1 /* Copyright 2002-2019 CS Systèmes d'Information
2 * Licensed to CS Systèmes d'Information (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;
18
19 import org.hipparchus.RealFieldElement;
20 import org.orekit.time.AbsoluteDate;
21 import org.orekit.time.FieldAbsoluteDate;
22
23 /** Defines a tropospheric model, used to calculate the path delay imposed to
24 * electro-magnetic signals between an orbital satellite and a ground station.
25 * <p>
26 * Models that implement this interface split the delay into hydrostatic
27 * and non-hydrostatic part:
28 * </p>
29 * <pre>
30 * δ = δ<sub>h</sub> + δ<sub>nh</sub>
31 * </pre>
32 * With:
33 * <ul>
34 * <li> δ<sub>h</sub> = hydrostatic delay </li>
35 * <li> δ<sub>nh</sub> = non-hydrostatic (or wet) delay </li>
36 * </ul>
37 * @author Bryan Cazabonne
38 */
39 public interface DiscreteTroposphericModel extends MappingFunction {
40
41 /** Calculates the tropospheric path delay for the signal path from a ground
42 * station to a satellite.
43 *
44 * @param elevation the elevation of the satellite, in radians
45 * @param height the height of the station in m above sea level
46 * @param parameters tropospheric model parameters.
47 * @param date current date
48 * @return the path delay due to the troposphere in m
49 */
50 double pathDelay(double elevation, double height, double[] parameters, AbsoluteDate date);
51
52 /** Calculates the tropospheric path delay for the signal path from a ground
53 * station to a satellite.
54 *
55 * @param <T> type of the elements
56 * @param elevation the elevation of the satellite, in radians
57 * @param height the height of the station in m above sea level
58 * @param parameters tropospheric model parameters.
59 * @param date current date
60 * @return the path delay due to the troposphere in m
61 */
62 <T extends RealFieldElement<T>> T pathDelay(T elevation, T height, T[] parameters, FieldAbsoluteDate<T> date);
63
64 /** This method allows the computation of the zenith hydrostatic and
65 * zenith wet delay. The resulting element is an array having the following form:
66 * <ul>
67 * <li>double[0] = D<sub>hz</sub> → zenith hydrostatic delay
68 * <li>double[1] = D<sub>wz</sub> → zenith wet delay
69 * </ul>
70 * @param height the height of the station in m above sea level.
71 * @param parameters tropospheric model parameters.
72 * @param date current date
73 * @return a two components array containing the zenith hydrostatic and wet delays.
74 */
75 double[] computeZenithDelay(double height, double[] parameters, AbsoluteDate date);
76
77 /** This method allows the computation of the zenith hydrostatic and
78 * zenith wet delay. The resulting element is an array having the following form:
79 * <ul>
80 * <li>T[0] = D<sub>hz</sub> → zenith hydrostatic delay
81 * <li>T[1] = D<sub>wz</sub> → zenith wet delay
82 * </ul>
83 * @param <T> type of the elements
84 * @param height the height of the station in m above sea level.
85 * @param parameters tropospheric model parameters.
86 * @param date current date
87 * @return a two components array containing the zenith hydrostatic and wet delays.
88 */
89 <T extends RealFieldElement<T>> T[] computeZenithDelay(T height, T[] parameters, FieldAbsoluteDate<T> date);
90
91 }