The quadcopter drone is a very popular design for an unmanned aerial vehicle (UAV). It consists of a flight controller and four electronic speed controllers (ESCs), one for each motor. The flight controller is equipped with a radio to receive flight commands provided by the pilot and the inertial measurement unit (IMU). The IMU provides information (such as velocity and orientation) that are necessary for autonomous stabilization of the vehicle, using the internal accelerometer, gyroscope, and sometimes the magnetometer and GPS receiver.
Resources
Quadcopter Drone Reference Design
Drone Examples - powered by NXP