• State Not Answered
  • Locked Locked
  • Replies 24 replies
  • Subscribers 1 subscriber
  • Views 10463 views
  • Users 0 members are here
Options
Related
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Different distance with GPS/Ultratrack

gobozov
over 5 years ago
Same bike ride, more than 3 miles difference in distance. First is GPS, Second is Ultratrack. Track itself looks accurate, but distance significantly different.

https://connect.garmin.com/modern/activity/3129841992
https://connect.garmin.com/modern/activity/3233801585
  • 0 over 5 years ago
    OK, I feel so silly.

    I've never ever seen the UltraTrak on my Instinct until a few minutes ago. It's only available to setup within an activity. I've only been changing the way the data is being recorded, either Smart recording or one second recording.

    I can say right now I'm not evening thinking about trying UltraTrak as I'm totally happy with how it works right now and battery use/life, but, it's nice to know if I ever do need something like that, it's there.
  • 0 over 5 years ago
    Yeah, the Smart recording vs. one second is a different thing. In this case they are so similar to each other, one second made no sense to use. With really long activities, my Bluetooth link would time out before file transfer was complete, and I would have to re-try several times. Also the larger FIT files would cause the watch to drag down when browsing the activities among other problems it seemed to cause. Smart recording works very well. Also Smart is within the error produced by GPS fix error, so really there is no reason to use 1 second unless you need that last bit of accuracy to see which tree you peed on.
  • 0 over 5 years ago
    It's really interesting to try and analyze your track! As noted, the implementation on the 5 series is quite different than the 3 so mostly I'm left just guessing. It does seem to create a more erratic track than I would expect. I wonder if there might be some compromise by carrying your coyote stick or having the dog on a leash. WDR is best utilized with a consistent arm swing and maybe the other sensors in play are also affected. Your SPMs are pretty low so that might also be a residual effect. Hiking doesn't provide stride length stats so that's another missing piece I'd like to see. The elevation profile seems quite good! Not so much for the 3 (me) - that's a limitation on Connect. How does the file size (number of records) compare with a straight GPS recording?

    Like you have stated, you'd probably normally just use GPS in this scenario. Still great to see a test performed and shared. Thanks!! I still get really good results in challenging environments but hard to say if I'd have the same experience hiking in your area.
  • 0 over 3 years ago

    I think you are right, there is some BUG in ultratrac processing. I took both of your rides and compare them in maplorer.com. It shows length of:
    - GPS recording 18,22km or 11.32mi
    - ultratrac recording 16,7km or 10.8mi

    This makes only 8.70561% difference.

    I think these results are acceptable in comparison with Garmin processing which shows
    - GPS recording 19.05km
    - ultratrac recording 13,82km

    and with Gramin processing difference is whooping 31.8223%

    I would say there is lots of room for improvement.