Question: what is pixhawk flight controller?
Answer: The Pixhawk® 1 autopilot is a popular general purpose flight controller based on the Pixhawk-project FMUv2 open hardware design (it combines the functionality of the PX4FMU + PX4IO). It runs PX4 on the NuttX OS. Originally manufactured by 3DR® this board was the original standard microcontroller platform for PX4.