The "brain" of a drone that reads sensor data, processes pilot inputs, and calculates the precise motor speeds needed to maintain stability and execute maneuvers in the air.
FCS has the following components:
Flight Control Unit (FCU), Onboard Sensors (Inertial Measurement Unit (IMU); Barometer; Magnetometer (Compass); GPS/GNSS Module)
Electronic Speed Controllers (ESCs)
Flight Software/Firmware
Part of Data Link (Radio Links)