AntexLoader.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
* limitations under the License.
*/
package org.orekit.gnss.antenna;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Optional;
import java.util.regex.Pattern;
import org.hipparchus.exception.DummyLocalizable;
import org.hipparchus.geometry.euclidean.threed.Vector3D;
import org.hipparchus.util.FastMath;
import org.orekit.annotation.DefaultDataContext;
import org.orekit.data.DataContext;
import org.orekit.data.DataLoader;
import org.orekit.data.DataProvidersManager;
import org.orekit.data.DataSource;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitIllegalArgumentException;
import org.orekit.errors.OrekitMessages;
import org.orekit.gnss.PredefinedGnssSignal;
import org.orekit.gnss.RadioWave;
import org.orekit.gnss.SatInSystem;
import org.orekit.gnss.SatelliteSystem;
import org.orekit.time.AbsoluteDate;
import org.orekit.time.TimeScale;
import org.orekit.utils.TimeSpanMap;
/**
* Factory for GNSS antennas (both receiver and satellite).
* <p>
* The factory creates antennas by parsing an
* <a href="ftp://www.igs.org/pub/station/general/antex14.txt">ANTEX</a> file.
* </p>
*
* @author Luc Maisonobe
* @since 9.2
*/
public class AntexLoader {
/** Default supported files name pattern for antex files. */
public static final String DEFAULT_ANTEX_SUPPORTED_NAMES = "^\\w{5}(?:_\\d{4})?\\.atx$";
/** Pattern for delimiting regular expressions. */
private static final Pattern SEPARATOR = Pattern.compile("\\s+");
/** Satellites antennas. */
private final List<TimeSpanMap<SatelliteAntenna>> satellitesAntennas;
/** Receivers antennas. */
private final List<ReceiverAntenna> receiversAntennas;
/** GPS time scale. */
private final TimeScale gps;
/** Simple constructor. This constructor uses the {@link DataContext#getDefault()
* default data context}.
*
* @param supportedNames regular expression for supported files names
* @see #AntexLoader(String, DataProvidersManager, TimeScale)
*/
@DefaultDataContext
public AntexLoader(final String supportedNames) {
this(supportedNames, DataContext.getDefault().getDataProvidersManager(),
DataContext.getDefault().getTimeScales().getGPS());
}
/**
* Construct a loader by specifying a {@link DataProvidersManager}.
*
* @param supportedNames regular expression for supported files names
* @param dataProvidersManager provides access to auxiliary data.
* @param gps the GPS time scale to use when loading the ANTEX files.
* @since 10.1
*/
public AntexLoader(final String supportedNames,
final DataProvidersManager dataProvidersManager,
final TimeScale gps) {
this.gps = gps;
satellitesAntennas = new ArrayList<>();
receiversAntennas = new ArrayList<>();
dataProvidersManager.feed(supportedNames, new Parser());
}
/**
* Construct a loader by specifying the source of ANTEX auxiliary data files.
*
* @param source source for the ANTEX data
* @param gps the GPS time scale to use when loading the ANTEX files.
* @since 12.0
*/
public AntexLoader(final DataSource source, final TimeScale gps) {
try {
this.gps = gps;
satellitesAntennas = new ArrayList<>();
receiversAntennas = new ArrayList<>();
try (InputStream is = source.getOpener().openStreamOnce();
BufferedInputStream bis = new BufferedInputStream(is)) {
new Parser().loadData(bis, source.getName());
}
} catch (IOException ioe) {
throw new OrekitException(ioe, new DummyLocalizable(ioe.getMessage()));
}
}
/** Add a satellite antenna.
* @param antenna satellite antenna to add
*/
private void addSatelliteAntenna(final SatelliteAntenna antenna) {
try {
final TimeSpanMap<SatelliteAntenna> existing = findSatelliteAntenna(antenna.getSatInSystem());
// this is an update for a satellite antenna, with new time span
existing.addValidAfter(antenna, antenna.getValidFrom(), false);
} catch (OrekitException oe) {
// this is a new satellite antenna
satellitesAntennas.add(new TimeSpanMap<>(antenna));
}
}
/** Get parsed satellites antennas.
* @return unmodifiable view of parsed satellites antennas
*/
public List<TimeSpanMap<SatelliteAntenna>> getSatellitesAntennas() {
return Collections.unmodifiableList(satellitesAntennas);
}
/** Find the time map for a specific satellite antenna.
* @param satInSystem satellite in system
* @return time map for the antenna
*/
public TimeSpanMap<SatelliteAntenna> findSatelliteAntenna(final SatInSystem satInSystem) {
final Optional<TimeSpanMap<SatelliteAntenna>> existing =
satellitesAntennas.
stream().
filter(m -> m.getFirstSpan().getData().getSatInSystem().equals(satInSystem)).
findFirst();
if (existing.isPresent()) {
return existing.get();
} else {
throw new OrekitException(OrekitMessages.CANNOT_FIND_SATELLITE_IN_SYSTEM,
satInSystem.getPRN(), satInSystem.getSystem());
}
}
/** Add a receiver antenna.
* @param antenna receiver antenna to add
*/
private void addReceiverAntenna(final ReceiverAntenna antenna) {
receiversAntennas.add(antenna);
}
/** Get parsed receivers antennas.
* @return unmodifiable view of parsed receivers antennas
*/
public List<ReceiverAntenna> getReceiversAntennas() {
return Collections.unmodifiableList(receiversAntennas);
}
/** Parser for antex files.
* @see <a href="ftp://www.igs.org/pub/station/general/antex14.txt">ANTEX: The Antenna Exchange Format, Version 1.4</a>
*/
private class Parser implements DataLoader {
/** Index of label in data lines. */
private static final int LABEL_START = 60;
/** Supported format version. */
private static final double FORMAT_VERSION = 1.4;
/** Phase center eccentricities conversion factor. */
private static final double MM_TO_M = 0.001;
/** {@inheritDoc} */
@Override
public boolean stillAcceptsData() {
// we load all antex files we can find
return true;
}
/** {@inheritDoc} */
@Override
public void loadData(final InputStream input, final String name)
throws IOException, OrekitException {
int lineNumber = 0;
try (BufferedReader reader = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
// placeholders for parsed data
SatInSystem satInSystem = null;
String antennaType = null;
SatelliteType satelliteType = null;
String serialNumber = null;
int satelliteCode = -1;
String cosparID = null;
AbsoluteDate validFrom = AbsoluteDate.PAST_INFINITY;
AbsoluteDate validUntil = AbsoluteDate.FUTURE_INFINITY;
String sinexCode = null;
double azimuthStep = Double.NaN;
double polarStart = Double.NaN;
double polarStop = Double.NaN;
double polarStep = Double.NaN;
double[] grid1D = null;
double[][] grid2D = null;
Vector3D eccentricities = Vector3D.ZERO;
int nbFrequencies = -1;
PredefinedGnssSignal predefinedGnssSignal = null;
Map<RadioWave, FrequencyPattern> patterns = null;
boolean inFrequency = false;
boolean inRMS = false;
for (String line = reader.readLine(); line != null; line = reader.readLine()) {
++lineNumber;
switch (line.substring(LABEL_START).trim()) {
case "COMMENT" :
// nothing to do
break;
case "ANTEX VERSION / SYST" :
if (FastMath.abs(parseDouble(line, 0, 8) - FORMAT_VERSION) > 0.001) {
throw new OrekitException(OrekitMessages.UNSUPPORTED_FILE_FORMAT, name);
}
// we parse the general setting for satellite system to check for format errors,
// but otherwise ignore it
SatelliteSystem.parseSatelliteSystem(parseString(line, 20, 1));
break;
case "PCV TYPE / REFANT" :
// TODO
break;
case "END OF HEADER" :
// nothing to do
break;
case "START OF ANTENNA" :
// reset antenna data
satInSystem = null;
antennaType = null;
satelliteType = null;
serialNumber = null;
satelliteCode = -1;
cosparID = null;
validFrom = AbsoluteDate.PAST_INFINITY;
validUntil = AbsoluteDate.FUTURE_INFINITY;
sinexCode = null;
azimuthStep = Double.NaN;
polarStart = Double.NaN;
polarStop = Double.NaN;
polarStep = Double.NaN;
grid1D = null;
grid2D = null;
eccentricities = Vector3D.ZERO;
predefinedGnssSignal = null;
patterns = null;
inFrequency = false;
inRMS = false;
break;
case "TYPE / SERIAL NO" :
antennaType = parseString(line, 0, 20);
try {
satelliteType = SatelliteType.parseSatelliteType(antennaType);
final String satField = parseString(line, 20, 20);
if (!satField.isEmpty()) {
satInSystem = new SatInSystem(satField);
if (satInSystem.getSystem() == SatelliteSystem.MIXED) {
// MIXED satellite system is not allowed here
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, line);
}
satelliteCode = parseInt(line, 41, 9); // we drop the system type
cosparID = parseString(line, 50, 10);
}
} catch (OrekitIllegalArgumentException oiae) {
// this is a receiver antenna, not a satellite antenna
serialNumber = parseString(line, 20, 20);
}
break;
case "METH / BY / # / DATE" :
// ignoreds
break;
case "DAZI" :
azimuthStep = FastMath.toRadians(parseDouble(line, 2, 6));
break;
case "ZEN1 / ZEN2 / DZEN" :
polarStart = FastMath.toRadians(parseDouble(line, 2, 6));
polarStop = FastMath.toRadians(parseDouble(line, 8, 6));
polarStep = FastMath.toRadians(parseDouble(line, 14, 6));
break;
case "# OF FREQUENCIES" :
nbFrequencies = parseInt(line, 0, 6);
patterns = new HashMap<>(nbFrequencies);
break;
case "VALID FROM" :
validFrom = new AbsoluteDate(parseInt(line, 0, 6),
parseInt(line, 6, 6),
parseInt(line, 12, 6),
parseInt(line, 18, 6),
parseInt(line, 24, 6),
parseDouble(line, 30, 13),
gps);
break;
case "VALID UNTIL" :
validUntil = new AbsoluteDate(parseInt(line, 0, 6),
parseInt(line, 6, 6),
parseInt(line, 12, 6),
parseInt(line, 18, 6),
parseInt(line, 24, 6),
parseDouble(line, 30, 13),
gps);
break;
case "SINEX CODE" :
sinexCode = parseString(line, 0, 10);
break;
case "START OF FREQUENCY" :
try {
predefinedGnssSignal = PredefinedGnssSignal.valueOf(parseString(line, 3, 3));
grid1D = new double[1 + (int) FastMath.round((polarStop - polarStart) / polarStep)];
if (azimuthStep > 0.001) {
grid2D = new double[1 + (int) FastMath.round(2 * FastMath.PI / azimuthStep)][grid1D.length];
}
} catch (IllegalArgumentException iae) {
throw new OrekitException(iae, OrekitMessages.UNKNOWN_RINEX_FREQUENCY,
parseString(line, 3, 3), name, lineNumber);
}
inFrequency = true;
break;
case "NORTH / EAST / UP" :
if (!inRMS) {
eccentricities = new Vector3D(parseDouble(line, 0, 10) * MM_TO_M,
parseDouble(line, 10, 10) * MM_TO_M,
parseDouble(line, 20, 10) * MM_TO_M);
}
break;
case "END OF FREQUENCY" : {
final String endFrequency = parseString(line, 3, 3);
if (predefinedGnssSignal == null || !predefinedGnssSignal.toString().equals(endFrequency)) {
throw new OrekitException(OrekitMessages.MISMATCHED_FREQUENCIES,
name, lineNumber, predefinedGnssSignal, endFrequency);
}
// Check if the number of frequencies has been parsed
if (patterns == null) {
// null object, an OrekitException is thrown
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, line);
}
final PhaseCenterVariationFunction phaseCenterVariation;
if (grid2D == null) {
double max = 0;
for (final double v : grid1D) {
max = FastMath.max(max, FastMath.abs(v));
}
if (max == 0.0) {
// there are no known variations for this pattern
phaseCenterVariation = (polarAngle, azimuthAngle) -> 0.0;
} else {
phaseCenterVariation = new OneDVariation(polarStart, polarStep, grid1D);
}
} else {
phaseCenterVariation = new TwoDVariation(polarStart, polarStep, azimuthStep, grid2D);
}
patterns.put(predefinedGnssSignal, new FrequencyPattern(eccentricities, phaseCenterVariation));
predefinedGnssSignal = null;
grid1D = null;
grid2D = null;
inFrequency = false;
break;
}
case "START OF FREQ RMS" :
inRMS = true;
break;
case "END OF FREQ RMS" :
inRMS = false;
break;
case "END OF ANTENNA" :
if (satelliteType == null) {
addReceiverAntenna(new ReceiverAntenna(antennaType, sinexCode, patterns, serialNumber));
} else {
addSatelliteAntenna(new SatelliteAntenna(antennaType, sinexCode, patterns,
satInSystem, satelliteType, satelliteCode,
cosparID, validFrom, validUntil));
}
break;
default :
if (inFrequency) {
final String[] fields = SEPARATOR.split(line.trim());
if (fields.length != grid1D.length + 1) {
throw new OrekitException(OrekitMessages.WRONG_COLUMNS_NUMBER,
name, lineNumber, grid1D.length + 1, fields.length);
}
if ("NOAZI".equals(fields[0])) {
// azimuth-independent phase
for (int i = 0; i < grid1D.length; ++i) {
grid1D[i] = Double.parseDouble(fields[i + 1]) * MM_TO_M;
}
} else {
// azimuth-dependent phase
// azimuth is counted from Y/North to X/East in Antex files
// we will interpolate using phase angle in right-handed frame,
// so we have to change azimuth to 90-α and renormalize to have
// a 0° to 360° range with same values at both ends, closing the circle
final double antexAziDeg = Double.parseDouble(fields[0]);
final double normalizedAziDeg = (antexAziDeg <= 90.0 ? 90.0 : 450.0) - antexAziDeg;
final int k = (int) FastMath.round(FastMath.toRadians(normalizedAziDeg) / azimuthStep);
for (int i = 0; i < grid2D[k].length; ++i) {
grid2D[k][i] = Double.parseDouble(fields[i + 1]) * MM_TO_M;
}
if (k == 0) {
// copy X/East azimuth values to close the circle
System.arraycopy(grid2D[0], 0, grid2D[grid2D.length - 1], 0, grid2D[0].length);
}
}
} else if (inRMS) {
// RMS section is ignored (furthermore there are no RMS sections in both igs08.atx and igs14.atx)
} else {
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, line);
}
}
}
} catch (NumberFormatException nfe) {
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, "tot");
}
}
/** Extract a string from a line.
* @param line to parse
* @param start start index of the string
* @param length length of the string
* @return parsed string
*/
private String parseString(final String line, final int start, final int length) {
return line.substring(start, FastMath.min(line.length(), start + length)).trim();
}
/** Extract an integer from a line.
* @param line to parse
* @param start start index of the integer
* @param length length of the integer
* @return parsed integer
*/
private int parseInt(final String line, final int start, final int length) {
return Integer.parseInt(parseString(line, start, length));
}
/** Extract a double from a line.
* @param line to parse
* @param start start index of the real
* @param length length of the real
* @return parsed real
*/
private double parseDouble(final String line, final int start, final int length) {
return Double.parseDouble(parseString(line, start, length));
}
}
}