Wrong Time and Date on Furuno GPS

[jac]

I have a secondary GPS that is only really used to feed position to the Icom DSC radio.

For some reason the GPS is convinced that right now it is 13:35 on August 24 2003. So time is right for UTC - just a few decades out.

Two questions.

Is there an obvious way to make this show the correct date?

If not - am I correct to assume that this is not a major problem- the position is ok so in an emergency would transmit that anyway

 

[Roberto]

Position and time are ok, date not.
Search "gps rollover date" for explanation.

Some gps sets can be adjusted, the older ones very often not.

 

[RunAgroundHard]

I had this on a Navman 5500, model from around the year 2000. The date went wonky twice, the first time fixed by a patch, the second time no patch available. I continued to use it, but the tide feature was useless and so was the feed to the DSC VHF as the dat and time were now wrong, but the position was ok. After about 3 years of wrong dates, I have just bought an new plotter to replace it. The plotter functionality worked fine for all these years with the long date, hence I assume yours will as well.

 

[st599]

I have a secondary GPS that is only really used to feed position to the Icom DSC radio.

For some reason the GPS is convinced that right now it is 13:35 on August 24 2003. So time is right for UTC - just a few decades out.

Two questions.

Is there an obvious way to make this show the correct date?

If not - am I correct to assume that this is not a major problem- the position is ok so in an emergency would transmit that anyway

The GPS message has a 10 bit week number, so someone hasn't anticipated it going back zero. You should be 1024 weeks out.

In about 15 years time, the same will happen to many computer systems that use seconds since 00:00:00 UTC 1 January 1970 as a measure of time.

 

[jac]

Position and time are ok, date not.
Search "gps rollover date" for explanation.

Some gps sets can be adjusted, the older ones very often not.

Thanks for that.

That does explain it. Furuno site says the GP32 can’t be reset to accept the up to date date. Choice to make now I guess!!

 

[Sandy]

My Garmin GPS did the same in 2021, it went back to 2002. A firmware update fixed the problem.

 

[Boathook]

Thanks for that.

That does explain it. Furuno site says the GP32 can’t be reset to accept the up to date date. Choice to make now I guess!!

Just seen this thread.

My Furuno GP-31 had problems at the roll over a few year back. I spoke to Furuno at the time and there was no software update for the unit. The time and position is spot on but the date is way out.

I use it to give my DSC radio a position fix. When I have tested the DSC by doing a test transmission to Solent coastguard I get an automatic acknowledgement so hopefully in a real emergency it will work OK.

 

[Roberto]

Just seen this thread.

My Furuno GP-31 had problems at the roll over a few year back. I spoke to Furuno at the time and there was no software update for the unit. The time and position is spot on but the date is way out.

I use it to give my DSC radio a position fix. When I have tested the DSC by doing a test transmission to Solent coastguard I get an automatic acknowledgement so hopefully in a real emergency it will work OK.

I think the DSC message only contains time hh:mm, not date.

From:
https://www.itu.int/dms_pubrec/itu-r/rec/m/R-REC-M.493-15-201901-I!!PDF-E.pdf

8.1.3 Message 3
Message 3 is the time indication coordinated universal time (UTC) when the coordinates were valid consisting of four digits coded on the principles described in Table A1-2, in pairs starting from the first and second digits.
– The first two digits indicate the time in hours.
– The third and fourth digits indicate the part of the hours in minutes.
– If the time cannot be included the four time indicating digits should be transmitted automatically as “8 8 8 8”.