[LEAPSECS] welcome to a new practical time scale

Steve Allen sla at ucolick.org
Sat Oct 18 11:28:47 EDT 2014


India has just launched the third of its seven Indian Regional
Navigation Satellite System (IRNSS) satellites.  IRNSS uses its own
reference time scale IRNSS Network Timing (IRNWT) which has two
centers (I and II) each of which maintain two time scale (A and B).

According to
http://www.isro.org/Tender/Istrac/ISTRAC-05-2013-14.pdf
section 3.1.14

  a. The definition of epoch for IRNWT-II will be similar to GALILEO
     start of epoch and GPS roll over.

  b. IRNWT start epoch 00:00:00 (WN= 0, TOW= 0) shall be
     1999-08- 21T23:59:47 UTC.  The time format is similar to GPS i.e
     week number and time of week modulo 604800.

   c. At the start epoch, TAI shall be ahead of IRNWT-II by 32 leap
      seconds

and IRNWT will deviate less than 20 ns from TAI.

I'll be modifying my time scales plots to show IRNWT at the same
offset as the earlier incarnation of the BeiDou System Time.

Welcome to the new member of the time scale club.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory--ISB   Natural Sciences II, Room 165    Lat  +36.99855
1156 High Street            Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m


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