"Blunkett u-turn on data privacy plans"

[Brian Morrison]

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On Sat, 1 Mar 2003 16:27:41 +0000 in T1eSF4799NY+Ewx+@perry.co.uk Roland
Perry <ukcrypto@netcomuk.co.uk> wrote:

> >To maintain constant positioning data, the phone battery will last
> >only half a day at best.
> 
> I was going to mention battery life, but didn't for several reasons.
> 
> First of all, I suspect that a seriously mass produced GPS processor 
> would be able to take advantage of a lower power design.

Quite likely, but the problem is that GPS is so very processor intensive
because you have to constantly run a 12 channel correlator and crunch
furiously to work out pseudo-range to each SV and then minimise the
errors to get position. That is not very conducive to battery life under
any circumstances.

> 
> Secondly, my GSM phone already has a 600mAH battery, with 1.2AH as an 
> option.

Which is not a lot when you add additional processing on top of the
usual stuff.

> 
> Thirdly, I rather think that early 3G phones will have substantial 
> batteries and reduced life expectations anyway, as getting their
> standby life to exceed 50 hours has been one the main design
> challenges.

Quite. And probably for similar reasons too, constant calculation
apparently being a fact of 3G life at present. Maybe as networks evolve
and learn how to improve efficiency things will get better. But it
gladdens my heart to see that it will be hard to maintain location data
on every user, they will be unamused by their battery life anyway and if
they find out that the network is assisting its decline by keeping tabs
on them, well they might just decide to turn the bloody things off.

> 
> (I note that my above-mentioned GSM phone, normally 7days/240 mins,
> has about a one day battery life if I'm using GPRS, which as well as
> being "always on", is obviously "always draining the battery".)

Which is why I don't leave it always on, I suffer the extra time to set
a connection up each time I want it....

- -- 

Brian Morrison

bdm at fenrir dot org dot uk
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