References: <email@example.com> <4Ini9.firstname.lastname@example.org>
Subject: Re: Extracting time from GSM / mobile phone transmissions?
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Date: Thu, 19 Sep 2002 19:03:13 GMT
NNTP-Posting-Date: Thu, 19 Sep 2002 14:03:13 CDT
Organization: Road Runner - Texas
> > I have in the past asked about a cheap way of extracting *accurate*
> > time from GPS (not possible), or timecode signals (possible).
> > What about doing it from mobile phone signals. These are everywhere in
> > the developed world, although AFAIK the standards differ between e.g.
> > the USA and Europe.
> > Also this needs to work in a light aircraft, say 20000ft, so the
> > reception might not be too great.
> The mobile phone is out of question in an aircraft - the cellular network
> does not stand the antenna height. In many countries (including mine,
> Finland) the use of mobile phones is prohibited in an aircraft of any
> due to air safety reasons.
> The horizon distance at an altitude of 20000 ft is about 160 NM - enough
> wake up all the GSM ground stations in an average-size European country.
Regulations aside, I think he's asking about only receiving signals from the
base station to use them for getting time, not transmitting on GSM freqs.
We need a cellular engineer to join in and tell us if time is available on
GSM phone channels.
Why isn't GPS accurate enough ?