The concept of Autonomous Vehicles (AVs), such as self-driving cars and Unmanned Aerial Vehicles (UAVs), has been widely explored in recent years. The aims of this thesis are to develop, implement and test, both hardware (HW) and software (SW) system of a multirotor UAV for indoor applications. There are many quadrotors that are commercially available nowadays, however, off-the-shelf quadrotors usually lack the ability to be reprogrammed and are unsuitable for use as research platforms. Therefore, an HW selection has been carried out in the first part of the project, starting from Commercial-Off-the-Shelf (COTS) components.. The quadrotor autopilot is based on ‘Pixhawk 4 mini’ and it is able to fly indoor using stationary ultrasonic beacons (‘Marvelmind Set HW v4.9’) as GPS.