Recently been doing a lot of running training and been tracking my runs using a Fitbit Charge 2 to upload to Strava. Charge 2 only has connected GPS rather than built in so I have to carry my phone (Samsung S6) with me to get the GPS tracking.
I have noticed that on a number of occasions the tracking recorded is somewhat out of kilter with the route I know I took. If you're able, take a look at the Strava link below for an example.
If not able to see the Strava link maybe the picture below will show the issue.
If you zoom in on the route you can see for example the sections through Charlton Hayes and Catbrain are quite wiggly, those roads are virtually straight and I certainly didn't wiggle along it like a drunken sailor as the GPS track would suggest. Likewise in the top left part of the route, there is a section where it looks like I broke off the road into the woodland before coming back to the road; I didn't. There are other sections where the GPS track wanders away from the road that I know I took. Where it cuts corners I guess its because I lost GPS signal briefly and it has just joined the points where I lost and regained signal.
I know GPS is dependent on a number of factors, visibility of satellites etc, but this particular route was on a nice clear evening with very little cloud cover, there are sections through trees but some of those are more accurate than the open road.
I am wondering if it is to do with how I am carrying my phone while running. The two options I have are in a bum bag (fanny pack for US folks) or in a sport sleeve on my arm. I am inclined to think that the bum bag is more likely to cause issues as it is fully enclosed and then surrounded by other bits and bobs in the bag, carbo gel packs etc. The bum bag doesn't claim to have any sort of RFID protection.
The attached example was using the arm sleeve.
If I measure the above route on Google Maps it measures at 11.3 miles whereas the GPS track puts it at 11.9 miles. I realise that's not a massive discrepancy but would be grateful for any suggestions for improving the accuracy of the tracking.