Odd tablet GPS behaviour

[fifer]

Recently I sailed over to the isle of man and used a Samsung Galaxy tab s 8 with opencpn and osenc charts to record my track. As you can see the GPS fix wandered a lot despite having a good fix to >12 satellites and any sleep/power save options being turned off.

This happened the following day also.

My Garmin GPSMap 4xx worked perfectly.

Any ideas on what the root cause of the issue might be?

 

[Hoolie]

The "deviations" are all oriented N/S and E/W so it's unlikely to be a GPS problem and more likely to be computational problem within your tablet

 

[fifer]

The "deviations" are all oriented N/S and E/W so it's unlikely to be a GPS problem and more likely to be computational problem within your tablet

And I guess that could either be hardware or software faults in the tablet itself (as opposed to opencpn which just uses the GPS position calculated by the tablet)?

I would be surprised if it were due to lack of computational grunt and/or ram

 

[Lon nan Gruagach]

Recently I sailed over to the isle of man and used a Samsung Galaxy tab s 8 with opencpn and osenc charts to record my track. As you can see the GPS fix wandered a lot despite having a good fix to >12 satellites and any sleep/power save options being turned off.

This happened the following day also.

My Garmin GPSMap 4xx worked perfectly.

Any ideas on what the root cause of the issue might be?

Maths fault. a calculation is using 1's complement instead of 2's complement meaning that as a digit rolls over the carry isnt done until the next increment (/decrement)

Imaging the plot of repeatedly adding 1 but instead of the carry from 9 to 10 happening when the 9 turns to 0 but when 0 turns to 1
0, 11, 12, 13, 14, 15, 16, 17, 18, 19, 10, 21, 22

How many arc seconds are the deviations? Bettcha a dime its some power of 2

If its possible, reinstall the drivers.....

 

[fifer]

Interesting point. I'm guessing by reinstall drivers you mean root the tablet and install a fresh Android version? It's doesn't sound like the sort of thing a factory reset would fix.

I'm open to the idea of rooting the tablet. It's 3.5 years old now and I could flash a clean stock android without all the Samsung bloat