Keep having problems accessing sats about once a week

My 910 will work great for about a week, then I have to log on and download "gpsquickfix". It will work fine again and access the sats in a reasonable length of time, then it will start taking 5 minutes and sometimes longer before it see the sats. I have the latest software and updates. Nothing has changed in the mounting location. Anybody know what gives? I have a friend with a much less expensive Garmin 330 and he has never had to update his unit and it accesses the sats very quickly. Is there someting wrong with the TT, did I make a mistake purchasing it. This is very frustrating. When it's happening, I can even step outside the car with the unit in a clear area and it still won't pick up the sats any quicker.
Thanks, Don

 

Don,

I have the SAME problem....once I got the GPSFIX it took a TON of time to get the sats and the first route with it was all messed up. Try disabling GPSquickfix and if for some reason you get an update...dont install it. I have not been doing that and my 910 is working like a champ.

Regards!

 

The GPS Quickfix is basically just an update that allows the unit to find satellites a little faster (in theory I suppose). Even though they are in geosynchrous orbit they do change fractionally and this is the logic behind the quickfix as explained to me by TT support. I have had the same problem and I find that usually when that is the case I have moved the unit from the location where I turned it off. It is almost like it wakes up and says "Where am I?". TT support indicates that the unit takes extra time to reorient itself when this has happened. The quickfix has not always been available and I personally think satellite acquisition is a little faster with it. Maybe some of the technical experts can suggest a resolution for you that will allow you the speed of the quickfix but without the problems you have been experiencing.

 

I have had the same problem and am very unhappy with my 910! This is my first and last TT product. I have had two different systems in the past and have never had to update weekly. By the time this thing finds the satellites, I'm almost at my destination, with the help of old fashioned maps.

 

Can't figure out how to disable GPSquickfix... can anyone help me?

Thanks,

Nuno.

 

Support?? Unbelievable. The sats are most definitely not in geosynchronous orbit. That is precisely why a GPS receiver has to spend time figuring out where they all are. This is where the quickfix file comes in, it describes the orbital paths of the sats. What changes slightly over time is the orbital path (ephemeris) itself. That is why the quickfix file has only a limited validity.

I have explained how, and why, quickfix works, several times. The latest...https://www.tomtomforums.com/showpost.php?p=17647&postcount=10

This is right. Well, it actually wakes up says "I assume that I am here, so the satellites must be there.... Oh, there not! In that case, where am I?"

To cut down on 'looking' time, the receiver makes a guess that you are starting in the location where you last turned it off. In the case that this is right (usually) the fix is found faster. The downside of this guessing, is that it wastes time looking where it thinks the sats are even when they are not (because your location changed). The bigger the change in location, the longer the time taken to find the 'real' location.

 

What you've all said makes sense, but if that's the case, why isn't my friend with an inexpensive Garmin having the same issues. He has said to me that he uses it perioically and it locks on quickly, no matter where he is!

 

My guess is he has better reception in his area than you do, a clearer 'sky-view' (less trees, buildings, more sky!). Have you tried yours where he lives? Or he where you live? Do you really believe him when he says 'no matter where he is!'?

Chances are, both devices use the same GPS reciever chip (SirfStar III), so the only differences would result from the differences in your locations, i.e.: local variation. Of course, he does not have the ability to use quickfix, so when you are both in the same location (and you have recent quickfix data), your TT should be significantly faster. I would be really surprised if it wasn't.

The effects I have described below are applicable to all GPS receivers, without exception. Move any GPS a considerable distance while it is switched off and it will take longer to get a fix. They all have to do the same calculation to figure out a fix, the only thing that can vary is the processing power (hence speed) that they apply to calculating it. As both systems are undoubtedly using the same GPS chip I would not expect to see any difference, if both were at the same location (and you did not use quickfix).