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  1. #1
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    GPRS, Bluetooth and GPS

    Hi.

    I would like to know if its possible in mobile java on a nokia phone to build a setup like this

    bluetooth GPS <-> Nokia Bluetooth-phone.

    Then i would like to read the messages from my bluetooth GPS unit on the Nokie phone, and transmit the message via GPRS to an server.

    Is this possible in Java? Or are there some security restrictions that would interfer with this idea?

  2. #2
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    Re: GPRS, Bluetooth and GPS

    Here is almost similar threat.
    http://discussion.forum.nokia.com/fo...=GPS+bluetooth
    BR
    Ali

  3. #3
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    GPRS (EDGE) > GPS ?

    Can we make that :
    When devaice Don't have GPS whe are attempting to force the GPRS
    (or EDGE on S40v5) to play like an GPS i think that will be posible
    if i'm correct but maby i'm not ...

  4. #4
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    Re: GPRS (EDGE) > GPS ?

    You are likely talking about Cell-IDs (as in order to be able to use network based locationing the phone has to support JSR-179 and the operator has to provide such service).

    If this is the case, the please note that Cell ID does not tell anything about the location, just the ID of the cell tower your phone is currently connected to.
    On some devices the CellID information can be retrieved with using system property mechanism, but on Series 40 devices you eed to sign your MIDlet with an operator certificate, which in general requires close partnering with the operator in question.

    Hartti

  5. #5
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    Re: GPRS, Bluetooth and GPS

    ok let me explayn what i'm tryng to do in mat way
    we know that GPS use satellites we have cell towers ok
    so we know that JSR-179 can't tell the location of the CellPhone
    we are going to do it this way
    Aw = T2 - T1
    so the Aw is the Cellphone the T1 is the time that we send
    request and T2 is the time that we recave the answer of the requset
    and we can understend the location of the cell phone
    it's simple i think

    Petko


    Maby we need a new thread ?
    Last edited by piko1; 2008-10-11 at 22:17.

  6. #6
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    Re: GPRS, Bluetooth and GPS

    I did not really understand, but I would say that no.
    Seems that you need to study a little how cell network works and also check the basics on geometry.

    In short, you can skip the following detailed (and hurried) answer. But I'll try to explain my view.

    we know that GPS use satellites we have cell towers ok
    What do you mean by "we have cell towers"?

    so we know that JSR-179 can't tell the location of the CellPhone
    If the phone does not support JSR-179, then yes, correct. Otherwise, no. Or then I do not understand.

    Aw = T2 - T1
    so the Aw is the Cellphone the T1 is the time that we send
    request and T2 is the time that we recave the answer of the requset
    and we can understend the location of the cell phone
    Ummmm... no. Or to be more exact. I do not understand.

    Seems that you want to measure the time between two requests.
    And by requests I think that you mean sending some kind of "ping" to the cell tower and measuring the time between receiving the signal back and sending it.
    This kind of low-level control of the cellular interface is not available.
    Additionally the timers on the phones are not accurate enough.
    And finally, you would need to know the location of the Cell tower (which you do not know) and still you would only be able to place the phone a certain distance of that tower in space, which geometrically speaking is a sphere (ball). Yes, the cross-section of that ball and earth's surface is a circle, but still a circle. You would still need two more measurements with different cell towers, in order to be able to pin-point your location . This is definitely not possible.

    Hartti

  7. #7
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    Re: GPRS, Bluetooth and GPS

    ok see the graphic:
    http://files.myopera.com/piko1/album.../Gprs-Gps1.jpg

    did you understend what i'm trayng to do now

    This kind of low-level control of the cellular interface is not available.
    Additionally the timers on the phones are not accurate enough.
    1.Why we need only 100 from the second
    2.O'ryl think again how many time your GSM need to call a nommber ?

    PS. the Stw - S =? must be Stw-AwS =? i correct the Graphic
    Last edited by piko1; 2008-10-11 at 22:58.

  8. #8
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    Re: GPRS, Bluetooth and GPS

    did you understend what i'm trayng to do now
    Yes, now I understand that my guess above was correct.
    Your calculation only gives you radius, not a location. (as I told above, see the point where I talk about earth's surface)

    My comment on the timers was a little too broad. The JTWI spec defines clock accuracy requirement of 40 millisecond (0.04). Some phones might have more accurate VM and some do not.

    2.O'ryl think again how many time your GSM need to call a nommber ?
    Sorry, I did not understand what you mean.

    Hartti

  9. #9
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    Re: GPRS, Bluetooth and GPS

    Quote Originally Posted by hartti View Post
    Sorry, I did not understand what you mean.

    Hartti

    can you try to call some one any one i mean
    how many time the GSM need's to complite the call?


    yes i know that my calalculation only gives me the radius
    but i want to know if i'am in the right direction

  10. #10
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    Re: GPRS, Bluetooth and GPS

    End-to-end call timing cannot be used in here. Too many other things affect that.

    Hartti

  11. #11
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    Re: GPRS, Bluetooth and GPS

    a call can depend on loads of stuff, even more if u want to use the cell network as a data carrier... setting up a http connection for example has a turnaround time of around 3 to 6 seconds, depending on loads of things (network usage, signal strength etc)...

    in ur math u are talking about a difference in time, still if u want to know if the distance from the celltower has increased/decreased u still will have to know the distance between u and the tower at T1 so that u can see how much u moved at T2...
    btw, did u take into account cell-switching ? At some point the network will change cell-tower and if u cant read out the specific cell-id u wont know about it, which results in T2-T1 getting lower whilst ur walking away from ur original position (so distanbce bigger but T2-T1 smaller)...

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