Detection of Displacement Shifts by Control Charts in GPS Monitoring

The two kinds of statistical process control algorithms for detecting the small displacement shifts in the monitoring data obtained by the Global Position System (GPS) receiver are comparatively studied in this paper. The Shewhart and Cumulative Sum (CUSUM) charts are applied to the simulated and the experiment GPS coordinates, and their effectiveness in detecting the small and large persistent shifts are evaluated. The result shows that the Shewart chart is useful in detecting large shifts in GPS real-time data, but it can’t find small shifts. The CUSUM chart appears to be an ideal candidate for detecting the GPS coordinate changes in deformation monitoring since it can detect the small and persistent shifts hidden in a GPS time series data.