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.gnss.metric.messages.common;
18
19 import org.hipparchus.util.FastMath;
20
21 /** User Range Accuracy.
22 * @see "IS-GPS-200K, 4 March 2016, Section 20.3.3.3.1.3"
23 * @author Luc Maisonobe
24 * @author Bryan Cazabonne
25 * @since 11.0
26 */
27 public class UserRangeAccuracy implements AccuracyProvider {
28
29 /** User Range Accuracy indicator. */
30 private final int uraIndex;
31
32 /**
33 * Simple constructor.
34 * @param index integer value of the user range accuracy
35 */
36 public UserRangeAccuracy(final int index) {
37 this.uraIndex = index;
38 }
39
40 /** {@inheritDoc} */
41 @Override
42 public double getAccuracy() {
43 // Cast index to a double value
44 final double id = (double) uraIndex;
45 // Compute accuracy
46 if (uraIndex < 7) {
47 if (uraIndex == 1) {
48 return 2.8;
49 } else if (uraIndex == 3) {
50 return 5.7;
51 } else if (uraIndex == 5) {
52 return 11.3;
53 } else {
54 return FastMath.pow(2.0, 0.5 * id + 1.0);
55 }
56 } else if (uraIndex < 15) {
57 return FastMath.pow(2.0, id - 2.0);
58 } else {
59 // Data shall not be used
60 return 8192.0;
61 }
62 }
63
64 }