1   /* Copyright 2022-2025 Thales Alenia Space
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 org.hipparchus.CalculusFieldElement;
20  import org.orekit.bodies.FieldGeodeticPoint;
21  import org.orekit.bodies.GeodeticPoint;
22  import org.orekit.time.AbsoluteDate;
23  import org.orekit.time.FieldAbsoluteDate;
24  
25  /** Constant provider for {@link AzimuthalGradientCoefficients} and {@link FieldAzimuthalGradientCoefficients}.
26   * @since 12.1
27   * @author Luc Maisonobe
28   */
29  public class ConstantAzimuthalGradientProvider implements AzimuthalGradientProvider {
30  
31      /** Constant parameters. */
32      private final AzimuthalGradientCoefficients a;
33  
34      /** Simple constructor.
35       * @param a constant parameters (may be null if no gradients are available)
36       */
37      public ConstantAzimuthalGradientProvider(final AzimuthalGradientCoefficients a) {
38          this.a = a;
39      }
40  
41      /** {@inheritDoc} */
42      @Override
43      public AzimuthalGradientCoefficients getGradientCoefficients(final GeodeticPoint location,
44                                                                   final AbsoluteDate date) {
45          return a;
46      }
47  
48      /** {@inheritDoc} */
49      @Override
50      public <T extends CalculusFieldElement<T>> FieldAzimuthalGradientCoefficients<T> getGradientCoefficients(final FieldGeodeticPoint<T> location,
51                                                                                                               final FieldAbsoluteDate<T> date) {
52          final T zero = date.getField().getZero();
53          return a == null ?
54                      null :
55                      new FieldAzimuthalGradientCoefficients<>(zero.newInstance(a.getGnh()),
56                                                               zero.newInstance(a.getGeh()),
57                                                               zero.newInstance(a.getGnw()),
58                                                               zero.newInstance(a.getGew()));
59      }
60  
61  }