TomTom Problems with SiRF

[Dave]

Just so people don't drive themeselves crazy, there is a known problem with TomTom GPS Driver, which will in theory cause problems with TomTom's entire range of products (although I've only tested it in Navigator) where if you run your GPS Receiver in SiRF mode (most run in NMEA as default) and you are WEST of Prime Meridian, eg Greenwich in the UK, then you will not get a position on the map. Instead TomTom products will dump you somewhere off in the sea, way outside Europe somewhere.



I've reported this problem to TomTom, and they will investigate this further. Other products like Destinator do not have this problem, and you can verify this problem quite easily by running WinFast Navigator (on our downloads page).



Anyone travelling EAST of Meridian will be okay, the problem happens when effectively the cordinates reach ZERO at Meridian and then go into a NEGATIVE figure when you travel WEST of Meridian.

[StuBFrost]

I asked TomTom about this months ago and they said that there was nothing wrong with their product.



I had tested my Sirf GPS on a PC and it worked fine. I tested it with a PocketPC GPS viewer and it was fine. Tried it with TomTom and it was off.



Stuart Frost

[Dave]

I did some very early SiRF tests with the Navman back in December 2001, but due to SiRF issues with the Navman sleeve anyway, I had partially put it down to this. But from what I recall I was getting exactly the same problem and this was back in the days of SmartPath Trips and City, so I believe the problem has been there probably from the start. Like most though, I suspect eveyrone is happy running in NMEA mode so many don't see a problem with this, but with the new SiRF II chipsets coming out, especially for sleeve design with lower power consumption I think there will be more of a trend switch to SiRF II over the next 6-12 months on handheld receivers.



I've sent TomTom comparison screenshots from the same location in various products so they can see that it is their driver that is at fault in SiRF mode. In theory they can test this in Western France, or anything west of Meridian. A very strange bug though!

[RedDragon]

Wow, what a strange bug! I think I just replicated it...



I switched my Pretec CompactGPS card over to SiRF for the first time today. On driving home from work (only a few miles, but across the Prime Meridian) all seemed fine until suddenly the map went blank and I was in the middle of nowhere! The GPS co-ords where reported as North 0 East 270... now I don't remember being that close to the equator!



Switching back to NMEA got me back to norm.



Paul

[Dave]

Unfortunately TomTom say they weren't aware of this problem, and there's still no known fix.

[pauls13]

I have the same problem an I am using a destinator gps which I believe is the leadtek 9531, tom tom have told me to change the protocol to NMEA but I dont know how, can anyone help?

[Dave]

Paul, I replied in this thread

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