Degrading GPS signal...

[CynicX]

Hey guys, I havent posted in a while but I had a quick question.

I own a 330XL (old now but has worked for me great). Anyway when I first got it I'd always have full signal and if you checked further I would notice 12-13 satellite it was reading from, maybe even 14 when I wasnt looking.

As time has passed I noticed the amount of satellites I'm connected too getting less. Probably 8-9 months after I bought it the most I'd notice was 9-10.

Now a year and half of constant use (5-6 days a week, on for about 10, used for navigation nearly constantly) I'm noticing the signal bar dropping from 5 to 4 which means its seeing 7 satellites, sometimes 6 (4 bars).

Around 3 bars, which I've had in the city cause of buildings and such its lags so badly it nearly becomes unusable. My greatest fear is this will continue to happen until the max I can get is 3-4 satellites even out of the city...

Ive done a hard reset, several times. I've also used the clear flash program several times.

Nothing else with its functionality is amiss.

What do you guys think? Is there something I can do? Is this happening to everyone with less satellite connections? Is the GPS sensor "wearing out"?

Thanks for any help...

 

[dhn]

Do not know whether this will help but use Explorer to clear out the ephem folder on your unit and delete all the sub folders from here:
C:\Documents and Settings\yourname\My Documents\TomTom\HOME\Downloads\complete\ephemeris\

Now connect to Home and dl a new gpsquickfix file.

See if that helps.

 

[CynicX]

Do not know whether this will help but use Explorer to clear out the ephem folder on your unit and delete all the sub folders from here:
C:\Documents and Settings\yourname\My Documents\TomTom\HOME\Downloads\complete\ephemeris\

Now connect to Home and dl a new gpsquickfix file.

See if that helps.

Thanks dhn.

I just tried it but its hard to tell. I'll have to see at work tomorrow. I did as you said and then walked around outside for a bit. I got a max of 9 satellites. Which is good however that is out in the open, not covered up quite a bit in my work vehicle.

How many satellites do you usually have?

 

[dhn]

It depends........my device, etc.

Sometimes 7 or 8, sometimes I actually do hit double digit.

 

[CynicX]

Hmm...dhn, so far it seems like clearing those files may have helped. Today I've noticed around 9 satellites and even up too 11 on occasion.

I was kind of hoping this would give me an excuse to get a new Tomtom. But I guess its good, I'm still waiting for the search for city option. Hopefully they will implement that one day...

 

[spook45]

snip....I was kind of hoping this would give me an excuse to get a new Tomtom. ....snip

Excuse??? We don't need no stinking excuse.

 

[canderson]

The only "Degrading GPS signal" I ever received from my TomTom is when I blow a turn and Suzie advises "Turn around when possible". I know what she really means ... "Yo, stupid, you missed your turn and there's no possible way I can get you started back in the right direction without a u-turn. Pay attention next time!" Yes, I feel degraded by my GPS.

Seriously -

I haven't ever heard of degraded performance on a TomTom. One could imagine oscillator drift for which compensation wasn't possible or a few other exotic possibilities in the electronics, but usually the chip/antenna combination is pretty binary - they either work or they don't. I've heard rare instances of the antenna being poorly soldered and intermittent on some units, but not those made by TomTom.

 

[CynicX]

It seems its back to the way it was. 4-5 bars, 7 max satellites. I dont know maybe I'm making normal operation into a problem that doesnt exist.

There are some really good deals going on, I esp like the 540TM for 200ish on amazon. But it seems like the longer I wait the better the deals get anyway. I know as soon as I buy something the next generation will come out with even better features that I'll want and the prices on what I get will drop even further.

How often do you guys think Tomtom will release an edition with lifetime traffic and lifetime maps? I've never seen this before, I'd hate to let a good deal go. But I'd also hate to have a TT that functions perfectly laying around.

I need to find a job making more money that doesnt require me driving all over the state. Kill two birds with one stone...

 

[dhn]

How often do you guys think Tomtom will release an edition with lifetime traffic and lifetime maps? I've never seen this before, I'd hate to let a good deal go. But I'd also hate to have a TT that functions perfectly laying around

I believe TT announced that most, if not all new models inroduced in the States as of Q2 2010 would have these options. Initially, they are true to their word.

 

[CynicX]

I noticed I have a lot of crap on my device.

After I make an explorer back up can I just format the device and expect home to take care of the rest? Or is there more too it then that?

I have my recently downloaded map so I wouldnt think that would be a problem. I would figure home would see the device and install the application for it. Then the only thing I might need to do is get POI (which I dont use, and might be built into the map anyway?) and I would need a voice which I can get free from home...

Am I forgetting something? Is this a bad idea? I recently noticed while looking at satellite the devices actual memory usage is higher then it used to be too. I dont know if something is conflicting internally and weighing this thing down and I'm getting degraded performance versus when it was new...

 

[dhn]

What kind of 'crap' are you referring to?

I wouldn't count on Home to take care of anything to be honest.

You can make the Explorer backup and format the internal of the unit. Don't use quickformat. Then use Explorer to restore your backup, but that'll restore everything (and should) that you initially backed up.

So, what is it you really think needs deleting?

I get the idea you're trying to equate backing up, formating and restoring to a fresh install of Windows which DOES get bogged down over time with true crap installed all over the place.

It's not really the same situation when it comes to the gps.

 

[CynicX]

What kind of 'crap' are you referring to?

I wouldn't count on Home to take care of anything to be honest.

You can make the Explorer backup and format the internal of the unit. Don't use quickformat. Then use Explorer to restore your backup, but that'll restore everything (and should) that you initially backed up.

So, what is it you really think needs deleting?

I get the idea you're trying to equate backing up, formating and restoring to a fresh install of Windows which DOES get bogged down over time with true crap installed all over the place.

It's not really the same situation when it comes to the gps.

This is what I was referring too. But if its not the same then I guess there is no sense.

I think I'm just looking for more out of my current unit. Like I said, it doesnt seem to get the same quality signal, it appears to use more of the available memory then it once did. I guess I was thinking of it more like a Windows OS and less like a Linux OS and maybe it was just getting "bogged down" (your choice words are exactly what I was thinking)...

I think its just time for me to bite the bullet and get a new unit. It appears my current unit will only break if I help it and I'll never have the features that the newer ones have regardless of what I do or how well it works.

And as you probably know I've been looking into new Tomtom's for quite some time (if you read my other post from months back). I'm a bit of a geek so the hardware inside the unit is important to me regardless of how much better it does or doesnt function.

I've been reading up a little on the XXL's sirfstar IV chipset. Seems like its pretty trick compared to the III. Any comments about that technology? Doesnt seem anyone is having a problem, I'm more curious if anyone is seeing the benefits over other chipsets Tomtom uses or prior Sirfstar version....

 

[dhn]

You're ahead of me with knowing what chipset is in the XXL series.

I have three units here: a 720, an XXL 540 and a unit that is similar to a EASE model. I just turned all 3 on. In the house. The 720 grabbed a signal first and showed 7 satelites. Then the 540 XXL grabbed it and showed 6. The EASE (a completely different chipset) then got it and showed 5 satellites.

Not overly scientific, I know but also no indication the 540 was more robust than the other units....

 

[canderson]

I've been reading up a little on the XXL's sirfstar IV chipset. Seems like its pretty trick compared to the III. Any comments about that technology? Doesnt seem anyone is having a problem, I'm more curious if anyone is seeing the benefits over other chipsets Tomtom uses or prior Sirfstar version....

The XXL has the IV? News to me, too.

The biggest benefit to the IV is the lower power consumption. The additional channels won't matter unless/until Europe ever gets the Galileo system up and running -- there's not as many satellites in the air as the IV has channels and won't be in the foreseeable future! It's also supposed to deal better with multipath issues which might help things just a little in "urban canyons". I don't see it as a huge improvement for automotive navigation apart from a little bit better battery life -- and the backlight is a huge consumer there. The phone and PDA guys who count every little milliamp are going to appreciate it more (specifically, the SiRFatLas IV platform). Haven't seen any of the usual suspects in the handhelds (e.g., Garmin, DeLorme, etc.) pick up on the IV yet.

Navigon was the first (and only) group I have seen using the IV in an automotive unit.

 

[Michael Quinlan]

My 740 seems to have a harder time finding a GPS signal as it gets older. The other day it took a good 10 minutes to get a signal, located in the same spot it has been since I got it. Right next to it, with no better view of the sky, was my Motorola Droid, which got a signal within 10-15 seconds.

One time in the past few months my 740 rebooted on its own in the middle of a drive, and it took 30 minutes for it to get a signal.

I'm at the tail end of my warranty and am probably going to push for a replacement.

 

[CynicX]

The XXL has the IV? News to me, too.

The biggest benefit to the IV is the lower power consumption. The additional channels won't matter unless/until Europe ever gets the Galileo system up and running -- there's not as many satellites in the air as the IV has channels and won't be in the foreseeable future! It's also supposed to deal better with multipath issues which might help things just a little in "urban canyons". I don't see it as a huge improvement for automotive navigation apart from a little bit better battery life -- and the backlight is a huge consumer there. The phone and PDA guys who count every little milliamp are going to appreciate it more (specifically, the SiRFatLas IV platform). Haven't seen any of the usual suspects in the handhelds (e.g., Garmin, DeLorme, etc.) pick up on the IV yet.

Navigon was the first (and only) group I have seen using the IV in an automotive unit.

I could be wrong. My assumption of that was the internet. First I found it on wiki on there tomtom page. I always take that with a grain of salt. But I found it somewhere else when researching the chipset itself with them saying it was going into certain tomtom models (but didnt specify)...

From reading that I just assumed it was common knowledge and you'd guys would know. Since you and dhn dont I beginning to wonder whats actually in there. You'd think Sirfstar or TomTom would document this information somewhere or somewhere better for the public to see...

Anyway I've read its biggest benefit is power consumption to compete in todays hand held market against the all in one chipsets. But I've also read its more accurate to then previous SirfStar versions the wording from the articles made it seem like it was a good bit more accurate too.

 

[dhn]

Well, just checked the diagnostic screen on the 540 XXL unit I have here. According to it, the gps set starts with GL. So, it appears NOT to be a sirfIII or any sirf chip at all.

 

[mvl]

I checked in a store and all the current tomtom's have the Broadcomm GL2 chipset, except for the GO x30's which has the Sirf3. Even the GO 740 has the GL2.

But they all seem to have perfectly fine reception except for tall building locations. I think TT tuned the software or installed better antennas in the newer devices.

You're stuck in the never ending cycle of feature creep with consumer electronics. Here's how I look at things:

- every consumer electronics device will be worth 50% of what you paid in one year. So consider it rent, if you're willing to pay half the cost for a year's worth of value, then go get the new gadget
- get comfortable with craigslist, you can buy and sell used for much cheaper, and really monetize the 50% rule. It also allows you to feel comfortable buying up when the "rent" is worth it

I do the above, and I'm on my 6th Tomtom. My wife is so good at craigslist, that I've actually turned a profit on a couple of my Tomtom sales (so I used them for a year nearly "free"). For now, I'm gladly keeping my 740 for weekdays / 930 for weekends, until something more valuable (eg: HD traffic) comes out.

 

[killerz298]

I have noticed the same thing on my GO 920 the past month or so. I update on computer almost daily but the past month or so it seems to be dropping the signal more and more frequently and takes some time to get a fix when it first turns on. This unit is about 2 years old but has only recently started having this problem.

 

[canderson]

I have noticed the same thing on my GO 920 the past month or so. I update on computer almost daily but the past month or so it seems to be dropping the signal more and more frequently and takes some time to get a fix when it first turns on. This unit is about 2 years old but has only recently started having this problem.

In your case, it could be just a problem with a bad ephemeris file. Does Home offer you a new GPSQuickFix file each time you connect to Home?

I'd kill off any files in your 920's "ephem" folder (one each tlv, txt and ee file), and all of the sub-folders in your computer's My Documents/TomTom/Home/Downloads/complete/ephemeris folder.

Then use Home to connect and get a fresh one.

That will assure you're getting a current and non-corrupt file. There's one type of "bad" one that will keep future ones from loading.