Race 2: GPS and distance accuracy vs previous Suunto models
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@jjpaz Thanks for posting these results and continuing to dig into this topic. I find it quite interesting since I used to think that Suunto watches, in general, measured just a bit long. There was a time when Suunto’s GPX traces were a bit “jiggly” (some people referred to it as “zig-zagging”) and the assumption was that these wiggles added a slight increase to an activities overall distance.
However, over the past year, beginning with software 2.39.20, a fair amount of smoothing has been added to the traces and I’ve come to regard Suunto’s distance accuracy among the best. (I commented on this change over here. You’ll notice in the example I gave how the Vertical added slightly to the GNSS distance, presumably due to 3D distance, and the 955 subtracted from it, presumably due to the applied algorithm based on pace, cadence, stride length, etc.)
I find it interesting that, after working so hard to perfect their GNSS accuracy and tracing, Suunto has chosen to apply further distance calculations based on… who knows.
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I may have to backtrack my observation that Suunto used to use GNSS distance alone to calculate activity distance. I just went back and looked at some older “Running” and “Walk” activities (using the new & improved Quantified Self) and noticed that sometimes activity distance was actually shorter than GNSS distance, even for older models like the SV1, 9PP, and even 9P. Not by much, perhaps only 20-40m over 5km in certain cases, but something nonetheless.
I’m mostly a trail runner, though. For these activities, GNSS distance and activity distance almost always align or activity distance is slightly longer due to elevation gain/loss.
Perhaps all Suunto watches do share the same distance algorithm (which makes sense), but the newer models are registering less-accurate GNSS accuracy and therefore applying more distance correction?