[Asterisk-Users] GPS-enabled cell phone/PDA

[Juergen K. Zick]

Some more recent phones have the possibility to be connected to seperate 
GSM-boxes. E.g. there is a plug-in for the (older) Nokia 9210(i)/9290(i) 
Communicators and most of the Symbian phones with Bluetooth support can be 
connected to any Bluetooth-enabled GPS-mouse ...

I think, getting the position data with a defined accuracy is not the 
problem. I'm quite satisfied with the location delivered by the CB channels 
of the base stations. Crucial is indeed, what kind of location based 
service you want to build and how the data gets to the server ... With 
flatrate contracts regarding SMS or GPRS-data it's not even a real question 
of costs anymore ...

But we slowly are getting completely OT for ASTERISK ;-) ...

For more info about "context awareness" and "location based services" 
probably take some time to read what some colleagues here are doing in 
research http://www.ist-mobilife.org/

-Jürgen





>> > Its my understanding the cell phone coordinates are sent to the cell phone
>> > provider and their equipment reads (and holds) that data. Its not part
>> > of any data available to you in any form unless you talk to the cell
>> > provider and convience them you have a valid need. Highly unlikely in
>> > the US anyway. Even if you could convience them to provide it, they
>> > would likely demaand some sort of out-of-band data transmission facility.
>>
>
>
>GSM networks have the Cell ID available to the phone, however that's not
>much use without the location of the cellsite.
>
>There are now location based services, whereby you can query the network
>and they'll give out an approximate location (most cells are sectored
>[6 sectors per cell) which gives a direction, the cell also knows what
>power the phone is transmitting with, and the power it's received so can
>make a good approximation of where the phone is (within 60 degrees
>angle). However it's likely a phone will be picked up by several cells,
>so the network can triangulate and make a better aproximation.
>
>Making the information available to end-users is problematic due to
>privacy issues, unless the user explicitly agrees to give the info away.
>
>With GPS units, the info is stored in the phone and can send it out
>using SMS or other means.
>
>-------------
>It was my impression that only a handful of cellphones have full GPS units 
>in them.  Benefon and some Motorola units made for the former Nextel come 
>to mind.  The Benefon units do send SMS reports, and in fact, I have 
>written code to control and track these units via SMS using a Nokia 31 GSM 
>terminal.  Unfortunately, aside from their unique GPS/SMS capability, the 
>Benefons are not very attractive products, in my opinion.  And they are 
>expensive.  The Motorola units contain Java machines and a well defined 
>API for accessing the location data.  I have not worked with them.  There 
>have undoubtedly been changes in the marketplace since I did this work 
>about 2 years ago.
>
>As I understand it (but don't have thorough knowledge and could be 
>mistaken), other units generally only receive GPS satellite signals and 
>relay the data to cellular provider networks where the actual location 
>calculation is done.  This can be done with assistance of data obtained 
>based on tower proximity, which jumpstarts the iterative process of 
>approximation.  I think it is called assisted GPS or some such...
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