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Fenix 6X Pro GPS accuracy (tunnels)

Wiggyben
over 4 years ago

Just back from a run with 2 other Garmin users. We went through a 0.18 mile long tunnel and turned back once through it. After the run I noticed that I had recorded 0.35 mile distance less than my mates. On looking at all 3 maps I realised that my Fenix 6X had not recorded me going through the tunnel but had added on the time it took to get through the tunnel and back, in other words my pace for that particular mile was also way out!

Both my mates were using less expensive Garmin's (which recorded them going through the tunnel) so naturally disappointed. Has anyone else had issues with tracking through or near to long tunnels? Are there any settings to tweak or tips/tricks when going through tunnels? I run this route regular and have noticed it before on my watch while other running buddies seem to record correct distances. It is as if my particular GPS receiver is weak and cannot cope when the signal is weak.

  • 0 over 4 years ago in reply to Wiggyben
    Wiggyben said:
    Trying it again this weekend but going a little further once through the tunnel.

    Try going far enough to be out of the cutting approaching the tunnel portal and clear of what appears to be, from aerial images, heavy tree cover around the tunnel portal.

  • 0 over 4 years ago in reply to Scillonian

    Returned from this mornings run, watch still a problem. Ran the same track to the tunnel with another Garmin user (Fenix 6S Pro), their accuracy being better than mine. At the 2.8 mi mark my Garmin read 2.7 but at the 3.7 mi mark mine read 3.4! I had lost 0.3mi while my mates Fenix was pretty much spot on. What is strange is when I run in open sky view (streets) etc the watch appears fine. It seems to be one particular track when my watch does not perform as good as anyone else's. Today I had set to data record every second, GPS/GLONAS and used manual pause. So today, I lost the 0.3 mi well before the tunnel! Could I have a faulty/weak GPS chip or do I just except my watch will under perform whenever I run in this tree lined area. Cost me £600 and wish I kept my Fenix 5.

  • 0 over 4 years ago in reply to Wiggyben

    Do you run with anyone who also has a f6X and can run this course with you so you can compare like for like?

    Trees leaves are a killer for GNSS signals. Now that trees are coming into leaf, GNSS tracks that have been good through the winter are now starting to wander on tree covered section of the road. They will (hopefully) get better again once the trees loose their leaves.

    Without a direct comparison with another f6X, it could be that in this particular situation the smaller size of the f6S gives it a slight edge over the f6X in GNSS signal reception.

  • 0 over 4 years ago in reply to Scillonian

    Don’t run with another 6X user but know of one so perhaps could arrange. Understand the tree canopy issue but don’t get why the smaller 6S would perform better? Read lots tonight about the underperforming 6X, some citing that the GPS receiver points down when running, runners trying to wear upside down or wrong wrist. Lots of moans and think this will be my last Fenix for sure. Considering spending £200 on Stryd pod just for distance accuracy!

  • 0 over 4 years ago

    I had somehow related issue today while cycling with Quatix6 (FW 16.60).

    After the tour I saw 83 km/h as my max speed!

    Looked a the map location where it was recorded -- directly after leaving a tunnel. Speed in tullen seems to be recorded as 0 km/h, and then come distance correction with GPS fix.

    So I assume distance should be correct, but speed in and after tunnel are both not realistic

  • 0 over 4 years ago in reply to Illya

    There is absolutely no way for the device to record cycling speed without GPS unless you have a cadence sensor. When running it can guess the speed from the accelerometer data, but when cycling there is very little acceleration and deceleration. 

  • 0 over 4 years ago in reply to silentvoyager

    If there is no acceleration, it would be reasonable to assume, that speed is constant.

  • 0 over 4 years ago in reply to Illya

    Perhaps, but I bet it would be difficult to achieve reasonable accuracy. There is always small acceleration from pedaling and deceleration from friction and air resistance. I don't know if accelerometer in Fenix is accurate enough to track that. And number of people who may need that is quite small for Garmin to care unlike the running case where a lot of people run on treadmills. 

  • 0 over 3 years ago

    it may be the battery level of the running pod is too low. So no signal transmitted  to the watch.

  • 0 over 3 years ago

    It may be the battery level of the running pod is  low