I noticed that I can perfectly build the APM Navio binaries without the PX4Firmware and PX4NuttX modules. However, that also means that the Navio doesn’t have any visibility to the drivers distributed within the PX4Firmware module. Please correct me if I am wrong.
e.g.:
https://github.com/PX4/Firmware/blob/master/src/drivers/mkblctrl/mkblctrl.cpp
https://github.com/PX4/Firmware/blob/master/src/drivers/trone/trone.cpp
Yes, you’re correct. Linux boards (incl. Navio) don’t depend on PX4 middleware.
I’m sorry, but I’ll be extremely thankful if you could rephrase that a bit because I don’t quite grasp the meaning of this quote. Anywho, I kind of guess the answer is yes 
Or you’re worrying about any FOSS issues?
I meant that without those drivers from the PX4Firmware module, I cannot connect/use the TeraragerOne camera or the MikroKopter ESC with the Navio.
I get it now. Yes, it seems that these features are PX4 middleware-specific. I do think that this is not extremely difficult to port these drivers over to ArduPilot. Especially TeraragerOne. We’ll take a look into it later. But I cannot make any promises on ETA. Is there any significant advantages that MikroKopter ESCs have that other don’t?
That will be fantastic since the TeraRanger sensor are great for sense & avoidance case scenarios on small vehicles.
BTW, I noticed your comments in the PX4 github issue #44. Hopefully, we soon can use the PX4 Flight Stack with the Navio as an alternative to the APM firmware. In that case, you will not need to port those drivers over to the ArduPilot.
Regarding the The MikroKopter ESCs, they have one main significant advantages for our research project. It allows us to monitor the motors RPM & Current during the flight so we can detect any motor failure or the loss of a propeller.
