Fenix 6X Pro - why do my GPS tracks have straight line sections?

If you notice the problem within an activity. Try to increase the cadence (or fake it with arm movement) for some seconds and see whats happening.

Do you think an accelerometer is playing a part in the GNSS track recording?  If that's the case then we should all get onto Garmin and get them to rewrite the firmware. I expect an 'every second' track recording to record the output of the GNSS receiver every second regardless of what that output is. I don't mind if ridiculous spikes are removed but choosing to intepret slow movement as drift is a poor decision, if that's what's happening

Not the accelerometer itself. But cadence (which comes from accelerometer data) and speed (which comes both from gps and accelerometer data)

I understand.  I might try and replicate your experiment.  Holding the watch steady would remove obvious accelerometer output and it's easy to walk slowly!  What you're suggesting might explain the straight-line sections in the tracks I've recorded.

Maybe it's a little firmware algorithm designed to remove 'nesting' from our tracks....

You can just go out for a really slow walk with low cadence and see how the device behaves. I think speed threshold is around 0.3-0.5 m/s so you need to walk slower than that  And cadence below 1 per second. It looks really stupid if you have neighbors around ;) But it would be easy to replicate.

Yes, if you have the same problem like I did have then its solvable in the software. But, it might give false movement when actually standing still (due to GPS drift). So, maybe an option for enable/disable it would be best 

Thanks. I will try this when I have a quiet day. I don't have these problems with my eTrex 20x. Personally I don't care about 'GPS drift-nesting' I just want an unadulterated track. I can chop the lunch break 'nests' out later if I care enough :-)

Aaah .. that does make some sense ...

Over time I've noticed the 'straight bits' tend to happen on steep terrain where I am moving quite slowly, but am moving forwards a bit. When I am scrambling, ie moving very vertically and not much horizontal, I get the usual nest of a track which I don't pay much attention to. I can get these straight bits after finishing a scramble and starting to move horizontally again. Maybe Garmin needs to re-look at their algorithms? 

My Edge 830 does have a setting to stop tracking at very slow bike speeds, ie auto-pause. But I always have that switched off for the same reason. Auto-pause on the bike seems to cause more issues than it is supposed to help with.

Maybe the Fenix has a hidden auto 'Auto-Pause'

There might be something to this suggestion. The most obvious straight-line sections I've had were crawling up Great Gable in the snow/ice without spikes on and similarly going up Dollywaggon Pike's east ridge. A tricky snow-filled section had me going very slowly. I have stopped for a bite to eat for 10 mins or so and have been surprised at the lack of an obvious 600 point 'nest'.  Give me lunch-spot nests over screwed tracks every day.....I just want a track which faithfully records where I went :-)

However if I was writing an algorithm designed to remove drift-nesting then it would start recording once the location had moved 20 metres or more. I've got straight sections which last much longer than that. Here's my Great Gable track. https://connect.garmin.com/modern/activity/8067402747  The climb up the NW ridge should have been full of scrambly wriggles. I even walked around the summit before stopping for a bite at the southernmost tip of the track. That detour went completely unrecorded. It looks like I reached the summit plateau and headed straight for a sarnie. I didn't!