Mistake in reading NRCAN PPP Corrections?

[intenna (Brian Lindens)]

I’m going through first time PPK processing and I think I’ve made a mistake?

We submitted our base station to NRCAN PPP and received this back:

What I am very unclear on is the difference between the estimated position in ITRF14 and the “a priori” position. Reading the online explanation I understood that the ITRF14 position (not the a priori position) is our PPP-corrected position?

I’m then trying to run the files through Emlid Studio. My understanding is that I use the corrected position input into Emlid studio (with the old base .obs file) to get the absolutely positioned base, yes?

[wizprod (Christian Grüner)]

@intenna

Reading the online explanation I understood that the ITRF14 position (not the a priori position) is our PPP-corrected position?

Correct. The a Priori position is the position of which the calculations start to iterate from.

@intenna

My understanding is that I use the corrected position input into Emlid studio (with the old base .obs file) to get the absolutely positioned base, yes?

Yep, that is correct.
Remember to account for the missing antenna height in your PPP calculation.

[intenna (Brian Lindens)]

Ah great! The one thing that worried me was after we ran the PPK corrections WITHOUT the NRCAN corrections originally. After getting the NRCAN corrections and re-running the PPK process through Emlid Studio, the rover height locations only changed by about 0.2m.

This is slightly confusing to me because the Base position after NRCAN correction changed by a ~7m (height).

And yes, I added in the missing antenna height corrections, thanks.

[andrew.belov]

Hi Brian,

Please find answers to your questions down below:

@intenna

What I am very unclear on is the difference between the estimated position in ITRF14 and the “a priori” position. Reading the online explanation I understood that the ITRF14 position (not the a priori position) is our PPP-corrected position?

As @wizprod has written above, the ITRF14 position is your PPP-corrected position.
A priori Position (Approx) is taken from the RINEX header.

@intenna

After getting the NRCAN corrections and re-running the PPK process through Emlid Studio, the rover height locations only changed by about 0.2m.

Could you please send us your logs to support@emlid.com so that we could process and analyze them?