On Wed, 09 Dec 2020 13:26:32 +0000, Andy Burns wrote:

> Martin Gregorie wrote:
>
>> I don't think that affects a GPS receiver's startup process: it still
>> needs the almanac data to determine the exact time:
>
> But every satellite sends a NAV message every 30 seconds, receive just
> one of those and you know the TOW (time of week)
>
I'm far from certain that I've ever seen anything like that trickling out
of the serial port of a Garmin GPS2 or GPS35 and its certainly not listed
here:

https://w3.cs.jmu.edu/bernstdh/Web/common/help/nmea-sentences.php

or here:

https://opencpn.org/wiki/dokuwiki/doku.php?
id=opencpn:opencpn_user_manual:advanced_features:nmea_sentences&do=siteexport_a
ddpage

so my guess is that its used internally by the receiver and never output
as an NMEA message. As I said, the only time and date message listed is
ZDA, which contains UTC, day, month, year and local time zone


--
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Martin    | martin at
Gregorie  | gregorie dot org

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