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645M 5.90 Really bad GPS tracks

As in the title, I updated to the 5.90 firmware two runs ago and both of them have been abysmal when it comes to GPS track accuracy.

The watch has been reset to default settings after the firmware update and I selected the same settings as before:

- Smart Recording (1s recording doesn't change the accuracy, tested it)

- GPS+Galileo on first run, GPS only today

- same atmospheric conditions in all runs I compared. 

- Same route along a river without any trees

Today's run. Off completely, I ran on the path in the park and then along the river.

Here's the bad part from wednesday's run, again running along the river:

and here are both of those parts from last sunday's run, where I had firmware 4.20 on the watch (same settings again):

Unacceptable if you ask me

  • GPS version is still 2.50 though?  (The +- 4m track offset while running is still there as well :( )

  • GPS is a free service provided by the US Govt and the accuracy is +/- 4m RMS according to them.  Note that that's an average so you should *expect* it sometimes to be significantly worse. Atmospheric conditions can significantly distort the timing signals even with a clear sky. Galileo is theoretically better but still in development and many people have found worse performance in practice so far.  You may get better performance using GPS+GLONASS instead. You can also try just GPS on its own as combining the signals doesn't necessarily improve accuracy and in some circumstances can make it worse - you also get improved battery life as a bonus - perhaps that's the reason why this is the Garmin default. 

    The only thing in the update that should have affected GPS was the ability to take an location from the phone, to reduce initial fix time. From your charts that doesn't seem to be the problem though. It is possible that you have a faulty device but the fact that you've only just started seeing this problem suggests it is just a coincidence with the firmware update. 

  • All true what you say, but I observe the same effect: my running track today was much less accurate after 5.90 update than it used to be ever since with all old firmware versions.

  • Oh come on, that's such a generic useless response... 

    I reverted to 4.20 again and the routes immediately became great again. Unfortunately the spotify app was updated, so can't use it anymore on the old firmware

  • Did two more runs that again looked better now. Maybe really a strange coincidence of update and weather....? I will keep an eye on it...

  • After I read your comment I checked some of my runs. I do always the same route and I can compare old runs with Firmware 4.20, newer runs with Firmware 5.90 and the latest with 6.20. The route is not that easy than yours because there are lots of trees and the Signal should be worse, but it looks always fine and always the same accuracy, so I have no difference with the GPS on new Firmware.