My partner and I both have the same model Edge 1000, with the same update (15.50) and same system settings (recording every second) and polling GPS and GLONASS.
When we go out for a ride together and do exactly the same route, we have noticed a difference in the distance traveled between our two devices. The difference in distance is about 17 meters per 1 km traveled, with my device recording the greater distance and my partner's the lesser. So after today's 50km ride, her device was nearly 900m less.
Given that our devices are the same model with same settings how can this happen or be explained? Is there something else that needs to be checked on the devices and how do I know what device is showing the more accurate reading?