Could your GPS be overestimating distances? Yes, it seems so!
GPS has become the backbone of our mobile lives. We use it to get around both foreign and familiar cities, to find Tinder matches nearby and to determine exactly how much to pay for services such as on-demand rides. But did it occur to us that these devices might not always offer the most accurate estimations of overall distance?
Thankfully it did occur to researchers at the University of Austria who have taken the time to investigate. In case you didn't know (you didn't), GPS satellites work by taking coordinates between two short points and then calculating the distance. The system does this over and over again as the distance unfolds, calculating the distance between these points and then adding them all up. The distances are tiny, but since the earth is curved, each calculation has a small overestimation of the actual distance covered. Given enough calculations, a not-insignificant gap grows between the actual and calculated distances.
The research actually found that this measurement technique can actually add up to 20% to the distance calculation! This means that in the worst case scenario, the GPS could overestimate the actual distance by one mile for every five traveled. Those who rely on satellite-based GPS to track distances (such as those who stay fit on the road) might want to re-consider how victorious we feel at the end of a run!
The implications of this discovery could reach further than just distance runners and athletes. There's also potential for overestimation of distance any time travelers are charged for distances calculated via GPS technology. If the distances are not accurate, then there is a built-in systematic error that creates an overcharging situation. For cabs with satellite-based GPS, this could indeed be a legitimate issue. Thankfully, many on-demand ride-sharing services use a phone-based GPS that also leverages cell tower triangulation to more accurately place a driver on the map.
The researchers have proposed a solution that would fix this error: basically, the GPS could use the velocity of the movement to double check the distance. Since distance equals the rate of speed multiplied by time, the GPS could basically check itself for accuracy. Now we'll all just have to run a bit further!