FixedTroposphericDelay.java
/* Copyright 2011-2012 Space Applications Services
* Licensed to CS Communication & Systèmes (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.models.earth.troposphere;
import java.util.Collections;
import java.util.List;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.analysis.interpolation.PiecewiseBicubicSplineInterpolatingFunction;
import org.hipparchus.analysis.interpolation.PiecewiseBicubicSplineInterpolator;
import org.hipparchus.util.FastMath;
import org.hipparchus.util.MathUtils;
import org.orekit.annotation.DefaultDataContext;
import org.orekit.bodies.FieldGeodeticPoint;
import org.orekit.bodies.GeodeticPoint;
import org.orekit.data.DataContext;
import org.orekit.data.DataProvidersManager;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.models.earth.weather.FieldPressureTemperatureHumidity;
import org.orekit.models.earth.weather.PressureTemperatureHumidity;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.FieldAbsoluteDate;
import org.orekit.utils.FieldTrackingCoordinates;
import org.orekit.utils.InterpolationTableLoader;
import org.orekit.utils.ParameterDriver;
import org.orekit.utils.TrackingCoordinates;
/** A static tropospheric model that interpolates the actual tropospheric delay
* based on values read from a configuration file (tropospheric-delay.txt) via
* the {@link DataProvidersManager}.
* @author Thomas Neidhart
*/
@SuppressWarnings("deprecation")
public class FixedTroposphericDelay implements DiscreteTroposphericModel, TroposphericModel {
/** Singleton object for the default model. */
private static FixedTroposphericDelay defaultModel;
/** Abscissa grid for the bi-variate interpolation function read from the file. */
private final double[] xArr;
/** Ordinate grid for the bi-variate interpolation function read from the file. */
private final double[] yArr;
/** Values samples for the bi-variate interpolation function read from the file. */
private final double[][] fArr;
/** Interpolation function for the tropospheric delays. */
private PiecewiseBicubicSplineInterpolatingFunction delayFunction;
/** Creates a new {@link FixedTroposphericDelay} instance.
* @param xArr abscissa grid for the interpolation function
* @param yArr ordinate grid for the interpolation function
* @param fArr values samples for the interpolation function
*/
public FixedTroposphericDelay(final double[] xArr, final double[] yArr, final double[][] fArr) {
this.xArr = xArr.clone();
this.yArr = yArr.clone();
this.fArr = fArr.clone();
delayFunction = new PiecewiseBicubicSplineInterpolator().interpolate(xArr, yArr, fArr);
}
/** Creates a new {@link FixedTroposphericDelay} instance, and loads the
* delay values from the given resource via the {@link DataContext#getDefault()
* default data context}.
*
* @param supportedName a regular expression for supported resource names
* @see #FixedTroposphericDelay(String, DataProvidersManager)
*/
@DefaultDataContext
public FixedTroposphericDelay(final String supportedName) {
this(supportedName, DataContext.getDefault().getDataProvidersManager());
}
/**
* Creates a new {@link FixedTroposphericDelay} instance, and loads the delay values
* from the given resource via the specified data manager.
*
* @param supportedName a regular expression for supported resource names
* @param dataProvidersManager provides access to auxiliary data.
* @since 10.1
*/
public FixedTroposphericDelay(final String supportedName,
final DataProvidersManager dataProvidersManager) {
final InterpolationTableLoader loader = new InterpolationTableLoader();
dataProvidersManager.feed(supportedName, loader);
if (!loader.stillAcceptsData()) {
xArr = loader.getAbscissaGrid();
yArr = loader.getOrdinateGrid();
for (int i = 0; i < yArr.length; ++i) {
yArr[i] = FastMath.toRadians(yArr[i]);
}
fArr = loader.getValuesSamples();
delayFunction = new PiecewiseBicubicSplineInterpolator().interpolate(xArr, yArr, fArr);
} else {
throw new OrekitException(OrekitMessages.UNABLE_TO_FIND_RESOURCE, supportedName);
}
}
/** Returns the default model, loading delay values from the file
* "tropospheric-delay.txt" via the {@link DataContext#getDefault() default data
* context}.
*
* <p>This method uses the {@link DataContext#getDefault() default data context}.
*
* @return the default model
*/
@DefaultDataContext
public static FixedTroposphericDelay getDefaultModel() {
synchronized (FixedTroposphericDelay.class) {
if (defaultModel == null) {
defaultModel = new FixedTroposphericDelay("^tropospheric-delay\\.txt$");
}
}
return defaultModel;
}
/** {@inheritDoc} */
@Override
@Deprecated
public double pathDelay(final double elevation, final GeodeticPoint point,
final double[] parameters, final AbsoluteDate date) {
return pathDelay(new TrackingCoordinates(0.0, elevation, 0.0), point,
TroposphericModelUtils.STANDARD_ATMOSPHERE, parameters, date).getDelay();
}
/** {@inheritDoc}
* <p>
* All delays are affected to {@link TroposphericDelay#getZh() hydrostatic zenith}
* and {@link TroposphericDelay#getSh() hydrostatic slanted} delays, the wet delays
* are arbitrarily set to 0.
* </p>
*/
@Override
public TroposphericDelay pathDelay(final TrackingCoordinates trackingCoordinates, final GeodeticPoint point,
final PressureTemperatureHumidity weather,
final double[] parameters, final AbsoluteDate date) {
// limit the height to 5000 m
final double h = FastMath.min(FastMath.max(0, point.getAltitude()), 5000);
// limit the elevation to 0 - π
final double ele = FastMath.min(FastMath.PI, FastMath.max(0d, trackingCoordinates.getElevation()));
// mirror elevation at the right angle of π/2
final double e = ele > 0.5 * FastMath.PI ? FastMath.PI - ele : ele;
return new TroposphericDelay(delayFunction.value(h, MathUtils.SEMI_PI), 0.0,
delayFunction.value(h, e), 0.0);
}
/** {@inheritDoc} */
@Override
@Deprecated
public <T extends CalculusFieldElement<T>> T pathDelay(final T elevation, final FieldGeodeticPoint<T> point,
final T[] parameters, final FieldAbsoluteDate<T> date) {
return pathDelay(new FieldTrackingCoordinates<>(date.getField().getZero(), elevation, date.getField().getZero()),
point,
new FieldPressureTemperatureHumidity<>(date.getField(), TroposphericModelUtils.STANDARD_ATMOSPHERE),
parameters, date).getDelay();
}
/** {@inheritDoc}
* <p>
* All delays are affected to {@link FieldTroposphericDelay#getZh() hydrostatic zenith}
* and {@link FieldTroposphericDelay#getSh() hydrostatic slanted} delays, the wet delays
* are arbitrarily set to 0.
* </p>
*/
@Override
public <T extends CalculusFieldElement<T>> FieldTroposphericDelay<T> pathDelay(final FieldTrackingCoordinates<T> trackingCoordinates,
final FieldGeodeticPoint<T> point,
final FieldPressureTemperatureHumidity<T> weather,
final T[] parameters, final FieldAbsoluteDate<T> date) {
final T zero = date.getField().getZero();
final T pi = zero.getPi();
// limit the height to 5000 m
final T h = FastMath.min(FastMath.max(zero, point.getAltitude()), zero.newInstance(5000));
// limit the elevation to 0 - π
final T ele = FastMath.min(pi, FastMath.max(zero, trackingCoordinates.getElevation()));
// mirror elevation at the right angle of π/2
final T e = ele.getReal() > pi.multiply(0.5).getReal() ? ele.negate().add(pi) : ele;
return new FieldTroposphericDelay<>(delayFunction.value(h, date.getField().getZero().newInstance(MathUtils.SEMI_PI)),
date.getField().getZero(),
delayFunction.value(h, e),
date.getField().getZero());
}
/** {@inheritDoc} */
@Override
public List<ParameterDriver> getParametersDrivers() {
return Collections.emptyList();
}
}