Why a Single GPS Filter Threshold Silently Erases Real Location Data

A software engineer building a mileage tracking app discovered that using one fixed GPS displacement threshold caused valid movement data to be quietly discarded, particularly in slow-traffic scenarios like Bangalore congestion. The core problem was that a stationary phone's GPS position drifts by several metres, causing a parked vehicle to falsely accumulate distance if small steps are not filtered out. However, applying a single global minimum threshold also strips out legitimate slow movement such as walking or crawling through traffic. The engineer's solution involved context-aware, speed- and time-gap-dependent thresholds, along with a rolling history window to distinguish genuine slow movement from GPS jitter. All configurable values were consolidated into a single serialisable data object, allowing threshold tuning without requiring a full app release.