The Swiss Federal Institute of Sport Magglingen (SFISM) conducted a study to investigate the accuracy of the recorded distances obtained by eight GNSS-enabled sport watches. These were Apple Series 4, Coros Apex 46mm, Garmin’s fénix® 5X and Forerunner® 935, Polar’s Vantage M, Vantage V and V800, and Suunto 9 Baro. All devices were assessed in various areas and at varying speeds, under varying external circumstances. The results of the total 36 measurements showed that regarding recorded distances the overall GNSS accuracy was moderate to good, with mean absolute percentage errors ranging from 3.2% to 6.1% when assessed in urban, forest, and track and field areas. However, only the three Polar products reported an average mean absolute percentage error of <5%.
Noticeably, in the unobstructed conditions of an open area, 6 out of the 8 sport watches were able to accurately record distance. In the obstructed conditions of forest and urban areas, accuracy was limited, with a general underestimation of the covered distance. Furthermore, the data assessed during running showed significantly higher error rates in most devices compared to walking and cycling.
The authors concluded that the use of all investigated sport watches can be recommended, especially for distance recording in open areas.
Gilgen-Ammann R, Schweizer T, Wyss T
Accuracy of Distance Recordings in Eight Positioning–Enabled Sport Watches: An Instrument Validation Study