[Geowanking] Re: E911 // cellular trilateration accuracy

[Dennis Crowley]

> Speaking of Verizon's A-GPS... Is there any way we can get access  
> to this yet? And if not, is there any open source projects that are  
> using tower data?

i'd be real surprised if there was any way to get access to Verizon's  
data (and for free - ha!).

as for determining location based on GSM tower info, check out what  
Intel Research in Seattle is doing with PlaceLab  (think: wardriving  
w/ GSM modems).  it requires a pre-existing data set (GSM towers  
mapped to lat/longs) and the PlaceLab client running on your device,  
but once the data is collected i've heard the resolution is around 10  
feet or so.

	http://placelab.org/

(ps:  i think the only available data set is Seattle... anyone know  
otherwise about NYC?)

/d
____________
dennis crowley
founder, dodgeball.com

+ dens at dodgeball.com
+ 917-301-2028
____________




On Apr 12, 2006, at 4:24 PM, Kevin Elliott wrote:

> Speaking of Verizon's A-GPS... Is there any way we can get access  
> to this yet? And if not, is there any open source projects that are  
> using tower data?
>
> Kevin
>
> On Apr 12, 2006, at 12:32 PM, Dan Melinger wrote:
>
>> Out of the larger carriers in the US, it's my understanding that  
>> Verizon and Sprint are using A-GPS and the GSM guys, T-Mobile and  
>> Cingular are using alternative technology like Uplink Time  
>> Difference of Arrival (U-TDOA) technology provided by TruePosition.
>>
>> A-GPS requires a chip in the phone while U-TDOA doesn't.
>>
>>
>> On Apr 12, 2006, at 12:46 PM, Anthony Townsend wrote:
>>
>>> It's the FCC not the FAA, and my understanding is that none of  
>>> the US
>>> carriers are using tower triangluation (EOTD or other variants)  
>>> because of
>>> the cost of network upgrades. Instead they are pushing to cost to  
>>> you, the
>>> consumer, in the form of A-GPS equipped handsets.
>>>
>>>
>>>
>>> roger at sylvanascent.com (roger at sylvanascent.com) wrote @ 4/10/06  
>>> 9:35 AM:
>>>
>>>> I think this is a great question. I talked to a gentleman from  
>>>> South Africa
>>>> last year at Where 2 who claimed to be a GSM expert. He said  
>>>> that GSM can
>>>> locate you within something like 3 meters with no GPS support  
>>>> just using
>>>> the towers, and that this was built into the GSM spec. He spoke  
>>>> of a case
>>>> in South Africa where they located some sort of criminal using  
>>>> the GSM
>>>> records.
>>>>
>>>> He said that CDMA on the other hand, cannot locate so precisely.
>>>>
>>>> So, to me, A-GPS was designed to make CDMA users locatable to  
>>>> the same
>>>> degree as GSM.
>>>>
>>>> As an aside, does anyone know which type of cell phones are more  
>>>> lethal?
>>>>
>>>> Roger
>>>>
>>>> Original Message:
>>>> -----------------
>>>> From: Ian | Urban Mapping ian at urbanmapping.com
>>>> Date: Mon, 10 Apr 2006 01:42:23 -0400
>>>> To: geowanking at lists.burri.to
>>>> Subject: [Geowanking] E911 // cellular trilateration accuracy
>>>>
>>>>
>>>> At the risk of asking (another) obvious question, I continue my  
>>>> naïve streak
>>>> on this listserv…
>>>>
>>>>
>>>>
>>>> I’ve heard very different reports of how accurate cellphone  
>>>> tracking is—the
>>>> FAA mandates something like 50% of calls must be traceable to  
>>>> within a range
>>>> of 30m but I’ve heard some mobile pros say they’ve heard of it  
>>>> getting as
>>>> good as several feet. Obviously this varies depending on  
>>>> geography (urban,
>>>> rural, topography), but does anybody have any idea how the US  
>>>> wireless
>>>> carriers stack up? And how does this compare to phones with GPS?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Ian White  ::  Urban Mapping LLC  ::    
>>>> <mailto:ian at urbanmapping.com>
>>>> ian at urbanmapping.com
>>>>
>>>> 120 West 45th Street  20th Floor  ::  New York  NY  10036
>>>>
>>>> Tel.212.242.8267  :: Fax.866.385.8266  ::  www.urbanmapping.com
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> ------------------------------------------------------------------- 
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>>>>
>>>>
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>>
>> | dan melinger
>> | kamida :: socialight
>>
>> | email dan at socialight.com
>> | web http://socialight.com
>> | office +1 212 561 5155
>> | cell +1 917 494 5856
>> | skype melinger
>>
>>
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