RS3 Base/Rover combo in a remote area without Internet

[timd1971]

It will not be cm level. You will need to use a PPP service.

AUSPOS - Online GPS Processing Service

https://webapp.csrs-scrs.nrcan-rncan.gc.ca/geod/tools-outils/ppp.php

Intro to PPP with Reach Receivers

NGS OPUS uses the surrounding CORS as reference (think of bases logging data) and your file (rover). It PP the rover using surrounding CORS data. NGS uses PAGES software in determining the rover position. You can download the software, buts it’s very complicated to use. You use to be able to attend seminars in instructions to use. Most state geodetic agencies use to do this. PPP uses satellite ephemerides to PP the rover position. No CORS are involved in this method.