BetaLabs

Thank you very much for your post. This is a nice posting. I really like this post and absolutely very usefull to me. Thank you.

I wanted to research this subject and write a paper. Your post what a thousand words would not. Nice job.

agps ui crashes everytime i select settings, very frustrating, as it worked well for a few days. i really don't want to re flash my tablet, but have tried everything else i can think of. any ideas?

Comments #4 and #7, did you read these lines:

"You need set the reference location at the first time you use A-GPS and everytime you have moved a long distance (>300 kilometers / 185 miles) from your previous reference location. Whenever your Internet Tablet gets a GPS fix your reference location will be automatically updated accordingly."

Some instructions and how you can verify that it is working:

Usage instructions:
1. Set reference location in A-GPS UI
(that location will be used to download the assistance data)
2. AGPS-UI can be closed
3. Start maemo-mapper,Map etc

Steps 1-2 are needed only when you have travelled > 300km(~185mi) from previous location.
A-GPS will always run in the background if it is enabled in A-GPS UI settings.
When you have GPS fix, reference location will be automaticly updated.
So next time when assistance data is needed, your last fix position will be used to download the assistance data.

To verify that A-GPS is working you can look the visible satellites from maemo-mapper or Map application.

In Map application you should see the list of visible satellites as soon as it has connected to gpsd.
In maemo-mapper it should show something like 0/n (n ~ 10) as soon as "Establishing GPS fix" appears.

After that is up to how good reception you can get to those satellites.

If it shows 0/0, then there was some problem downloading the assistance data.

Preferred connection:
Preferred connection is used when you don't have any connection up.
If you have WLAN connection up when GPS needs assistance data, A-GPS will use that connection to download assistance data.

mark bawden: one settings crash was fixed in 0.10-1beta.

Hope this will clarify a bit more how it is working.

Just a fix for my previous post "it could NOT get a lock even after 20 mins of driving"

Oh, of course we should not forget that the AGPS implementation in the tablet is currently at a beta state. That means that sometimes the AGPS could not start when you request a GPS location.
You will notice that when you ask for a fix and you won't get it as fast as it should be.

George N: It seems that agps is working for you if you can see those 6 or 7 satellites in view right after you have started Map or Maemo mapper.

AGPS-ui is actually just a settings UI for supl. You don't need to run it every time. Supl will be running in the background and get the assistance data for your last fix position.

The position you set in the agps-ui doesn't have to be so precise. That's why there is no number input possibility.

First of all, thank you Marko for comment 19. I have noticed an indication such as 0/6 satellites. You confirm the meaning: the GPS "assistance" information is indicating how many satellites should be in view. That clarifies that assistance is working.

Comments 20 and 22 refer in part to the N810 having poor sensitivity in weak signal conditions. I would agree. If I walk away from trees and houses, my fix can be amazingly accurate. With a satellite picture loaded in Maemo Mapper, as I walk along a footpath, the fix puts me right in the middle of the path, error less than a meter. But any tree or building can make the fix erratic.

My guess is that "assisted" positioning with no cell phone means that the new software gets almanac and ephemeris information over the net. The Wikipedia article on assisted GPS teaches that assistance can take various forms. So, the assistance should help the N810 to get a fix faster, without waiting for so many data to trickle down from the satellites. But it does not entirely compensate if the receiver is weak, one would suppose.

Persons with more detailed knowledge may wish to clarify.

I just tested AGPS and I'm going to have to agree with comment #4 as well. This is plain silly. According to the required specifications, AGPS is typically done using assistance from cell towers. The N810 does not have such a luxury unless you are using the WiMax edition and that one is rare at best.

Is there anything real that Nokia can do to improve not just the performance of GPS, but also the reliability? I can't walk by anything taller than my arms without losing a signal, and that's with 60% of the sky open to my other side!

Not to mention, with a lock on 6/10 satellites, my location can jump .25 of a KM while standing still!

There are some things about the GPS that I do like, but in a lot of ways, how can anyone rely on this functionality? It seems more like false advertising just to get the logo on the box.
If sticking a GPS receiver in a small case entitles one to be considered "making a GPS enabled product" justifiably, I have a lucrative lead on business idea for any investors reading...

I guess I agree somewhat with number 4. If I step outside and get a fix, that location should over-ride the location that I put in by tapping the world map. The GPS is 1000 times more accurate than tapping a tiny world map.

I would be interested to have more explanation. Also, if the design is over-simple, then I hope that you keep working on it!

Having said all that, I followed the directions by tapping on the map and then stepped outside and the N810 did get a quick satellite fix. It seems that if it loses the fix because of physical obstructions, then it can recover quickly. So indeed even this beta is a great step forward.

Thanks!

On my first N810, the A-GPS beta was quite effective, reducing times from several minutes to a minute or less. Unfortunately the screen died, so I got a replacement. On the replacement, with the OS update and A-GPS beta installed and set, fix times vary from 3 mins to 40+ mins(!) in open country. It's depressing to be halfway to your destination before the GPS gets a fix... As previous posters have suggested, it would be really useful to have better feedback on the GPS status.

When first installed Diablo and ran AGPS all was well. Fix times were less than a minute.
After I installed Diablo update and cloned to my internal 2gb mmc all was not well, fix times went back to A LONG TIME.

Procedure I use:
I fire off AGPS
I try to put the point within a degree N and W of my position (why can't we enter numbers? or at least zoom into the continent)
I fire off Map w/GPS
I fire off Maemo mapper, check satellites in Maemo mapper
6 satellites or 7 sats show up in view.
I go away for 5 to 10 minutes - no satellites in use.

I've got the same clear sky where it ran quickly before the Diablo upgrade.

Are there any known apps that interfere with it?
Are there certain files I could clean out and reinstall?

My profession is mapping and this is very frustrating.

So do I understand correctly that AGPS does two things:

1) Queries the Internet when GPS is turned on to get the list of visible satellites, rather than spending time listening around to see which ones can be received.

2) Allows the user to input the current location (if it's changed much) so the satellite list is accurate.

So if there is no Internet connection, the fix will be as slow as before, right?

Now, why does it need the Internet? My Garmin iQue computes and displays the current satellite configuration as soon as its GPS is turned on. Why can't this device do that?

Folkssssssssss...please...what can i do to use my GPS in nokia N810...i bought this thing a year ago and i ever ever used the GPS Application...is so bad!...is terrible to me...please..any help will be very good!....thanks. alejo1820@yahoo.es