I seem to be having a problem with my Columbus unit that is progressively getting worse, but I can't find anything on this forum or the net regarding it. Maybe I'm just searching for the wrong thing!

On switching on and going to 'Map', my Columbus sees many satellites (usually between 7 & 11) and tracks most of them (5-10 usually). 3D tracking right from the start.

It soon starts to lose these and the number tracked soon drops (within a few minutes), the accuracy starts to wane until none are tracked. However, it can still 'see' a decent number of satellites and the hidden menu shows that the receiver is connected (see pictures).

Does any one have any ideas as to what is causing this and how to fix it?

Off the top of my head, I can't remember what SW version I have on there, but I updated it long before the problems started. I think it might be 381x or possibly 276x, I'll check if the answer is needed to progress this further.

I have VCDS if a scan is needed, but (apart from an open circuit fault caused by only having one aerial connected, there is nothing there).

Thanks in advance.

have you set the date on the unit, this is needed so that the columbus knows what satellites are where and if its wrong it will take an age or not get a fix at all.

This problem can be caused by a bad solder joint in the GPS aerial, try to replace it with another aerial.

Date settings don't matter because GPS almanac with all satellite positions is transmitted continuously. It can take up to 12 minutes to get a full almanac, but GPS receiver remembers the last received positions and locks to the satellites almost instantly.

This is starting to feel like a conspiracy!

Yesterday, I had the same problem. Columbus gets a decent fix, works well for 10 mins then starts to lose contact with satellites until nothing!

But, I had put a sat nav back on my iPhone (which has always worked in everything but the worst of locations), and that lost contact with the satellites at almost exactly the same time as the Columbus.

An hour of driving trying to reboot devices, etc. to no avail and I pulled in to a service station, pulled off the centre dash storage box and moved the GPS receiver on to the roof of the car (fortunately it was magnetic and it wasn't wet).

Then near perfect signal on the Columbus and the iPhone started working properly as well! Had no further problems from then on.

Did the US turn the GPS system back on at 9.30am yesterday?

have you set the date on the unit, this is needed so that the columbus knows what satellites are where and if its wrong it will take an age or not get a fix at all.

Actually found (by mistake) how to set the date last week while looking for something else. So I know that is not the problem.

This problem can be caused by a bad solder joint in the GPS aerial, try to replace it with another aerial.

Given that the GPS worked perfectly with no loss of signal whilst on the roof, I don't think that this is the case. But I am now considering an aerial with FM & GPS receivers built in (whilst I'm at it I might as well go triplex and put the phone cable in just in case I go for bluetooth phone capability anytime soon.

Date settings don't matter because GPS almanac with all satellite positions is transmitted continuously. It can take up to 12 minutes to get a full almanac, but GPS receiver remembers the last received positions and locks to the satellites almost instantly.

The GPS has been locking to position accurately from start up (even when not having used it for quite a while) - very impressed (quicker than the iPhone). Problem is that it loses this after about 10-12 minutes and starts to drift into fields.

Any suggestions for other things to look at or for suitable aerials would be much appreciated.

Do you have any other non-OEM electronic equipment in your car which can cause interference with GPS receiver, like mobile phone charger or car video recorder?

The only thing is a Belkin USB / cigarette lighter socket adapter (to charge iPhone). Nothing else.

But had that plugged in before & after everything started going wrong.

UPDATE:

For the past week I have been checking the system daily as I had moved the receiver slightly - and so far no significant problems. It still sees lots of satellites and tracks between 2 & 11 of them, mostly toward the upper end of that range.

The GPS receiver has a magnetic base and I have now found a piece of metal that it will stick to under the dash (underneath the dash storage box and to the passenger side, there is a bit of metal chassis that is magnetic) and this is the only significant difference, but it seems to be working.

Fingers crossed.