[time-nuts] Trimble Thunderbolt no longer determines the correct date

Tom Van Baak tvb at LeapSecond.com
Thu Jul 27 22:03:35 EDT 2017

> There is: There is a 13bit week number in message type 10.


Well, yes and no.

Yes -- paragraph in www.gps.gov/technical/icwg/IS-GPS-200D.pdf describes a 13-bit extended week number.

No -- because this is part of the new CNAV format and existing GPS SV do not transmit that information.

Interesting links and PDF's if you google: "Transmission Week Number" CNAV


> The new 13-bit week number is only provided by the new "CNAV" data,
> which in turn is (or will be) available only in newly added GPS signals.
> Based on the carrier frequencies used, only the newest of the new
> signals (L1C) will be available to common civilian receivers, even with
> compatible hardware and firmware.  This signal is unavailable from
> satellites earlier than Block III, which are currently (July 2016) not
> expected to begin to launch earlier than September 2016.  Given that it
> takes years to launch a full constellation of satellites, it's highly
> unlikely that CNAV data with "operational" status will be available to
> common civilian receivers in time for the April 2019 10-bit rollover.


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