TimeScales.java
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* 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,
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*/
package org.orekit.time;
import java.util.Collection;
import java.util.function.BiFunction;
import org.orekit.frames.EOPEntry;
import org.orekit.frames.Frames;
import org.orekit.utils.IERSConventions;
/**
* A collection of {@link TimeScale}s. This interface defines methods for obtaining
* instances of many common time scales.
*
* @author Luc Maisonobe
* @author Evan Ward
* @see TimeScalesFactory
* @see TimeScale
* @see LazyLoadedTimeScales
* @see #of(Collection, BiFunction)
* @since 10.1
*/
public interface TimeScales {
/**
* Get the International Atomic Time scale.
*
* @return International Atomic Time scale
*/
TAIScale getTAI();
/**
* Get the Universal Time Coordinate scale.
*
* @return Universal Time Coordinate scale
*/
UTCScale getUTC();
/**
* Get the Universal Time 1 scale.
*
* @param conventions IERS conventions for which EOP parameters will provide dUT1
* @param simpleEOP if true, tidal effects are ignored when interpolating EOP
* @return Universal Time 1 scale
* @see #getUTC()
* @see Frames#getEOPHistory(IERSConventions, boolean)
*/
UT1Scale getUT1(IERSConventions conventions, boolean simpleEOP);
/**
* Get the Terrestrial Time scale.
*
* @return Terrestrial Time scale
*/
TTScale getTT();
/**
* Get the Galileo System Time scale.
*
* @return Galileo System Time scale
*/
GalileoScale getGST();
/**
* Get the GLObal NAvigation Satellite System time scale.
*
* @return GLObal NAvigation Satellite System time scale
*/
GLONASSScale getGLONASS();
/**
* Get the Quasi-Zenith Satellite System time scale.
*
* @return Quasi-Zenith Satellite System time scale
*/
QZSSScale getQZSS();
/**
* Get the Global Positioning System scale.
*
* @return Global Positioning System scale
*/
GPSScale getGPS();
/**
* Get the Geocentric Coordinate Time scale.
*
* @return Geocentric Coordinate Time scale
*/
TCGScale getTCG();
/**
* Get the Barycentric Dynamic Time scale.
*
* @return Barycentric Dynamic Time scale
*/
TDBScale getTDB();
/**
* Get the Barycentric Coordinate Time scale.
*
* @return Barycentric Coordinate Time scale
*/
TCBScale getTCB();
/**
* Get the Greenwich Mean Sidereal Time scale.
*
* @param conventions IERS conventions for which EOP parameters will provide dUT1
* @param simpleEOP if true, tidal effects are ignored when interpolating EOP
* @return Greenwich Mean Sidereal Time scale
* @since 7.0
*/
GMSTScale getGMST(IERSConventions conventions, boolean simpleEOP);
/**
* Get the Indian Regional Navigation Satellite System time scale.
*
* @return Indian Regional Navigation Satellite System time scale
*/
IRNSSScale getIRNSS();
/**
* Get the BeiDou Navigation Satellite System time scale.
*
* @return BeiDou Navigation Satellite System time scale
*/
BDTScale getBDT();
/**
* Reference epoch for julian dates: -4712-01-01T12:00:00 Terrestrial Time.
* <p>Both <code>java.util.Date</code> and {@link DateComponents} classes
* follow the astronomical conventions and consider a year 0 between years -1 and +1,
* hence this reference date lies in year -4712 and not in year -4713 as can be seen
* in other documents or programs that obey a different convention (for example the
* <code>convcal</code> utility).</p>
*
* @return Julian epoch.
*/
AbsoluteDate getJulianEpoch();
/**
* Reference epoch for modified julian dates: 1858-11-17T00:00:00 Terrestrial Time.
*
* @return Modified Julian Epoch
*/
AbsoluteDate getModifiedJulianEpoch();
/**
* Reference epoch for 1950 dates: 1950-01-01T00:00:00 Terrestrial Time.
*
* @return Fifties Epoch
*/
AbsoluteDate getFiftiesEpoch();
/**
* Reference epoch for CCSDS Time Code Format (CCSDS 301.0-B-4): 1958-01-01T00:00:00
* International Atomic Time (<em>not</em> UTC).
*
* @return CCSDS Epoch
*/
AbsoluteDate getCcsdsEpoch();
/**
* Reference epoch for Galileo System Time: 1999-08-22T00:00:00 GST.
*
* @return Galileo Epoch
*/
AbsoluteDate getGalileoEpoch();
/**
* Reference epoch for GPS weeks: 1980-01-06T00:00:00 GPS time.
*
* @return GPS Epoch
*/
AbsoluteDate getGpsEpoch();
/**
* Reference epoch for QZSS weeks: 1980-01-06T00:00:00 QZSS time.
*
* @return QZSS Epoch
*/
AbsoluteDate getQzssEpoch();
/**
* Reference epoch for IRNSS weeks: 1999-08-22T00:00:00 IRNSS time.
*
* @return IRNSS Epoch
*/
AbsoluteDate getIrnssEpoch();
/**
* Reference epoch for BeiDou weeks: 2006-01-01T00:00:00 UTC.
*
* @return Beidou Epoch
*/
AbsoluteDate getBeidouEpoch();
/**
* Reference epoch for GLONASS four-year interval number: 1996-01-01T00:00:00 GLONASS
* time.
* <p>By convention, TGLONASS = UTC + 3 hours.</p>
*
* @return GLONASS Epoch
*/
AbsoluteDate getGlonassEpoch();
/**
* J2000.0 Reference epoch: 2000-01-01T12:00:00 Terrestrial Time (<em>not</em> UTC).
*
* @return J2000 Epoch
* @see AbsoluteDate#createJulianEpoch(double)
* @see AbsoluteDate#createBesselianEpoch(double)
*/
AbsoluteDate getJ2000Epoch();
/**
* Java Reference epoch: 1970-01-01T00:00:00 Universal Time Coordinate.
* <p>
* Between 1968-02-01 and 1972-01-01, UTC-TAI = 4.213 170 0s + (MJD - 39 126) x 0.002
* 592s. As on 1970-01-01 MJD = 40587, UTC-TAI = 8.000082s
* </p>
*
* @return Java Epoch
*/
AbsoluteDate getJavaEpoch();
/**
* Dummy date at infinity in the past direction.
*
* @return the earliest date.
*/
AbsoluteDate getPastInfinity();
/**
* Dummy date at infinity in the future direction.
*
* @return the latest date.
*/
AbsoluteDate getFutureInfinity();
/**
* Build an instance corresponding to a Julian Epoch (JE).
* <p>According to Lieske paper: <a
* href="http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1979A%26A....73..282L&defaultprint=YES&filetype=.pdf.">
* Precession Matrix Based on IAU (1976) System of Astronomical Constants</a>,
* Astronomy and Astrophysics, vol. 73, no. 3, Mar. 1979, p. 282-284, Julian Epoch is
* related to Julian Ephemeris Date as:</p>
* <pre>
* JE = 2000.0 + (JED - 2451545.0) / 365.25
* </pre>
* <p>
* This method reverts the formula above and computes an {@code AbsoluteDate} from the
* Julian Epoch.
* </p>
*
* @param julianEpoch Julian epoch, like 2000.0 for defining the classical reference
* J2000.0
* @return a new instant
* @see #getJ2000Epoch()
* @see #createBesselianEpoch(double)
*/
AbsoluteDate createJulianEpoch(double julianEpoch);
/**
* Build an instance corresponding to a Besselian Epoch (BE).
* <p>According to Lieske paper: <a
* href="http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1979A%26A....73..282L&defaultprint=YES&filetype=.pdf.">
* Precession Matrix Based on IAU (1976) System of Astronomical Constants</a>,
* Astronomy and Astrophysics, vol. 73, no. 3, Mar. 1979, p. 282-284, Besselian Epoch
* is related to Julian Ephemeris Date as:</p>
* <pre>
* BE = 1900.0 + (JED - 2415020.31352) / 365.242198781
* </pre>
* <p>
* This method reverts the formula above and computes an {@code AbsoluteDate} from the
* Besselian Epoch.
* </p>
*
* @param besselianEpoch Besselian epoch, like 1950 for defining the classical
* reference B1950.0
* @return a new instant
* @see #createJulianEpoch(double)
*/
AbsoluteDate createBesselianEpoch(double besselianEpoch);
/* Helpers for creating new instances. */
/**
* Create a set of time scales where all the data is loaded from the given functions.
*
* @param utcMinusTai offsets used to compute UTC. If the pre-1972 linear offsets are
* missing they will be added.
* @param eopSupplier function to retrieve the EOP data. Since the EOP have to be
* reloaded every time a different {@link IERSConventions} is
* requested this function may be called multiple times. The
* requested conventions and the created time scales are passed as
* arguments. Attempting to call {@link #getUT1(IERSConventions,
* boolean)} or {@link #getGMST(IERSConventions, boolean)} on the
* time scales argument may result in unbounded recursion. To
* ignore EOP corrections this function should return an empty
* collection.
* @return a set of time scales based on the given data.
* @see UTCTAIOffsetsLoader.Parser
* @see org.orekit.frames.EOPHistoryLoader.Parser
*/
static TimeScales of(
final Collection<? extends OffsetModel> utcMinusTai,
final BiFunction<
? super IERSConventions,
? super TimeScales,
? extends Collection<? extends EOPEntry>> eopSupplier) {
return new PreloadedTimeScales(utcMinusTai, eopSupplier);
}
}