Contents Choosing Base Setup Method Setting Up Base Over Known Point Setting Up Base Position Manually Averaging Base Position in FIX Applying Base Shift Determining Base Position Online Post-Processing Services AUSPOS—Online GPS Processing Service NOAA's Online Positioning User Service (OPUS) Precise Point Positioning Services How PPP Works Canadian Spatial Reference System Precise Point Positioning (CSRS-PPP) IBGE-PPP—Online Service for Post-Processing GNSS Data Static Processing