Originally Posted by
pdlamb
... ... While riding, the track show I'm following the road, and then there's a point a quarter mile off in a cornfield then back to the road in a sawtooth route, or it looks like I hiked into the woods and came back and kept riding. ...
...
Is there a way to apply some more filtering to the phone's GPS, or force either app to use a sanity check to smooth the track out?
I do not know why this happens, but i have occasionally seen it over the years in some of my tracks. It only seems to happen when my GPS has not been used regularly for weeks.
I suspect that the GPS has old data in it for some of the satellite orbits, and as some satellites move further away and another satellite comes into view, if the data on the orbit is old for the one that just came into view, I suspect that it plots the location using old data with some error. This is only a guess on my part.
If my guess is correct, the best solution is have your GPS turned on more often to load more recent orbit data for all satellites into it.