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Posts: 465 | Thanked: 149 times | Joined on Oct 2007
#761
Originally Posted by lardman View Post
P.S. Regarding using SSIDs to work out positions, this is probably the next step - to use GeoClue (in with whatever backend) rather than agps-ui. I hope so anyway
IP address, you mean?

I don't see how you're going to get any useful information from an SSID like "linksys", "default", "johns house", etc..
 

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Benson's Avatar
Posts: 4,930 | Thanked: 2,272 times | Joined on Oct 2007
#762
No, there are 2 SSIDs; the MAC address of the AP is also an SSID (BSSID, actually...), and that's what I meant.

Lardman, I haven't used it, and am not all that knowledgeable about GPS in general, so I guess a little less dogmatism (from me) would have been in order. But I think you're confusing AGPS with DGPS/WAAS. AGPS doesn't know a thing about the ionosphere, etc.

Last edited by Benson; 2008-06-24 at 08:07.
 
Posts: 2,102 | Thanked: 1,309 times | Joined on Sep 2006
#763
Lardman, I haven't used it, and am not all that knowledgeable about GPS in general, so I guess a little less dogmatism would have been in order.
My apologies, I was in a rush, so I should probably have phrased my answer differently.

But I think you're confusing AGPS with DGPS/WAAS. AGPS doesn't know a thing about the ionosphere, etc.
Rather than producing corrections in the way WAAS/DGPS would do (I know I'm here, so this is the error), the AGPS system provides the Ephermeris data which allows the AGPS chipset to know which satellites are in view and how quickly they are moving (to allow it to a) work out which frequency to try to record data from for each satellite, b) work out how much of a Doppler shift to apply to said frequencies due to the satellites movement).

I take back what I said about ionospheric disturbance, perhaps. For this reason: The satellites broadcast Almanac (gross pos'n/speed data) and Ephemeris (fine corrections), the GPS chipset must presumably then use this data to generate a list of frequencies (for the satellites it knows are in view) and frequency offsets (for the Doppler shifts of said satellites knowing their positions and speeds). The SUPL (AGPS) server presumably either provides the AGPS chipset with the raw Alamanac/Ephemeris data from which it does these calculations *or* with the pre-processed data (the former approach would require no processing on the SUPL server, it would simply forward the data it has received from the satellites/DoD; the latter approach would require that it models the location of the satellites and can provide the pos'n/speed for any position on Earth - wherever an AGPS chipset is sat and asking for directions).

From what I've read, there are a few different types of AGPS service, and one of these (at least) allows the AGPS chipset to send fragmentary signals back to the SUPL server and it will use brute force to work out the receiver's position (without the receiver needing to capture all of the signals, which contain the Almanac/ephemeris data).

So to sum up, I'm not completely clear on what is/can be done either, but for the last case, knowing ionispheric conditions is probably necessary.

It's an interesting topic, perhaps we should branch it off into a seperate thread to avoid polluting this one?
 
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Posts: 2,535 | Thanked: 6,681 times | Joined on Mar 2008 @ UK
#764
Originally Posted by dblank View Post
I don't see how you're going to get any useful information from an SSID like "linksys", "default", "johns house", etc..
But if you can see "linksys", "default" and "johns house" - and their associated MAC addresses by passively checking the APs in range, you can send that data over an active connection and get your location:

http://www.maemopeople.org/index.php..._triangulation

It's how, for example, the iPhone and iPod Touch - both without GPS - do their location-based services.
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Benson's Avatar
Posts: 4,930 | Thanked: 2,272 times | Joined on Oct 2007
#765
Nitpick: the 1G iPhone. The 2G iPhone (the one with 3G has GPS, doesn't it?
 
Posts: 243 | Thanked: 172 times | Joined on Sep 2007 @ silicon valley
#766
Someone I know is working on an academic research project, sponsored by nokia, which attempts to determine your location from wifi signal strength. Don't know more about it than that.
 
Posts: 465 | Thanked: 149 times | Joined on Oct 2007
#767
Originally Posted by Jaffa View Post
But if you can see "linksys", "default" and "johns house" - and their associated MAC addresses by passively checking the APs in range, you can send that data over an active connection and get your location:

http://www.maemopeople.org/index.php..._triangulation

It's how, for example, the iPhone and iPod Touch - both without GPS - do their location-based services.
Ah, I get it now.

I wonder how long it took Skyhook Wireless to drive all over the place and build their database, that's crazy

Hopefully they keep it up to date!
 
Posts: 31 | Thanked: 3 times | Joined on Jun 2008
#768
i just looked on the maemo site, and maemo 4.1 is out!!! unfortunetlly im a noob and dont know what its improvements are, but go check it out at the maemo site for yourself!!!
 
Posts: 7 | Thanked: 1 time | Joined on Jun 2008
#769
How do I install aGPS-ui on my newly updated N810? I googled aGPS-ui and got this:

http://catalogue.tableteer.nokia.com...ser/a/agps-ui/

I tried to install it but:

Application packages missing:

libglib2.0 (>=2.12.12-losso10)
libosso1 (>=2.16)
supl-daemon (>=0.27)

Where do I get these packages? :[
 
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Posts: 3,096 | Thanked: 1,525 times | Joined on Jan 2006 @ Michigan, USA
#770
To answer the question "What do we know about Diablo (Maemo 4.1) ?"

I know that using Diablo, it will let me run Microb under other window manager instead of only matchbox. Now you can have microb available under your favorite window manager.

This is awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
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To all my Maemo friends. I will no longer be monitoring any of my threads here on a regular basis. I am no longer supporting anything I did under maemo at maemo.org. If you need some help with something you can reach me at tablethacker.com or www.facebook.com/penguinbait. I have disabled my PM's here, and removed myself from Council email and Community mailing list. There has been some fun times, see you around.
 
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