DoubleDihedraFieldOfView.java
- /* Copyright 2002-2021 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.geometry.fov;
- import org.hipparchus.exception.LocalizedCoreFormats;
- import org.hipparchus.geometry.euclidean.threed.Rotation;
- import org.hipparchus.geometry.euclidean.threed.RotationConvention;
- import org.hipparchus.geometry.euclidean.threed.Vector3D;
- import org.hipparchus.geometry.partitioning.Region;
- import org.hipparchus.geometry.partitioning.RegionFactory;
- import org.hipparchus.geometry.spherical.twod.Sphere2D;
- import org.hipparchus.geometry.spherical.twod.SphericalPolygonsSet;
- import org.hipparchus.util.FastMath;
- import org.orekit.errors.OrekitException;
- /** Class representing a spacecraft sensor Field Of View with dihedral shape (i.e. rectangular shape).
- * @author Luc Maisonobe
- * @since 10.1
- */
- public class DoubleDihedraFieldOfView extends PolygonalFieldOfView {
- /** Build a Field Of View with dihedral shape (i.e. rectangular shape).
- * @param center Direction of the FOV center, in spacecraft frame
- * @param axis1 FOV dihedral axis 1, in spacecraft frame
- * @param halfAperture1 FOV dihedral half aperture angle 1,
- * must be less than π/2, i.e. full dihedra must be smaller then
- * an hemisphere
- * @param axis2 FOV dihedral axis 2, in spacecraft frame
- * @param halfAperture2 FOV dihedral half aperture angle 2,
- * must be less than π/2, i.e. full dihedra must be smaller then
- * an hemisphere
- * @param margin angular margin to apply to the zone (if positive,
- * points outside of the raw FoV but close enough to the boundary are
- * considered visible; if negative, points inside of the raw FoV
- * but close enough to the boundary are considered not visible)
- */
- public DoubleDihedraFieldOfView(final Vector3D center,
- final Vector3D axis1, final double halfAperture1,
- final Vector3D axis2, final double halfAperture2,
- final double margin) {
- super(createPolygon(center, axis1, halfAperture1, axis2, halfAperture2), margin);
- }
- /** Create polygon.
- * @param center Direction of the FOV center, in spacecraft frame
- * @param axis1 FOV dihedral axis 1, in spacecraft frame
- * @param halfAperture1 FOV dihedral half aperture angle 1,
- * must be less than π/2, i.e. full dihedra must be smaller then
- * an hemisphere
- * @param axis2 FOV dihedral axis 2, in spacecraft frame
- * @param halfAperture2 FOV dihedral half aperture angle 2,
- * must be less than π/2, i.e. full dihedra must be smaller then
- * an hemisphere
- * @return built polygon
- */
- private static SphericalPolygonsSet createPolygon(final Vector3D center,
- final Vector3D axis1, final double halfAperture1,
- final Vector3D axis2, final double halfAperture2) {
- final RegionFactory<Sphere2D> factory = new RegionFactory<Sphere2D>();
- final double tolerance = FastMath.max(FastMath.ulp(2.0 * FastMath.PI),
- 1.0e-12 * FastMath.max(halfAperture1, halfAperture2));
- final Region<Sphere2D> dihedra1 = buildDihedra(factory, tolerance, center, axis1, halfAperture1);
- final Region<Sphere2D> dihedra2 = buildDihedra(factory, tolerance, center, axis2, halfAperture2);
- return (SphericalPolygonsSet) factory.intersection(dihedra1, dihedra2);
- }
- /** Build a dihedra.
- * @param factory factory for regions
- * @param tolerance tolerance below which points are considered equal
- * @param center Direction of the FOV center, in spacecraft frame
- * @param axis FOV dihedral axis, in spacecraft frame
- * @param halfAperture FOV dihedral half aperture angle,
- * must be less than π/2, i.e. full dihedra must be smaller then
- * an hemisphere
- * @return dihedra
- */
- private static Region<Sphere2D> buildDihedra(final RegionFactory<Sphere2D> factory,
- final double tolerance, final Vector3D center,
- final Vector3D axis, final double halfAperture) {
- if (halfAperture > 0.5 * FastMath.PI) {
- throw new OrekitException(LocalizedCoreFormats.OUT_OF_RANGE_SIMPLE,
- halfAperture, 0.0, 0.5 * FastMath.PI);
- }
- final Rotation r = new Rotation(axis, halfAperture, RotationConvention.VECTOR_OPERATOR);
- final Vector3D normalCenterPlane = Vector3D.crossProduct(axis, center);
- final Vector3D normalSidePlus = r.applyInverseTo(normalCenterPlane);
- final Vector3D normalSideMinus = r.applyTo(normalCenterPlane.negate());
- return factory.intersection(new SphericalPolygonsSet(normalSidePlus, tolerance),
- new SphericalPolygonsSet(normalSideMinus, tolerance));
- }
- }