Hi Juha and Marcel
Thanks for your valuable hints.
I should have said that I am using PositionSource from QMl. So unless
I have missed something (always possible) I don't get the timestamp.
The longitudeValid and lattitudeValid are the next things I will test.
In the future it might be possible to use SatsInView / SatsInUse, but
SatelliteInfoSource is not yet available...
To prove / disprove the indicated behaviour I did a little test
1) GPS activated and position acquired in the little big city, then
turned off.
2) On the train on the way home, at least one city further on, GPS reactivated
a) First reading --> this is still the little-big-city, and 29.5 kms
away from the true location
47.3937924
8.48578765
b) Next reading --> GPS Acquired, now in the field next to the railway
line, close to true location (subsequent readings get even more precise)
47.5051796
8.84221178
--> Conclusion: The GPS Location immediately shown is the last
reading. Depending on how far the Jolla has travelled since then, this
reading may be wildly misleading.
Grüsse
chris
Zitat von Marcel <mar...@aliquis.de>:
Hi,
I can see the same behaviour, too. The timestamp is not really helpfull, as
this is the timestamp when you get the position, not when this position was
seen. And while waiting for a fix you get an updated position every
30 seconds
with a new, current timestamp. Another observation I made is that the
horizontal accuracy is always set to 15m and the vertical accuracy is not
valid while waiting for a fix.
If the fix is found you can get an accurate position like every second. I
would expect that while waiting for a fix the Valid-Properties (like
langitudeValid) of the Position should be false, and switch to true if they
are really valid after the GPS fix.
Greets,
Marcel
Am Freitag, 17. Januar 2014 schrieb Juha Siltanen <jsilt...@gmail.com>:
Chris,
I see the same behaviour. But won't the timestamp method in
QGeoPositionInfo help you? If the stamp differs a lot from current time,
then it is likely to be invalid in your case. At least that is what I see
in my application, the first update has the timestamp set to the time when
GPS was last used.
/jsl
2014/1/17 <christopher.l...@thurweb.ch>
> Hi all
>
> Is it possible that the Jolla GPS / GPS Software stack initially shows the
> last location acquired?
>
> This is the behaviour I am observing.
>
> At the moment I am sitting in an office building, which has poor GPS
> reception, yet my app immediately shows GPS Coordinates. By peaking I can
> see that the GPS icon is flashing, and thus no fix has been acquired.
>
> Having checked the GPS coordinates with Google Earth, the coords are
> actually for a location several kilometers away - in the middle of a set
of
> railway tracks that I travel along to and from work. As I do lots of
mobile
> development on the train, this is a plausible location for where the Jolla
> last got a fix.
>
> By comparison the same app running on my old Nokia N9 gets NaN from the
> GPS for longitude and lattitude until it gets a fix. I can then translate
> this into a user friendly text on the GUI "No valid position yet", and
stop
> the user from proceeding further into the app until a true fix is
acquired.
>
> If my understanding of the behaviour of the Jolla GPS is correct, is there
> anyway I can stop it giving me the old fix? It is important to my app that
> the coords shown are as accurate as possible, otherwise a recovery party /
> rescue helicopter may be mis-directed.
>
> Chris
>
> _______________________________________________
> SailfishOS.org Devel mailing list
>
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