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FR945 swim map vs swim distance (GPS Issue)

Hello again

owner of a new FR945 (firmware updated etc), when swimming open water, the distance recorded by the watch is accurate (i know that from A to B is about the distance shown on the watch) but wh I look at the map, it shows a wrong starting point, wrong end point, wrong track and most of the times a track that is way shorter than what i have done.

any idea?

many thanks

Nicolas

  • Post a link to the activity and we can have a look. Nothing I’ve experienced swimming this past summer.

  • Somewhere in this forum I saw similar issue, not sure if it was swimming or running, and I do not remember the solution. But I guess that refreshing the CPE file should help.

  • You should make it public I think.

  • To be honest I don’t think you swam far enough to to give the GPS a chance to record a track. Open water swimming is particularly difficult for GPS to track - it’s a combination of finding weak GPS signals in the short time the arm is out of the water and some magic algorithm in the watch. But for that to happen you have to give it a chance. In this case I don’t think you did. Was it an out and back? Was it a triangle, circle or square? Swim for 500m+ and see what it looks like.

  • Actually 200m should be more than enough to have proper GPS signal. In this track it can be clearly seen that there was NO GPS signal found at all. Only accelerometer data can be seen as distance (check the constant speed).

    The first thing what I would try is to renew the CPE file

    According to the support:

    1. Plug the watch into a computer
    2. Locate the drive for the watch
      • Mac: Found in the Finder under Devices, usually labelled Garmin or the device name (Example: Fenix 5)
      • Windows: Found under This PC on Windows 10, usually labelled with the device name (Example: Fenix 5)
    3. Open the drive
    4. Open the Garmin folder
    5. Locate and delete the RemoteSW folder
      • Mac: Empty the Trash on your computer after deleting the RemoteSW folder
    6. Safely disconnect the watch from the computer
    7. Allow the watch to return to the watch face/time
      Note: Power on the watch if needed
    8. Plug the watch back in to the computer, and sync with Garmin Express

    If that does not help, change GPS settings (for me GPS+GLONASS gives very very bad results, avoid that)

    If that still does not help, consider changing swimming style.

    When GPS signal will be found during swim, be prepared for extra distance recorded, if the signal is lost sometimes. (there is a nasty bug)

  • Mm i am very unsure because my old FR910XT starts recording perfectly even for 50m. 

    This was supposed to be triangle that i did on purpose (it was really a swim test for the gps track) and each side of the triangle was long enough to be noticeable. 

    I will do one today with both 910XT and 945 on the same wrist and share the outcome, i think this could be a good idea.

  • ok many thanks for this tech suggestion. Will try today and let you know the outcome!

  • Did you make the test? I have the same problem, the old 910XT does the job well, but new watch fails always (mine is Swim2, but I think it has the same GPS chip as 945).

    Today my watch measured 96m instead of 2 km (edit: the measured distance was about 2790m from accelerometers, the actual track length seems to be 96m according to strava distance correction). Of course 910XT could easily save the track.

    I would add to the to do list - sync with the phone (location ON on the phone) before the swim, even with newest CPE file.

    I tend to accept the idea that the GPS chip might be faulty... Or simply there is a strict routine what you have to do before each OW swim. As I use the watch only for sports (I wear a regular watch instead of a Garmin smartwatch usually), maybe it misses some important data, what Garmin forgot to tell the users.