Rinex Header vs Base position

I am hoping to understand the difference between the Rinex Header position of the base. And the Base position found in my downloaded csv file from the job. These two positions do not match, but both reference the uncorrected base position.

NOTE : Base was set out to get a correction with OPUS. Just wondering which are the actual initial coordinates that the Rover points were initially based off of.

Example attached
Base Position Help.pdf (444.7 KB)

I learned that the Rinex header doesn’t store the position you enter on Emlid Flow. It’s the position the base unit averages for itself with uncorrected GPS


To clarify I am trying to identify the position that the rover uses to correct to. I am having some trouble using Emlid Studio to correct my points and hoping to just use a block shift correction to salvage the data. But I need to know what to compare to

The Rover is supposed to use the position you enter in Emlid Flow for the base.

I don’t know about block shift methods, but I suggest just redoing your corrections in Emlid Studio.

Load the log file from the rover and the log file from the base into Emlid Studio. Then set the accurate position for the base station either manually or from a corrected .pos file. Then load the CSV. Don’t forget to set the rover rod height. That should do it

Hi @tcmesserschmidt,

The base position in the RINEX header is the last averaged epoch coordinate with an accuracy of a few meters. It is different from the one averaged in Emlid Flow. Thus, your RTK and PPK base positions may differ by several meters.

In the CSV file, you can see the base position used during your survey. And Rover used it as a reference.

I agree with @daygeckoart 's ideas on how to improve the accuracy.

  • You can process the data in PPK using the corrected base position from OPUS.

  • Or you can shift RTK data based on the calculated difference between the old and new base positions. You can read more about it here.