# Improvement of Hexacopter UAVs Attitude Parameters Employing Control and Decision Support Systems
## 1 Introduction  
DRONE is a generic name for a whole family of aerial, land, water, and underwater platforms. The term DRONE is an English acronym, one of the definitions being Dynamic Remotely Operated Navigation Equipment. The following main categories of vehicles belong to the DRONE family are as follows: UAV--unmanned aerial vehicle, UGV--unmanned ground vehicle and UUV--unmanned underwater vehicle. Aerial drones are also found under other names: UAV--unmanned aerial vehicle, UAS--unmanned aerial system, RPAS--remotely piloted aircraft system and ROAV--remotely operated air vehicle. UAVs fall into two main categories: fixed wing (airplane) and rotorcraft (single rotor--helicopter, or at least two rotors--multicopters). Recently (2020-2022), a third category of UAVs has seen rapid development: fixed-wing UAVs with vertical takeoff and landing (VTOL) capabilities [1; 2; 3], which combine the capabilities of an aircraft with those of a multirotor UAV, with either electric or combined propulsion [4; 5; 6] (electric with internal combustion engine) to extend flight range and develop superior flight performance, with the aim of being able to carry large payloads over long distances. The main purpose for which UAVs were originally developed was their use in military applications and special operations. Subsequently, they have been widely developed and employed in an increasing number of civilian applications: law enforcement surveillancemissions, firefighting assistance, securing borders, strategic and governmental targets, detecting illegal hunting, measuring landslides, monitoring incidents involving crowds of people, inspecting large industrial facilities, large buildings and constructions, oil and gas pipelines, inspection of continuous-flow machinery in quarries (to monitor temperatures in the area of high-friction pits using thermal imaging cameras), inspection of petrochemical installations (to detect cracks, fissures and leaks in pressure vessels using thermal imaging cameras) and, more recently, (2020-2022) home parcel delivery [7; 8], warehouse stock management [9; 10] using specialized software, passenger transport, air travel, etc. Multirotor drones have seen continuous development over the past ten years as the need for this type of platform has grown continuously, and they are employed in a wide range of activities and fields such as inspection of large industrial installations [11; 12], large buildings and constructions, oil and gas pipelines [13; 14], inspection of continuous-flow machinery in quarries (to monitor temperatures in the area of high-friction pits using thermal imaging cameras), inspection of petrochemical installations (to detect cracks, fissures and leaks that may occur in pressure vessels using thermal imaging cameras [15; 16]), etc. They can be equipped with a wide range of electromagnetic spectrum sensors [17; 18], gamma ray sensors [19], biological sensors [20; 21; 22] and chemical sensors [23; 24], which provide remote sensing functions. Electromagnetic sensors include visual spectrum, infrared or near-infrared cameras and radar systems. Some other electromagnetic wave detectors such as microwave and ultraviolet spectrum sensors are less used. Biological sensors can detect the presence of various microorganisms and other biological factors in the air. Chemical sensors employ laser spectroscopy to analyse the concentration of each element in the air. A UAV possesses almost all the characteristic strengths of a manned aircraft, in addition to surmounting the physical limitations of the pilots and thus preventing the human error. The absence of the pilot from the cockpit allows drones to be operated at their performance limit, thus increasing endurance, payload, altitude ceiling and manoeuvrability.