PhaseBuilder.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.estimation.measurements.gnss;
- import org.hipparchus.random.CorrelatedRandomVectorGenerator;
- import org.orekit.estimation.measurements.EstimationModifier;
- import org.orekit.estimation.measurements.GroundStation;
- import org.orekit.estimation.measurements.ObservableSatellite;
- import org.orekit.estimation.measurements.generation.AbstractMeasurementBuilder;
- import org.orekit.propagation.SpacecraftState;
- import org.orekit.time.AbsoluteDate;
- import org.orekit.utils.ParameterDriver;
- /** Builder for {@link Phase} measurements.
- * @author Luc Maisonobe
- * @since 10.1
- */
- public class PhaseBuilder extends AbstractMeasurementBuilder<Phase> {
- /** Ground station from which measurement is performed. */
- private final GroundStation station;
- /** Wavelength of the phase observed value [m]. */
- private final double wavelength;
- /** Simple constructor.
- * @param noiseSource noise source, may be null for generating perfect measurements
- * @param station ground station from which measurement is performed
- * @param wavelength phase observed value wavelength (m)
- * @param sigma theoretical standard deviation
- * @param baseWeight base weight
- * @param satellite satellite related to this builder
- */
- public PhaseBuilder(final CorrelatedRandomVectorGenerator noiseSource,
- final GroundStation station, final double wavelength,
- final double sigma, final double baseWeight,
- final ObservableSatellite satellite) {
- super(noiseSource, sigma, baseWeight, satellite);
- this.station = station;
- this.wavelength = wavelength;
- }
- /** {@inheritDoc} */
- @Override
- public Phase build(final SpacecraftState[] states) {
- final ObservableSatellite satellite = getSatellites()[0];
- final double sigma = getTheoreticalStandardDeviation()[0];
- final double baseWeight = getBaseWeight()[0];
- final SpacecraftState[] relevant = new SpacecraftState[] { states[satellite.getPropagatorIndex()] };
- // create a dummy measurement
- final Phase dummy = new Phase(station, relevant[0].getDate(), Double.NaN, wavelength, sigma, baseWeight, satellite);
- for (final EstimationModifier<Phase> 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.estimate(0, 0, relevant).getEstimatedValue()[0];
- // add the noise
- final double[] noise = getNoise();
- if (noise != null) {
- phase += noise[0];
- }
- // generate measurement
- final Phase measurement = new Phase(station, relevant[0].getDate(), phase, wavelength, sigma, baseWeight, satellite);
- for (final EstimationModifier<Phase> modifier : getModifiers()) {
- measurement.addModifier(modifier);
- }
- return measurement;
- }
- }