MeasurementObject.java
/* Copyright 2002-2026 Brianna Aubin
* Licensed to Hawkeye 360 (HE360) 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;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import org.hipparchus.Field;
import org.hipparchus.analysis.differentiation.Gradient;
import org.hipparchus.util.FastMath;
import org.orekit.orbits.CartesianOrbit;
import org.orekit.orbits.FieldCartesianOrbit;
import org.orekit.propagation.SpacecraftState;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.clocks.QuadraticClockModel;
import org.orekit.time.clocks.QuadraticFieldClockModel;
import org.orekit.utils.AbsolutePVCoordinates;
import org.orekit.utils.FieldAbsolutePVCoordinates;
import org.orekit.utils.FieldPVCoordinatesProvider;
import org.orekit.utils.PVCoordinatesProvider;
import org.orekit.utils.ParameterDriver;
import org.orekit.utils.ParameterDriversProvider;
import org.orekit.utils.TimeStampedFieldPVCoordinates;
import org.orekit.utils.TimeStampedPVCoordinates;
/** Abstract class underlying both observed and observing measurement
* objects. Contains the QuadraticClockModel and the ability to store a
* master list of all parameter drivers associated with the object.
*
* @author Brianna Aubin
* @since 14.0
*/
abstract class MeasurementObject implements ParameterDriversProvider {
/** Suffix for ground station position and clock offset parameters names. */
public static final String OFFSET_SUFFIX = "-offset";
/** Suffix for ground clock drift parameters name. */
public static final String DRIFT_SUFFIX = "-drift";
/** Suffix for ground clock drift parameters name.
* @since 12.1
*/
public static final String ACCELERATION_SUFFIX = "-acceleration";
/** Checkstyle is annoying sometimes. */
private static final String CLOCK_STRING = "-clock";
/** Clock offset scaling factor.
* <p>
* We use a power of 2 to avoid numeric noise introduction
* in the multiplications/divisions sequences.
* </p>
*/
private static final double CLOCK_OFFSET_SCALE = FastMath.scalb(1.0, -10);
/** Stores quadratic clock model. */
private final QuadraticClockModel quadraticClockModel;
/** Stores list of all ParameterDriver values. */
private final List<ParameterDriver> parameterDrivers = new ArrayList<>();
/** Name of the satellite. */
private final String name;
/** Simple constructor.
* @param name name of MeasurementObject
*/
protected MeasurementObject(final String name) {
this(name, createEmptyQuadraticClock(name));
}
/** Simple constructor.
* @param name name of MeasurementObject
* @param quadraticClock clock belonging to MeasurementObject
*/
protected MeasurementObject(final String name, final QuadraticClockModel quadraticClock) {
// Initialize member variables
this.name = name;
this.quadraticClockModel = quadraticClock;
// Add clock parameters
parameterDrivers.add(quadraticClockModel.getClockOffsetDriver());
parameterDrivers.add(quadraticClockModel.getClockDriftDriver());
parameterDrivers.add(quadraticClockModel.getClockAccelerationDriver());
}
/** Get the MeasurementObject name.
* @return name for the object
* @since 12.1
*/
public final String getName() {
return name;
}
/** Get the clock offset driver.
* @return clock offset driver
*/
public final ParameterDriver getClockOffsetDriver() {
return quadraticClockModel.getClockOffsetDriver();
}
/** Get the clock drift driver.
* @return clock drift driver
*/
public final ParameterDriver getClockDriftDriver() {
return quadraticClockModel.getClockDriftDriver();
}
/** Get the clock acceleration driver.
* @return clock acceleration driver
*/
public final ParameterDriver getClockAccelerationDriver() {
return quadraticClockModel.getClockAccelerationDriver();
}
/** Creates an quadratic clock with zero displacement.
* @param name name of object that is holding the clock
* @return new quadratic clock model
*/
protected static QuadraticClockModel createEmptyQuadraticClock(final String name) {
return new QuadraticClockModel(new ParameterDriver(name + CLOCK_STRING + OFFSET_SUFFIX,
0.0, CLOCK_OFFSET_SCALE,
Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY),
new ParameterDriver(name + CLOCK_STRING + DRIFT_SUFFIX,
0.0, CLOCK_OFFSET_SCALE,
Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY),
new ParameterDriver(name + CLOCK_STRING + ACCELERATION_SUFFIX,
0.0, CLOCK_OFFSET_SCALE,
Double.NEGATIVE_INFINITY, Double.POSITIVE_INFINITY));
}
/** Get a quadratic clock model valid at some date.
* @return quadratic clock model
* @since 12.1
*/
public final QuadraticClockModel getQuadraticClockModel() {
return quadraticClockModel;
}
/** Get emitting satellite clock provider.
* @param freeParameters total number of free parameters in the gradient
* @param date time of computations
* @param indices indices of the differentiation parameters in derivatives computations,
* must be span name and not driver name
* @return emitting satellite clock provider
*/
public QuadraticFieldClockModel<Gradient> getQuadraticFieldClock(final int freeParameters,
final AbsoluteDate date,
final Map<String, Integer> indices) {
return getQuadraticClockModel().toGradientModel(freeParameters, indices, date);
}
/** {@inheritDoc} */
@Override
public List<ParameterDriver> getParametersDrivers() {
return Collections.unmodifiableList(parameterDrivers);
}
/**
* Add a single parameter.
* @param parameterDriver parameter being added to the MeasurementObject
*/
protected final void addParameterDriver(final ParameterDriver parameterDriver) {
parameterDrivers.add(parameterDriver);
}
/**
* Create PV provider from position-velocity-acceleration vector and template state.
* @param templateState template state
* @param pvCoordinates position-velocity-acceleration
* @return position-velocity-acceleration provider
* @since 14.0
*/
public static PVCoordinatesProvider extractPVCoordinatesProvider(final SpacecraftState templateState,
final TimeStampedPVCoordinates pvCoordinates) {
if (templateState.isOrbitDefined()) {
final CartesianOrbit cartesianOrbit = new CartesianOrbit(pvCoordinates, templateState.getFrame(),
templateState.getOrbit().getMu());
return templateState.getOrbit().getType().convertType(cartesianOrbit);
} else {
return new AbsolutePVCoordinates(templateState.getFrame(), pvCoordinates);
}
}
/**
* Create PV provider from position-velocity-acceleration vector and template state.
*
* @param templateState template state
* @param pvCoordinates position-velocity-acceleration
* @return position-velocity-acceleration provider
* @since 14.0
*/
public static FieldPVCoordinatesProvider<Gradient> extractFieldPVCoordinatesProvider(final SpacecraftState templateState,
final TimeStampedFieldPVCoordinates<Gradient> pvCoordinates) {
final Field<Gradient> field = pvCoordinates.getDate().getField();
if (templateState.isOrbitDefined()) {
final FieldCartesianOrbit<Gradient> cartesianOrbit = new FieldCartesianOrbit<>(pvCoordinates, templateState.getFrame(),
field.getZero().newInstance(templateState.getOrbit().getMu()));
return templateState.getOrbit().getType().convertType(cartesianOrbit);
} else {
return new FieldAbsolutePVCoordinates<>(templateState.getFrame(), pvCoordinates);
}
}
}