RTK being real time can only use the current and past information. Post Processing benefits from the programs ability to take later information and calculate backwards to extend data partially or fully through some data gap. That may be just the inclusion of one more satellite for a few more seconds. You have to be prepared to use those differences to your own benefit. One way is to be sure that a few RTK points are located several times throughout your observation sessions. That allows you to better compare and possibly adjust your RTK observations. As much as you would like to assume that your RTK data is better than anything else, you would be wrong. There is very good reason for Post Processing to exist. In fact some RTK software can now instantly recognize such a reobservation and can automatically adjust point positions.?ÿ
Another point not mentioned that many are unfamiliar with is that some RTK solutions may be from L1 only data, not that that is bad. From time to time in the past I found that forcing an L1 only solution gave better precision than an L1/L2 solution. That possibility is now multiplied across several constellations. Post Processing is more conducive to using and comparing various frequencies of data.
I would surmise this same question has originated again and again from those who began GPS surveying from RTK only and not from those who began with static and then added RTK to the mix.
Paul in PA