SeasonalModel.java
/* Copyright 2002-2024 Thales Alenia Space
* 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,
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*/
package org.orekit.models.earth.weather;
import org.hipparchus.CalculusFieldElement;
import org.hipparchus.util.SinCos;
import org.hipparchus.util.FieldSinCos;
/** Seasonal model used in Global Pressure Temperature models.
* @see "Landskron, D. & Böhm, J. J Geod (2018)
* VMF3/GPT3: refined discrete and empirical troposphere mapping functions
* 92: 349. https://doi.org/10.1007/s00190-017-1066-2"
* @author Luc Maisonobe
* @since 12.1
*/
class SeasonalModel {
/** Constant. */
private final double a0;
/** Annual cosine amplitude. */
private final double a1;
/** Annual sine amplitude. */
private final double b1;
/** Semi-annual cosine amplitude. */
private final double a2;
/** Semi-annual sine amplitude. */
private final double b2;
/** Simple constructor.
* @param a0 constant
* @param a1 annual cosine amplitude
* @param b1 annual sine amplitude
* @param a2 semi-annual cosine amplitude
* @param b2 semi-annual sine amplitude
*/
SeasonalModel(final double a0, final double a1, final double b1, final double a2, final double b2) {
this.a0 = a0;
this.a1 = a1;
this.b1 = b1;
this.a2 = a2;
this.b2 = b2;
}
/** Evaluate a model for some day.
* @param sc1 sine and cosine of yearly harmonic term
* @param sc2 sine and cosine of bi-yearly harmonic term
* @return model value at specified day
* @since 13.0
*/
public double evaluate(final SinCos sc1, final SinCos sc2) {
return a0 + a1 * sc1.cos() + b1 * sc1.sin() + a2 * sc2.cos() + b2 * sc2.sin();
}
/** Evaluate a model for some day.
* @param <T> type of the field elements
* @param sc1 sine and cosine of yearly harmonic term
* @param sc2 sine and cosine of bi-yearly harmonic term
* @return model value at specified day
* @since 13.0
*/
public <T extends CalculusFieldElement<T>> T evaluate(final FieldSinCos<T> sc1, final FieldSinCos<T> sc2) {
return sc1.cos().multiply(a1).
add(sc1.sin().multiply(b1)).
add(sc2.cos().multiply(a2)).
add(sc2.sin().multiply(b2)).
add(a0);
}
}