RUT955 & Time Indications/System v Local/GGA message time

In monitoring GGA messages via CLI I noticed an apparent issue with the GGA time string did not match the actual time either local or UTC?

  • Unit is configured as UTC+10, Status>Overview>System LOCAL DEVICE TIME was correct Local time
    Status>System>Local Device Time was correct UTC time but how can both be “Local Device Time”?

  • NTP>General>Time synchronization CURRENT SYSTEM TIME was correct @ LOCAL TIME?

  • GPS>MAP Fix Time shows as UTC AM/PM? Does the 955 have a AM/PM/24 hour switch?

  • At 10am Local time, GGA message time was 020000.00 but with a GMT+10 hour time zone setting that did not fit as 10am local is 00 (midnight UTC)? One could see some relationship here with UTC Midnight-Time Zone=0200? But Time Zone is set GMT/UTC+10, appears to be with reverse sign?

  • Also observed with NTRIP On, every time I started NTRIP under CLI the GGA time string never changed going forward when GGA was updated? Should this be the case?

  • Stopping the CLI feed then restarting the NTRIP feed the current minutes & seconds would pickup correct, the hour was not related to local or UTC time. GGA time string would then remain sticky until CLI feed was again stopped/restarted. Should this be the case with GGA or should each GGA time message be updated every new GGA update?

Deciding I would simply run with UTC completely, 955 time notifications basically match up but GGA coming out with NTRIP was rather obscure? For example Local time was 13:23, UTC time was 03:23 but the GGA message time was 192300.00 which doesn’t fit any logic or offset when comparing what was occurring when using a time zone of GMT+10

Also is there meant to be a difference between “System” time and “Local” time definition wise? Is System time meant to always be UTC?

Did another time check @ 07:47(am 15/9/23) local time this morning, UTC Time 21:47 (14/9/23)
Status Overview System: Local Device Time 09:47 PM
Status System: Local Device Time 21:47
GPS Map Fix Time: 09:47 PM
NTP Current System Time: 09:47 PM
$GPGGA Message Time String 134700.00 (by definition supposed to be UTC time)

RUT-955 time zone currently set to UTC (NTP Time Zone)
GPS Synchronization is ON (Every 24 hours)
Enable NTP Client is ON
Default Time Servers


Firstly, if you check what the GNSS module receives from the satellites, you will see time in UTC.

Secondly, there is currently a known issue where the time displayed in Status → System does not always take the timezone into consideration. This should be fixed in the newer firmware.

The ‘Time zone’ option in Services → NTP → General only sets router’s timezone but not time itself. You can sync router with browser by pressing ‘Sync with Browser’ which sets an accurate time from the browser.

Now, if you are using ‘Etc/GMT+x’ option to configure your timezone, you need to use a reverse value. So if your timezone is GMT+10, set it to ‘Etc/GMT-10’. If the timezone is GMT-10, set it to ‘Etc/GMT+10’. This is intended, however, this can indeed be confusing. Not sure if this will be changed in the future.

You have the option to synchronize time using GPS as well. When both NTP and GPS synchronizations are enabled, they work with different time intervals. Essentially, these services can override each other. For instance, if GPS synchronization occurs every X minutes, and NTP client synchronization occurs every Y minutes, the time will be initially set to GPS time after X minutes, and after Y-X minutes it will switch to NTP client time.

Kind Regards,

Thanks, That cleared some things up however still can not correlate the GGA message time.

@ 10:43:59am this morning (UTC time 00:43:59) GGA message time was 024359.00
Unable to work out any time correlation with a supposedly UTC time that appears 2 hours ahead of actual UTC

As previously mentioned what is also observed with each sequential GGA message the Time is the same, within CLI at least? Stop/restart the script, new current time but every following GGA message time remains unchanged?

Request? Is it possible to have a AM:PM/24 hour switch for times that are UTC? Like GPS>Map Time being UTC time should be 24 hour time, not AM/PM ?

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