Your help needed in improving N810 GPS performance
 

I've created bug 2877 to let Nokia know that we are not thrilled with satellite acquisition times on N810.

Please go to

https://bugs.maemo.org/show_bug.cgi?id=2878

and vote for this bug.

Thanks.

Re: Your help needed in improving N810 GPS performance
 

using the statusbar process viewer, the following command will allow you to start the GPS and log NMEA output to the external card (without running the actual map program):

sh -c '/usr/libexec/navicore-gpsd-helper >>/media/mmc1/gpslog.txt'

It is not timestamped, but can show the acquisition process.

You can watch it better in an xterm, but this lets me turn the GPS on for my old zmapper I ported from the zaurus.

Re: Your help needed in improving N810 GPS performance
 

just voted for the bug. Here's hoping someone pays attention!!

Re: Your help needed in improving N810 GPS performance
 

Voted! #1 biggest irritant with the otherwise great n810!

Re: Your help needed in improving N810 GPS performance
 

It's interesting that so many people complain about this ... I'm running OS2008 build 2007.50-2 on an n810, and I get lock times of far less than a minute when in my car. The first lock time after purchase was under 3 minutes or so. The lock times compare favorably to my Garmin eTrex.

I wonder what causes some people to have such a poor experience? I was prepared to be underwhelmed, and was therefore pleasantly surprised by what I found.

Re: Your help needed in improving N810 GPS performance
 

Just added my vote. :D

I imagine that geographic and weather conditions play a significant part in this. Like if you're around tall steel buildings for example, I'm sure it doesn't help anything.

Re: Your help needed in improving N810 GPS performance
 

I just tried it today, but it locked fairly quickly. But it was on my dashboard with a very open view of the sky.

Re: Your help needed in improving N810 GPS performance
 

This would be a great GPS chip to have in a future tablet:

http://www.u-blox.com/products/lea_5h.html

1 second TTFF with offline AGPS, 4 HZ update rate, 50 channels, sees both GPS and Galileo sats.

Re: Your help needed in improving N810 GPS performance
 

Generic use mobile devices are always compromises, that thing is not: it's huge! The chip footprint is 8 times the footprint of the current TI chip, and that's what matters here (as long as a minimal level of performance is reached) -- anyone interested in high performance can just buy an external device.

If we look at the current crop of TI offerings, as we should for future products, the difference is actually 15 times (25 mm2 vs. 381 mm2). I'm sure the power requirement difference is in the same direction...

Re: Your help needed in improving N810 GPS performance
 

It's only 17x22 mm. Roughly the size of a miniSD card. Sure they could find space for it in a 5" tablet.

The chip is supposed to be very power efficient.

Re: Your help needed in improving N810 GPS performance
 

Heh :) Open the device and see, or talk to an engineer who was involved if you can.

With the N800 you would have a point, but the N810 has significantly smaller dimensions and includes a slide-out keyboard. The thing is absolutely packed full, finding four square centimeters of empty space is an impossibility, IMO.

EDIT: forgot to mention the FM radio: I don't know which chip they used in N800, but AFAIK even the cheap FM receiver chips are smaller than 30 mm2. That was too much for the N810...

Re: Your help needed in improving N810 GPS performance
 

Like they found space for fullsize SD slots and an internal slot in the N810? Oh, right. ;)

Re: Your help needed in improving N810 GPS performance
 

With the new patched gpsd the fix times are really comparable to a standalone GPS unit. So why bother?

Re: Your help needed in improving N810 GPS performance
 

I've taken the N810 out on a walk (cloudy day) on fairly open streets, and i did not get a lock between leaving my house and arriving at my destination (16 minutes).

Setting the device down (in the open) and not moving it seems to generally yield locks < 1 minute though. Is it normal for gps receivers to have more problems getting a lock when orientation varies frequently (hand-held)?

Re: Your help needed in improving N810 GPS performance
 

Yes, it takes longer when you are moving. Although I am usually able to get a lock while moving in a time range from 2 - 5 minutes, sometimes even faster. However, when you drive at 150 km/h it takes very long ;-)

Re: Your help needed in improving N810 GPS performance
 

Looks like it is the case ArnimS...
I usually let it get the fix putting it facing the sky near the windshield and then putting it wherever I want as it is very good in keeping the fix after it got it (while it takes forever to get it when it is not in a good position).

Re: Your help needed in improving N810 GPS performance
 

I do not thinks it is the movement that is the problem. I noticed the same thing with my BT-338 and I think it was my body (full of water...) that blocked some of the signal. If I held out my arm with the GPS in my hand I got a fix.

Re: Your help needed in improving N810 GPS performance
 

Consumer-grade GPS units in general have big problems getting initial lock if you're moving. Better keep still until it's got a fix, then start moving. (Some, particularly new GPS units, are better at this though. My TomTom Mark I GPS locks fast when still but takes a very long time if I move (in both cases it's located at its normal place in the car). I haven't yet tested my Holux M1200 for this.)

Re: Your help needed in improving N810 GPS performance
 

For the newbies in the crowd, can someone please provide me with the exact steps needed to patch the gps software in the Nokia N810 to possible fix this slow sat aquire issue.

I've downloaded the osso-gpsd_1.0-25.tar file. I've extracted the contents in to the internal memory of the Nokia. what do I need to type in to xterminal to actually apply the patch?

Any help would be appreciated.

Re: Your help needed in improving N810 GPS performance
 

Fullsize slots are not essential on N810 and neither is an FM radio. microSD cards work just fine. On the other hand, a high quality GPS receiver takes the device to a whole new level.

I wouldn't mind buying a tablet that was 1.5 mm thicker, or had a slightly smaller battery, in return for 1 second TTFF with offline AGPS. Perhaps this is just me.

Re: Your help needed in improving N810 GPS performance
 

No it's not just you. I also want AGPS enabled, simply because it's there (hmm, I wonder what else is there but doens't work... IVA, PowerVR, etc.).

I've added a bug/enhancement request for the AGPS: https://bugs.maemo.org/show_bug.cgi?id=2890

Re: Your help needed in improving N810 GPS performance
 

I suspect we will get PowerVR support when the successor to the N800/810's arrive. It will then be worth their time to put a developer on support.

Yesterday I got lost in New Orleans and the GPS locked on in about 2 minutes. Unfortunately, in those 2 minutes my iPhone found my location within 50 feet (without even having a GPS) and gave me directions to my destination :(

Re: Your help needed in improving N810 GPS performance
 

well, life is tough. try this in the middle of a desert. i wish n810 gps had faster aquisition times too, but hey, it is cheaper or as cheap as my Garmin Etrex Vista C, and I was actually able to use it for navigation during my trip to Costa Rica last month thanks to maemo mapper maptile caching (wayfinder doesn't have maps for central america and getting maps to garmin handhelds is pain in the ***, so i just used google maps for free!). and ofcourse you can use n810 for tons of other things and you can actually develop stuff yourself for it. no reason to whine imho, sorry for a long rant.

Re: Your help needed in improving N810 GPS performance
 

That is ridiculous. The built in GPS is a big selling point for the n810. What if the audio jack wouldn't play music for the first 30 minutes? Would it not matter because of the cool kickstand?

Re: Your help needed in improving N810 GPS performance
 

no, but one shouldn't expect n810 to perform well as a music player in hi-fi audiophile setup. if you need that you get dedicated device with good DAC like 5.5 gen ipod. same with gps or any other feature. when you get universal gadget like this for it's price there are compromises to be made. i'd be very happy if you can point me to device with the same feature set and expansion capabilities for the same price.

but i'm sure it's possible to improve current aquisition/reception quality in software and i'm all for augumenting it with wifi bssid based location info.

Re: Your help needed in improving N810 GPS performance
 

I would appreciate seeing this too.

Re: Your help needed in improving N810 GPS performance
 

The patch is no longer needed. It was only supposed to work until the end of February (it fixed a leap year bug). Even in February it apparently didn't help; the improvements people were seeing may have been due to a placebo effect.

Re: Your help needed in improving N810 GPS performance
 

There seems to be some debate in the bug thread about whether there is a real improvement, a placebo effect, and/or a leap date effect.

Since I don't have the background to evaluate the discussion, did not get a good fix today (after Feb. 28), and would like to install the gpsd patch without reflashing - is there anyone who would be kind and tolerant enough to give a newbie some easy directions (and where to download the patch)? For my part, I can get to be root in xterm. Thanks.

Re: Your help needed in improving N810 GPS performance
 

Some reported quantitative improvements, so I doubt the situation was that simple...

Re: Your help needed in improving N810 GPS performance
 

I know it is a big step but flashing to the newest OS 2008 (there was a more or less silent update, at least I didn't notice there was a new firmware) fixed all issues. I get fix in under 40s under clear sky...

Re: Your help needed in improving N810 GPS performance
 

I will be travelling and using the GPS in the near future. Reflashing (including any possible problems) has to wait until I return. So if there is a quick patch just to the GPS, I would install it now.:) If I knew where and how.:(

Re: Your help needed in improving N810 GPS performance
 

plese note before you do this you could do serious damage to your n810 causing you to have to reflash. however i have not suffered any issues at all...ymmv



xterminal
sudo gainroot
apt-get update
then when that completes
apt-get upgrade
(answer y to the 2 questions about downloading and installing stuff)



this will upgrade a boat load of stuff and when i did it just before 2/29 i saw a gps upgrade slip in - since then my lock time has been "spot on" on the order of my garmin ctrex legend c


once again i do not want to responsible for anybodies bad vacation experience and i can only advise what i did and the results of what i did.....

Re: Your help needed in improving N810 GPS performance
 

Thanks! I will give it a few hours to see if anyone posts a bad experience or more explicit warning, and then do a backup and give it a try.

Re: Your help needed in improving N810 GPS performance
 

Would not recommend what prk60091 posted. My tablet now is in infinite reboot. I'll have to reflash or something when I get home today. I am not worried and thought it would be fun to try, but the second yes on in the terminal can be a killer I guess.
Isaac.S

Re: Your help needed in improving N810 GPS performance
 

Thank you both, isaacs and prk60091, for sharing your experiences. Sounds like I should try this, but not until I have time to deal with any possible consequences.

Re: Your help needed in improving N810 GPS performance
 

Well, my GPS also improved (not that much, 10-20%) after flashing new 2007.51 image.
Never had a real problem with it. The idea is that acquiring a lock needs a clear view of the sky, lack of RF interference and metal objects around helps too.
I was fairly amused when I was checking the maps and forgot to disable GPS... took a lock in like a minute and a half. In the middle of the city.

AFAICS maemo-mapper caches GPS almanac. The problem is that w/o having a GPS run for two days at different times you wouldn't get the locations of all sats with enough precision to be able to predict positions at all times.
It'd be great if maemo-mapper could correllate and correct (at least partially) that stale data vs approximate current position, say, selectable on the map.
Could somewhat improve lock times in cases of reflections.

Re: Your help needed in improving N810 GPS performance
 

How is it going? Better? Worst? No change?

Thanks

bun

Re: Your help needed in improving N810 GPS performance
 

I'm ready to try it, but leery about losing installed software, especially claws mail which I've spent some time setting up.

Does anyone know if backup includes claws mail's setup data?

Is there a simple way to copy my RAM contents to an SD card so I can try to get application data back afterwards? I can get into xterm but am not familiar with the file system layout.

Re: Your help needed in improving N810 GPS performance
 

I posted the following comments in bugzilla:

-cold fix times are much shorter if the antenna is pointed to the south (in the north hemisphere) than towards the north. This suggests that the GPS chip does not use the correct doppler shift.

-hot fix times are short if a cold fix was done using the wayfinder map application. If I use, say, maemo mapper only, hot fixes are not shorter than the first fix (cold fix), suggesting that almanach or last position data is not saved correctly when using another application than the wayfinder map application.

Re: Your help needed in improving N810 GPS performance
 

None of them worked for me. I drove from NJ to Baltimore (65min) GPS is NOT locking. I rebooted the N810/2008OS it then locked in 21 min. I am ready to reflash or return to Nokia...


bun