GPS - Can't get a fix
 

I know that the GPS can take a long time to get a fix, but i've been walking around with my N810 for at least an hour out in the open and i couldn't get a fix.
I've also tried the A-GPS app, but the thing that puzzles me, is that i does find satellites, it just doesn't seem to use them:
http://justgeek.de/stuff/gps1.jpg
http://justgeek.de/stuff/gps2.jpg

Any ideas?

Re: GPS - Can't get a fix
 

with the A-GPS, if you don't click on your location properly, it will cause you to never got a lock.

Also, perhaps try not moving around until you get a lock for the first time.

Make sure you can see the sky clearly as well (tall buildings and lots of trees can block the signal)

Re: GPS - Can't get a fix
 

Thanks,
i clicked on my location as close as possible - is it possible to zoom in the map?

I've tried to stay in place for some time but probably not for more than 10 minutes or so, curiously, i've left the GPS on in my appartment for the last 2 hours, and i'm now up to 12 visible satellites, so appearently the walls don't block the signal completly. This is near the window on the 7th floor of a 17 floor building.

But i'm just confused, if the gps can see 12 satellites at the moment, why doesn't it get a fix? I would understand if it couldn't find them, then i would try to improve the reception. But if it sees 12?

Bye,
NsN

Re: GPS - Can't get a fix
 

I dont know which is a bigger problem, cant get a lock or cant get a reliable lock. Cant lock, simple, you just bought it, right? call Nokia and get a replacement. Cant get a reliable lock is problem. And that is what I have. Sometimes it locked within minutes, or more likely, it locked in 5 - 10 min. But occassionally, it never lock, and after 'waiting' for 30 min or so, a reboot, sometimes will get it locked within minutes. And sometimes, it just wont lock even after hrs and hrs. Mine is still 5 months old, I am really really thinking to get a replacement, as most user reported lock in under 2 min. :(

BTW, I digged out my GPS for the winCE machine, only about 3 yrs old. It also takes somtime to get locked. It is NOT or SiRF III unit. However, the difference is, this GPS will lock, after 4-5min and you can depend on it to lock after 4-5min. While the Nokia, no telling.

bun

Re: GPS - Can't get a fix
 

Not sure that's strictly true; I presume that once the satellites are in view, the ephemerides they provide will override those provided by agps, but then again one never knows. In any case you have 5 satellites in view there but no lock, I've seen that before and don't know what the cause is (except the gps chipset/snr level).

Re: GPS - Can't get a fix
 

You could contact Nokia, but the fact is that the N810's GPS is problematic and they are aware of this. If A-GPS doesn't help consider to get a BlueTooth GPS device with good chipset instead. I recommend Sirf-III. These go for 10-30 EUR/USD/GBP. If you do so, consider to contact Nokia about your decision.

Re: GPS - Can't get a fix
 

this is what i have found that works.

first open agps-beta while you have a net connection.
hit your location with some accuracy.
*close* agps (this is the step i found on this forum- that makes all the difference in the world)
(you will never get a fix if agps is still running)

open maemomapper or wayfinder
click on the satellite view you should see numbers of satellites

and voila you should have a fix within a minute or two.. it works for me within1-2 minutes if i am stationery.....longer if i am driving

Re: GPS - Can't get a fix
 

Read this off : http://andrew.daviel.org/N810-FAQ.html

Re: GPS - Can't get a fix
 

A-GPS is not a viable solution for many users. There should be better driver support for the GPS that comes with the N810 to allow lock with satellites much faster.

Re: GPS - Can't get a fix
 

enlighten me why is not agps a viable solution? you set it and forget it

Re: GPS - Can't get a fix
 

Because even with A-GPS it takes a long time to get a lock/fix...

Re: GPS - Can't get a fix
 

That's not the fault of agps (as far as we know), but with the chipset sensitivity/programming.

Re: GPS - Can't get a fix
 

you are correct 45 seconds to lock is a long time- that is how long it just took in my office.

it does not take longer than 45sec-1min if you use agps properly:

1. open agps while connected to the internet( make sure that in the settings a-gps support is checked off and allow packet data is checked off.

2. locate your position on the map. move the red dot to where you are located.

3. allow the agps to download the satellite info (depending on the speed of your connection - it can be as short as 1 min. when i fly before i leave i set my destination on the map and set agps do it stuff while i am home on my fast wifi connection.

4. CLOSE AGPS

5. open map or maemomapper (your choice) and you WILL have a connection w/i 1 min

Re: GPS - Can't get a fix
 

How do you know A-GPS is doing anything or when it's done? I don't see any sort of activity indicator or status bar. TX

Re: GPS - Can't get a fix
 

Fact is, for many people AGPS doesn't make the application much better at all. It remains barely if not at all usable. I can have 10 or 12 satelites in view, it doesn't matter anything. It just doesn't become green. No lock. Whether it knows about them or not doesn't matter.

Screw it. I was in the middle of Amsterdam waiting for several minutes, no lock. With AGPS. Then walking. Heck, for hours I had no lock. And sometimes it had a lock, and then gone again. Here south in mountains it isn't much better either.

With a Sirf-III BlueTooth GPS however... purrfect. Quick lock, stable lock, and more satelites in view as well.

Re: GPS - Can't get a fix
 

AGPS is of use when you have geographically moved a great distance and the GPS has been off during your move. you will need a net connection in order to use AGPS properly.


the killer for GPS and Time To Fix is the antennae and antennae sensitivity.. stand alone GPS devices have better TTF as they do not have any other electronic features apart form being a GPS device, a mobile device has many high frequency components in it which may affect the receiver....

GPS lock is pretty dodgy in built up areas, I have found.

Also a small delay to get a fix is just bearable IMO..

regards,

Re: GPS - Can't get a fix
 

Hmm... maybe I was just lucky but on a plane from Helsinki to Paris today I got fix in less than 5 minutes, with A-GPS disabled... (The tablet was on the window, though.)

Re: GPS - Can't get a fix
 

hmm, I sat for 40min on an airliner with ~9sats showing signals (had used agps earlier, but had 9 sats anyway, so that's immaterial) and no fix. So ymmv ;)

Re: GPS - Can't get a fix
 

lardman, if you recall I had the same problem and it cured itself immediately after popping battery.

I had sat n810 on the balcony whilst on holiday all afternoon.
It could see many sats but simply would not lock.
After I returned and found this out I popped the battery, put it back in the same place and it had a stable lock in a very short time.

My cargo cult suggestion, if you are expecting to use gps ensure you have given the device a hard reset before.

Re: GPS - Can't get a fix
 

Yea, but a hard reset kills the battery life....
It has never taken more than 10 mins to lock for me when I am in the car or walking. Obviously, it is faster when standing still. Usually, I start MM, get in the car, and by the time I am at the end of the (short) street, it works. Its still not as fast as say my Dad's built in Car GPS, or a iPhone AGPS, but it is fast enough for directions...

Re: GPS - Can't get a fix
 

A-gps isn't a total solution. It doesn't impact the sensitivity of the GPS, it provides a shorter list of satellites to search for and will by definition help some. There are a number of factors that can impact the fix time. I believe satellite communications works best line of sight. The odd tree could impact it. I wouldn't rule out driver changes but the issues are more likely the chip set itself or perhaps the antenna design. If the 1st GPS fix time is that important you, there's the option to purchase a separate bluetooth GPS receiver.

Re: GPS - Can't get a fix
 

A quick thing I learned about weak GPS, like the N810. If the tablet gets a "reflection" of the signal, it will mess up because the reflection is out of sync. Usually it will correct itself, but sometimes it just acts stupid a refuses to lock. That is why restarting works, because it forces a rescan of sorts.

Re: GPS - Can't get a fix
 

A-GPS should be called A-BS. I've tried it, and yeah there's a recognition that there should be 8-10 satellites visible -- but you can leave cheap N810 facing south, top up, shaking a dead chicken for hours and not get a lock. We just need to realize we've been ripped off.

Pausing on the street, pulling over your car, whatever -- your friends are sitting there with their iPhones wondering what's wrong with you. My wife won't even let me turn on the dumb N810 in the car any more.

Re: GPS - Can't get a fix
 

Satellite signal reflections from buildings in NYC can be a challenge for a GPS or almost any wireless device. Perhaps more so the N810's GPS. A-GPS won't overcome that kind of problem. I've found that A-GPS does help in Fresno CA but we don't do lots of tall buildings here. We all wish that Nokia had made a different choice for GPS chip in this device. You may not find this acceptable but a bluetooth GPS receiver with the Sirf-III chip would likely give you the performance you are seeking.

Re: GPS - Can't get a fix
 

There do seem to be some locations that are particularly bad and for no apparent reason. One really bad spot for me is on and around the Millenium Bridge over the Thames. I have tried numerous times and can never get a lock there. I suspect either something is jamming it or there are reflections from the bridge structure. Standing in the middle of the Thames you are a long way from the buildings.

If you walk a few yards up to St.Paul's and sit on the steps you can then always get a lock (after the usual random waiting period of course) despite being surrounded by buildings and having a stonking great cathedral next to you!

Re: GPS - Can't get a fix
 

It may be a little harder in NYC, but I have used my Pioneer in dash GPS unit very successfully. I have gone all over, including in between the tallest buildings with no problem. Yes, I was using a dedicated system but I am just pointing out that GPS does work in NYC. I feel that people are using excuses for the N810's GPS. GPS does work, the one in the N810 just sucks.

Re: GPS - Can't get a fix
 

Just my two cents on the issue of N810's GPS. If I'd purchased the N810 primarily as a GPS I would have returned it. Like many do it all devices not everything works as well as in a single function device. To me GPS was a plus but not a core requirement. The price of the N810 is justified for it's primary functions. I'll use the N810's GPS to learn about GPS use and and practical value. As much as I love gadgets they don't all make it into my inner circle of daily use. If the N810 GPS becomes unworkable I'll buy a bluetooth GPS receiver to improve the performance. I would still be spending less for GPS than if I purchased a quality stand alone GPS. On top of that I have an open source device that will be subject to free continuous improvement. That can't be said of proprietary units. Others may not agree with me but while they complain I'll be enjoying and daily using my N810 which has clearly made it to the inner most circle of my most used and loved gadgets.

Re: GPS - Can't get a fix
 

The N810 is my Swiss Army knife of computers.

When I need to use it's GPS I have to take into account it's limitations, but as George said "To me GPS was a plus but not a core requirement."
I too was frustrated by extremely long times to lock, since I've been using GPS since about '96 with an HP100LX. Since I loaded AGPS my lock times have been shortened IF I have time and net connection to run AGPS first after a move.

Getting off a plane after a long trip, no net, forget about it.

Re: GPS - Can't get a fix
 

The secret to my quick signal lock has always been using it with Nokia's HH-12 easy mount suction holder which makes for a fast lock. Putting the N810 in the cradle hold, turning on the map program, and twisting the holder so that the Nokia name is facing up and I'm getting under 30 second locks continuously. It's something about the water content in the human body when you actually hold the N810 in your hand it seems to block the signal. When it's in the holder, there's nothing affecting it, thus the quick sat fix. I remember testing it four days ago, indoors, at night holding it in my hand. Took me 2 minutes + to get a fix. Four days later, same conditions, same time, but in the HH-12 mount....fix time 20 seconds. I have never been disappointed by the sat time when the N810 is in it's mount. Now, I'm not discounting those that may have a less than working perfect GPS chip or the fact that location seriously affects the lock on, but all I can add to the conversation from my experience is that I am probably one of the few that doesn't have any GPS lock issues, but I give all the credit to the HH-12 mount for speeding up the sat time fix.

Sounds like I'm an HH-12 travelling salesman, but for me it's been the best thing for my sat acquisition time.

Re: GPS - Can't get a fix
 

I'm not convinced about the human body thing. I have tried sitting in the middle of a park with my N810 on the grass and also with it sitting on a bench and still had to wait 20 minutes.

I am running a number of these devices and have had three sitting on the same window sill. I can confirm that they have very different lock times. One of them is particularly poor and I can often wait several hours for that one to lock.

All my units were purchased at the same time from the same supplier and are running the same software versions. The poor one continually generates gpsd errors (even when locked) with no apparent cause.

The message is that manufacturing tolerances are probably to blame and, if your unit looks like it's a bad one, get it exchanged.

Re: GPS - Can't get a fix
 

Had a very frustrating experience again. Went for a 4-day visit to Berlin, and before going, I made sure the N810 had a proper GPS fix. When I got to Berlin it didn't get a fix, so I left it overnight at the hotel room window (19th floor) - but during the 4 day visit, it never got a fix, despite being with me , often in open places, in the day, and in the window every night.


Back here in Amsterdam it eventually got a fix again, but it is still very iffy. Whenever I start the map app (or maemo mapper), it can take hours for it to get a fix, even if it sees 10 satellites - it just doesn't lock to them.

Doesn't sound like a hardware problem to me - more likely software/firmware.

Re: GPS - Can't get a fix
 

julf, this again sounds exactly like my problem.
I now make a habit of rebooting properly before relying on gps.

I left mine all afternoon like you with no fix, after a reboot and placing in same spot i t got one very quickly.

Re: GPS - Can't get a fix
 

Tried a reboot (once again), and after 10 minutes 4 satellites are visible, but none in use - no fix :(

Re: GPS - Can't get a fix
 

I had the same problem while i was in Amsterdam. I bought a dedicated BlueTooth GPS with Sirf III chipset. Works perfect, fast lock, always have a lock, and don't lose lock either. They're sold on eBay (UK & DE) for 10-30 EUR.

If it takes a long time till satelites are visible you should try AGPS.

Also, there are reports minigpsd improves the internal GPS.

Re: GPS - Can't get a fix
 

Hi!

I have already been using AGPS, still doesn't seem to help. Will look into minigpsd, but you might be right, a separate bluetooth GPS receiver might be the answer - bit of a bummer, as I upgraded to a N810 especially to get the GPS capability.

Re: GPS - Can't get a fix
 

You're not the only person who is unhappy with the GPS of the N810, nor the only person who decided to buy the N810 for its GPS capability. What can I say? I share your pain. However, the N810 also has other (dis)advantages over the N800. If they're not worth it for you, you might want to sell the N810 and buy a different device instead (e.g. N800).

If you're using AGPS (and set it up correct) you should have satelites in view immediately. Not 10 minutes. However, for me, that still didn't solve the problem because I simply could not get a lock or if I had it it'd be so useless because it'd lose the lock. In the middle of Amsterdam (whole Amsterdam centre, Amsterdam Amstel).

Minigpsd isn't easy to set up IMO, but if you read the thread on ItT about it well you'll manage.

Re: GPS - Can't get a fix
 

Exactly the same experience with AGPS - the N810 sees the satellites, but doesn't get a fix.

Will try Minigpsd.

Re: GPS - Can't get a fix
 

Sometimes the A-GPS Beta does "lock up" so that the tablet will not get a fix. It has happened to me few times. I did fix it by going into A-GPS UI application and disable A-GPS. After that the tablet finds the satellites the old (slow) way, but does work after all. The other method (reboot) also helps.

I have had three different N810 tablets in my possession and all of them have been rather consistent with each others. All of them did get lock withing 2-5 minutes (without A-GPS) both in Texas and in Finland. With A-GPS the lock time is less than 1 minute. (Excluding cases with the A-GPS lockup issue above.)

So it could very well be that your N810 does have hardware defect (GPS antenna bad?) so that it doesn't get a fix. What I have noticed that the satellite signal strength needs to be over "30" (in MaemoMapper) to get a fix. If it is less, the tablet doesn't seem to get a lock, regardless how many satellites is visible. Have you checked the satellites signal strength if it is too weak? If it is then you should suspect HW defect.

Re: GPS - Can't get a fix
 

Hmm... I tend to get satellite signal strengths between 22 and 25, so it does indeed sound like something is wrong with the GPS receiver/antenna. Duh! I guess the N810 is out of warranty by now... :(

Re: GPS - Can't get a fix
 

That's sounds about same signal strength for my tablet if I try to get a lock inside my house. Doesn't the N810 have 1 year warranty?

To clarify at least the strongest satellite should show consistently over "30" signal strength. The other satellites can be weaker. I believe the GPS chipset needs to receive some data stream from one satellite in order to calculate fix. If the signal strength is too weak it will never get a good set of data, and will not get a fix. Once there is a fix the GPS can keep lock with weaker satellite signal.

I think there is some WiKi page where this is explained in great detail...