LOF.java
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package org.orekit.frames;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.Field;
import org.hipparchus.analysis.differentiation.FieldUnivariateDerivative2;
import org.hipparchus.analysis.differentiation.FieldUnivariateDerivative2Field;
import org.hipparchus.analysis.differentiation.UnivariateDerivative2;
import org.hipparchus.analysis.differentiation.UnivariateDerivative2Field;
import org.hipparchus.geometry.euclidean.threed.FieldRotation;
import org.hipparchus.geometry.euclidean.threed.FieldVector3D;
import org.hipparchus.geometry.euclidean.threed.Rotation;
import org.hipparchus.geometry.euclidean.threed.RotationConvention;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.utils.AngularCoordinates;
import org.orekit.utils.FieldAngularCoordinates;
import org.orekit.utils.FieldPVCoordinates;
import org.orekit.utils.PVCoordinates;
/**
* Interface for local orbital frame.
*
* @author Vincent Cucchietti
*/
public interface LOF {
/**
* Get the rotation from input to output {@link LOF local orbital frame}.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromLOFInToLOFOut(LOF, LOF, FieldAbsoluteDate, FieldPVCoordinates)} method must be called and
* the complete rotation transform must be extracted from it.
*
* @param field field to which the elements belong
* @param in input commonly used local orbital frame
* @param out output commonly used local orbital frame
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the field elements
*
* @return rotation from input to output local orbital frame
*
* @since 11.3
*/
static <T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromLOFInToLOFOut(final Field<T> field,
final LOF in, final LOF out,
final FieldAbsoluteDate<T> date,
final FieldPVCoordinates<T> pv) {
return out.rotationFromLOF(field, in, date, pv);
}
/**
* Get the transform from input to output {@link LOF local orbital frame}.
*
* @param in input commonly used local orbital frame
* @param out output commonly used local orbital frame
* @param date date of the transform
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the field elements
*
* @return rotation from input to output local orbital frame.
*
* @since 11.3
*/
static <T extends CalculusFieldElement<T>> FieldTransform<T> transformFromLOFInToLOFOut(final LOF in, final LOF out,
final FieldAbsoluteDate<T> date,
final FieldPVCoordinates<T> pv) {
return out.transformFromLOF(in, date, pv);
}
/**
* Get the rotation from input to output {@link LOF local orbital frame}.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromLOFInToLOFOut(LOF, LOF, AbsoluteDate, PVCoordinates)} method must be called and
* the complete rotation transform must be extracted from it.
*
* @param in input commonly used local orbital frame
* @param out output commonly used local orbital frame
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return rotation from input to output local orbital frame.
*
* @since 11.3
*/
static Rotation rotationFromLOFInToLOFOut(final LOF in, final LOF out, final AbsoluteDate date, final PVCoordinates pv) {
return out.rotationFromLOF(in, date, pv);
}
/**
* Get the transform from input to output {@link LOF local orbital frame}.
*
* @param in input commonly used local orbital frame
* @param out output commonly used local orbital frame
* @param date date of the transform
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return rotation from input to output local orbital frame
*
* @since 11.3
*/
static Transform transformFromLOFInToLOFOut(final LOF in, final LOF out, final AbsoluteDate date,
final PVCoordinates pv) {
return out.transformFromLOF(in, date, pv);
}
/**
* Get the rotation from input {@link LOF local orbital frame} to the instance.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromLOF(LOF, FieldAbsoluteDate, FieldPVCoordinates)} method must be called and
* the complete rotation transform must be extracted from it.
*
* @param field field to which the elements belong
* @param fromLOF input local orbital frame
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the field elements
*
* @return rotation from input local orbital frame to the instance
*
* @since 11.3
*/
default <T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromLOF(final Field<T> field,
final LOF fromLOF,
final FieldAbsoluteDate<T> date,
final FieldPVCoordinates<T> pv) {
// First compute the rotation from the input LOF to the pivot inertial
final FieldRotation<T> fromLOFToInertial = fromLOF.rotationFromInertial(field, date, pv).revert();
// Then compute the rotation from the pivot inertial to the output LOF
final FieldRotation<T> inertialToThis = this.rotationFromInertial(field, date, pv);
// Output composed rotation
return fromLOFToInertial.compose(inertialToThis, RotationConvention.FRAME_TRANSFORM);
}
/**
* Get the rotation from input {@link LOF commonly used local orbital frame} to the instance.
*
* @param fromLOF input local orbital frame
* @param date date of the transform
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the field elements
*
* @return rotation from input local orbital frame to the instance
*
* @since 11.3
*/
default <T extends CalculusFieldElement<T>> FieldTransform<T> transformFromLOF(final LOF fromLOF,
final FieldAbsoluteDate<T> date,
final FieldPVCoordinates<T> pv) {
// Get transform from input local orbital frame to inertial
final FieldTransform<T> fromLOFToInertial = fromLOF.transformFromInertial(date, pv).getInverse();
// Get transform from inertial to output local orbital frame
final FieldTransform<T> inertialToLOFOut = this.transformFromInertial(date, pv);
// Output composition of both transforms
return new FieldTransform<>(date, fromLOFToInertial, inertialToLOFOut);
}
/**
* Get the transform from an inertial frame defining position-velocity and the local orbital frame.
*
* @param date current date
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the fields elements
*
* @return transform from the frame where position-velocity are defined to local orbital frame
*
* @since 9.0
*/
default <T extends CalculusFieldElement<T>> FieldTransform<T> transformFromInertial(final FieldAbsoluteDate<T> date,
final FieldPVCoordinates<T> pv) {
final Field<T> field = date.getField();
if (isQuasiInertial()) {
return new FieldTransform<>(date, pv.getPosition().negate(), rotationFromInertial(field, date, pv));
} else if (pv.getAcceleration().equals(FieldVector3D.getZero(field))) {
// we consider that the acceleration is not known
// compute the translation part of the transform
final FieldTransform<T> translation = new FieldTransform<>(date, pv.negate());
// compute the rotation part of the transform
final FieldRotation<T> r = rotationFromInertial(date.getField(), date, pv);
final FieldVector3D<T> p = pv.getPosition();
final FieldVector3D<T> momentum = pv.getMomentum();
final FieldTransform<T> rotation = new FieldTransform<>(date, r,
new FieldVector3D<>(p.getNorm2Sq().reciprocal(), r.applyTo(momentum)));
return new FieldTransform<>(date, translation, rotation);
} else {
// use automatic differentiation
// create date with independent variable
final FieldUnivariateDerivative2Field<T> fud2Field = FieldUnivariateDerivative2Field.getUnivariateDerivative2Field(field);
final FieldAbsoluteDate<FieldUnivariateDerivative2<T>> fud2Date = date.toFUD2Field();
// create PV with independent variable
final FieldPVCoordinates<FieldUnivariateDerivative2<T>> fud2PV = pv.toUnivariateDerivative2PV();
// compute rotation
final FieldRotation<FieldUnivariateDerivative2<T>> fud2Rotation = rotationFromInertial(fud2Field, fud2Date,
fud2PV);
// turn into FieldTransform whilst adding the translation
final FieldAngularCoordinates<T> fieldAngularCoordinates = new FieldAngularCoordinates<>(fud2Rotation);
return new FieldTransform<>(date, new FieldTransform<>(date, pv.negate()),
new FieldTransform<>(date, fieldAngularCoordinates));
}
}
/**
* Get the rotation from inertial frame to local orbital frame.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromInertial(FieldAbsoluteDate, FieldPVCoordinates)} method must be
* called and the complete rotation transform must be extracted from it.
* </p>
*
* @param field field to which the elements belong
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
* @param <T> type of the field elements
*
* @return rotation from inertial frame to local orbital frame
*
* @since 9.0
*/
<T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromInertial(Field<T> field, FieldAbsoluteDate<T> date,
FieldPVCoordinates<T> pv);
/**
* Get the rotation from input {@link LOF local orbital frame} to the instance.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromLOF(LOF, AbsoluteDate, PVCoordinates)} method must be called and
* the complete rotation transform must be extracted from it.
*
* @param fromLOF input local orbital frame
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return rotation from input local orbital frame to the instance
*
* @since 11.3
*/
default Rotation rotationFromLOF(final LOF fromLOF, final AbsoluteDate date, final PVCoordinates pv) {
// First compute the rotation from the input LOF to the pivot inertial
final Rotation fromLOFToInertial = fromLOF.rotationFromInertial(date, pv).revert();
// Then compute the rotation from the pivot inertial to the output LOF
final Rotation inertialToThis = this.rotationFromInertial(date, pv);
// Output composed rotation
return fromLOFToInertial.compose(inertialToThis, RotationConvention.FRAME_TRANSFORM);
}
/**
* Get the rotation from input {@link LOF local orbital frame} to the instance.
*
* @param fromLOF input local orbital frame
* @param date date of the transform
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return rotation from input local orbital frame to the instance
*
* @since 11.3
*/
default Transform transformFromLOF(final LOF fromLOF, final AbsoluteDate date, final PVCoordinates pv) {
// First compute the rotation from the input LOF to the pivot inertial
final Transform fromLOFToInertial = fromLOF.transformFromInertial(date, pv).getInverse();
// Then compute the rotation from the pivot inertial to the output LOF
final Transform inertialToThis = this.transformFromInertial(date, pv);
// Output composed rotation
return new Transform(date, fromLOFToInertial, inertialToThis);
}
/**
* Get the transform from an inertial frame defining position-velocity and the local orbital frame.
*
* @param date current date
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return transform from the frame where position-velocity are defined to local orbital frame
*/
default Transform transformFromInertial(final AbsoluteDate date, final PVCoordinates pv) {
if (isQuasiInertial()) {
return new Transform(date, pv.getPosition().negate(), rotationFromInertial(date, pv));
} else if (pv.getAcceleration().equals(Vector3D.ZERO)) {
// compute the rotation part of the transform assuming there is no known acceleration
final Rotation r = rotationFromInertial(date, pv);
final Vector3D p = pv.getPosition();
final Vector3D momentum = pv.getMomentum();
final AngularCoordinates angularCoordinates = new AngularCoordinates(r,
new Vector3D(1.0 / p.getNorm2Sq(), r.applyTo(momentum)));
return new Transform(date, pv.negate(), angularCoordinates);
} else {
// use automatic differentiation
// create date with independent variable
final UnivariateDerivative2Field ud2Field = UnivariateDerivative2Field.getInstance();
final UnivariateDerivative2 dt = new UnivariateDerivative2(0, 1, 0);
final FieldAbsoluteDate<UnivariateDerivative2> ud2Date = new FieldAbsoluteDate<>(ud2Field, date).shiftedBy(dt);
// create PV with independent variable
final FieldPVCoordinates<UnivariateDerivative2> ud2PVCoordinates = pv.toUnivariateDerivative2PV();
// compute Field rotation
final FieldRotation<UnivariateDerivative2> ud2Rotation = rotationFromInertial(ud2Field, ud2Date,
ud2PVCoordinates);
// turn into Transform whilst adding translation
final AngularCoordinates angularCoordinates = new AngularCoordinates(ud2Rotation);
return new Transform(date, pv.negate(), angularCoordinates);
}
}
/**
* Get the rotation from inertial frame to local orbital frame.
* <p>
* This rotation does not include any time derivatives. If first time derivatives (i.e. rotation rate) is needed as well,
* the full {@link #transformFromInertial(AbsoluteDate, PVCoordinates) transformFromInertial} method must be called and
* the complete rotation transform must be extracted from it.
*
* @param date date of the rotation
* @param pv position-velocity of the spacecraft in some inertial frame
*
* @return rotation from inertial frame to local orbital frame
*/
Rotation rotationFromInertial(AbsoluteDate date, PVCoordinates pv);
/** Get flag that indicates if current local orbital frame shall be treated as pseudo-inertial.
* @return flag that indicates if current local orbital frame shall be treated as pseudo-inertial
*/
default boolean isQuasiInertial() {
return false;
}
/** Get name of the local orbital frame.
* @return name of the local orbital frame
*/
String getName();
}