SignalInSpaceAccuracy.java
/* Copyright 2002-2024 CS GROUP
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* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
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package org.orekit.gnss.metric.messages.common;
/** Signal-In-Space Accuracy (SISA).
* @see "Galileo OS Signal-In-Space Interface Control Document, Issue 1.3, December 2016, Table 76"
* @author Bryan Cazabonne
* @since 11.0
*/
public class SignalInSpaceAccuracy implements AccuracyProvider {
/** Signal In Space Accuracy indicator. */
private final int sisaIndex;
/**
* Simple constructor.
* @param index integer value of the signal in space accuracy
*/
public SignalInSpaceAccuracy(final int index) {
this.sisaIndex = index;
}
/** {@inheritDoc} */
@Override
public double getAccuracy() {
// Cast index to a double value
final double id = (double) sisaIndex;
// Compute accuracy
if (sisaIndex < 50) {
// Accuracy is between 0 cm and 49 cm with 1 cm resolution
return 0.01 * id;
} else if (sisaIndex < 75) {
// Accuracy is between 50 cm and 98 cm with 2 cm resolution
return 0.01 * (50.0 + 2.0 * (id - 50.0));
} else if (sisaIndex < 100) {
// Accuracy is between 1 m and 2 m with 4 cm resolution
return 1.0 + 0.04 * (id - 75.0);
} else if (sisaIndex < 126) {
// Accuracy is between 2 m and 6 m with 16 cm resolution
return 2.0 + 0.16 * (id - 100.0);
} else {
// Spare or No Accuracy Predicition Available (NAPA)
return -1.0;
}
}
}