> I'm looking around for the GPS chipset that uses the lowest
> current. So far, if this survey is any guide,
> http://yona_n.tripod.com/gps/gps-survey.html
> the Philips ones appear to have the lowest consumption. If
> anyone has an alternative I'd be glad to hear about it

> Meaning that in the client's application the GPS would have to
> be on all the time. His original intention was for a unit to run for
> 15 - 20 days on 3 or 4 AA batteries (and it has other power-
> hungry things to do as well, not just GPS)

That's say 3000 mAH/20 days/24 hours =~ 6 mA average.
That's pretty low for a GPS.
There is a Casio watch with GPS in - presumably it has a better battery life
than that.
Any chance of using eg solar charging to add energy to the system?

Might some sort of inertial navigation allow you to use a lower average
current with GPS update less frequently? I undertand some Japanese in-city
systems do this to allow navigation in heavily built up areas.

                RM







but it looks to me as
> if you could quite easily stuff a set of batteries in half a day. He's
> short of space too, otherwise I'd suggest a larger battery. Even
> 6 x AA is going to be pushing it
>
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>
>

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