Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle

Details Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle

Aug 1993

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1993a%26a...275..645c&link_type=abstract

Astronomy and Astrophysics, Vol. 275, p. 645 (1993)

Astronomy and Astrophysics

Astrophysics

3

Astrometry, Earth: General, Ephemerides

Scientific paper

Present observations using modern astrometric techniques are supposed to provide the Earth orientation parameters, and therefore UT1, with an accuracy better than ±1 mas.
In practice, UT1 is determined through the intermediary of Greenwich Sidereal Time (GST), using both the conventional relationship between Greenwich Mean Sidereal Time (GMST) and UTl (Aoki et al. 1982) and the so-called "equation of the equinoxes" limited to the first order terms with respect to the nutation quantities. This highly complex relation between sidereal time and UT1 is not accurate at the milliaresecond level which gives rise to spurious terms of milliaresecond amplitude in the derived UTl.
A more complete relationship between GST and UT1 has been recommended by Aoki & Kinoshita (1983) and Aoki (1991) taking into account the second order terms in the difference between GST and GM ST, the largest one having an amplitude of 2.64 mas and a 18.6 yr-period. This paper explains how this complete expansion of GST implicitly uses the concept of "nonrotating origin" (NRO) as proposed by Guinot in 1979 and would, therefore, provide a more accurate value of UTl and consequently of the Earth's angular velocity. This paper shows, moreover, that such a procedure would be simplified and conceptually clarified by the explicit use of the NRO as previously proposed (Guinot 1979; Capitaine et al. 1986).
The two corresponding options (implicit or explicit use of the NRO) are shown to be equivalent for defining the specific Earth's angle of rotation and then UT1. The of the use of such an accurate procedure which has been proposed in the new IERS standards (McCarthy 1992a) instead of the usual one are estimated for the practical derivation of UT1.

Affiliated with

Also associated with

No associations

Rating

Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Accurate procedure for deriving UTI at a submilliarcsecond accuracy from Greenwich Sidereal Time or from the stellar angle will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1490160