Problems Finding Satellites - Page 2 - TomTomForums.com

dwgsp · 07-09-2009, 02:41 PM

I can see how a bad quickgpsfix would cause slow satellite lock the next time that you power on the gps device, but once the ephemeris data has been received from the satellites you should be good to go. Perhaps there is a bug in the TomTom software.

/Don

CynicX · 07-09-2009, 05:01 PM

I see what you are saying. If I had a bad gpsfix it would have initially taken a long time, or even given me problems for awhile. However I HAD a good signal then all of a sudden lost it, had terrible reception all day, then toward the end of the day it came back to normal...

I usually plug it in every day for the latest mapshare updates. Therefore I've been resetting it everyday, and its been working flawlessly.

I'm curious to see how it works if I dont update/reset it for a few days/weeks. Keep in mind I usually navigate to about 4-6 locations I've never been too 6 days a week, about 8-10 hours a day. So this thing sees a TON of use...

**mvl** · 07-11-2009, 10:41 PM

Quote:

Originally Posted by mikealder

I fail to see why the qGPS data is even needed, use the device on a regular basis and it serves no purpose, I haven't used it on any of my units that support it for quite some time (years not months or weeks) and I get a position fix in under 30 seconds, quite often in less than 10 seconds isn't unusual, why run the risk of duff data corupting the positional accuracy - Mike

My understanding is that the satellite-broadcasted ephemeris is only good for a few hours. If you turn your Tomtom back on within those few hours, you reacquire signal in 10-30 seconds.

I'm not sure what a "few hours" is, but it certainly is less than an 8-hour work day. My experience is that without quickgpsfix, the signal lock takes about 3-5 minutes on average if the device has been off for a few hours.

Now that I have a bluetooth connection, I enable autoquickgps fix. It downloads the file via bluetooth without having to plug into a computer, and I always have 5-10-second locks (except when Tomtom has a bad file)

FYI - The bad quickgpsfix file released recently appears to affect only models with the Hammerhead GPS. Hammerhead is used on most (not all) ONE/XL models. The SIRF chip used on most GO models was not affected this week.

**gatorguy** · 07-12-2009, 09:58 AM

MVL, is the "bad quickfix update" you refer to the one from 3 weeks ago, or has another flawed one been offered since?

**mvl** · 07-12-2009, 09:52 PM

It appears the hammerhead models got a bad quickgpsfix a couple of days ago. I've seen many posts on this forum reporting problems connecting to satellites. All one/xl, no GO models.

This is different from the bad sirf quickgpsfix a few weeks ago.

**gatorguy** · 07-13-2009, 03:52 AM

Just my opinion, but I don't think just a flawed quickfix file would cause intermittant sat lock. Many of the complaints aren't about initial satellite reception. Instead reception is being affected during use.

**mvl** · 07-13-2009, 05:18 AM

It's quite possible that an east cost satellite is misbehaving. However, if this was the case, I would expect to see both the SIRF (GO) and Hammerhead (ONE/XL) chips reporting issues. Still haven't seen a GO owner report issues.

Well, now that I think of it, I saw 4 bars on my GO every now and then over the past few days, it normally has 5 bars. Maybe there is a satellite issue and the SIRF chip is powerful enough to overcome it.

**gatorguy** · 07-13-2009, 06:16 AM

Certainly possible. Some of the complaints just aren't typical of a bad quickfix update. Call me gun-shy, but there's been too many satellite reception related problems from different chip sources lately. Just makes me suspicious anymore.

CynicX · 07-13-2009, 09:15 AM

I read a while back that the pentagons latest satellite launch was equipped with new tech for new civilian frequency called "L5". Going to be used for, air traffic control or something like that. Anyway this new frequency was interfering with normal signals from the satellite making them less accurate, 10 fold if I remember correctly....

I wonder if that has something to do with it? I also read a lot of stuff on the of a "magnetic anomaly" on the east coast of South America. It was technical article and above my had but it was mentioned that Hubble was shut down while passing through this area to prevent damage.

So much information and its hard to tell whats true or not...

EDIT :

GPS Satellite Glitches Fuel Concern on Next Generation - WSJ.com

That is the article I read. About the Locheed Martin satellite interference....

**dhn** · 07-13-2009, 09:22 AM

In Britain, the Department of Defence (I think it is) has regular gps satellite signal jamming exercises. They announce ahead of time the location in the British Isles that might be affected, the date and the hours.