Runner 3 correction algorithm

zeehond Registered Users Posts: 2
Apprentice Traveler
edited January 24 in TomTom Sports
I've been using my Runner 3 for a while now and am happy with it's GPS accuracy, the line is very close to where I'm running. While taking a corner however, it tends to cut off a lot of the route. Below is an example of one of my runs, I added the red line to show where I actually ran.


As you see on the straight parts it's all okay, but the corners are cut off, this doesn't seem to have anything to do with accuracy but it looks like a correction algorithm is used to round off corners and make sure there are no measuring errors. It's quite extreme though and as you see, I came from the left top of the image and before reaching the corner, the line already starts to move into that direction. When taking a small streets towards the "Zomerstraat" you see it cuts off even more as there are two 90 degree corners following each other very quickly. After that the route takes us south and once again, the line starts moving to the side before I'm reaching the corner.

Is it possible to change something in my settings about this correction algorithm? It's quite annoying and makes my runs appear shorter than they actually are. I've measured this (12km) run and it's around 400 meters longer than measured with my watch.


  • tfarabaugh
    tfarabaugh Posts: 16,936
    There is nothing to change and it is totally normal. I would guess from the map you are running in a city and you are getting interference from the buildings which is throwing off the track. I have this on every GPS watch from every brand I have tried. It ultimately has very little impact on the distance recorded. The nature of GPS is that each data point collected is only accurate to within 15-30m of your actual location. The watch collects the data points and then tries to figure out a route using them (considering that some points may overlap or duplicate). The watch then smooths the data to come up with the most reasonable route taken according to the algorithm it is programmed with. This is why every watch, even two of the same model, will come up with different distances, as they are collecting different GPS data.

    I imagine this is not what you were hoping to hear but let me know if this answered your question. If it did, please mark it as a solution so other can look for it if they have the same question.
  • zeehond
    zeehond Registered Users Posts: 2
    Apprentice Traveler
    Thanks for your reply, it works the same when I'm in open terrain so buildings don't have anything to do with it. Unfortunately it does have a lot of impact on the distance. I've tested numerous times, the distance is usually around 200-400 meters less on 10km (measured with another device and compared with a distance measuring site) and even more on routes with a lot of corners like a mountainbike trail.