[LEAPSECS] UT1 offset

[Gary E. Miller]

Yo Tom!

On Tue, 2 Jan 2024 06:44:01 -0800
Tom Van Baak <tvb at LeapSecond.com> wrote:

> Can you give some references to your observation? I don't recall
> seeing UT1 mentioned in the first couple of decades of GPS
> documentation. The system runs on GPS time, the WGS84 coordinate
> system, broadcast ephemeris including SV clock corrections. Where
> does UT1 appear in those?

From the IS-200M:

30.3.3.5.1.1 User Algorithm for Application of the EOP.

"For UT1, Table 30-VIII documents the relationship between GPS time and
UT1 with ΔUTGPS and ΔU̇ TGPS. Users who may need ΔUT1 (UT1-UTC)
as detailed in Chapter 5 of IERS Technical Note 36: IERS Conventions
(2010) can calculate this parameter from UT1-UTC, or more accurately
as (UT1-GPS) + (GPS-UTC), using intermediate quantities (UT1-GPS) and
(GPS-UTC) which are produced during calculation of UT1 and UTC. r


RGDS
GARY
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Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
	gem at rellim.com  Tel:+1 541 382 8588

	    Veritas liberabit vos. -- Quid est veritas?
    "If you can't measure it, you can't improve it." - Lord Kelvin
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