[time-nuts] frequency and time from cell

[Jim Lux]

On 9/27/12 10:41 PM, Majdi S. Abbas wrote:
> On Fri, Sep 28, 2012 at 07:38:03AM +0200, bg at lysator.liu.se wrote:
>> Dont you have GPS/Cs locked cell networks anymore in the US?
>>
>> http://www.endruntechnologies.com/cdma.htm
>
> 	Björn,
>
> 	Past experience with CDMA TOD references here is that they
> fare much worse than WWVB TOD references.
>
> 	Haven't tried using them for frequency, but I wouldn't be
> surprised at similar results there.
>
>

the cell site might be locked to a good reference, but that doesn't mean 
the propagated signal you can receive is. As I understand it, one of the 
uses of good timing is/was to do Time Difference of Arrival (TDOA) to 
meet E-911 location accuracy requirements.  These days, with A-GPS in 
most phones, I wonder if that's still the case.