Software-determined position uncertainty is main indicator of solution accuracy in PPP, as a reference solution may not available. Research presents novel analysis of PPP uncertainty realism in southern Ontario, and quantifies data collection periods necessary to meet integrated survey specifications. Data collected from 55 reference stations over three months in 2011. “Truth” position solutions computed from data by NRCan Bernese relative GPS data processing. PPP solutions computed using York-PPP software developed at York, based on NRCan on-line software.