[gta02] GPS performance issues on GTA02v5

Daniel Willmann daniel at openmoko.org
Fri Apr 25 03:35:44 CEST 2008

On Thu, 24 Apr 2008 23:03:52 +0100
Ian Stirling <OpenMoko at mauve.plus.com> wrote:

> Werner Almesberger wrote:
> > Neng-Yu Tu (Tony Tu) wrote:
> >> u-blox has strange behavior is: If you start fix at indoor, then
> >> go out door, then the fix will take much longer than direct start
> >> fix at outdoor.
> > 
> > By the way, does this also happen with GTA02v4 ?
> > 
> > It's normal for GPS to dislike movement, but there shouldn't be
> > such an extreme difference when just walking outside and then
> > remaining immobile. (What was it again ? <1 minute vs. >10
> > minutes ?)
> > 
> My GTA01 will never get a lock indoors (in my house)
> It will occasionally pick up 5-6 satellites.
> It will always get a lock outdoors, and sometimes retain it if taken 
> indoors.

That's probably because it can't download ephemeris indoors. If you get
a lock outdoors it will have that information and be able to maintain a
lock indoors. But ephemeris information ages quickly so within a couple
of hours you'll loose that lock again if you are not able to download
new ephemeris data.

Daniel Willmann
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