1 /* Copyright 2002-2021 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.models.earth.troposphere;
18
19 import java.util.List;
20
21 import org.hipparchus.Field;
22 import org.hipparchus.CalculusFieldElement;
23 import org.hipparchus.util.MathArrays;
24 import org.orekit.bodies.FieldGeodeticPoint;
25 import org.orekit.bodies.GeodeticPoint;
26 import org.orekit.time.AbsoluteDate;
27 import org.orekit.time.FieldAbsoluteDate;
28 import org.orekit.utils.ParameterDriver;
29
30 /** Defines a tropospheric model, used to calculate the path delay imposed to
31 * electro-magnetic signals between an orbital satellite and a ground station.
32 * <p>
33 * Models that implement this interface split the delay into hydrostatic
34 * and non-hydrostatic part:
35 * <p>
36 * δ = δ<sub>h</sub> + δ<sub>nh</sub>
37 * <p>
38 * With:
39 * <ul>
40 * <li> δ<sub>h</sub> = hydrostatic delay </li>
41 * <li> δ<sub>nh</sub> = non-hydrostatic (or wet) delay </li>
42 * </ul>
43 * @author Bryan Cazabonne
44 */
45 public interface DiscreteTroposphericModel {
46
47 /** Calculates the tropospheric path delay for the signal path from a ground
48 * station to a satellite.
49 *
50 * @param elevation the elevation of the satellite, in radians
51 * @param point station location
52 * @param parameters tropospheric model parameters
53 * @param date current date
54 * @return the path delay due to the troposphere in m
55 */
56 double pathDelay(double elevation, GeodeticPoint point, double[] parameters, AbsoluteDate date);
57
58 /** Calculates the tropospheric path delay for the signal path from a ground
59 * station to a satellite.
60 *
61 * @param <T> type of the elements
62 * @param elevation the elevation of the satellite, in radians
63 * @param point station location
64 * @param parameters tropospheric model parameters
65 * @param date current date
66 * @return the path delay due to the troposphere in m
67 */
68 <T extends CalculusFieldElement<T>> T pathDelay(T elevation, FieldGeodeticPoint<T> point, T[] parameters, FieldAbsoluteDate<T> date);
69
70 /** Get the drivers for tropospheric model parameters.
71 * @return drivers for tropospheric model parameters
72 */
73 List<ParameterDriver> getParametersDrivers();
74
75 /** Get tropospheric model parameters.
76 * @return tropospheric model parameters
77 */
78 default double[] getParameters() {
79 final List<ParameterDriver> drivers = getParametersDrivers();
80 final double[] parameters = new double[drivers.size()];
81 for (int i = 0; i < drivers.size(); ++i) {
82 parameters[i] = drivers.get(i).getValue();
83 }
84 return parameters;
85 }
86
87 /** Get tropospheric model parameters.
88 * @param field field to which the elements belong
89 * @param <T> type of the elements
90 * @return tropospheric model parameters
91 */
92 default <T extends CalculusFieldElement<T>> T[] getParameters(final Field<T> field) {
93 final List<ParameterDriver> drivers = getParametersDrivers();
94 final T[] parameters = MathArrays.buildArray(field, drivers.size());
95 for (int i = 0; i < drivers.size(); ++i) {
96 parameters[i] = field.getZero().add(drivers.get(i).getValue());
97 }
98 return parameters;
99 }
100
101 }