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running indoors -- use GPS+GLONASS or better to rely on accelerometer?

Former Member
Former Member over 9 years ago
Hello-

I recently upgraded from the Forerunner 10 to the 230, so I have no experience using a Forerunner for indoor running because the 10 did not have an accelerometer. I noticed that the GPS + GLONASS finds the signal from inside my apartment --because it happened accidentally a few times when I was playing with settings.

For indoor track workouts, would it be better to use the GPS+GLONASS or keep that off and rely on the accelerometer? I realize the former would use more battery but I am most interested in whatever would result in the most accurate pace and distance data.

Thank you!
Emily
  • 0 over 9 years ago
    Don't use GPS inside. For the kind of data you're looking for, have you considered using a footpod?
  • Former Member
    0 Former Member over 9 years ago
    Don't use GPS inside. For the kind of data you're looking for, have you considered using a footpod?


    No, I was hoping the accelerometer would be accurate enough. I prefer to be minimalist (no foot pad or HR strap) if possible.
  • 0 over 9 years ago
    No, I was hoping the accelerometer would be accurate enough. I prefer to be minimalist (no foot pad or HR strap) if possible.


    No footpod needed then. The watch itself should do just fine without GPS.
  • Former Member
    0 Former Member over 9 years ago
    No footpod needed then. The watch itself should do just fine without GPS.


    Got it! Thank you. If I use GPS+GLONASS and keep my activity tracking on at all times, do you know how much battery life I can expect?

    I also have my watch on 1-sec versus smart recording, but from what I understand, that is just a file size issue and not a battery issue. Do you mind confirming? As far as file size goes, is there any concern there? I upload my runs to Garmin Connect on a daily basis.

    Thanks again for your prompt reply.
  • 0 over 9 years ago
    Got it! Thank you. If I use GPS+GLONASS and keep my activity tracking on at all times, do you know how much battery life I can expect?

    I also have my watch on 1-sec versus smart recording, but from what I understand, that is just a file size issue and not a battery issue. Do you mind confirming? As far as file size goes, is there any concern there? I upload my runs to Garmin Connect on a daily basis.

    Thanks again for your prompt reply.


    On a full charge with GPS in use, you have something like 10+ hrs of battery life, and you can actually charge it while it's in use with something like a rechargeable cell phone charger.

    The main difference between the "Run" and "Run Indoor" profiles is that GPS (should be/is) turned off for indoor, and inside, GPS doesn't really work. (no view of the satellites)
  • Former Member
    0 Former Member over 9 years ago
    Got it. Thanks again!
  • 0 over 9 years ago
    Every second recording may take a bit extra battery (based on some tests I did with a 920) but don't think worth worrying about.

    As for file sizes, no real issue. Bit slower to upload through BT of course but the activity FIT files are binary so aren't huge for sure.
  • Former Member
    0 Former Member over 9 years ago
    Every second recording may take a bit extra battery (based on some tests I did with a 920) but don't think worth worrying about.

    As for file sizes, no real issue. Bit slower to upload through BT of course but the activity FIT files are binary so aren't huge for sure.


    Super helpful - thanks!
  • Former Member
    0 Former Member over 9 years ago
    You also don't want to use gps/glonass indoors, even if you find a satellite. Because your position is not really changing.
    Means with gps on, the forerunner will think you stayed at the same place for the whole time, which will probably result in faulty data for your activity.
  • 0 over 9 years ago
    The OP was talking about an indoor track so would be moving. There is a difference though between merely getting a GPS signal indoors and a strong, continuous and so reliable one so, in the main, probably best not to use GPS. Probably worth trying a few laps in each mode and see which mode comes out better for you.