GPS Drift While Standing Still: Why Distance Can Keep Increasing
Why a stationary phone can appear to move and how to interpret unwanted distance accumulation.
A GPS-derived position is an estimate, not a pin fixed to the exact physical location. When the phone is stationary, its reported coordinates can wander around the real position. If a tracker adds the distance between every pair of coordinates, the trip counter can increase even though the user has not moved.
The geometry of drift
Imagine a point that alternates around a small area. The straight-line distance between each pair is small, but adding many segments can produce a surprisingly large total. The route may look like a zigzag even though the phone remained still. This is a common reason that short sessions are disproportionately affected by GPS noise.
What filtering can do
A tracker can ignore tiny movements or require a point to meet a quality threshold before adding distance. That reduces some false accumulation, but may also omit genuine movement at very low speed. The threshold is a compromise and should not be described as perfect. Different hardware and environments may need different handling.
How to test for drift
Place the phone in a safe, stationary location outdoors and observe whether the location estimate changes. Note the reported accuracy and how the trip counter behaves. Repeat in a different open area if necessary. Do not compare this brief test with a long outdoor route without accounting for the difference in signal conditions.
When the result is not suitable
If the distance continues to climb significantly while stationary, treat that session as poor quality. Reset it only after you understand the control behavior, and do not use the result for reimbursement, competition or any task requiring certified measurement. Report the conditions and device details if asking the site owner to investigate.
Frequently asked questions
Why does distance increase while I stand still?
Coordinate noise can create small false segments that accumulate.
Should all small movements be ignored?
No. A filter must balance stationary drift against real slow movement.
Technical references
These references explain the underlying browser and positioning concepts. They do not imply endorsement of this website.