GPS Watch Accuracy: peer reviewed University Study says V800 best

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Polar V800 is the most accurate recorder of distance – it’s official(ish)

A new GPS accuracy study of sports watches from the Swiss Federal Institute of Sport (Magglingen) finds an ageing Polar V800 to be the most accurate recorder of distance. Many runners have known either the V800 or Suunto Ambit 3 to be the most accurate for many years so it is interesting to have this validated by scientists.

The study by Drs Gilgen-Ammann, Schweizer and Wyss can be found here and was peer-reviewed by Pobiruchin & Wiesner in early 2020. Interestingly the authors also have another study solely on the Polar Vantage here. Nevertheless, the study looks at 3 Polar devices, 2 oldish Garmin Fenix 5 based watches, the top-end Suunto, a Coros and an Apple Watch 4. That’s a reasonable selection, albeit biased towards Polar and I will also say that reasonable firmware versions were used but that a fairer reflection of Garmin might have used more recent devices.

Note: Part-funded by Polar

Here are the headline results for you to decipher before I add some comments.


Image Source: the study

The great thing with scientists is that they talk in a sciencey language and it just sounds so ‘correct’, for example, the authors say “the recorded systematic errors (limits of agreements) ranged between 3.7 (±195.6) m and –101.0 (±231.3) m for the V800” and “The Bland-Altman analyses showed an underestimation by all watches in the forest“. However to draw the ‘correct’ conclusions you have to ask the ‘correct’ questions in the right way. The question of GNSS accuracy in sports usage is highly complex.

Anyway, I’ve gone through their methodology and I have some comments. I would preface all of what I am going to say in that I do NOT think it is possible to produce a scientific study that accounts for all the variables when recording a GNSS track for running and I would also say that, taken in the round, this study arrives at reasonable results in a reasonable way.

My Comments on the study

Hardware + Data Issues

The authors take several good precautions; over and above those I would add these comments


Test Performance

Image Source: the study

Take Out

In reality, this study and all the tests that we all do still don’t really answer the question of what is the most accurate GNSS in a sports watch. Each method has its own flaws.

HOWEVER, as more diverse studies with dissimilar methodologies are undertaken then if the same watches keep coming out on top (Ambit, V800) and the same watches do NOT keep coming out on top (Garmin) then I think you probably can draw some obvious conclusions from that. Of course, obvious is not scientific.

Here are my test results, FIT files, analysis and methodology…I don’t claim it’s science.

Test Route For GPS Devices + Methodology – Results Link






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