Speed and distance from the wrist with GPS calibration
Your Polar device (Grit X, Grit X Pro, Ignite, M430, Vantage M, Vantage M2, Vantage V, Vantage V2) can measure speed and distance from your wrist movements with a built-in accelerometer. This feature is handy when running indoors on a treadmill for example, or just in places where GPS is not always available such as in valleys, around tall buildings or under tree cover. Note that speed and distance is measured from the wrist only when a stride sensor or GPS is not used in a session.
To ensure maximum accuracy check that you’ve set your handedness and height correctly in your physical settings. Best accuracy is obtained when running at a pace that is natural and feels comfortable for you.
During a training session you can see your current speed, and the distance you’ve gone so far on the watch display. Right after your session you’ll see a summary with info about your speed and distance covered. Sync your watch with the Flow app and web service for a more detailed analysis.
How GPS calibration works
To enhance the accuracy of speed and distance measured from the wrist, the watch uses GPS offset calibration. The watch compares speed values measured with the accelerometer with values measured with GPS, and calculates momentary speed calibration offset values based on the difference.
- Sport profile used must be running or walking type (listed below)
- Steady pace speed is at least 7 km/h for at least 15 minutes
- The terrain you run on is flat enough
This feature is available in the following sport profiles:
- Road running
- Trail running
- Treadmill running
- Track and field running
- Ultra running
When a calibration factor is successfully defined it’s saved onto your device. The watch stores the previous 20 calibration factors, and uses the average of them to calibrate speed and distance in sessions in which GPS or a stride sensor is not available. Note that the factors cannot be viewed.