It would be an option to connect both to AOG. The thing is, that the system with moving baseline and the UBX RelPosNED sentence is Ublox specific.
It works like this: #1 sends RTCM to #2, so connect #1 TX2 to #2 RX2.
#2 calculates the relative position to #1: heading, 3 vectors of direction, and length of vector to #1 this contains the RelPosNED sentence,that is Ublox specific.
#1 delivers position as every other GPS chip. When feeded with NRTIP it gives an absolute position, if not the normal GPS dissolution, whereas the heading and roll is allways correct, as it is relative from the 2 receivers.
So what the ESP32 does:
Feed one unit with NTRIP
Get position
Get relative vectors
Calculate roll (trigonometry)
Correct the antenna position by using roll and virtual Antenna movement (trigonometry)
Checks the sentences, the flags (GPS valid…), and the accuracy (length of vector to other antenna (suggested in Ublox manual))
Generate NMEA sentence (PAOGI (one for all) or GGA (position) + VTG (speed) + HDT (heading))
Transmit via UDP/ Wi-Fi or USB
It is doable in AOG, but you go back to USB. I like UDP since you can connect/ disconnected and Windows won’t care.
With the ESP32 solution it’s similar to a commercial solution, you get corrected data. Building is easy: the Ardusimple boards fit to Arduino uno layout, the esp too. Build a stack, connect to Arduino IDE, flash, configure in Webinterface- done. No IMU needed, maybe Wi-Fi router (with GSM for RTK) or connect ESP32 via USB