SP3File.java

  1. /* Copyright 2002-2012 Space Applications Services
  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.files.sp3;

  19. import java.util.ArrayList;
  20. import java.util.Collections;
  21. import java.util.LinkedHashMap;
  22. import java.util.List;
  23. import java.util.Locale;
  24. import java.util.Map;
  25. import java.util.function.Function;

  27. import org.hipparchus.geometry.euclidean.threed.Vector3D;
  28. import org.orekit.files.general.EphemerisFile;
  29. import org.orekit.frames.Frame;
  30. import org.orekit.propagation.BoundedPropagator;
  31. import org.orekit.time.AbsoluteDate;
  32. import org.orekit.time.TimeScale;
  33. import org.orekit.utils.CartesianDerivativesFilter;
  34. import org.orekit.utils.TimeStampedPVCoordinates;

  36. /**
  37.  * Represents a parsed SP3 orbit file.
  38.  * @author Thomas Neidhart
  39.  * @author Evan Ward
  40.  */
  41. public class SP3File implements EphemerisFile {
  42.     /** String representation of the center of ephemeris coordinate system. **/
  43.     public static final String SP3_FRAME_CENTER_STRING = "EARTH";

  45.     /** File type indicator. */
  46.     public enum SP3FileType {
  47.         /** GPS only file. */
  48.         GPS,
  49.         /** Mixed file. */
  50.         MIXED,
  51.         /** GLONASS only file. */
  52.         GLONASS,
  53.         /** LEO only file. */
  54.         LEO,
  55.         /** Galileo only file. */
  56.         GALILEO,
  57.         /** COMPASS only file. */
  58.         COMPASS,
  59.         /** QZSS only file. */
  60.         QZSS,
  61.         /** undefined file format. */
  62.         UNDEFINED
  63.     }

  65.     /** Orbit type indicator. */
  66.     public enum SP3OrbitType {
  67.         /** fitted. */
  68.         FIT,
  69.         /** extrapolated or predicted. */
  70.         EXT,
  71.         /** broadcast. */
  72.         BCT,
  73.         /** fitted after applying a Helmert transformation. */
  74.         HLM,
  75.         /** other type, defined by SP3 file producing agency.
  76.          * @since 9.3
  77.          */
  78.         OTHER;

  80.         /** Parse a string to get the type.
  81.          * @param s string to parse
  82.          * @return the type corresponding to the string
  83.          */
  84.         public static SP3OrbitType parseType(final String s) {
  85.             final String normalizedString = s.trim().toUpperCase(Locale.US);
  86.             if ("EST".equals(normalizedString)) {
  87.                 return FIT;
  88.             } else if ("BHN".equals(normalizedString)) {
  89.                 // ESOC navigation team uses BHN for files produced
  90.                 // by their main parameter estimation program Bahn
  91.                 return FIT;
  92.             } else if ("PRO".equals(normalizedString)) {
  93.                 // ESOC navigation team uses PRO for files produced
  94.                 // by their orbit propagation program Propag
  95.                 return EXT;
  96.             } else {
  97.                 try {
  98.                     return valueOf(normalizedString);
  99.                 } catch (IllegalArgumentException iae) {
  100.                     return OTHER;
  101.                 }
  102.             }
  103.         }

  105.     }

  107.     /** Time system used throughout this SP3 file. */
  108.     public enum TimeSystem {
  109.         /** Global Positioning System. */
  110.         GPS,
  111.         /** GLONASS. */
  112.         GLO,
  113.         /** GALILEO. */
  114.         GAL,
  115.         /** International Atomic Time. */
  116.         TAI,
  117.         /** Coordinated Universal Time. */
  118.         UTC,
  119.         /** Quasi-Zenith System. */
  120.         QZS
  121.     }

  123.     /** File type. */
  124.     private SP3FileType type;

  126.     /** Time system. */
  127.     private TimeSystem timeSystem;

  129.     /** Epoch of the file. */
  130.     private AbsoluteDate epoch;

  132.     /** GPS week. */
  133.     private int gpsWeek;

  135.     /** Seconds of the current GPS week. */
  136.     private double secondsOfWeek;

  138.     /** Julian day. */
  139.     private int julianDay;

  141.     /** Day fraction. */
  142.     private double dayFraction;

  144.     /** Time-interval between epochs. */
  145.     private double epochInterval;

  147.     /** Number of epochs. */
  148.     private int numberOfEpochs;

  150.     /** Coordinate system. */
  151.     private String coordinateSystem;

  153.     /** Data used indicator. */
  154.     private String dataUsed;

  156.     /** Orbit type. */
  157.     private SP3OrbitType orbitType;

  159.     /** Key for orbit type.
  160.      * @since 9.3
  161.      */
  162.     private String orbitTypeKey;

  164.     /** Agency providing the file. */
  165.     private String agency;

  167.     /** Indicates if data contains velocity or not. */
  168.     private CartesianDerivativesFilter filter;

  170.     /** Time scale of dates in the ephemeris file. */
  171.     private TimeScale timeScale;

  173.     /** Time scale, as specified in the file. */
  174.     private String timeScaleString;

  176.     /** Standard gravitational parameter in m^3 / s^2. */
  177.     private final double mu;

  179.     /** Number of samples to use when interpolating. */
  180.     private final int interpolationSamples;

  182.     /** Maps {@link #coordinateSystem} to a {@link Frame}. */
  183.     private final Function<? super String, ? extends Frame> frameBuilder;

  185.     /** A map containing satellite information. */
  186.     private Map<String, SP3Ephemeris> satellites;

  188.     /**
  189.      * Create a new SP3 file object.
  190.      *
  191.      * @param mu                   is the standard gravitational parameter in m^3 / s^2.
  192.      * @param interpolationSamples number of samples to use in interpolation.
  193.      * @param frameBuilder         for constructing a reference frame from the identifier
  194.      */
  195.     SP3File(final double mu,
  196.             final int interpolationSamples,
  197.             final Function<? super String, ? extends Frame> frameBuilder) {
  198.         this.mu = mu;
  199.         this.interpolationSamples = interpolationSamples;
  200.         this.frameBuilder = frameBuilder;
  201.         // must be linked has map to preserve order of satellites in the file.
  202.         satellites = new LinkedHashMap<>();
  203.     }

  205.     /**
  206.      * Set the derivatives filter.
  207.      *
  208.      * @param filter that indicates which derivatives of position are available.
  209.      */
  210.     void setFilter(final CartesianDerivativesFilter filter) {
  211.         this.filter = filter;
  212.     }

  214.     /**
  215.      * Set the time scale.
  216.      *
  217.      * @param timeScale use to parse dates in this file.
  218.      */
  219.     void setTimeScale(final TimeScale timeScale) {
  220.         this.timeScale = timeScale;
  221.     }

  223.     /**
  224.      * Set the string used to define the time scale.
  225.      *
  226.      * @param timeScaleString the time scale identifier used in the file.
  227.      */
  228.     void setTimeScaleString(final String timeScaleString) {
  229.         this.timeScaleString = timeScaleString;
  230.     }

  232.     /** Returns the {@link SP3FileType} associated with this SP3 file.
  233.      * @return the file type for this SP3 file
  234.      */
  235.     public SP3FileType getType() {
  236.         return type;
  237.     }

  239.     /** Set the file type for this SP3 file.
  240.      * @param fileType the file type to be set
  241.      */
  242.     void setType(final SP3FileType fileType) {
  243.         this.type = fileType;
  244.     }

  246.     /** Returns the {@link TimeSystem} used to time-stamp position entries.
  247.      * @return the {@link TimeSystem} of the orbit file
  248.      */
  249.     public TimeSystem getTimeSystem() {
  250.         return timeSystem;
  251.     }

  253.     /** Set the time system used in this SP3 file.
  254.      * @param system the time system to be set
  255.      */
  256.     void setTimeSystem(final TimeSystem system) {
  257.         this.timeSystem = system;
  258.     }

  260.     /** Returns the data used indicator from the SP3 file.
  261.      * @return the data used indicator (unparsed)
  262.      */
  263.     public String getDataUsed() {
  264.         return dataUsed;
  265.     }

  267.     /** Set the data used indicator for this SP3 file.
  268.      * @param data the data used indicator to be set
  269.      */
  270.     void setDataUsed(final String data) {
  271.         this.dataUsed = data;
  272.     }

  274.     /** Returns the start epoch of the orbit file.
  275.      * @return the start epoch
  276.      */
  277.     public AbsoluteDate getEpoch() {
  278.         return epoch;
  279.     }

  281.     /** Set the epoch of the SP3 file.
  282.      * @param time the epoch to be set
  283.      */
  284.     void setEpoch(final AbsoluteDate time) {
  285.         this.epoch = time;
  286.     }

  288.     /** Returns the GPS week as contained in the SP3 file.
  289.      * @return the GPS week of the SP3 file
  290.      */
  291.     public int getGpsWeek() {
  292.         return gpsWeek;
  293.     }

  295.     /** Set the GPS week of the SP3 file.
  296.      * @param week the GPS week to be set
  297.      */
  298.     void setGpsWeek(final int week) {
  299.         this.gpsWeek = week;
  300.     }

  302.     /** Returns the seconds of the GPS week as contained in the SP3 file.
  303.      * @return the seconds of the GPS week
  304.      */
  305.     public double getSecondsOfWeek() {
  306.         return secondsOfWeek;
  307.     }

  309.     /** Set the seconds of the GPS week for this SP3 file.
  310.      * @param seconds the seconds to be set
  311.      */
  312.     void setSecondsOfWeek(final double seconds) {
  313.         this.secondsOfWeek = seconds;
  314.     }

  316.     /** Returns the julian day for this SP3 file.
  317.      * @return the julian day
  318.      */
  319.     public int getJulianDay() {
  320.         return julianDay;
  321.     }

  323.     /** Set the julian day for this SP3 file.
  324.      * @param day the julian day to be set
  325.      */
  326.     void setJulianDay(final int day) {
  327.         this.julianDay = day;
  328.     }

  330.     /** Returns the day fraction for this SP3 file.
  331.      * @return the day fraction
  332.      */
  333.     public double getDayFraction() {
  334.         return dayFraction;
  335.     }

  337.     /** Set the day fraction for this SP3 file.
  338.      * @param fraction the day fraction to be set
  339.      */
  340.     void setDayFraction(final double fraction) {
  341.         this.dayFraction = fraction;
  342.     }

  344.     /** Returns the time interval between epochs (in seconds).
  345.      * @return the time interval between epochs
  346.      */
  347.     public double getEpochInterval() {
  348.         return epochInterval;
  349.     }

  351.     /** Set the epoch interval for this SP3 file.
  352.      * @param interval the interval between orbit entries
  353.      */
  354.     void setEpochInterval(final double interval) {
  355.         this.epochInterval = interval;
  356.     }

  358.     /** Returns the number of epochs contained in this orbit file.
  359.      * @return the number of epochs
  360.      */
  361.     public int getNumberOfEpochs() {
  362.         return numberOfEpochs;
  363.     }

  365.     /** Set the number of epochs as contained in the SP3 file.
  366.      * @param epochCount the number of epochs to be set
  367.      */
  368.     void setNumberOfEpochs(final int epochCount) {
  369.         this.numberOfEpochs = epochCount;
  370.     }

  372.     /** Returns the coordinate system of the entries in this orbit file.
  373.      * @return the coordinate system
  374.      */
  375.     public String getCoordinateSystem() {
  376.         return coordinateSystem;
  377.     }

  379.     /** Set the coordinate system used for the orbit entries.
  380.      * @param system the coordinate system to be set
  381.      */
  382.     void setCoordinateSystem(final String system) {
  383.         this.coordinateSystem = system;
  384.     }

  386.     /** Returns the {@link SP3OrbitType} for this SP3 file.
  387.      * @return the orbit type
  388.      */
  389.     public SP3OrbitType getOrbitType() {
  390.         return orbitType;
  391.     }

  393.     /** Returns the orbit type key for this SP3 file.
  394.      * @return the orbit type key
  395.      * @since 9.3
  396.      */
  397.     public String getOrbitTypeKey() {
  398.         return orbitTypeKey;
  399.     }

  401.     /** Set the orbit type key for this SP3 file.
  402.      * @param oTypeKey the orbit type key to be set
  403.      * @since 9.3
  404.      */
  405.     void setOrbitTypeKey(final String oTypeKey) {
  406.         this.orbitTypeKey = oTypeKey;
  407.         this.orbitType    = SP3OrbitType.parseType(oTypeKey);
  408.     }

  410.     /** Returns the agency that prepared this SP3 file.
  411.      * @return the agency
  412.      */
  413.     public String getAgency() {
  414.         return agency;
  415.     }

  417.     /** Set the agency string for this SP3 file.
  418.      * @param agencyStr the agency string to be set
  419.      */
  420.     void setAgency(final String agencyStr) {
  421.         this.agency = agencyStr;
  422.     }

  424.     /** Add a new satellite with a given identifier to the list of
  425.      * stored satellites.
  426.      * @param satId the satellite identifier
  427.      */
  428.     public void addSatellite(final String satId) {
  429.         // only add satellites which have not been added before
  430.         satellites.putIfAbsent(satId, new SP3Ephemeris(satId));
  431.     }

  433.     @Override
  434.     public Map<String, SP3Ephemeris> getSatellites() {
  435.         return Collections.unmodifiableMap(satellites);
  436.     }

  438.     /** Get the number of satellites contained in this orbit file.
  439.      * @return the number of satellites
  440.      */
  441.     public int getSatelliteCount() {
  442.         return satellites.size();
  443.     }

  445.     /**
  446.      * Set the formal accuracy for a satellite.
  447.      *
  448.      * @param index    is the index of the satellite.
  449.      * @param accuracy of the satellite, in m.
  450.      */
  451.     void setAccuracy(final int index, final double accuracy) {
  452.         int n = index;
  453.         for (final SP3Ephemeris ephemeris : satellites.values()) {
  454.             if (n == 0) {
  455.                 ephemeris.setAccuracy(accuracy);
  456.                 return;
  457.             }
  458.             n--;
  459.         }
  460.     }

  462.     /**
  463.      * Get the formal accuracy for a satellite.
  464.      *
  465.      * @param index    is the index of the satellite.
  466.      * @return accuracy of the satellite, in m.
  467.      */
  468.     double getAccuracy(final int index) {
  469.         int n = index;
  470.         for (final SP3Ephemeris ephemeris : satellites.values()) {
  471.             if (n == 0) {
  472.                 return ephemeris.getAccuracy();
  473.             }
  474.             n--;
  475.         }
  476.         return Double.NaN;
  477.     }

  479.     /** Tests whether a satellite with the given id is contained in this orbit
  480.      * file.
  481.      * @param satId the satellite id
  482.      * @return {@code true} if the satellite is contained in the file,
  483.      *         {@code false} otherwise
  484.      */
  485.     public boolean containsSatellite(final String satId) {
  486.         return satellites.containsKey(satId);
  487.     }

  489.     /**
  490.      * Adds a new P/V coordinate for a given satellite.
  491.      *
  492.      * @param satId the satellite identifier
  493.      * @param coord the P/V coordinate of the satellite
  494.      */
  495.     void addSatelliteCoordinate(final String satId, final SP3Coordinate coord) {
  496.         satellites.get(satId).coordinates.add(coord);
  497.     }

  499.     /** An ephemeris for a single satellite in a SP3 file. */
  500.     public class SP3Ephemeris implements SatelliteEphemeris, EphemerisSegment {

  502.         /** Satellite ID. */
  503.         private final String id;
  504.         /** Ephemeris Data. */
  505.         private final List<SP3Coordinate> coordinates;
  506.         /** Accuracy in m. */
  507.         private double accuracy;

  509.         /**
  510.          * Create an ephemeris for a single satellite.
  511.          *
  512.          * @param id of the satellite.
  513.          */
  514.         SP3Ephemeris(final String id) {
  515.             this.id = id;
  516.             this.coordinates = new ArrayList<>();
  517.         }

  519.         @Override
  520.         public String getId() {
  521.             return this.id;
  522.         }

  524.         @Override
  525.         public double getMu() {
  526.             return mu;
  527.         }

  529.         @Override
  530.         public String getFrameCenterString() {
  531.             return SP3_FRAME_CENTER_STRING;
  532.         }

  534.         @Override
  535.         public String getFrameString() {
  536.             return getCoordinateSystem();
  537.         }

  539.         @Override
  540.         public Frame getFrame() {
  541.             return frameBuilder.apply(getFrameString());
  542.         }

  544.         @Override
  545.         public String getTimeScaleString() {
  546.             return timeScaleString;
  547.         }

  549.         @Override
  550.         public TimeScale getTimeScale() {
  551.             return timeScale;
  552.         }

  554.         @Override
  555.         public int getInterpolationSamples() {
  556.             return interpolationSamples;
  557.         }

  559.         @Override
  560.         public CartesianDerivativesFilter getAvailableDerivatives() {
  561.             return filter;
  562.         }

  564.         @Override
  565.         public List<SP3Coordinate> getCoordinates() {
  566.             return Collections.unmodifiableList(this.coordinates);
  567.         }

  569.         /** Returns a list containing only {@code this}. */
  570.         @Override
  571.         public List<SP3Ephemeris> getSegments() {
  572.             return Collections.singletonList(this);
  573.         }

  575.         @Override
  576.         public AbsoluteDate getStart() {
  577.             return coordinates.get(0).getDate();
  578.         }

  580.         @Override
  581.         public AbsoluteDate getStop() {
  582.             return coordinates.get(coordinates.size() - 1).getDate();
  583.         }

  585.         @Override
  586.         public BoundedPropagator getPropagator() {
  587.             return EphemerisSegment.super.getPropagator();
  588.         }

  590.         /**
  591.          * Set the accuracy for this satellite.
  592.          *
  593.          * @param accuracy in m.
  594.          */
  595.         void setAccuracy(final double accuracy) {
  596.             this.accuracy = accuracy;
  597.         }

  599.         /**
  600.          * Get the formal accuracy for this satellite.
  601.          *
  602.          * <p>The accuracy is limited by the SP3 standard to be a power of 2 in mm.
  603.          * The value returned here is in meters.</p>
  604.          *
  605.          * @return magnitude of one standard deviation, in m.
  606.          */
  607.         public double getAccuracy() {
  608.             return accuracy;
  609.         }

  611.     }

  613.     /** A single record of position clock and possibly derivatives in an SP3 file. */
  614.     public static class SP3Coordinate extends TimeStampedPVCoordinates {

  616.         /** Serializable UID. */
  617.         private static final long serialVersionUID = 20161116L;
  618.         /** Clock correction in s. */
  619.         private final double clock;
  620.         /** Clock rate in s / s. */
  621.         private final double clockRate;

  623.         /**
  624.          * Create a coordinate with only position.
  625.          *
  626.          * @param date     of validity.
  627.          * @param position of the satellite.
  628.          * @param clock    correction in s.
  629.          */
  630.         SP3Coordinate(final AbsoluteDate date,
  631.                       final Vector3D position,
  632.                       final double clock) {
  633.             this(date, position, Vector3D.ZERO, clock, 0);
  634.         }

  636.         /**
  637.          * Create a coordinate with position and velocity.
  638.          *
  639.          * @param date      of validity.
  640.          * @param position  of the satellite.
  641.          * @param velocity  of the satellite.
  642.          * @param clock     correction in s.
  643.          * @param clockRate in s / s.
  644.          */
  645.         SP3Coordinate(final AbsoluteDate date,
  646.                       final Vector3D position,
  647.                       final Vector3D velocity,
  648.                       final double clock,
  649.                       final double clockRate) {
  650.             super(date, position, velocity, Vector3D.ZERO);
  651.             this.clock = clock;
  652.             this.clockRate = clockRate;
  653.         }

  655.         /**
  656.          * Returns the clock correction value.
  657.          *
  658.          * @return the clock correction in s.
  659.          */
  660.         public double getClockCorrection() {
  661.             return clock;
  662.         }

  664.         /**
  665.          * Returns the clock rate.
  666.          *
  667.          * @return the clock rate of change in s/s.
  668.          */
  669.         public double getClockRateChange() {
  670.             return clockRate;
  671.         }

  673.     }

  675. }
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