InterSatellitesPhaseBuilder.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.estimation.measurements.generation;
- import java.util.Map;
- import org.hipparchus.random.CorrelatedRandomVectorGenerator;
- import org.orekit.estimation.measurements.EstimationModifier;
- import org.orekit.estimation.measurements.ObservableSatellite;
- import org.orekit.estimation.measurements.gnss.InterSatellitesPhase;
- import org.orekit.propagation.SpacecraftState;
- import org.orekit.propagation.sampling.OrekitStepInterpolator;
- import org.orekit.time.AbsoluteDate;
- import org.orekit.utils.ParameterDriver;
- /** Builder for {@link InterSatellitesPhase} measurements.
- * @author Bryan Cazabonne
- * @since 10.3
- */
- public class InterSatellitesPhaseBuilder extends AbstractMeasurementBuilder<InterSatellitesPhase> {
- /** Wavelength of the phase observed value [m]. */
- private final double wavelength;
- /** Satellite which receives the signal and performs the measurement.
- * @since 12.0
- */
- private final ObservableSatellite local;
- /** Satellite which simply emits the signal.
- * @since 12.0
- */
- private final ObservableSatellite remote;
- /** Simple constructor.
- * @param noiseSource noise source, may be null for generating perfect measurements
- * @param local satellite which receives the signal and performs the measurement
- * @param remote satellite which simply emits the signal
- * @param wavelength phase observed value wavelength (m)
- * @param sigma theoretical standard deviation
- * @param baseWeight base weight
- */
- public InterSatellitesPhaseBuilder(final CorrelatedRandomVectorGenerator noiseSource,
- final ObservableSatellite local, final ObservableSatellite remote,
- final double wavelength, final double sigma, final double baseWeight) {
- super(noiseSource, sigma, baseWeight, local, remote);
- this.wavelength = wavelength;
- this.local = local;
- this.remote = remote;
- }
- /** {@inheritDoc} */
- @Override
- public InterSatellitesPhase build(final AbsoluteDate date, final Map<ObservableSatellite, OrekitStepInterpolator> interpolators) {
- final double sigma = getTheoreticalStandardDeviation()[0];
- final double baseWeight = getBaseWeight()[0];
- final SpacecraftState[] relevant = new SpacecraftState[] {
- interpolators.get(local).getInterpolatedState(date),
- interpolators.get(remote).getInterpolatedState(date)
- };
- // create a dummy measurement
- final InterSatellitesPhase dummy = new InterSatellitesPhase(local, remote, relevant[0].getDate(),
- Double.NaN, wavelength, sigma, baseWeight);
- for (final EstimationModifier<InterSatellitesPhase> modifier : getModifiers()) {
- dummy.addModifier(modifier);
- }
- // set a reference date for parameters missing one
- for (final ParameterDriver driver : dummy.getParametersDrivers()) {
- if (driver.getReferenceDate() == null) {
- final AbsoluteDate start = getStart();
- final AbsoluteDate end = getEnd();
- driver.setReferenceDate(start.durationFrom(end) <= 0 ? start : end);
- }
- }
- // estimate the perfect value of the measurement
- double phase = dummy.estimateWithoutDerivatives(0, 0, relevant).getEstimatedValue()[0];
- // add the noise
- final double[] noise = getNoise();
- if (noise != null) {
- phase += noise[0];
- }
- // generate measurement
- final InterSatellitesPhase measurement = new InterSatellitesPhase(local, remote, relevant[0].getDate(),
- phase, wavelength, sigma, baseWeight);
- for (final EstimationModifier<InterSatellitesPhase> modifier : getModifiers()) {
- measurement.addModifier(modifier);
- }
- return measurement;
- }
- }