GPS Back to the Future?

[SteveG]

So there we were chugging along towards Cowes in virtually no wind, yesterday 14th September when I thought "That's odd. The Standard Horizon chart plotter said we should have about 1.5kts of tide with us. Wrong! We clearly had about 1 knot against us". Turns out that the chart plotter thought it was 29th January 2005!! That explained the tidal error, but what's going on here? I tried reinitialising, resetting the date via settings, but couldn't find anything that would allow me to override GPS time. My boat is a Feeling, not a DeLorean, so what's going on? I was fine last week. Do I have a Millenium effect?
I thought I should check with the handheld Magellan - ancient, but still works as backup. Guess what the handheld said - it was 29th January 2005 too!! Has the GPS system gone haywire? Have those naughty Russians been interfering with it?
Thought I would have another look today 15th September 2024. Funnily enough the system says it is now 30th January 2005. Consistent, but not correct! Any thoughts out there? Does everyone else's system work OK? It's certainly odd that two systems made by different manufacturers 15years apart both started to exhibit the same problem at the same time.

 

[Bouba]

19 years younger…take it

 

[Sandy]

This happened on my Garmin a couple of years ago. I contacted Garmin support and they sent a firmware update. Plugged it in and went to make a pot of tea, after 20 mins I was back in the correct year.

A call to SH should sort you out.

 

[S04]

The fact that the dates are 1024 weeks apart would suggest that it's a rollover issue. However on two different devices from different manufacturers and of different vintage seems odd if it has only just happened

 

[AntarcticPilot]

It's to do with the rollover of a counter in the GPS. Older models couldn't cope with it; modern ones can.

 

[st599]

The week is transmitted as a 10bit number, so maxes out at 1023 then goes back to zero. So approximately every 20 years it will wrap around - should be dealt with in the plotter software. If it isn't, then you'll have the wrong time and possibly use the wrong data in calculating position.

 

[chriswesterman]

So there we were chugging along towards Cowes in virtually no wind, yesterday 14th September when I thought "That's odd. The Standard Horizon chart plotter said we should have about 1.5kts of tide with us. Wrong! We clearly had about 1 knot against us". Turns out that the chart plotter thought it was 29th January 2005!! That explained the tidal error, but what's going on here? I tried reinitialising, resetting the date via settings, but couldn't find anything that would allow me to override GPS time. My boat is a Feeling, not a DeLorean, so what's going on? I was fine last week. Do I have a Millenium effect?
I thought I should check with the handheld Magellan - ancient, but still works as backup. Guess what the handheld said - it was 29th January 2005 too!! Has the GPS system gone haywire? Have those naughty Russians been interfering with it?
Thought I would have another look today 15th September 2024. Funnily enough the system says it is now 30th January 2005. Consistent, but not correct! Any thoughts out there? Does everyone else's system work OK? It's certainly odd that two systems made by different manufacturers 15years apart both started to exhibit the same problem at the same time

As AntarcticPilot said its an old GPS module. An early CP180i I had was fitted with a polestargps module. Later ones had a Ublox which still work fine with correct tide dates. ( I had the same problem a few months ago.) The good news is that it is easily replaceable at least on the CP180i I had. There are plenty of Ublox modules arround for about £15, just need to make sure you get one with the right connectors.

 

[SteveG]

Thanks to all. Will start off by attempting to contact ST and see if they are interested in helping.

 

[SteveG]

Well now. nearly two weeks on and not a peep out of SH. Silly me, expecting some kind of helpful service - not even an offer of an extortionately expensive replacement! Maybe their email system is down!
On a more practical note, I looked up Ublox. There seem to be a lot of modules and from many makers too, most of which are associated with drone use. I wonder whether this precludes some of them. GNSS seems to be the order of the day now. Is the NMEA data the same as GPS? I believe I can reset the NMEA Baud rate as per the handbook if necessary.
Chriswesterman was right there are plenty of modules about, but which one? Anyone know specific module number that would do the business?
Many thanks to all.

 

[snowbird30ds]

Try calling yaesu uk in hampshire instead of emailing, their service is usually great.

 

[B27]

Well now. nearly two weeks on and not a peep out of SH. Silly me, expecting some kind of helpful service - not even an offer of an extortionately expensive replacement! Maybe their email system is down!
On a more practical note, I looked up Ublox. There seem to be a lot of modules and from many makers too, most of which are associated with drone use. I wonder whether this precludes some of them. GNSS seems to be the order of the day now. Is the NMEA data the same as GPS? I believe I can reset the NMEA Baud rate as per the handbook if necessary.
Chriswesterman was right there are plenty of modules about, but which one? Anyone know specific module number that would do the business?
Many thanks to all.

GNSS global navigation satellite system, generic term
GPS global positioning system, US/NATO's GNSS.
Beidou is China's GNSS.
etc.
The NMEA or whatever is the output of the receiver/processor and will be the same whether it's receiving GPS, Beidou or several rival GNSS's at once.

I've used some Ublox modules which are available cheaply as 'breakout boards' for hobbyist use with arduino or whatever.