KlobucharIonoCoefficientsLoader.java
/* Copyright 2002-2024 CS GROUP
* Licensed to CS GROUP (CS) under one or more
* 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,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
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*/
package org.orekit.models.earth.ionosphere;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.text.ParseException;
import java.util.regex.Pattern;
import org.orekit.annotation.DefaultDataContext;
import org.orekit.data.AbstractSelfFeedingLoader;
import org.orekit.data.DataContext;
import org.orekit.data.DataLoader;
import org.orekit.data.DataProvidersManager;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
import org.orekit.time.DateComponents;
/** Loads Klobuchar-Style ionospheric coefficients a given input stream.
* A stream contains the alphas and betas coefficient for a given day.
* <p>
* They are obtained from <a href="ftp://ftp.aiub.unibe.ch/CODE/">University of Bern Astronomical Institute ftp</a>.
* Find more on the files at the <a href="http://www.aiub.unibe.ch/research/code___analysis_center/klobuchar_style_ionospheric_coefficients/index_eng.html">Astronomical Institute site</a>.
* <p>
* The files are UNIX-style compressed (.Z) files.
* They have to be extracted to UTF-8 text files before being read by this loader.
* <p>
* After extraction, it is assumed they are named CGIMDDD0.YYN where DDD and YY substitute day of year and 2-digits year.
* <p>
* The format is always the same, with and example shown below. Only the last 2 lines contains the Klobuchar coefficients.
* <p>
* Example:
* </p>
* <pre>
* 2 NAVIGATION DATA GPS RINEX VERSION / TYPE
* INXFIT V5.3 AIUB 06-JAN-17 09:12 PGM / RUN BY / DATE
* CODE'S KLOBUCHAR-STYLE IONOSPHERE MODEL FOR DAY 001, 2017 COMMENT
* Contact address: code(at)aiub.unibe.ch COMMENT
* Data archive: ftp.unibe.ch/aiub/CODE/ COMMENT
* www.aiub.unibe.ch/download/CODE/ COMMENT
* WARNING: USE DATA AT SOUTHERN POLAR REGION WITH CARE COMMENT
* 1.2821D-08 -9.6222D-09 -3.5982D-07 -6.0901D-07 ION ALPHA
* 1.0840D+05 -1.3197D+05 -2.6331D+05 4.0570D+05 ION BETA
* END OF HEADER
* </pre>
*
* <p>It is not safe for multiple threads to share a single instance of this class.
*
* @author Maxime Journot
*/
public class KlobucharIonoCoefficientsLoader extends AbstractSelfFeedingLoader
implements DataLoader {
/** Default supported files name pattern. */
public static final String DEFAULT_SUPPORTED_NAMES = "CGIM*0\\.*N$";
/** Pattern for delimiting regular expressions. */
private static final Pattern SEPARATOR = Pattern.compile("\\s+");
/** The alpha coefficients loaded. */
private double[] alpha;
/** The beta coefficients loaded. */
private double[] beta;
/**
* Constructor with supported names given by user. This constructor uses the {@link
* DataContext#getDefault() default data context}.
*
* @param supportedNames regular expression that matches the names of the RINEX files
* with Klobuchar coefficients.
* @see #KlobucharIonoCoefficientsLoader(String, DataProvidersManager)
*/
@DefaultDataContext
public KlobucharIonoCoefficientsLoader(final String supportedNames) {
this(supportedNames, DataContext.getDefault().getDataProvidersManager());
}
/**
* Constructor that uses user defined supported names and data context.
*
* @param supportedNames regular expression that matches the names of the RINEX
* files with Klobuchar coefficients.
* @param dataProvidersManager provides access to auxiliary data files.
*/
public KlobucharIonoCoefficientsLoader(final String supportedNames,
final DataProvidersManager dataProvidersManager) {
super(supportedNames, dataProvidersManager);
this.alpha = null;
this.beta = null;
}
/**
* Constructor with default supported names. This constructor uses the {@link
* DataContext#getDefault() default data context}.
*
* @see #KlobucharIonoCoefficientsLoader(String, DataProvidersManager)
* @see #KlobucharIonoCoefficientsLoader(String)
*/
@DefaultDataContext
public KlobucharIonoCoefficientsLoader() {
this(DEFAULT_SUPPORTED_NAMES);
}
/** Returns the alpha coefficients array.
* @return the alpha coefficients array
*/
public double[] getAlpha() {
return alpha.clone();
}
/** Returns the beta coefficients array.
* @return the beta coefficients array
*/
public double[] getBeta() {
return beta.clone();
}
@Override
public String getSupportedNames() {
return super.getSupportedNames();
}
/** Load the data using supported names .
*/
public void loadKlobucharIonosphericCoefficients() {
feed(this);
// Throw an exception if alphas or betas were not loaded properly
if (alpha == null || beta == null) {
throw new OrekitException(OrekitMessages.KLOBUCHAR_ALPHA_BETA_NOT_LOADED,
getSupportedNames());
}
}
/** Load the data for a given day.
* @param dateComponents day given but its DateComponents
*/
public void loadKlobucharIonosphericCoefficients(final DateComponents dateComponents) {
// The files are named CGIMDDD0.YYN where DDD and YY substitute day of year and 2-digits year
final int doy = dateComponents.getDayOfYear();
final String yearString = String.valueOf(dateComponents.getYear());
this.setSupportedNames(String.format("CGIM%03d0.%2sN", doy, yearString.substring(yearString.length() - 2)));
try {
this.loadKlobucharIonosphericCoefficients();
} catch (OrekitException oe) {
throw new OrekitException(oe,
OrekitMessages.KLOBUCHAR_ALPHA_BETA_NOT_AVAILABLE_FOR_DATE,
dateComponents.toString());
}
}
/** {@inheritDoc} */
public boolean stillAcceptsData() {
return true;
}
/** Load Klobuchar-Style ionospheric coefficients read from some file.
* @param input data input stream
* @param name name of the file (or zip entry)
* @exception IOException if data can't be read
* @exception ParseException if data can't be parsed
*/
public void loadData(final InputStream input, final String name)
throws IOException, ParseException {
int lineNumber = 0;
String line = null;
// Open stream and parse data
try (BufferedReader br = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
for (line = br.readLine(); line != null; line = br.readLine()) {
++lineNumber;
line = line.trim();
// Read alphas
if (line.length() > 0 && line.endsWith("ALPHA")) {
final String[] alpha_line = SEPARATOR.split(line);
alpha = new double[4];
for (int j = 0; j < 4; j++) {
alpha[j] = Double.parseDouble(alpha_line[j].replace("D", "E"));
}
}
// Read betas
if (line.length() > 0 && line.endsWith("BETA")) {
final String[] beta_line = SEPARATOR.split(line);
beta = new double[4];
for (int j = 0; j < 4; j++) {
beta[j] = Double.parseDouble(beta_line[j].replace("D", "E"));
}
}
}
} catch (NumberFormatException nfe) {
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, line);
}
// Check that alphas and betas were found
if (alpha == null || beta == null) {
throw new OrekitException(OrekitMessages.NO_KLOBUCHAR_ALPHA_BETA_IN_FILE, name);
}
}
}