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

[Steve Kennedy]

On Fri, Feb 24, 2006 at 07:17:52AM -0600, Rich Adamson wrote:

> 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.


Steve

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