Notifications about lost GPS lock

Libor Poutnik Striz shared this question 1 year ago
Answered

Does Locus always notify about lost GPS lock even if GPS subsystem stops working correctly? ( if told so, in my case by 3 beeps -

E.g. if GPS "freezes" and stops responding, or keeps returning last known state. ( Some devices are known to be problematic) .

As I have suspicion it does not, as I have missed several times turning on the GPX route, realizing GPS stopped working and I was not notified. ( And no, it was not because of bad signal or too few satellites. )

Edit: eventually, can there be a difference, if screen is always ON , or screen is OFF and device in a pocket ?

I do not use GPS OFF feature, as it seems to work better for me with GPS ON.

Comments (21)

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I have similar problem on Sony Xperia Z1. GPS can stop working for no apparent reason, maybe once a day or less, while cycle touring. But Locus Pro to the rescue. My settings:

  1. settings > GPS & location > Position Lost (setting is not just toggle, single tap reveals hidden array of settings)
  2. Enable: set
  3. Repeat: set, 60s
  4. Beep: 5

When I hear unique 5 beeps I can quickly go to GPS screen, disable/ reenable GPS & now all working again. I do have my own open topic for auto-restart. Menions suggestion for auto-off workaround was not useful.

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I have not set the warning repetition as I thought once is enough. But it seems I do not get it even once, sometimes. I have set the repetition now and I will see....

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I have found the repetition quite useful - imagine the notification when road noise is too much to hear phone, or you are distracted or maybe off the bike when GPS drops out. I am quite happy for reminder each minute that my track points are not being recorded.

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Hello guys,

I'll try to explain how it works now. Maybe you will have an suggestion for improvements.

  • you start GPS in Locus, it search for satellites and tries to obtain "fix" (valid GPS location). Once it happen, timer is set.
  • this timer countdown for defined time and when it reach zero, notification is played.
  • timer is reset to default starting value every time, new "fix" is obtained
  • timer is destroyed only in case, "GPS" is turned off in Locus (manually or by closing Locus).
  • this means that if you turn off GPS source in your system manually, Locus should notify on lost fix as well. It do not depend on system settings

Screen on/off ... it depends if GPS is required by any service. If you use for example track recording, then there will be no difference (GPS is needed all the time). You may notice small white popup "GPS turned on", when Locus disabled GPS to conserve battery because it was not needed.

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The timer is hardcoded to 60s as I understand, correct ? I suppose active navigation should mean GPS is required.

AFA I understand. Normal GPS operation is providing locations and sat stats every second.I suppose if working GPS loses the lock, it actively notifies Locus and Locus gets it.But if GPS does not work correctly, can it fool Locus it is working, e.g repeating last data forever? Does Locus analyze if subsequent GPS data differs ?

As sometimes it seems to me Locus gets fooled, thinking all is OK,not notifying me and keeping old position and sat stats.

But I have to verify the cases. It often notifies me, and sometimes not.

Edit: E.g., I can have displayed on the top bar SAT stats 12/18 satalittes, ( at least could in past - have to verify for current Locus ) - the numbers still for several minutes, while for these several minutes GPS is not working. IMHO, if Locus determines the data flow get stalled in constant line, it should be evaluated as GPS lock lost and reset the GPS info data. Eventually, evaluate it as GPS malfunction.

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>As sometimes it seems to me Locus gets fooled, thinking all is OK,

>not notifying me and keeping old position and sat stats.

with my particular phone I have never experienced that

Generally I am more concerned to quickly disable/ reenable (so track position is not lost) than to observe the GPS stats, but next time I will take more notice on current operation before a reset.

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I have mentioned the stats only as an indicator Locus GPS status may not reflect the reality.

As to disable/enable GPS, you must first know you should do so. Watching the screen you notice it yourself, but if you are in screen off batterysaving mode, with voice guidance, you has to rely on acoustic warnings. And now, with new BRouter hint systems and hints less frequent, you may not notice you are not receiving the hints for several kilometres. ( as happened in my 104 km tour in September where I was mislead to a detour, not being notified about GPX turn ).

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Thanks Menion, explanation fully understood, and I would have thought that would be the case anyway.

I probably repeat myself, but when my Xperia GPS "drops out" during track recording Locus provides immediate notification, that is Locus is immediately aware there is problem. The only way I know to fix this is to tap the GPS "map" once to turn off GPS, then tap again to turn on GPS. The GPS responds immediately with new position, so very quick to correct. I am quite happy you don't write new code to handle this unusual situation, but you can see here that a coding "hack" would be possible to automatically restore GPS operation as per my open topic.

BTW you say "if you turn off GPS source in your system manually, Locus should notify on lost fix" - yes I know that, and experience that myself, but I have question/ suggestion - if user has manually turned off GPS (especially if tap on Locus GPS map to perform) surely there is no need to then notify the user? I nearly wrote a topic for this suggestion once but never did (until now).

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@Libor: yes it's hardcoded to 60 s (+ "GPS sleep" parameter from GPS auto-off is enabled).

If GPS lost connection to enough satellites to be able to compute location, it stops sending it's data. It works that at normal situation, location is received from system once per second as you wrote. If there are no valid data, then system SHOULD NOT send old data again and again. Anyway if any modified ROM do this, then Locus do not check these data on duplicities. It should be small problem - location may be same over time and main difference should be time, when location was created. But if Android send same location again, I should expect that it just change time to current. (too much "should" I see :) )

To your edit: this is probably caused by fact, that Locus display old received data. If GPS has any troubles, it stop sending updates, but Locus do not know it has a problem. Locus just display last received data and waits on new data. I may change it and reset state of satellites when it's older then certain time, but it do not solve main problem here - notification.

@Andrew: Do you really think there is no need to notify user on "Lost GPS fix" in case he manually disable GPS in system? Except fact, that as a developer I have no possibility to detect this :) , I still think it's very usable. Other app may disable GPS, you may disable it by accident in top toolbar (Samsung) or on any widget, you may forget that track recording is still running, etc etc ...

On your device, it's really enough to just disable GPS "IN LOCUS" satellite screen and then turn it again on, and it works fine then, am I understand correctly?

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Note that I do not use custom ROM, nor is my phone even rooted ( Xperia M dual, A4.3 ).

I will now focus on, If it is Locus or me, who misses the notification...

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1) I assume some firmware/ hardware bug in my phone (unrooted V5.1.1), because when I observe Locus "Lost GPS fix" notification there is (generally) very good clear sky, no "real world" explanation. I am sure it has nothing to do with a bad GPS signal, but some Android problem. I can live with it because the Locus notification is fully reliable, and workaround is simple (although not automatic/ ideal).

2) @Menion sorry I wasn't clear. When the Locus user taps the Locus GPS satellite screen to explicitly turn off the GPS, surely the user is fully aware of his/her action that GPS operation will cease until they turn it back on? In this, and only this situation, I don't see why a notification is required. Its like user hits their thumb with hammer, no warning that pain will occur is required. BUT as I said, am happy with current operation.

>On your device, it's really enough to just disable GPS "IN LOCUS" satellite screen and then turn it again on, and it works fine then, am I understand correctly?

Absolutely 100% every single time (has only happened maybe 20 times in last year), when Locus gives "Lost GPS fix" notification all I have to do is turn it off then on again from satellite screen & operation (track recording) is immediately restored.

I hope that's clear? Sometimes so tricky to explain oneself online accurately.

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All clear thanks. I remember same happen to me as well, once

maybe twice. Nothing serious ... it's just an software (Android) and

usually "no ability to repeat issue - low chance to fix it" :).

Well let's start little bit - from start. You wrote "if user has manually turned off GPS (especially if tap on Locus GPS map
to perform) surely there is no need to then notify the user?
" - you probably mean a disabling GPS in Locus satellite screen, right? So you want to hear "Lost GPS fix" notification in this case as well? Because now it should not happen. Disabling GPS in Locus cancel "timer" I wrote about it before.

Hmm, 20 times per year ... quite a lot.

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> Absolutely 100% every single time (has only happened maybe 20 times inlast year), when Locus gives "Lost GPS fix" notification all I have todo is turn it off then on again from satellite screen & operation(track recording) is immediately restored.

This works for me for 3 from 4 cases. For 1 of 4 I have also globally disable GPS a/o restart the applications. It sometimes does not help but restart of Android always helps. Some says turn ON/OFF Airplane mode helps -even for the same device - but I cannot confirm it.

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@Menion

>you probably mean a disabling GPS in Locus satellite screen, right?

yes, I should have been clearer

>So you want to hear "Lost GPS fix" notification in this case as well?

no, as explained, but don't spend more time on this minor comment sorry

>Hmm, 20 times per year ... quite a lot.

not really, just lots of cycling & track recording, that lost fix may be once every 10..20 hours (just guessing)

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60s is not big deal for hikers, but for cars, 60s may be too much. One can easily miss the junctions or crossroad to turn, as it is 2km on motorways, almost 1 km in the city.

It may be useful to have an option to automatically switch the screen ON when GPS lock loss occurs.

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> location may be same over time and main difference should be time, whenlocation was created. But if Android send same location again, I shouldexpect that it just change time to current. (too much "should" I see :) )

Does it happen the GPS location keeps to be identically the same, even if physically location is static ? Is not it dancing around ? Even if they are, there are very frequent SAT stats changes.

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Logically it should not be of course. Even a most precise surveyors GPS units change it's location over time. I just guess what Android may do on background with received data.

Anyway agree that 60 secs should be quite a problem in a car. On second side in car is usually device in handler and you see screen. You also notice that screen stopped to update. Maybe once I introduce something like navigation profile, this parameter may be dynamically modified based on current profile.

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Few profile ideas are pending.. :-) I rotate foot, bike and car backups that have drawbacks they affect all settings, not only to-be-in-profile ones.

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Don't tell me about it ... I do not rotate profiles over backup, but always spend five minutes before bike, run, car to change all back to what I need :). But this is different story ...

Hope I gave you and Andrew here enough information. If you will want discuss something more, I'm here ;). Btw. just for your information as you do not watch this topic:: http://help.locusmap.eu/topic/reset-gps-when-lost-signal#comment-28146

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Nothing is better than if a product particular behaviour irritates or annoys its author :-)

Thanks, I have noticed that thread and looking forward to some auto recoveries of GPS issues.One of Murphy's law must say: Bad GPS reviews appear after you buy the device.

Edit: It may be just my feelings, but I have realized it may matter the interval between manualy switching GPS OFF and ON. My experince says to wait about 5 seconds, like if short intervals has less percantage of success.

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Oki guys, thanks for information. As I wrote in second topic, it will be little bit improved in next version, so we should talk a few months later if this still happen to you or if small change helped.