Why post-processing is important Print

Storing and using autonomous GPS data (no real-time or post processing) would be the ONLY way to keep your data in WGS84 as it came from the satellites. This is not practical since...

The accuracy of this data is only accuracte to 15 m since it remains uncorrected

and

Most GIS datasets you will want to combine your GPS data are not WGS-84

Therefore it is impossible to avoid datum issues when moving GPS data to a GIS