Where is the Ardusimple Antenna Reference Point (ARP) and how does it relate to the L1/L2 Phase Centers?

Q&A forumCategory: QuestionsWhere is the Ardusimple Antenna Reference Point (ARP) and how does it relate to the L1/L2 Phase Centers?
David Forrest asked 2 weeks ago

I would guess that the physical center of the puck is pretty close to the centers, but I was wondering if you had better data on the centers and how they relate to a reference point

Matioupi replied 2 weeks ago

Hi, your question is related to mine : https://www.ardusimple.com/question/antenna-mode-l-handling/
I guess ardusimple antenna do not have official ARP as you can find in the NOAA antenna database with sketches for atennas and phase center to arp offsets (http://www.ngs.noaa.gov/ANTCAL/ : site is off right now due to US shutdown)
Common practice is that the ARP is on the antenne symetry center axis, and at the bottom of the mounting thread. ARdusimple antenna does not have such mounting thread, so The point should be defined on the symetry axis and i the lowest flange of the antenna.
As for the ARP to L1PC ARP L2PC and PCV values, there are two ways to access it. Make a full absolute calibration which requires heavy equipement (e.g. https://www.ife.uni-hannover.de/absolute-antenna-calibration.html?&L=1 )
A simpler method which will only give you the ARP to L1PC offset (no PCV) is to make a serie of measurement on the same reference point (or at least 2 very close levelled points) with a know “reference” antenna, and then you can access the ARP-L1PC value as the difference of the computations from the u-blox (which so far are always given at phase center) and the correct height derived from the fully known antenna. I have planned to do this with the ardusimple IP version of antenna but did not had time yet to do so.