1   /* Copyright 2002-2025 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.propagation.analytical.gnss;
18  
19  import org.orekit.annotation.DefaultDataContext;
20  import org.orekit.attitudes.AttitudeProvider;
21  import org.orekit.attitudes.FrameAlignedProvider;
22  import org.orekit.data.DataContext;
23  import org.orekit.frames.Frame;
24  import org.orekit.frames.Frames;
25  import org.orekit.propagation.Propagator;
26  import org.orekit.propagation.analytical.gnss.data.GNSSConstants;
27  import org.orekit.propagation.analytical.gnss.data.SBASOrbitalElements;
28  import org.orekit.utils.IERSConventions;
29  
30  /**
31   * This nested class aims at building a SBASPropagator.
32   * <p>It implements the classical builder pattern.</p>
33   * @since 11.0
34   * @author Bryan Cazabonne
35   */
36  public class SBASPropagatorBuilder {
37  
38      /** The SBAS orbital elements. */
39      private final SBASOrbitalElements orbit;
40  
41      /** The Earth gravity coefficient used for SBAS propagation. */
42      private double mu;
43  
44      /** The attitude provider. */
45      private AttitudeProvider attitudeProvider;
46  
47      /** The mass. */
48      private double mass;
49  
50      /** The ECI frame. */
51      private Frame eci;
52  
53      /** The ECEF frame. */
54      private Frame ecef;
55  
56      /** Initializes the builder.
57       * <p>The SBAS orbital elements is the only requested parameter to build a SBASPropagator.</p>
58       * <p>The attitude provider is set by default be aligned with the EME2000 frame.<br>
59       * The Earth gravity coefficient is set by default to the
60       *  {@link org.orekit.propagation.analytical.gnss.data.GNSSConstants#SBAS_MU SBAS_MU}.<br>
61       * The mass is set by default to the
62       *  {@link org.orekit.propagation.Propagator#DEFAULT_MASS DEFAULT_MASS}.<br>
63       * The ECI frame is set by default to the
64       *  {@link org.orekit.frames.Predefined#EME2000 EME2000 frame}.<br>
65       * The ECEF frame is set by default to the
66       *  {@link org.orekit.frames.Predefined#ITRF_CIO_CONV_2010_SIMPLE_EOP CIO/2010-based ITRF simple EOP}.
67       * </p>
68       * <p>This constructor uses the {@link DataContext#getDefault() default data context}.</p>
69       *
70       * @param sbasOrbElt the SBAS orbital elements to be used by the SBAS propagator.
71       * @see #attitudeProvider(AttitudeProvider provider)
72       * @see #mu(double coefficient)
73       * @see #mass(double mass)
74       * @see #eci(Frame inertial)
75       * @see #ecef(Frame bodyFixed)
76       * @since 12.0
77       */
78      @DefaultDataContext
79      public SBASPropagatorBuilder(final SBASOrbitalElements sbasOrbElt) {
80          this(sbasOrbElt, DataContext.getDefault().getFrames());
81      }
82  
83      /** Initializes the builder.
84       * <p>The SBAS orbital elements is the only requested parameter to build a SBASPropagator.</p>
85       * <p>The attitude provider is set by default to be aligned with the EME2000 frame.<br>
86       * The Earth gravity coefficient is set by default to the
87       *  {@link org.orekit.propagation.analytical.gnss.data.GNSSConstants#SBAS_MU SBAS_MU}.<br>
88       * The mass is set by default to the
89       *  {@link org.orekit.propagation.Propagator#DEFAULT_MASS DEFAULT_MASS}.<br>
90       * The ECI frame is set by default to the
91       *  {@link org.orekit.frames.Predefined#EME2000 EME2000 frame}.<br>
92       * The ECEF frame is set by default to the
93       *  {@link org.orekit.frames.Predefined#ITRF_CIO_CONV_2010_SIMPLE_EOP CIO/2010-based ITRF simple EOP}.
94       * </p>
95       *
96       * @param sbasOrbElt the SBAS orbital elements to be used by the SBAS propagator.
97       * @param frames     set of reference frames to use to initialize {@link
98       *                   #ecef(Frame)}, {@link #eci(Frame)}, and {@link
99       *                   #attitudeProvider(AttitudeProvider)}.
100      * @see #attitudeProvider(AttitudeProvider provider)
101      * @see #mu(double coefficient)
102      * @see #mass(double mass)
103      * @see #eci(Frame inertial)
104      * @see #ecef(Frame bodyFixed)
105      */
106     public SBASPropagatorBuilder(final SBASOrbitalElements sbasOrbElt, final Frames frames) {
107         this.orbit            = sbasOrbElt;
108         this.mass             = Propagator.DEFAULT_MASS;
109         this.eci              = frames.getEME2000();
110         this.ecef             = frames.getITRF(IERSConventions.IERS_2010, true);
111         this.mu               = GNSSConstants.SBAS_MU;
112         this.attitudeProvider = new FrameAlignedProvider(eci);
113     }
114 
115     /** Sets the attitude provider.
116      *
117      * @param userProvider the attitude provider
118      * @return the updated builder
119      */
120     public SBASPropagatorBuilder attitudeProvider(final AttitudeProvider userProvider) {
121         this.attitudeProvider = userProvider;
122         return this;
123     }
124 
125     /** Sets the Earth gravity coefficient.
126     *
127     * @param coefficient the Earth gravity coefficient
128     * @return the updated builder
129     */
130     public SBASPropagatorBuilder mu(final double coefficient) {
131         this.mu = coefficient;
132         return this;
133     }
134 
135     /** Sets the mass.
136      *
137      * @param userMass the mass (in kg)
138      * @return the updated builder
139      */
140     public SBASPropagatorBuilder mass(final double userMass) {
141         this.mass = userMass;
142         return this;
143     }
144 
145     /** Sets the Earth Centered Inertial frame used for propagation.
146      *
147      * @param inertial the ECI frame
148      * @return the updated builder
149      */
150     public SBASPropagatorBuilder eci(final Frame inertial) {
151         this.eci = inertial;
152         return this;
153     }
154 
155     /** Sets the Earth Centered Earth Fixed frame assimilated to the WGS84 ECEF.
156      *
157      * @param bodyFixed the ECEF frame
158      * @return the updated builder
159      */
160     public SBASPropagatorBuilder ecef(final Frame bodyFixed) {
161         this.ecef = bodyFixed;
162         return this;
163     }
164 
165     /** Finalizes the build.
166      *
167      * @return the built SBASPropagator
168      */
169     public SBASPropagator build() {
170         return new SBASPropagator(orbit, eci, ecef, attitudeProvider, mass, mu);
171     }
172 
173 }