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Using the GPS Features of Your Cell Phone?

Posted by Cliff on from the everyone-else-knows-my-coords-why-can't-I dept.

travik asks: "I use a Nokia 3650. The cell phone already knows my co-ordinates (E911 service). It has Bluetooth. Why can't I send the coordinates using Bluetooth to my laptop, and use a mapping application to give me my location and directions to where i want to go. I've searched Google and also read up on old posts, no one seems to be doing it. Why?"

4 of 45 comments (clear)

  1. It's.... kinda possible by EnglishTim · · Score: 4, Interesting

    I wrote a program for my palmpilot that queried my mobile (a T68i) for it's current cell. I was going to make this into a program that would give me reminders based on my location, but I never got around to finishing it...

    The big problem is finding a record of all the cell values and their locations - I never found one for my service (O2), although I was able to get a list of all the cells on the way to work, just by running the program.

    The accuracy isn't great, although it gets better in central London. Near Oxford Street I was getting a new cell every 100 yards or so...

    1. Re:It's.... kinda possible by spiff42 · · Score: 5, Interesting

      I'm currently working on my PhD project involving location based services. From my research, I've discovered that a much more accurate location estimate is possible than the simple "strongest cell tower". Basically you meassure the signal strengths from all available towers (or access points), and do some calculations based on this information. Finally you find the best match in a database of location/signal-strengths, and interpolate a position.

      I first saw this technology used on WLAN. Ehahau uses this technology to provide location based services on WLAN, and it works great. In our test setup at the university, we get arround 1 meter error in the position.

      I've been in touch with a group of people at The IT-University of Denmark, who are working on using this technology on GSM cellphones. The biggest problem here is getting access to the data. The cellphone companies simply do not want to provide this information. Our collaborative guess was that they want to keep this information to themselves, probably to sell extra services.

      The main drawback of this technology is that a huge amount of calibration is needed to make it work. On WLAN our buildings have been calibrated in a grid of 3x3 meters, which makes quite a lot of calibration points when we want coverage of the entire campus. But the cool thing about it is that it does not require any extra hardware to do the localization. A labtop or PDA with wireless will do the job.

      /Spiff

  2. Not exactly the same, but... by oojah · · Score: 5, Interesting

    This guy tracks his location by phone.

    Where is Calum?

    Cheers,

    Roger

    --
    Do you have any better hostages?
  3. All CDMA has GPS, but not carriers by mockojumbie · · Score: 5, Interesting
    All CDMA phones in the last couple of years' generations have had GPS chipsets from Qualcomm, you can't get CDMA chips without it. The carriers OTOH, are waffling trying to figure out how to make money. All current CDMA phones must communicate with a SnapTrac server to using MS-assisted or MS-based; the carriers are not leaping to install these servers in their systems. We're authoring a Brew/Linux/PHP LBS system for a carrier, the first nationwide launch is still months away.

    You can download the location of ~all cell towers from the FCC
    http://wireless.fcc.gov/geographic/fcc_db.html
    (big files) as they are publically licensed, but you can't know the carrier's private ID # of the tower without matching the tower's license to what you phone tells you, as some do.

    The first test launch of a stand-alone GPS phone is several quarters away... The CDMA chips are basically capable, but need some extra hardware and firmware since they don't get a kick-start from the tower/server communication.

    Right now, if your carrier doesn't have the PUBLIC servers installed (they will not use their e-911 servers for commercial use for liability reasons) then you can't have GPS.

    And BTW, the carrier's servers do know your location because of the MS-* handshaking and communication (which allows the ephemeris calculations to be done faster on your phone), it's a question of whether it gets saved or tapped.

    It's---a-small-world-after----all---...

    --
    Sigs are for propeller heads.