| Subject: | Re: Can I call 911 in another area code? |
| From: | Geoff |
| Posting date: | 10-03-2008 |
| Content: | |
On Sun, 09 Mar 2008 20:53:29 GMT, Han wrote:
>"Bilbo" wrote in news:%WWAj.2624$HA3.1956@trnddc02:
>
>> Another enhancement on the horizon is GPS ability in cell phones.
>
>I just got a new cell phone 6 months ago. One of the cheapest available.
>It doesn't even have a "camera", let alone a gps chip. I did buy a Garmin
>GPS receiver, but I see no way to plug one into the other .
>
>As you mentioned, privacy does become an issue then, especially since I
>tend to believe that GPS records could easily be faked as a "route" or
>"track" can be entered (I think) into programs such as MapSource.
It was my understanding that all phones must be deployed with EGPS
chips in them. I know my mother's phone was replaced by her provider
free of charge (a senior benefit for her emergency-use cell phone) and
the letter stated this was to comply with federal law.
In any event, even if your phone doesn't have GPS it can still be
located, cheaply and accurately by trilateration or more accurately,
multilateration of its emitted signal. If the phone is GSM enabled it
certainly has this technology. This is the famous "ping" location
method described in the media in missing person cases.
The phone is identified, the time of arrival of the signals from that
phone are determined at multiple cell sites. Since all cell sites are
synchronized with GPS time signals the TDOA of the cell phone ping
delta-T's are known. Calculate c * dt and you have the difference in
range from each tower that can hear the signal. Solve the simultaneous
equations and you have the position. The user need not be aware of the
track. If the phone is on, it can be tracked. GPS need not be enabled
or present in the phone. One can estimate the position of a phone
faster with ping methods than querying the GPS inside the phone. Add
directional information from tower antennas and signal strength and
you have a pretty good idea of the location of that phone.
Anyone concerned with "privacy" shouldn't own a mobile phone. Lose the
Internet connection while your at it too. |
