Bad GPS lock and inaccurate navigation? Check that your clock is set correctly.

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Ockie

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Henceforth AKA OckieMoto :-)
So, I have had non stop GPS issues with my Meizu M2 Note GPS. Lock took ages if at all, and if it did get a lock, once you start driving the thing would just be all over the place to the point you just actually could not use it. Then a peep posted in the Vodacom section that he noticed that Vodacom is pushing a time setting to his phone that is 3 minutes fast. I checked mine and compared it to my laptop and he was right. I then synced my phone clock manually with a internet time keeping website and once done I noticed my phone GPS going on and it found a lock almost immediately .... while indoors nogal. Took it for a drive now while going to the shops and true as bob, my GPS is working flawlessly while navigating now too.

I kind of feel bad, I have been blaming Meizu and Mediatek for this issue, thinking they put a k@k GPS receiver in the chip or bad antennas into the phone body. Turns out it was just my phone time that was out. Can you imagine. So, if you have something similar happen to you, give this a go a see if it sorts you out.
 
Ockie said:
So, I have had non stop GPS issues with my Meizu M2 Note GPS. Lock took ages if at all, and if it did get a lock, once you start driving the thing would just be all over the place to the point you just actually could not use it. Then a peep posted in the Vodacom section that he noticed that Vodacom is pushing a time setting to his phone that is 3 minutes fast. I checked mine and compared it to my laptop and he was right. I then synced my phone clock manually with a internet time keeping website and once done I noticed my phone GPS going on and it found a lock almost immediately .... while indoors nogal. Took it for a drive now while going to the shops and true as bob, my GPS is working flawlessly while navigating now too.

I kind of feel bad, I have been blaming Meizu and Mediatek for this issue, thinking they put a k@k GPS receiver in the chip or bad antennas into the phone body. Turns out it was just my phone time that was out. Can you imagine. So, if you have something similar happen to you, give this a go a see if it sorts you out.
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Wow very interesting.
 
Ockie said:
Then a peep posted in the Vodacom section that he noticed that Vodacom is pushing a time setting to his phone that is 3 minutes fast.
Click to expand...

Strange. Saw that thread too. I wonder if all Vodacom subscribers are suffering from this issue?

Would be interesting if Vodacom smartphone subscribers can compare their network time to this;

http://time.is/

I'm on CellC and my time is pretty much spot on.
 
Ockie said:
So, I have had non stop GPS issues with my Meizu M2 Note GPS. Lock took ages if at all, and if it did get a lock, once you start driving the thing would just be all over the place to the point you just actually could not use it. Then a peep posted in the Vodacom section that he noticed that Vodacom is pushing a time setting to his phone that is 3 minutes fast. I checked mine and compared it to my laptop and he was right. I then synced my phone clock manually with a internet time keeping website and once done I noticed my phone GPS going on and it found a lock almost immediately .... while indoors nogal. Took it for a drive now while going to the shops and true as bob, my GPS is working flawlessly while navigating now too.

I kind of feel bad, I have been blaming Meizu and Mediatek for this issue, thinking they put a k@k GPS receiver in the chip or bad antennas into the phone body. Turns out it was just my phone time that was out. Can you imagine. So, if you have something similar happen to you, give this a go a see if it sorts you out.
Click to expand...

Sounds like interference or confused GPS antenna/processing.

GPS signals usually include the time which is part of the calculation. Time on the phone I don't think plays a part.
 
quovadis said:
Sounds like interference or confused GPS antenna/processing.

GPS signals usually include the time which is part of the calculation. Time on the phone I don't think plays a part.
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I am not even going to pretend to know how or why it worked. I just know it did. I do know that it is pretty important for the satellites to know exactly what time it is and that they be synced and that they somehow use the time of the signal traveling from the satellite to receive to do the location thing, but how exactly etc I dont know.

What I do know is that this seemed to the the issue with my GPS in my phone.
 
GPS is a "there and back" signal, your time has nothing to do with it as it as GPS uses its own time only. You could never syncronise your time accurately enough, nanoseconds will be enough to throw the signal off.

That being said I have no idea why that worked for you. My phone died and I haven't reset the time yet, it's showing 2:43am on 1 January, I used GPS to get to the restaurant I'm at right now.
 
Bad software on the device (or is it the whole OS? Not Android user, so not affected by the issue). The hardware is obviously fine.
As others have already chimed in, GPS keeps its own perfect time, and some devices can actually update their clocks based on GPS-provided time.
 
Strange you should mention his, earlier today my phone was a day ahead with its time from Mtn servers,

Had to set it to GPS to get correct time.
 
sicelo.m said:
Bad software on the device (or is it the whole OS? Not Android user, so not affected by the issue). The hardware is obviously fine.
As others have already chimed in, GPS keeps its own perfect time, and some devices can actually update their clocks based on GPS-provided time.
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Lol yeah 1.4 billion users would've already complained if it was a bad OS.
 
backstreetboy said:
Lol yeah 1.4 billion users would've already complained if it was a bad OS.
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Okay. Factor I didn't consider. (although those 1.4bil users don't all have to deal with 3+ minutes issues, I hope).

@Ockie - which A-GPS/SUPL servers are configured on your device? That's where your 3 minute issue would have the most influence. In fact, I will be very surprised if SUPL communication isn't your entire problem in a nutshell.
 
sicelo.m said:
Okay. Factor I didn't consider. (although those 1.4bil users don't all have to deal with 3+ minutes issues, I hope).

@Ockie - which A-GPS/SUPL servers are configured on your device? That's where your 3 minute issue would have the most influence. In fact, I will be very surprised if SUPL communication isn't your entire problem in a nutshell.
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mmmmm I dont know. How would I check that?
 
Indeed .. could be hard-coded to supl.google.com. I did mention earlier I don't use Android. On my phone, I can choose different SUPL servers as necessary (not that there are many options out there to choose from)
Screenshot-20160828-201803.png

Either way, access to the SUPL servers is usually (or should say always?) encrypted. So with a large time difference, you might not be able to get A-GPS working as the SUPL server will refuse to communicate with your device due to failing certificate verification tests. In that case, you will only depend on 'raw' (hardware) GPS, which can take a while to lock even when the device has a relatively good GPS chip.

Guess I should retract my 'bad software' comment :wtf:
 
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Used Waze on my way to work again this morning. Not in navigation mode, just let it follow my route. Was 100% accurate and no issues. Cant believe I have a working GPS in my phone. :p
 
Ockie said:
Used Waze on my way to work again this morning. Not in navigation mode, just let it follow my route. Was 100% accurate and no issues. Cant believe I have a working GPS in my phone. :p
Click to expand...

Yup, could never understand how you had such problems with GPS on the MTK chipset :-) glad it's working now.
 
Hmm.... so switching to Vodacom and setting auto time update might make hatching eggs in Pokemon Go a whole lot easier?
 
I actually played around with this to test Ockie's theory. What I found was:
- Setting the Time-zone to something other than your own does not seem to make a difference, provided the time is accurate/aligned with that of the GPS System
- If I changed my time 3-5min either way (fast/late) it does not seem to make a difference to get and maintain GPS lock
- If I change my time anything beyond 10min fast/late, it takes quite a while to lock on. I did not move around to see if it maintains GPS lock. Accuracy seems all over the place, fluctuating from 4-30meters.
- If I change my time beyond 15min fast/late, it never locks onto a position.

Curious, actually.
 
I have been having the same issue using 2 different phones. both times I was using Telkom mobile.

It locks on fine but when using maps in navigation mode, it randomly says GPS signal lost every few minutes even if it has line of sight with the sky.

I have synced up to time.is and issue persists.

any advice
 
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