Movement or Distance Gained While Not Moving

GPS drift is caused by many external factors and consumer grade GPS devices cannot account for these. GPS drift causes the device to appear to be moving on its own.  It is most obvious when looking at a track or when zoomed in all the way while at a standstill.

Satellites send their signal through the atmosphere down to earth. The atmosphere distorts this signal, and other environmental factors (such as trees, hills, mountains, buildings, cars, reflective surfaces and more) can further degrade the signal.

In the past, a satellite signal weakened by the environment caused a loss of position. High sensitivity chips were created so that it was no longer a question of if you had a position lock, but how accurate that position lock would be.

Now only the weakest signal prevents the device from locating your general position, but as a result, the decrease in accuracy that is introduced by the environment causes GPS drift. In other words, the device is more sensitive than the environment allows it to be accurate.

Being mindful of the limitations of consumer GPS devices will help alleviate concerns regarding their accuracy.