Re: the GPS impending leap second bit

From: M. Warner Losh <imp_at_BSDIMP.COM>
Date: Thu, 19 Jan 2006 12:26:23 -0700 (MST)

In message: <>
            Steve Allen <sla_at_UCOLICK.ORG> writes:
: On Thu 2006-01-19T18:30:02 +0000, Markus Kuhn hath writ:
: > GPS sends out announcements within days after IERS does, which is
: > excellent service.

IERS announced the leap second on July 4th, about 6 weeks before it
was encoded into GPS stream. This didn't happen until mid to late

The Canadian time service was announcing the leap second months before
July (I have a friend who has been writing software to decode the
world's time broadcast stations, and he was amused by this).

: Yes, and no, for some notes from the NTP newsgroup imply that the
: setting of the GPS impending leap bit caused some GPS units to insert
: leap seconds every day at 0h UT.

We noted that the GPS system started to advertise leap seconds in the
middle of August. This causes the HP SmartClocks to hickup at the
alternate leap second time...

: Furthermore, in
: we see that the Saab AIS units introduced the leap second immediately
: and needed a firmware update to fix the condition.

Cute. Older Motorola Oncore receivers had a firmware bug that caused
a three second blimp in their time code when it had been 1024 weeks
since the last leap second as well.

Received on Thu Jan 19 2006 - 11:28:00 PST

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