Improving Elevation Accuracy

I use a Wahoo Elemnt Bolt to record and transfer my rides into RWGPS. The ride metrics from the Elemnt Android app do not agree very well with RWGPS elevation ascent and descent, mainly on flat segments of my rides where RWGPS is consistently higher by a large margin, as shown in the example below.

Example based on a ride performed on 19-May-2018: for a total distance of 63.3km, RWGPS reports a total elevation of 583m. For the first 16.0km which was very hilly, RWGPS reports a total elevation of 350m. The remaining 47.3km was very flat, so the remaining 233m of elevation seems suspiciously high.

Moreover, the Elemnt Android app reported a total elevation of 468m only.

So I decided to analyze the raw data of the ride exported from RWGPS based on different data smoothing approaches, as follows:

- no data smoothing: elevation for first 16.0km = 378m, elevation for last 43.3km = 350m

- moving average (25 seconds): elevation for first 16.0km = 328m, elevation for last 43.3km = 151m

- exponential smoothing (factor of 92%): elevation for first 16.0km = 321m, elevation for last 43.3km = 147m

I don’t know how RWGPS smoothes the data, but the results above seem to indicate that ride elevation accuracy could be improved by doing a little more smoothing.



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