMotionInterpolator instance. In the latter case, the original string representation of the name of the interpolation method can be found in the Properties (get) collection.

When writing an attitude file, and this property is non-null, it overrides "InterpolationMethod" in Properties (get). However, if this property is null, the value in Properties (get) is used.

Specified by:

getInterpolator in class StkAttitudeFile.Attitude

setInterpolator

public void setInterpolator(RotationalMotionInterpolator value)

Description copied from class: StkAttitudeFile.Attitude

Sets the interpolator to use to interpolate this attitude data.

When reading an attitude file, this property may be null if the "InterpolationMethod" property did not exist in the file or if it could not be automatically mapped to an RotationalMotionInterpolator instance. In the latter case, the original string representation of the name of the interpolation method can be found in the Properties (get) collection.

When writing an attitude file, and this property is non-null, it overrides "InterpolationMethod" in Properties (get). However, if this property is null, the value in Properties (get) is used.

Specified by:

setInterpolator in class StkAttitudeFile.Attitude

createAxes

public Axes createAxes()

Creates an Axes whose time-varying orientation is computed by interpolating over the attitude data held by this instance.

Specified by:

createAxes in class StkAttitudeFile.Attitude

Returns:

The point.