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Ephemeris missing

6125703
over 2 years ago

My FR255 is showing "ephemeris missing" even after an hour activity with gps tracking and syncing several times with Garmin Connect Mobile on Android. I even tried powering it off and restarting, but another sync still didn't change the status.

This is the first time I tried to use the watch offline, without syncing for about 48 hours before using the gps only mode.

Doesn't Garmin save ephemeris being broadcast from satellites?  I am under the impression from other gps units that it should be possible after receiving for less than an hour. I expected to be able to use the watch in the mountains without any phone service for you to a week or two, so it's disappointing if it can't even handle a few days without the phone?

  • 0 over 2 years ago in reply to ovekvam
    ovekvam said:
    Maybe Garmin Express asks the watch for location for the Ephemeris file?

    Yeah, maybe.
    Or they use geolocation based on IP.

  • 0 over 2 years ago in reply to 6125703
    6125703 said:

    Maybe something like picking zones on a map so GCM can fetch multiple files and then provide the right one to the watch during later syncs without internet.

    Or maybe something like allowing the watch to sync and store multiple ephemeris files for different regions and switch between them. Maybe an option to get region files to cover all loaded courses?

    Ok, understood.

    Interesting idea, maybe you want to share it with Garmin:

    www.garmin.com/.../

  • 0 over 2 years ago

    My ephemeris went "missing" again, roughly 12 days after my last post that it had fixed itself and gone back to "current". During this time, I was continuing to do 6-7 daily, 1 hour long GPS activities per week. I synced to the phone 1-2 times per week. So don't put too much stock in the Garmin suggestion that it would go stale after "30 days" without syncing. It may fail much sooner.

    Also, I again saw flawed distance measurement. It is not just a matter of getting a faster lock but degraded functionality even after showing a green satellite lock! In SatIQ (auto-select) mode, my recurring route measures as 3.39 miles with valid ephemeris but the last walk measured only 3.22 miles with missing ephemeris. There is no visible deviation or gap on the track when displayed in GCM, but the distance metric is wrong anyway. I assume the pace metrics are also wrong since they are based on distance.

    I also struggled to get it to repair the ephemeris file again with multiple sync attempts and watch restarts. I think what finally repaired it was enabling the bluetooth connection and entering a gps activity mode at the same time. Once it had a green lock with the bluetooth link active, I was finally able to see it show "ephemeris: current" in the status screen. I don't think I've seen this documented anywhere.