EncounterLOF.java
/* Copyright 2002-2023 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.orekit.frames.encounter;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.Field;
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.Vector3D;
import org.hipparchus.geometry.euclidean.twod.FieldVector2D;
import org.hipparchus.geometry.euclidean.twod.Vector2D;
import org.hipparchus.linear.Array2DRowFieldMatrix;
import org.hipparchus.linear.Array2DRowRealMatrix;
import org.hipparchus.linear.FieldMatrix;
import org.hipparchus.linear.MatrixUtils;
import org.hipparchus.linear.RealMatrix;
import org.hipparchus.util.MathArrays;
import org.orekit.frames.LOF;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.utils.FieldPVCoordinates;
import org.orekit.utils.PVCoordinates;
import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
/**
* Interface for encounter local orbital frame.
* <p>
* Encounter local orbital frame are defined using two objects, one of them is placed at the origin and the other is
* expressed relatively to the origin.
*
* @author Vincent Cucchietti
* @since 12.0
*/
public interface EncounterLOF extends LOF {
/**
* {@inheritDoc} It is unnecessary to use this method when dealing with {@link EncounterLOF}, use
* {@link #rotationFromInertial(Field, FieldPVCoordinates)} instead.
*/
@Override
default <T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromInertial(Field<T> field,
FieldAbsoluteDate<T> date,
FieldPVCoordinates<T> pv) {
return rotationFromInertial(field, pv);
}
/**
* {@inheritDoc} It is unnecessary to use this method when dealing with {@link EncounterLOF}, use
* {@link #rotationFromInertial(PVCoordinates)} instead.
*/
@Override
default Rotation rotationFromInertial(AbsoluteDate date, PVCoordinates pv) {
return rotationFromInertial(pv);
}
/**
* Get the rotation from inertial to this encounter local orbital frame.
* <p>
* <b>BEWARE: The given origin's position and velocity coordinates must be given in the frame in which this instance
* has been expressed in.</b>
*
* @param field field to which the elements belong
* @param origin position-velocity of the origin in the same inertial frame as the one this instance has been expressed
* in.
* @param <T> type of the field elements
*
* @return rotation from inertial to this encounter local orbital frame
*/
default <T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromInertial(final Field<T> field,
final FieldPVCoordinates<T> origin) {
return rotationFromInertial(field, origin, getFieldOther(field));
}
/**
* Get the rotation from inertial to this encounter local orbital frame.
* <p>
* <b>BEWARE: The given origin's position and velocity coordinates must be given in the frame in which this instance
* has been expressed in.</b>
*
* @param origin position-velocity of the origin in some inertial frame
*
* @return rotation from inertial to this encounter local orbital frame
*/
default Rotation rotationFromInertial(final PVCoordinates origin) {
return rotationFromInertial(origin, getOther());
}
/**
* Get the rotation from inertial to this encounter local orbital frame.
* <p>
* <b>BEWARE: The given origin's position and velocity coordinates must be given in the frame in which this instance
* has been expressed in.</b>
*
* @param field field to which the elements belong
* @param origin position-velocity of the origin in the same inertial frame as other
* @param other position-velocity of the other in the same inertial frame as origin
* @param <T> type of the field elements
*
* @return rotation from inertial to this encounter local orbital frame
*/
<T extends CalculusFieldElement<T>> FieldRotation<T> rotationFromInertial(Field<T> field,
FieldPVCoordinates<T> origin,
FieldPVCoordinates<T> other);
/**
* Get the rotation from inertial to this encounter local orbital frame.
* <p>
* <b>BEWARE: The given origin's position and velocity coordinates must be given in the frame in which this instance
* has been expressed in.</b>
*
* @param origin position-velocity of the origin in the same inertial frame as other
* @param other position-velocity of the other instance in the same inertial frame as origin
*
* @return rotation from inertial to this encounter local orbital frame
*/
Rotation rotationFromInertial(PVCoordinates origin, PVCoordinates other);
/**
* Project given {@link RealMatrix matrix} expressed in this encounter local orbital frame onto the collision plane.
*
* @param matrix matrix to project, a 3 by 3 matrix is expected
*
* @return projected matrix onto the collision plane defined by this encounter local orbital frame
*/
default RealMatrix projectOntoCollisionPlane(RealMatrix matrix) {
final RealMatrix projectionMatrix = computeProjectionMatrix();
return projectionMatrix.multiply(matrix.multiplyTransposed(projectionMatrix));
}
/**
* Get the 2x3 projection matrix that projects values expressed in this encounter local orbital frame to the collision
* plane.
*
* @return 2x3 projection matrix
*/
default RealMatrix computeProjectionMatrix() {
// Remove axis normal to collision plane from the identity matrix
final RealMatrix identity = MatrixUtils.createRealIdentityMatrix(3);
final List<double[]> projectionMatrixDataList = Arrays.stream(identity.getData())
.filter(values -> !Arrays.equals(values,
getAxisNormalToCollisionPlane().toArray()))
.collect(Collectors.toList());
// Map list<double[]> to double[][]
final double[][] projectionMatrixData = new double[2][3];
for (int i = 0; i < 2; i++) {
projectionMatrixData[i] = projectionMatrixDataList.get(i);
}
return new Array2DRowRealMatrix(projectionMatrixData);
}
/**
* Project given {@link RealMatrix matrix} expressed in this encounter local orbital frame onto the collision plane
* defined by this same encounter local orbital frame.
*
* @param matrix matrix to project, a 3 by 3 matrix is expected
* @param <T> type of the field elements
*
* @return projected matrix onto the collision plane defined by this encounter local orbital frame
*/
default <T extends CalculusFieldElement<T>> FieldMatrix<T> projectOntoCollisionPlane(FieldMatrix<T> matrix) {
final FieldMatrix<T> projectionMatrix = computeProjectionMatrix(matrix.getField());
return projectionMatrix.multiply(matrix.multiplyTransposed(projectionMatrix));
}
/**
* Get the 2x3 projection matrix that projects values expressed in this encounter local orbital frame to the collision
* plane defined by this same encounter local orbital frame.
*
* @param field field to which the elements belong
* @param <T> type of the field elements
*
* @return 2x3 projection matrix
*/
default <T extends CalculusFieldElement<T>> FieldMatrix<T> computeProjectionMatrix(Field<T> field) {
// Remove axis normal to collision plane from the identity matrix
final FieldMatrix<T> identity = MatrixUtils.createFieldIdentityMatrix(field, 3);
final List<T[]> projectionMatrixDataList = Arrays.stream(identity.getData())
.filter(values -> !Arrays.equals(values,
getAxisNormalToCollisionPlane(
field).toArray()))
.collect(Collectors.toList());
// Map list<C[]> to C[][]
final T[][] projectionMatrixData = MathArrays.buildArray(field, 2, 3);
for (int i = 0; i < 2; i++) {
projectionMatrixData[i] = projectionMatrixDataList.get(i);
}
return new Array2DRowFieldMatrix<>(projectionMatrixData);
}
/**
* Get the axis normal to the collision plane (i, j or k) in this encounter local orbital frame.
*
* @param field field of the elements
* @param <T> type of the field elements
*
* @return axis normal to the collision plane (i, j or k) in this encounter local orbital frame
*/
<T extends CalculusFieldElement<T>> FieldVector3D<T> getAxisNormalToCollisionPlane(Field<T> field);
/**
* Project given {@link Vector3D vector} expressed in this encounter local orbital frame onto the collision plane.
*
* @param vector vector to project
*
* @return projected vector onto the collision plane defined by this encounter local orbital frame
*/
default Vector2D projectOntoCollisionPlane(Vector3D vector) {
final RealMatrix projectionMatrix = computeProjectionMatrix();
final RealMatrix vectorInMatrix = new Array2DRowRealMatrix(vector.toArray());
return new Vector2D(projectionMatrix.multiply(vectorInMatrix).getColumn(0));
}
/**
* Project given {@link Vector3D vector} expressed in this encounter local orbital frame onto the collision plane.
*
* @param vector vector to project
* @param <T> type of the field elements
*
* @return projected vector onto the collision plane defined by this encounter local orbital frame
*/
default <T extends CalculusFieldElement<T>> FieldVector2D<T> projectOntoCollisionPlane(
final FieldVector3D<T> vector) {
final FieldMatrix<T> projectionMatrix = computeProjectionMatrix(vector.getX().getField());
final FieldMatrix<T> vectorInMatrix = new Array2DRowFieldMatrix<>(vector.toArray());
return new FieldVector2D<>(projectionMatrix.multiply(vectorInMatrix).getColumn(0));
}
/** Get other's position and velocity coordinates.
* @param field field of the element
* @param <T> type of the element
*
* @return other's position and velocity coordinates
*/
<T extends CalculusFieldElement<T>> FieldPVCoordinates<T> getFieldOther(Field<T> field);
/**
* Get the axis normal to the collision plane (i, j or k) in this encounter local orbital frame.
*
* @return axis normal to the collision plane (i, j or k) in this encounter local orbital frame
*/
Vector3D getAxisNormalToCollisionPlane();
/** Get other's position and velocity coordinates.
* @return other's position and velocity coordinates
*/
PVCoordinates getOther();
/** 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
*/
@Override
default boolean isQuasiInertial() {
return true;
}
}