The GPS from liapac IIRC had a 'sleep' mode which allowed it to wake up
and get its first fix every 20 seconds or so.  It might be enough for you.

You might want to tell your customer to wait a year though.  Since cell
phones are getting GPS there are a lot more chip fabs that have single
chip low power gps designs in the works, some of them even including
much of the analog front end on the chip.  These should be on the market
in a year, and should be cheap in five.

-Adam

Jinx wrote:

>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
>
>But there's an added complication - the client wants the GPS
>part to be asleep most of the time (to save batteries) and update
>the GPS data to the PIC every 10 - 20 seconds. This seems to
>be not possible, as the way I read it, if you power-down the GPS,
>it takes at least 45 seconds after power-up for "time to first fix".
>Is that correct, or is there a work-around ?
>
>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) 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
>
>--
>http://www.piclist.com hint: The PICList is archived three different
>ways.  See http://www.piclist.com/#archives for details.
>
>
>
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--
http://www.piclist.com hint: The PICList is archived three different
ways.  See http://www.piclist.com/#archives for details.