More than a phone with a GPS navigator

Andy Green andy at
Fri Mar 28 14:59:42 CET 2008

Hash: SHA1

Somebody in the thread at some point said:
| On Fri, 28 Mar 2008 12:27:56 +0100, Andy Green <andy at> wrote:
|> | What's the advantage of the other ways of locating yourself (GSM, WiFi)
|> | over GPS?
|> Power, and they work inside buildings away from windows.
| Inside a building your essential location (as read from the GPS receiver
| the last time before entering the building) stays the same. Once you've
| come home, you're staying home until you go outside and get a GPS signal
| that tells you're somewhere else.

Yeah... I just don't think people will want to run all the peripherals
all the time because of what it will do to the battery life.  You're not
wrong but I increasingly see all of the assets, even the CPU, as being
things that are kept completely off unless you identified you use them
for a specific purpose for a brief period -- triggered immediately by
user actions or long period polling.  For the vast bulk of the time the
device is drawing almost no power at all bar what the GSM side demands
in standby.  This is the only path to really good "phone style" battery
life I think.

|> GSM at least will be powered anyway in the normal case, so polling that
|> every 10 minutes
| Or whenever we get an interrupt from the accelerometers -- you can't
| really move if you don't accelerate.

Yeah.  But we can move around in the office with it in our pockets and
so on.

| That's the point: while you're inside a building, all you have to know
| is that you're still inside.

Well you can know where you are in the building from AP scan monitoring.
~ In an office building for example you might go to a meeting room or a
cafeteria and want that as a different "place", but you never get to the
open sky moving around between these places.

|> I really would love WLAN to scavenge open connections as well at the

| One has to be careful about that. IANAL, but it might be illegal in some
| countries to use someone's private network even if it's left unencrypted

Fine, the user doesn't enable it if he feels it makes a problem.

- -Andy
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