Fenix 6X Sapphire - Problem with GPS Total Distance.

Been using the Fenix 6X Sapphire (Sony GPS chip) and have noticed,  it always shows a shorter distance traveled than my other Garmin products.

Last week (In order to test it) I went on a short hike. I brought along my Oregon 650, Fenix 3 Sapphire and the new GPSMAP 66i.

After the hike, the total travel distance was:

Fenix 3 Sapph. 7.59mi

Oregon 650      7.55mi

GPSMAP 66i    7.57mi

and

Fenix 6X Sapph 7.46 

So far, the Fenix 6X always reports the shortest distance.  I hope Garmin becomes aware of it and sends a fix in the near future.

  • It's not that it's calculating the distance wrong. It's that the track has variations between the devices. No two devices are going to record exactly the same track as each other. As a result, the total distance will be slightly different between the devices.

    It could be that the Fenix is "cutting corners" when you make a turn, or it could be that the other devices had more instances of tracks drifting. Or some combination of those things. Whatever the case may be, none of your devices are calculating the distances of their recorded tracks incorrectly,it's just that the tracks got recorded a little different for whatever reason. Considering you hiked 7.5 miles (presumably not in a straight line), it's not far-fetched for the reported distance to be different by 500ft or so (basically, a 1.3% margin of error). 500ft means the track may have only been different from the other tracks by 5 feet in 100 different places.

  • I agree, however I feel the longer the distance the greater the inconsistency percentage. 

    Soon I’ll be going on a 50+ mile hike. That should provide a better indication of how the Fenix 6X performs when compared my other Garmin products including the Foretrex. 


    Should the difference between my 6X and all my other Garmin GPS devices be large, ’ll post and or contact Garmin.  

    Thanks 

  • The past weekend I did a trail run that was ≈27km. My watch was almost spot on with the distance signs along the run. In the end my watch said 26.41 and I think that is more correct than 27... One thing that is important to me is that it is consistent, something that my F3 always was. I haven't done enough runs with my F6 to say it is consistent but so far I don't see any issues with the distance.
    https://connect.garmin.com/modern/activity/4081333616

    I'm not a pace runner, I rely on HR during a run.

    Best regards,
    Tobias

  • @Beowlfs, there is a fundamental issue with the Sony chip.  It happens the same to the Sunnto 9 which uses the same Sony chip.  

  • @Beowolfs, there is a noise-related fundamental problem with the Sony chip. Someone professionally tested the newest Sunnto 9 which uses the same GPS chip.  It can't track the speed, turns and stops correctly compared to other GPS watches, not with the Sony chip.  If you use Strava, look at the fine details of the speed like the picture I attached for your reference.  It was walking. There shows a lot of speed jumps (the excessive ripples in the speed reported).  The correct speed was 2.8mph.  However, it magically turned the walking to "running" at 6mph !  The distance traveled was also way off.

    Noise issue

  • It is because there is a noise-related fundamental issue with the new GPS chip. Unfortunately, very few developers fix the issue although the solution is available.  Many products follow the same reference design and so the performance becomes me-too. Someone professionally tested the Sunnto 9 which uses the same GPS chips.  It was simply walking at about 2.8mp, but it can't track the distance, speed, turns and stops correctly. The setting is with the performance mode (means full power). Unfortunately, the low power GPS chip comes with a severe compromise on GPS accuracy and precision!

    Everyone can try to repeat the test with Strava. Choose a place with multipath fading (i.e. buildings and trees nearby and reflection), walk and make some right-angle turns and stops (a few seconds to 20s).  Look at the speed chart on the Strava.  Here inserted an example.

    There are so much excessive speed ripples (due to noise).  It magically turned the walking to "running" at 6mph, which wasn't correct.  It explains why the distance traveled was completely off.  When the speed is wrong, especially when making turns and stops, the distance becomes wrong.

  • I just posted this to a similar Reddit thread but thought it could be good over here too. I’ve got three runs at this point that all on the watch were short. 

    One was a week or so ago, five miles that I followed a course I created and ported over via EasyRoute. I was also following a structured workout at the time. At one point on the course the route I drew wasn’t available and I had to deviate. It was a deviation that added distance not subtracted because I had to go around. Plus I ran probably a .25+ mile before I realized I was off and had to backtrack, etc, etc. Well towards the end of the loop which according to the drawn route would have been over five miles many watch was showing like 4.65. I finished the loop and even made it back to my car and it didn’t tick over 4.89. I thought it had something to do with the structured workout with the course following but I’m not quite sure. 

    The other thing that was odd with the 5 mile run is when I pull up the GPS track on Garmin Connect their own mile markers show the run was over five miles. 

    I did an 8 mile run this past Saturday following a route built on EasyRoute and ported over but no structured workout this time. Same thing happened here. The route should have ended about a quarter mile past my start point but it was well under that when I finished. 

    Same similar results with a five mile run I did yesterday. Looking back at the drawn course for the 8 and 5 miler the watch mile markers seem to be like an 1/8th of a mile past where the drawn map is. 

    I did have one run that was 3 miles that hit the mile markers for a drawn course dead on, so it may be something with longer runs. 

    I always set to 1 sec recording and GPS+Glonass when I get a new watch. I did double check that before this last five miler and it was set correctly. 

    Additionally I looked back at the actual gps tracks, they’re nearly spot on. On the last run the watch even perfectly nailed a 170 degree turn. Very rarely is the gps track off the route I was on and even when it is it’s maybe a meter or two at best. 

    I have a feeling it’s the algorithm on the watch is calculating the distance between points incorrectly but I don’t know enough about that math to prove it. 

    I reached out to support and they told me how to adjust my gps settings (real helpful). I’ve got a shorter run tomorrow but I’ll see how it compares. I have a longer run this weekend that I might go full DCRainmaker and run with three watches. I’ll have two follow a course and one not then compare the results.

  • I run a 1.5-mile out-and-back run all the time, it's a specific start and finish point that I've measured on Google Earth to be 1.50 miles, basically to the inch. So far, my F6 has measured between 1.49-1.51, but never any higher or lower than that. I just attribute the difference to mild variations in how I go around corners, and maybe not starting, turning around, or finishing at exactly the same spot every time. At any rate, a 1.49-1.51mi range for something that is actually precisely 1.50mi is pretty ok to me.

    Remember that these (and EVERY OTHER wearable GPS) only have a 5 meter accuracy. So it's not surprising that every time the trail turns you get a couple meters of discrepancy between multiple devices. Until we get dual-band GPS chips for wearbable devices, that's just something we have to put up with.