I built a tool to mimic the receiver's orbit at a much smaller scale, letting us test the transmitter in the lab instead of relying only on field tests.
The spacing accounted for the optics that would be used on the flat transmitter, so the setup stayed as representative of the real system as possible. It rotated at the same rate as the drone and could also oscillate, to imitate turbulence and other variables the real receiver would experience in flight.
I attached an accelerometer to the rig to validate that the oscillation frequencies actually matched what we were targeting.