In recent years, multirotor Unmanned Aerial Vehicles (UAV) came to the attention of the scientific world. Ingenuity experiment, the first drone to fly on another planet is their last success. UAVs are widely used in different sectors thanks to their small dimensions, the possibility to hover, the great precision of maneuvers and the limited costs. In fact, UAVs are employed for military and scientific applications. They are also used in rescue and healthcare operations, precision agriculture, shipping and delivery services, as well as for hobby, for filming and for FPV races. The purpose of this thesis is designing, modeling and assembling a multirotor for indoor applications and designing and testing on-board guidance algorithms.