RelativisticJ2ClockOneWayGNSSPhaseModifier.java
- /* Copyright 2002-2024 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.modifiers;
- import java.util.Collections;
- import java.util.List;
- import org.orekit.estimation.measurements.EstimatedMeasurementBase;
- import org.orekit.estimation.measurements.EstimationModifier;
- import org.orekit.estimation.measurements.gnss.OneWayGNSSPhase;
- import org.orekit.utils.Constants;
- import org.orekit.utils.ParameterDriver;
- /**
- * Class modifying theoretical one-way phase measurements with relativistic J2 clock correction.
- * <p>
- * Relativistic clock correction of the effects caused by the oblateness of Earth on
- * the gravity potential.
- * </p>
- * <p>
- * The time delay caused by this effect is computed based on the orbital parameters of the
- * emitter's orbit.
- * </p>
- *
- * @author Louis Aucouturier
- * @since 11.2
- *
- * @see "Teunissen, Peter, and Oliver Montenbruck, eds. Springer handbook of global navigation
- * satellite systems. Chapter 19.2. Equation 19.18 Springer, 2017."
- */
- public class RelativisticJ2ClockOneWayGNSSPhaseModifier extends AbstractRelativisticJ2ClockModifier implements EstimationModifier<OneWayGNSSPhase> {
- /**
- * Modifier constructor.
- * @param gm Earth gravitational constant (mu) in m³/s².
- * @param c20 Earth un-normalized second zonal coefficient (Signed J2 constant, is negative) (Typical value -1.0826e-3).
- * @param equatorialRadius Earth equatorial radius in m.
- */
- public RelativisticJ2ClockOneWayGNSSPhaseModifier(final double gm,
- final double c20,
- final double equatorialRadius) {
- super(gm, c20, equatorialRadius);
- }
- /** {@inheritDoc} */
- @Override
- public List<ParameterDriver> getParametersDrivers() {
- return Collections.emptyList();
- }
- /** {@inheritDoc} */
- @Override
- public void modifyWithoutDerivatives(final EstimatedMeasurementBase<OneWayGNSSPhase> estimated) {
- // Relativistic clock correction
- final double dtJ2 = relativisticJ2Correction(estimated);
- // Wavelength
- final double wavelength = estimated.getObservedMeasurement().getWavelength();
- // Update estimated value taking into account the relativistic effect.
- final double cOverLambda = Constants.SPEED_OF_LIGHT / wavelength;
- final double[] newValue = estimated.getEstimatedValue().clone();
- newValue[0] = newValue[0] - dtJ2 * cOverLambda;
- estimated.modifyEstimatedValue(this, newValue);
- }
- }