Taking a long time finding satellites

[itsonelouder]

I download the QuickGPS fix update every day and yet it's still taking a long time to get reception in one particular area, we're talking more than 10 mins. Why would this be and is there anything I can do to fix it?

 

[dhn]

It has been known that certain locations (and vehicles) have what are essentially 'gps blockers' implemented.

If you are not getting a gps signal in one location only, that may be a reason. Also, remember that tall buildings, trees, etc are known to interfere with a signal.

 

[itsonelouder]

This is on and near a motorway (freeway) though. Trees and tall building definitely not the problem. Other times it's ok, just lately I've been having problems in this one area.

 

[dhn]

'Lately' means how current? I know you say you dl the gps files on a regular basis but, just for the heck of it, delete anything in the \ephem folder on your unit and then go here (use Explorer)

c:\documents and settings\yourname\my documents\TomTom\Home\Downloads\Complete\ephemeris

and delete any sub folders found there.

Connect to Home and a new gps file should be offered. Install and disconnect properly from Home using the Device Disconnect icon.

See if you still have the issie.

 

[canderson]

This is on and near a motorway (freeway) though. Trees and tall building definitely not the problem. Other times it's ok, just lately I've been having problems in this one area.

Anywhere near a lay-by or rest stop where trucks tend to hang out? They're frequently the source of jammer problems.

 

[itsonelouder]

'Lately' means how current? I know you say you dl the gps files on a regular basis but, just for the heck of it, delete anything in the \ephem folder on your unit and then go here (use Explorer)

c:\documents and settings\yourname\my documents\TomTom\Home\Downloads\Complete\ephemeris

and delete any sub folders found there.

Connect to Home and a new gps file should be offered. Install and disconnect properly from Home using the Device Disconnect icon.

See if you still have the issie.

I did that, went to update and got an error

 

[dhn]

What error? Can you cut & paste contents here?

 

[itsonelouder]

I've done a restore now.

 

[itsonelouder]

I'm trying it again because I didn't disconnect and reconnect as you said.

 

[itsonelouder]

I didn't get the error this time so I'll see how it goes.

 

[itsonelouder]

This is on and near a motorway (freeway) though. Trees and tall building definitely not the problem. Other times it's ok, just lately I've been having problems in this one area.

Anywhere near a lay-by or rest stop where trucks tend to hang out? They're frequently the source of jammer problems.

This could be the problem but it's only recently been happening on the same stretch of motorway. I even stopped just off the motorway and waited several minutes but it didn't get a signal. I then set off again and eventually I got a signal but it was a bit worrying as I rely on it so much for my job. I'm a multidrop driver and I didn't have problems before about a week ago.

 

[itsonelouder]

So far so good Dhn, my TomTom is inside my flat, by the window and has got a signal. It didn't have one before so it's encouraging. Have I been downloading too many GPS fixes because I've been doing it every day?

 

[dhn]

No, but one of them downloaded may have contained crappy data, causing the signal to be thrown off somewhat.

However, the proof is in the pudding. If you travel to the same location and lose the signal again, it may well be a gps blocking situation for which there really is not much more you can do .................

 

[canderson]

This could be the problem but it's only recently been happening on the same stretch of motorway. I even stopped just off the motorway and waited several minutes but it didn't get a signal. I then set off again and eventually I got a signal but it was a bit worrying as I rely on it so much for my job.

The fact that your problem is so tied to a particular location is pretty good evidence that there's something in the area that is interfering with your reception. What I'd like you to do if this occurs again is to look at the signal quality (not just whether you have a GPS fix). Tap the satellite bars on the right side of the screen, then I believe there will be another smaller set of bars in the lower right, and tap those. Should take you to the GPS 'signal' screen that shows a bunch of vertical bars. Tell us the number that are gray or blue (vs white), and about how tall they are on the scale.

 

[Andy_P]

Also, any TT is likely to take MUCH longer to get a "fix" while you are moving, and the faster you are going, the longer it takes

 

[itsonelouder]

This could be the problem but it's only recently been happening on the same stretch of motorway. I even stopped just off the motorway and waited several minutes but it didn't get a signal. I then set off again and eventually I got a signal but it was a bit worrying as I rely on it so much for my job.

The fact that your problem is so tied to a particular location is pretty good evidence that there's something in the area that is interfering with your reception. What I'd like you to do if this occurs again is to look at the signal quality (not just whether you have a GPS fix). Tap the satellite bars on the right side of the screen, then I believe there will be another smaller set of bars in the lower right, and tap those. Should take you to the GPS 'signal' screen that shows a bunch of vertical bars. Tell us the number that are gray or blue (vs white), and about how tall they are on the scale.

All the bars were white. At one point I think I had 1 grey bar

 

[canderson]

Well that certainly explains why you were unable to get a lock - no reception on any but one satellite, and not very good on that one, either. What you need is 4+ blue bars in order to get a fix. Something in that area was/is REALLY messing with your reception. Next time, as you drive away from the area, watch what happens to the number of satellites (they start as gray bars) you see.

 

[itsonelouder]

Ok, I guess I'll just have to live with it.

 

[itsonelouder]

Just out of interest, what exactly is blocking the signal?

 

[canderson]

We have no way of knowing that from here. It's something that would require some sleuthing on your end to discover.

Given that you are out in open ground with no obstructions or nearby things to reflect signals (drives a GPS nuts when it gets the same signal twice, or even once indirectly), it does leave the one obvious other source - interference. It may not be that your signal is being 'blocked' as much as it is being 'jammed'. In fact, given that it takes out pretty much the entire constellation of satellites at once, I'd give good odds that this is the case.

Without being able to see the area, I'd have no way to take a guess about a specific source.

Could you provide, roughly we understand, the coordinates for where the problem begins and where it ends? All we'll have here to observe it is Google, but we may spot something of interest in a high res satellite shot. Other than that...