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GPS: Completely unacceptable

Dennis.stevens1982
over 4 years ago

Hey all,

I have posted my problems with the Fenix 6X Pro in German Forums here and here. Maybe I get some new advices here.

First things first:
FW V5.00
GPS V2.7
3D-Speed: OFF
3D-Distance: OFF
Data recording:Every second

When I used the Fenix for the first time, it ran on FW V4.30.0 and had acceptable performances in measuring distances. On a ~12.5km run it measured for example between 12.01 and 12.1 km. Which was in accuracy comparable to the Forerunner 245 which I have used before- and really OK for me.

My focus in running are the pace and the heart-rate. Which are the most important parameters in addition to my own body sensation. If I run 12km in 5:25 with a HR of approx 160 I am fine. If I feel great after the run, the training was perfect for me.

The pace is a function of time and distance - and now on the Fenix the distance is a huge problem since update to FW 5.00.

On 15th December 2019 (my Fenix received V5.00 the day before) the GPS accuracy became really bad. But each time I follow advices like waiting 25 minutes until the Fenix has updated her satellite-almanach or updating to GPS V2.7, in the first session after such updates the Fenix delivers accurate distances. But each following training it gets worse.

Examples:
1. updating the satellite-allmanach: Distance 12.06km, time 1:05:15, pace 5:25min/km
2. next training (still with GPS V2.6): Distance 11.78km, time 1:08:45, pace 5:50min/km
3. After Update to GPS 2.7: Distance 12.06km, time: 1:07:07h, Pace: 5:34 min/km
4: Next training 11.87km in 1:09:50 h, pace 5:53min/km
5: today 11.37 km, time 1:07:25h, pace 5:56min/km

The distance I run is always the same: 12.5km

Training 1 and 3 proof (to me) that after an update the Fenix works perfectly.

Training 3 and 5 reveal that it is not possible to rely on the pace. Since accuracy (690m deviation) is far beyond acceptable, two trainings in the same distance, with a deviation of 18 seconds are calculated to have a deviation in pace of 22 seconds. And such is not acceptable. 22 seconds in pace can make the difference between an easy aerobe training and an hard training. VO2Max depends on the pace and the heart-rate. In Training 3 the VO2Max was calculated with 49. In training 5 with 47. But the diference in heart rate was only 4 beats.

Important: I do not care for calculated Vo2Max. I just wanted to show how the GPS-accuracy has impact on many other parameters in the device.

Based on my experience, my best solution would be to downgrade to FW V4.30.0. But I was told that this is not possible since I have to downgrade sensor-fw and other software, too.

Can anybody help me with that problem? At the momment sport is just frustrating. And the reason for that is a sportwatch. Unbelievable.

kind regards!

Dennis

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  • 0 over 4 years ago in reply to Punch

    As I wrote. The Forerunner performed much better. So I will sell the Fenix and use my Forerunner instead. Or buy another Forerunner without that Sony chipset. Whatever. Just want to run and have comparable results on distance and heart rate. Would the results be false all in the same manner (e.g. distances between 11.7 and 11.9 km) then it would be ok for me since each training could be comparable. But with the Fenix each training is a riddle in trying to discover who had a bad day: Me or the watch.

  • 0 over 4 years ago in reply to Dennis.stevens1982

    i personally think that the fenix 6x is too big for sports that's why i bought the 6s.

    i think the bulk and the weight affect accuracy of HR and GPS.  

  • 0 over 4 years ago in reply to Dennis.stevens1982

    That's the thing, it's NOT an option you can turn on. On Strava, you can ask "gimme the GPS distance", and it would give you the number I gave you, more or less (there are different formulas to calculate a GPS distance I think).
    but DURING the run, I don't see how to get an accurate pace / distance. That's something we comment a lot online, and Garmin must have more road runners happy with this calculation (I find it quite reliable in a city, and maybe it is for typical road runs).

  • 0 over 4 years ago in reply to Punch

    HR, it's quite likely, yes.

    For the GPS, I don't think so. My F5X was moving much more on the wrist (it's much heavier), then maybe it's affecting it a bit. But the F6X isn't bigger than a Suunto 9 or Coros and it's weight make it stable on the wrist. And mine is not thick at all.

    And 3 weeks of battery, it's really great :)

  • 0 over 4 years ago in reply to RISBAC

    I don't think they calculate the distance "from another source".
    Unless you wear a footpod - then yes.


    We can only assume that the algorithm used is "wrong" and too many "wrong" GPS points, and with that the distance, are deleted. And thats also probably the reason why the actual pace rises and falls more or less randomly.

    And before someone start to jell that it is in an acceptable range - no, it's not, especially due the older Garmin Fenix models had not such a problem.

    And last thing - GPS positioning is OK - the algorithm behind cause the errors.

  • 0 over 4 years ago in reply to tiefflieger666
    tiefflieger666 said:
    And thats also probably the reason why the actual pace rises and falls more or less randomly.

    Which is another point that makes my training so frustrating. I have a good constant pace. And Fenix calculates values that vary within 3 min/km...across a distance of less than 100m.

  • 0 over 4 years ago in reply to tiefflieger666

    It can use the accelerometer and is using it. Start recording a run from inside a building, and it will count some distance, even without any GPS. I often do it from the train station, and it's working, just like Suunto was doing too with the Ambit.

    Maybe it's not using it anymore when the GPS signal is found, of course I can't know that. But doing more tests with the accelerometer, I noticed that it's not very accurate. It took me two calibrations to get an accurate distance... but at a specific pace. If i accelerate or slow down, it's REALLY wrong. And as we all know, we run all the time at a steady pace when running on trails...

    Garmin doesn't have the DNA of a company doing devices for nature runs. They are coming from road running, and it's easy to see that. Most indicators are great for a road runner, and not that useful for a trail runner. The GPS performances are often really good for road runs. The distance auto correction is doing quite fine in a city, it avoids too long distances that the GPS is recording.

    But it's not good for nature runners. And even the instant pace is a real problem, it's often so wrong, it's not usable.

    So indeed, the GPS has not big issue, it's not as good as the old chipsets of the Ambit / V800, but it's good enough. And it makes battery life very comfortable. But Garmin should do better for the distance / pace calculation. At least, they should offer a way to choose between their calculation and another mode (like pure GPS calculation...).

  • 0 over 4 years ago in reply to tess
    philipshambrook said:
    Why? 
    tess said:
    It's not strange at all.  The amount of satellites and type will vary in different regions and at different times.

    Mmm... In every region or city you will use your Garmin there will be the same or more satellite if you use GPS+GLONASS than only GPS. 

    It's logic but you can check here:

    www.gnssplanningonline.com/

    If using only GPS, the track is really more accurate than GPS+ GLONASS/GALILEO,  this means that Garmin algorithm is not really optimized to use  different satellite constellations (Multi GNSS) and work better if have less satellites available but from the same constellations. 

  • 0 over 4 years ago in reply to Simone.01

    All that tells you is how many satellites are healthy. It tells you nothing about those that are visible at any location at any specific time. I did have an app on my iPhone for that but don't have it anymore. Try GPS Plan for the iPhone.