donderdag 9 maart 2017

Strava stuk deel 2, de oplossing / Broken Strava part 2, the solution

Dat sommige reacties uitgebreider zijn dan de blog zelf, is algemeen bekend.

english  For English please scroll down.

Dat als de reactie te lang zou worden, deze dan niet geplaatst kan worden was mij nog niet bekend.

Voor Belgisch lees gerust verder.

Via de messenger ontving ik onderstaand bericht van Jan Bens vanuit België, deze reactie op het vorige blog wil ik jullie niet onthouden.
En aangezien zijn Engels verhaal leest als een spannend boek, ga ik dat niet verpesten door het te vertalen.  ;-)

Hey André, ik had een antwoord op je bericht over Strava getyped maar dit blijkt te lang te zijn. Dus dan maar even langs hier: 
englishHey André,

I have the same problem on my Android phone: "One Plus 2". Strage thing is: it worked flawlessly up until One Plus pushed an update of the Operating system in August 2016 (going from Android 6.0.1 to 6.1.x)
Long story really short: reboot the phone after a full charge of the battery.

As an engineer I tried narrowing down the problem and 1 week ago I think I found it.
Long story (not so) short:
- Maybe it's Strava? Tried Trackme, GPS logger, Real time GPS tracker, ... All have te same issue.
- Suspected blacked out screen (I drive a diamond frame bike, with my backpack to work and my phone goes in there) So I started riding with the screen on (completely useless since I can't see it) Worked for a week or 2, then nothing...
- Suspected battery saving settings, as did you: added all sorts of exeptions in the menu (not only Strava but every GPS-using app) Worked for a week, afther that: no luck!
- A-GPS data maybe: updated it every time on WiFi, again: no.
- A GPS reset app: that should help?!? Guess again.
- I checked my phone every 5 minutes (I was getting black outs going from 5s up to 10 minutes in the tracks) This works sometimes, but the average speed dropped dramaticaly and it wasn't practical.
- Searched the internet for it: Marshmallow really does have a chronic GPS problem according to a select group of users but even Google techs can't figure out how, or let alone reproduce the problem on the Nexus phones...
- One guy online suggested it could be interference from GSM signals:
- I've tried other sim cards (oter networks), 1G, 2G, 3G, 4G, or multiple (the perks of a dual sim phone), Wifi On, Wifi Off, same with BT, flight mode (GPS is only recieving thus still works on flight mode (psst: you MUST try it in an Airbus 320! Awesome! Hey, what now my GPS works in a plane going 800km/h but not on solid ground????)
All this gave just about completely random results. I had no clue whatsover, all hope was lost and I just used Strava to get some basic info on starting time, and resetted the app right before I made an attempt on a KOM of a segment.

The only thing I knew was wat the problem exactly is: when you start recording, once it got your GPS position(which is already harder to get) it keeps going right up to a moment where it is impossible to get a signal, looses the fix (under a bridge, tree, lots of reflections,...) of after a certain time (I guess 10 minutes) or up untill the app stops asking for GPS (Autopauze in Strava) and from that moment, it will not get a fix again! Whatever you try! (waving, clear sky, screen lit, open other GPS apps,... Right up to the moment when you shut down the app requesting for GPS and reboot that one. From then on, the same happens: 1 chance to get a fix, no more up untill you restart the initial app requesting for a GPS signal)
I didn't know what caused it to happen. I just lived with it 😞

This went on for months...

A Happy New year: In January it worked flawlessly. :-?
2 Weeks back on Monday, I noticed somehow that it stopped working again when it went from going perfectly normal recording to nothing, only 3mins before I got home one day from work. (all other times it's gone long before that)
The only thing that was different this time, compared to the week before, was that it went below 15% of battery while riding, and the GPS-track died on a rough estimate 10mins later. That triggers the battery saving mode.
The next day, fully charged, back to work and tere it was again: the same problem, again, right on time, after 7 minutes of riding.
2 Days went by like this and suddenly, my morning track was recorded completely.
What?!? How?!?

Then a lightbulb lit up in my mostly empty brain. The loss of GPS position is not a result of being IN the "battery saving mode" but just a once occuring action triggers it: the actual GOING INTO the "battery saving mode"!
How so?
My phone died the moment I wanted to plug it the evening before that last perfect recording. Exactly after 1 full charge on the phone. And YES: on Sunday evening I rebooted my phone as well, just a thing I do once in a while.

I'm still doing tests to prove this and to replicate the problem voluntarily. After 1 week of testing it still holds true but that's only 12 rides or so.
I would like all you guys to go ahead ad test this as well:
Reboot the phone
Test a GPS-app (should work great)
That is: at least right up to the point were the battery saving mode kicks in.
Even after a full charge it should still have problems up to the point where you reboot your phone and all is well again.

I hope this helps you André.
Best regards from Belgium,


Small update: I've "abused" Strava the last few days and it still holds true.
Started the app, knowing it wouldn't get a GPS fix the first 5 minutes (indoors): perfect recording the moment I stepped outside.
I drained my battery below 15% (9% to be exact) before starting to charge again with the threshold for the battery saving mode set to 5% no. No problems noticed.

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