org.orekit.time

Interface TimeScales

All Known Implementing Classes:

AbstractTimeScales, LazyLoadedTimeScales

public interface TimeScales

A collection of TimeScales. This interface defines methods for obtaining instances of many common time scales.

Since:

10.1

Author:

Luc Maisonobe, Evan Ward

See Also:

TimeScalesFactory, TimeScale, LazyLoadedTimeScales, of(Collection, BiFunction)

Method Summary

Modifier and Type	Method and Description
AbsoluteDate	createBesselianEpoch(double besselianEpoch) Build an instance corresponding to a Besselian Epoch (BE).
AbsoluteDate	createJulianEpoch(double julianEpoch) Build an instance corresponding to a Julian Epoch (JE).
BDTScale	getBDT() Get the BeiDou Navigation Satellite System time scale.
AbsoluteDate	getBeidouEpoch() Reference epoch for BeiDou weeks: 2006-01-01T00:00:00 UTC.
AbsoluteDate	getCcsdsEpoch() Reference epoch for CCSDS Time Code Format (CCSDS 301.0-B-4): 1958-01-01T00:00:00 International Atomic Time (not UTC).
AbsoluteDate	getFiftiesEpoch() Reference epoch for 1950 dates: 1950-01-01T00:00:00 Terrestrial Time.
AbsoluteDate	getFutureInfinity() Dummy date at infinity in the future direction.
AbsoluteDate	getGalileoEpoch() Reference epoch for Galileo System Time: 1999-08-22T00:00:00 GST.
GLONASSScale	getGLONASS() Get the GLObal NAvigation Satellite System time scale.
AbsoluteDate	getGlonassEpoch() Reference epoch for GLONASS four-year interval number: 1996-01-01T00:00:00 GLONASS time.
GMSTScale	getGMST(IERSConventions conventions, boolean simpleEOP) Get the Greenwich Mean Sidereal Time scale.
GPSScale	getGPS() Get the Global Positioning System scale.
AbsoluteDate	getGpsEpoch() Reference epoch for GPS weeks: 1980-01-06T00:00:00 GPS time.
GalileoScale	getGST() Get the Galileo System Time scale.
IRNSSScale	getIRNSS() Get the Indian Regional Navigation Satellite System time scale.
AbsoluteDate	getIrnssEpoch() Reference epoch for IRNSS weeks: 1999-08-22T00:00:00 IRNSS time.
AbsoluteDate	getJ2000Epoch() J2000.0 Reference epoch: 2000-01-01T12:00:00 Terrestrial Time (not UTC).
AbsoluteDate	getJavaEpoch() Java Reference epoch: 1970-01-01T00:00:00 Universal Time Coordinate.
AbsoluteDate	getJulianEpoch() Reference epoch for julian dates: -4712-01-01T12:00:00 Terrestrial Time.
AbsoluteDate	getModifiedJulianEpoch() Reference epoch for modified julian dates: 1858-11-17T00:00:00 Terrestrial Time.
AbsoluteDate	getPastInfinity() Dummy date at infinity in the past direction.
QZSSScale	getQZSS() Get the Quasi-Zenith Satellite System time scale.
AbsoluteDate	getQzssEpoch() Reference epoch for QZSS weeks: 1980-01-06T00:00:00 QZSS time.
TAIScale	getTAI() Get the International Atomic Time scale.
TCBScale	getTCB() Get the Barycentric Coordinate Time scale.
TCGScale	getTCG() Get the Geocentric Coordinate Time scale.
TDBScale	getTDB() Get the Barycentric Dynamic Time scale.
TTScale	getTT() Get the Terrestrial Time scale.
UT1Scale	getUT1(IERSConventions conventions, boolean simpleEOP) Get the Universal Time 1 scale.
UTCScale	getUTC() Get the Universal Time Coordinate scale.
static TimeScales	of(Collection<? extends OffsetModel> utcMinusTai, BiFunction<? super IERSConventions,? super TimeScales,? extends Collection<? extends EOPEntry>> eopSupplier) Create a set of time scales where all the data is loaded from the given functions.

Method Detail

getTAI

TAIScale getTAI()

Get the International Atomic Time scale.

Returns:

International Atomic Time scale

getUTC

UTCScale getUTC()

Get the Universal Time Coordinate scale.

Returns:

Universal Time Coordinate scale

getUT1

UT1Scale getUT1(IERSConventions conventions,
                boolean simpleEOP)

Get the Universal Time 1 scale.

Parameters:

conventions - IERS conventions for which EOP parameters will provide dUT1

simpleEOP - if true, tidal effects are ignored when interpolating EOP

Returns:

Universal Time 1 scale

See Also:

getUTC(), Frames.getEOPHistory(IERSConventions, boolean)

getTT

TTScale getTT()

Get the Terrestrial Time scale.

Returns:

Terrestrial Time scale

getGST

GalileoScale getGST()

Get the Galileo System Time scale.

Returns:

Galileo System Time scale

getGLONASS

GLONASSScale getGLONASS()

Get the GLObal NAvigation Satellite System time scale.

Returns:

GLObal NAvigation Satellite System time scale

getQZSS

QZSSScale getQZSS()

Get the Quasi-Zenith Satellite System time scale.

Returns:

Quasi-Zenith Satellite System time scale

getGPS

GPSScale getGPS()

Get the Global Positioning System scale.

Returns:

Global Positioning System scale

getTCG

TCGScale getTCG()

Get the Geocentric Coordinate Time scale.

Returns:

Geocentric Coordinate Time scale

getTDB

TDBScale getTDB()

Get the Barycentric Dynamic Time scale.

Returns:

Barycentric Dynamic Time scale

getTCB

TCBScale getTCB()

Get the Barycentric Coordinate Time scale.

Returns:

Barycentric Coordinate Time scale

getGMST

GMSTScale getGMST(IERSConventions conventions,
                  boolean simpleEOP)

Get the Greenwich Mean Sidereal Time scale.

Parameters:

conventions - IERS conventions for which EOP parameters will provide dUT1

simpleEOP - if true, tidal effects are ignored when interpolating EOP

Returns:

Greenwich Mean Sidereal Time scale

Since:

7.0

getIRNSS

IRNSSScale getIRNSS()

Get the Indian Regional Navigation Satellite System time scale.

Returns:

Indian Regional Navigation Satellite System time scale

getBDT

BDTScale getBDT()

Get the BeiDou Navigation Satellite System time scale.

Returns:

BeiDou Navigation Satellite System time scale

getJulianEpoch

AbsoluteDate getJulianEpoch()

Reference epoch for julian dates: -4712-01-01T12:00:00 Terrestrial Time.

Both java.util.Date and 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 convcal utility).

Returns:

Julian epoch.

getModifiedJulianEpoch

AbsoluteDate getModifiedJulianEpoch()

Reference epoch for modified julian dates: 1858-11-17T00:00:00 Terrestrial Time.

Returns:

Modified Julian Epoch

getFiftiesEpoch

AbsoluteDate getFiftiesEpoch()

Reference epoch for 1950 dates: 1950-01-01T00:00:00 Terrestrial Time.

Returns:

Fifties Epoch

getCcsdsEpoch

AbsoluteDate getCcsdsEpoch()

Reference epoch for CCSDS Time Code Format (CCSDS 301.0-B-4): 1958-01-01T00:00:00 International Atomic Time (not UTC).

Returns:

CCSDS Epoch

getGalileoEpoch

AbsoluteDate getGalileoEpoch()

Reference epoch for Galileo System Time: 1999-08-22T00:00:00 GST.

Returns:

Galileo Epoch

getGpsEpoch

AbsoluteDate getGpsEpoch()

Reference epoch for GPS weeks: 1980-01-06T00:00:00 GPS time.

Returns:

GPS Epoch

getQzssEpoch

AbsoluteDate getQzssEpoch()

Reference epoch for QZSS weeks: 1980-01-06T00:00:00 QZSS time.

Returns:

QZSS Epoch

getIrnssEpoch

AbsoluteDate getIrnssEpoch()

Reference epoch for IRNSS weeks: 1999-08-22T00:00:00 IRNSS time.

Returns:

IRNSS Epoch

getBeidouEpoch

AbsoluteDate getBeidouEpoch()

Reference epoch for BeiDou weeks: 2006-01-01T00:00:00 UTC.

Returns:

Beidou Epoch

getGlonassEpoch

AbsoluteDate getGlonassEpoch()

Reference epoch for GLONASS four-year interval number: 1996-01-01T00:00:00 GLONASS time.

By convention, TGLONASS = UTC + 3 hours.

Returns:

GLONASS Epoch

getJ2000Epoch

AbsoluteDate getJ2000Epoch()

J2000.0 Reference epoch: 2000-01-01T12:00:00 Terrestrial Time (not UTC).

Returns:

J2000 Epoch

See Also:

AbsoluteDate.createJulianEpoch(double), AbsoluteDate.createBesselianEpoch(double)

getJavaEpoch

AbsoluteDate getJavaEpoch()

Java Reference epoch: 1970-01-01T00:00:00 Universal Time Coordinate.

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

Returns:

Java Epoch

getPastInfinity

AbsoluteDate getPastInfinity()

Dummy date at infinity in the past direction.

Returns:

the earliest date.

getFutureInfinity

AbsoluteDate getFutureInfinity()

Dummy date at infinity in the future direction.

Returns:

the latest date.

createJulianEpoch

AbsoluteDate createJulianEpoch(double julianEpoch)

Build an instance corresponding to a Julian Epoch (JE).

According to Lieske paper: Precession Matrix Based on IAU (1976) System of Astronomical Constants, Astronomy and Astrophysics, vol. 73, no. 3, Mar. 1979, p. 282-284, Julian Epoch is related to Julian Ephemeris Date as:

 JE = 2000.0 + (JED - 2451545.0) / 365.25
 

This method reverts the formula above and computes an AbsoluteDate from the Julian Epoch.

Parameters:

julianEpoch - Julian epoch, like 2000.0 for defining the classical reference J2000.0

Returns:

a new instant

See Also:

getJ2000Epoch(), createBesselianEpoch(double)

createBesselianEpoch

AbsoluteDate createBesselianEpoch(double besselianEpoch)

Build an instance corresponding to a Besselian Epoch (BE).

According to Lieske paper: Precession Matrix Based on IAU (1976) System of Astronomical Constants, Astronomy and Astrophysics, vol. 73, no. 3, Mar. 1979, p. 282-284, Besselian Epoch is related to Julian Ephemeris Date as:

 BE = 1900.0 + (JED - 2415020.31352) / 365.242198781
 

This method reverts the formula above and computes an AbsoluteDate from the Besselian Epoch.

Parameters:

besselianEpoch - Besselian epoch, like 1950 for defining the classical reference B1950.0

Returns:

a new instant

See Also:

createJulianEpoch(double)

of

static TimeScales of(Collection<? extends OffsetModel> utcMinusTai,
                     BiFunction<? super IERSConventions,? super TimeScales,? extends Collection<? extends EOPEntry>> eopSupplier)

Create a set of time scales where all the data is loaded from the given functions.

Parameters:

utcMinusTai - offsets used to compute UTC. If the pre-1972 linear offsets are missing they will be added.

eopSupplier - function to retrieve the EOP data. Since the EOP have to be reloaded every time a different 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 getUT1(IERSConventions, boolean) or getGMST(IERSConventions, boolean) on the time scales argument may result in unbounded recursion. To ignore EOP corrections this function should return an empty collection.

Returns:

a set of time scales based on the given data.

See Also:

UTCTAIOffsetsLoader.Parser, EOPHistoryLoader.Parser