New GPS malfunction on Xiaomi Mi2 with Miui V5

[Desmond]

I 've checked that gps doesn't work fine with miui v5 roms in Xiaomi Mi2, especially with the app Oruxmaps. It lose signal when recording a track and doesn't register the elevation correctly.

straight lines indicate times when the route stops recording

 

[kiswum]

Last week tested GPS with my mi2 and Hongmi. Mi2 is very stable didn't saw any flaws. It runs on the latest mi5 miuiandroid rom
Here is the movie:

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Sent from my Xiaomi mi2 with Tapatalk. This is why my message could contain spelling mistakes. now Free

 

[Desmond]

Good video but, have you tried a country gps app? (walking or biking across the mountains)
Does it register elevation correctly?

 

[kiswum]

I have used sportstracker and that seems to work fine, but we don't have much hills here in the Netherlands. I can try to test in 2 weeks when I make a tour with the car.

Sent from my Xiaomi mi2 with Tapatalk. This is why my message could contain spelling mistakes. now Free

 

[ear8dmg]

I'm seeing this sort of thing on my MI2S as well. It's currently running MIUI 5 v 3.11.15 from here but I've noticed problems in previous versions.

I've done some testing and I think that mobile data access is interrupting GPS somehow. I initially noticed the problem using navigation apps, where it would report incorrect speeds or lose position.

I've since tested using MyTracks. Basically I turn on recording in Mytracks and obtain GPS lock. Then access something that will quickly use a fair bit of mobile data, while I'm moving. This causes the GPS to lose satellites and try to re-fix. The speed vs distance log will show travel at 0mph, even though distance has been covered. Performance mode makes the problem slightly less noticeable for navigation, as it seems to find satellites faster again after an interruption.

Mobile data access interrupting GPS seems to be repeatable and more likely to occur when data intensive apps are running. Possible workarounds ar to disable Google location services or enable airplane mode to minimise data traffic.

Performance mode seems to help finding satellites again faster, minimising the effect of the problem during navigation.

I really hope this is a software problem and not a hardware issue. HTC One X users have had similar complaints and that sometimes turned out to be lose antenna connections (GPS or other radio antennae) inside the phone, requiring repair in many cases.

 

[ear8dmg]

Just an update on this. I can work around this issue consistently by disabling Google Locatation Services.

A side effect is that some services like Google Now only update when other apps are using the GPS.

With Google Location Services enabled, the location is less precise and sometimes the accuracy reading goes up to 100s of metres, causing some apps to temporarily stop tracking GPS (due to the accuracy exceeding their threshold) and others to wander off route. By running MyTracks on my regular commute I've noticed that GPS drops out at particular repeatable locations. Coincidentally, these locations are all close to cell tower masts. My guess is that something is causing the GPS location to be over-riden by wi-fi or cell tower postioning.

I believe that this may be the same issue being experienced by some users of various different phones and tablets (LG G2, Nexus 4, 5 and 7). GPS performance when using Google Location Services startsts off OK and then deteriorates over time. A factory reset seems to cure it temporarily and several Nexus users have RMAd their devices or performed a factory reset, seeing an initial improvement side by side with the old one, only to find the new devices GPS performance subsequently deteriorates after a few weeks. Several users reported huge improvements from RMAd devices, only for signs of deterioration to occur shortly afterwards.

According to this forum thread Google have acknowledged the issue and are working on a fix: http://productforums.google.com/forum/#!topic/nexus/EkllXr0ZlZM

Some people have reported that clearing the Google maps cache also brings a temporary improvement but I've not tried it myself.

 

[ear8dmg]

Further update. I thought I'd got a reliable workaround in disabling Google Location Services. That was at least stopping the navigation interruptions and wandering.

Updated from 3.11.22 to 3.11.29 at the weekend.

This morning, my first time navigating after the update, GPS in Tomtom Android (even with location services off) was terrible - keeping wandering off the route. I noticed that, although Google Location Services was claiming to be turned off in the menu, it gave no disclaimer warning for turning on or off until after I'd rebooted the phone. Could something in the updates themselves be contributing to problems? Perhaps chaging network location settings in the background without intervention from the user? I suspect a cache problem too.

I've rebooted and run GPS Status & Toolkit to make sure I'm getting a reasonable number of satellites. We'll see if it behaves during my commute later in the day.