naif0008.tls
上传用户：center1979
上传日期：2022-07-26
资源大小：50633k
文件大小：4k
- KPL/LSK
- LEAPSECONDS KERNEL FILE
- ===========================================================================
- Modifications:
- --------------
- 2005, Aug. 3 NJB Modified file to account for the leapsecond that
- will occur on December 31, 2005.
-
- 1998, Jul 17 WLT Modified file to account for the leapsecond that
- will occur on December 31, 1998.
-
- 1997, Feb 22 WLT Modified file to account for the leapsecond that
- will occur on June 30, 1997.
-
- 1995, Dec 14 KSZ Corrected date of last leapsecond from 1-1-95
- to 1-1-96.
- 1995, Oct 25 WLT Modified file to account for the leapsecond that
- will occur on Dec 31, 1995.
- 1994, Jun 16 WLT Modified file to account for the leapsecond on
- June 30, 1994.
- 1993, Feb. 22 CHA Modified file to account for the leapsecond on
- June 30, 1993.
- 1992, Mar. 6 HAN Modified file to account for the leapsecond on
- June 30, 1992.
- 1990, Oct. 8 HAN Modified file to account for the leapsecond on
- Dec. 31, 1990.
- Explanation:
- ------------
- The contents of this file are used by the routine DELTET to compute the
- time difference
- [1] DELTA_ET = ET - UTC
-
- the increment to be applied to UTC to give ET.
- The difference between UTC and TAI,
- [2] DELTA_AT = TAI - UTC
- is always an integral number of seconds. The value of DELTA_AT was 10
- seconds in January 1972, and increases by one each time a leap second
- is declared. Combining [1] and [2] gives
- [3] DELTA_ET = ET - (TAI - DELTA_AT)
- = (ET - TAI) + DELTA_AT
- The difference (ET - TAI) is periodic, and is given by
- [4] ET - TAI = DELTA_T_A + K sin E
- where DELTA_T_A and K are constant, and E is the eccentric anomaly of the
- heliocentric orbit of the Earth-Moon barycenter. Equation [4], which ignores
- small-period fluctuations, is accurate to about 0.000030 seconds.
- The eccentric anomaly E is given by
- [5] E = M + EB sin M
- where M is the mean anomaly, which in turn is given by
- [6] M = M + M t
- 0 1
- where t is the number of ephemeris seconds past J2000.
- Thus, in order to compute DELTA_ET, the following items are necessary.
- DELTA_TA
- K
- EB
- M0
- M1
- DELTA_AT after each leap second.
- The numbers, and the formulation, are taken from the following sources.
- 1) Moyer, T.D., Transformation from Proper Time on Earth to
- Coordinate Time in Solar System Barycentric Space-Time Frame
- of Reference, Parts 1 and 2, Celestial Mechanics 23 (1981),
- 33-56 and 57-68.
- 2) Moyer, T.D., Effects of Conversion to the J2000 Astronomical
- Reference System on Algorithms for Computing Time Differences
- and Clock Rates, JPL IOM 314.5--942, 1 October 1985.
- The variable names used above are consistent with those used in the
- Astronomical Almanac.
- begindata
- DELTET/DELTA_T_A = 32.184
- DELTET/K = 1.657D-3
- DELTET/EB = 1.671D-2
- DELTET/M = ( 6.239996D0 1.99096871D-7 )
- DELTET/DELTA_AT = ( 10, @1972-JAN-1
- 11, @1972-JUL-1
- 12, @1973-JAN-1
- 13, @1974-JAN-1
- 14, @1975-JAN-1
- 15, @1976-JAN-1
- 16, @1977-JAN-1
- 17, @1978-JAN-1
- 18, @1979-JAN-1
- 19, @1980-JAN-1
- 20, @1981-JUL-1
- 21, @1982-JUL-1
- 22, @1983-JUL-1
- 23, @1985-JUL-1
- 24, @1988-JAN-1
- 25, @1990-JAN-1
- 26, @1991-JAN-1
- 27, @1992-JUL-1
- 28, @1993-JUL-1
- 29, @1994-JUL-1
- 30, @1996-JAN-1
- 31, @1997-JUL-1
- 32, @1999-JAN-1
- 33, @2006-JAN-1 )
- begintext
English
