GPS accuracy at ongoing track record / GPS Genauigkeit

[realeasy]

Hi there,



may i have a problem or not, i`m not sure.

Let me explain...i use oruxmaps on a SK17i (SonyEriccson Mini Pro), Version 6.0.9.

Sometimes with the build in GPS and sometimes (in order to save energy) with an QStarz 818XT (manually fixed).

No matter, which source i use, the last times i recorded a track more than an hour, it seemed to me, that, with ongoing recording the accuracy decreased more and more.

Example:

http://i.imgur.com/7aBnFcZ.png">



at the beginning, with QStarz, the position in the map fits with the reality



http://i.imgur.com/PELJji4.png">



at the end, with QStarz, the position in the map is about 100m away from the reality (bt worked - connection was established!)



The same situation, if i use the onboard GPS.

I changed settings in the GPS-Sensor section, but nothing changed.

In older recordings I could not determine (comparing through Google Earth).





Any help would be appreciated.





Noch mal statt in holprigem Englisch auf Deutsch.

Also, ich nutze OM in der Version 6.0.9. auf einem SE Mini Pro (seit mittlerweile 4 Jahren).

Zur besseren Genauigkeit outdoor und Akkuschonung habe ich mir noch einen QStarz 818 XT zugelegt und bin damit sehr zufrieden.

In letzter Zeit habe ich festgestellt (Bilder siehe oben), dass, egal ob ich das interne GPS oder das externe nutze, nach einiger Zeit der Aufzeichnung (mind. 1 h) die Genauigkeit der Position immer schlechter wird.

Stimmte sie am Anfang der Route noch teilweise bis auf 1m (oder weniger) genau, weicht sie zum Schluss teilweise bis zu 100m ab.

Hinzuzufügen ist, dass ich mittlerweile zwischenzeitlich die BT-Verbindung erneuere, GPS ein- und ausschalte (während Trackaufzeichnung), es ändert nichts, sobald OM wieder aufzeichnet, wird die Position nicht akkurat angegeben.

Ich habe jetzt (über Google Earth) alte Trackaufzeichnungen verglichen, da trat dies nicht auf.



Hat jemand irgendeine Idee?



Thanks

Easy

[orux]

Hi there,



may i have a problem or not, i`m not sure.

Let me explain...i use oruxmaps on a SK17i (SonyEriccson Mini Pro), Version 6.0.9.

Sometimes with the build in GPS and sometimes (in order to save energy) with an QStarz 818XT (manually fixed).

No matter, which source i use, the last times i recorded a track more than an hour, it seemed to me, that, with ongoing recording the accuracy decreased more and more.

Example:



at the beginning, with QStarz, the position in the map fits with the reality



at the end, with QStarz, the position in the map is about 100m away from the reality (bt worked - connection was established!)



The same situation, if i use the onboard GPS.

I changed settings in the GPS-Sensor section, but nothing changed.

In older recordings I could not determine (comparing through Google Earth).





Any help would be appreciated.





Noch mal statt in holprigem Englisch auf Deutsch.

Also, ich nutze OM in der Version 6.0.9. auf einem SE Mini Pro (seit mittlerweile 4 Jahren).

Zur besseren Genauigkeit outdoor und Akkuschonung habe ich mir noch einen QStarz 818 XT zugelegt und bin damit sehr zufrieden.

In letzter Zeit habe ich festgestellt (Bilder siehe oben), dass, egal ob ich das interne GPS oder das externe nutze, nach einiger Zeit der Aufzeichnung (mind. 1 h) die Genauigkeit der Position immer schlechter wird.

Stimmte sie am Anfang der Route noch teilweise bis auf 1m (oder weniger) genau, weicht sie zum Schluss teilweise bis zu 100m ab.

Hinzuzufügen ist, dass ich mittlerweile zwischenzeitlich die BT-Verbindung erneuere, GPS ein- und ausschalte (während Trackaufzeichnung), es ändert nichts, sobald OM wieder aufzeichnet, wird die Position nicht akkurat angegeben.

Ich habe jetzt (über Google Earth) alte Trackaufzeichnungen verglichen, da trat dies nicht auf.



Hat jemand irgendeine Idee?



Thanks

Easy

Hello;



try using 0 seconds in 'settings--sensors--gps--minimum time'



with this setting, the gps is always on. This should increase the accuracy because the GPS is not turned off between two consecutive measures.





orux

[realeasy]

Thank you,

 i will give it a try, again.

But, if you take a look at my second picture, at this time (approximately 10min) the extern sensor was constantly connected.

So the smartphone (and OM) was.

That was because i wanted to check what didn`t work correctly.



As i said i`m not sure, but in my minds thats first time happened with the last two updates to 6.0.9.

[rvb]

I saw a lot of gpx tracks, made by different equipment and software. Most of the time (~90%) they are nearly spot on, sometimes they have a big deviation ~100m.

[realeasy]

Ok, i see....but why?!   :?:

Why there is sometimes a deviation of more than 100m?



Could it depend from the duration of the recording in the newer versions?



To show, what i mean, i give 3 examples (kml):



1. hike, last year with an older Version of OM http://s000.tinyupload.com/?file_id=86307585045109566042">//http://s000.tinyupload.com/?file_id=86307585045109566042

it`s nearly spot on, the biggest deviation is really max. 25 - 30m (weak gps through the woods); duration (with breaks) ~ 4 hours; intern GPS



2. hike, this year with an updated (in my mind version 6.0.7) http://s000.tinyupload.com/?file_id=00890497050644658407">//http://s000.tinyupload.com/?file_id=00890497050644658407

more dev. (max. 30m); duration ~1,5h; intern GPS



3. last hike, a week ago...   (version 6.0.9) http://s000.tinyupload.com/?file_id=50552600542767594199">//http://s000.tinyupload.com/?file_id=50552600542767594199

in the last hour, dev. partly >100m; duration ~ 4 hours; extern GPS



Do i compare the position from the extern gps with google maps, than it`s (nearly) spot on.

[rvb]

walk the track with 2 or more devices.



could be that the gps-receiver is better than the other.

[orux]

walk the track with 2 or more devices.



could be that the gps-receiver is better than the other.

And/or save different tracks using two/three different apps simultaneous in the same device.





orux

[realeasy]

Hmm, so first, thank you all for your advices.

I think i`ll test it simultaneously with a Galaxy S5.



It`s hard to imagine, that the extern GPS-Sensor is that bad...because whenever i use it with maps or bluetooth-gps it shows the exact position. In bluetooth-gps with an dev. mainly from 1- 3m.