# Anti-Collision System for Small Civil Aircraft
## 2 Anti-Collision Systems
### Selected Published Research Results in the Field of Anti-Collision Systems  
The algorithms to prevent collisions between various unmanned electrical aerial vehicles (UAV) performing the common goal of moving in the same area are derived in [4]. The condition for these algorithms to work is that all the vehicles are communicating with each other. The results of research work on an anti-collision system with a radar detector of obstacles are discussed in the paper [5]. The main tasks set for this system are the detection of static and moving obstacles, estimation of the distance between an aircraft and an obstacle, as well as their relative velocity. As stated in [6], the 3D laser radar is widely used in unmanned driving systems due to its high precision, strong anti-interference ability, and omni-directional scanning. It is used for anti-collision detection. Its disadvantage is the dependence on the weather. The technology of UAV equipped with a low-power FM ranging radar to construct an anti-collision system is listed in [7]. Radar data analysis and camera image processing are performed to achieve the collision avoidance system. The methods to avoid collisions between a robot and an obstacle, based on distance feedback, was given by a laser Time of Flight (TOF) sensor and are listed in [8]. Two solutions are presented: the former (GCT: Geometry Consistent Trajectory) preserves the geometrical properties of the trajectory, while the latter (TCT: Time Consistent Trajectory) aims at preserving the time properties of the trajectory. The anti-collision function is vital to the UAV [9] to ensure that the UAV can fly more stably and safely. The proposed system can detect surrounding obstacles. The metrological characterization of the infrared distance sensor Teraranger One is given in [10]. A frontal anticollision system based on the sensor in question with the additional functionality of maintaining a fixed distance from the detected target has been suggested. An upgrade of the radar navigation system is listed in [11], particularly, its collision avoidance planning tool. In the paper [12], the anti-collision and obstacle avoidance control of moving sensors for a class of distributed parameter systems with a time-varying delay was investigated. The results of introducing a speed control by using ultrasound and accelerometer sensors to detect objects associated with a fuzzy controller to prevent collisions in enclosed spaces are listed in [13; 14]. By implementing this anti-collision model, navigation of aerial robots becomes safer. The study [15] is dedicated to solving a collision prevention task for autonomous unmanned aerial vehicles' team by Immune Neuro-Fuzzy Network (INFN) application. The goal of the research was to develop the machine learning algorithm for autonomous UAV. The improved algorithm for collision prevention based on the combination of immune neural network and fuzzy logic for the team of UAVs is proposed in the paper [16]. The method of calculating the collision probability between agents is listed in [17]. Then, the authors analyze the impact of the position error, the safety radius, and the relative distance on the collision probability. Despite the value of electronic means of conflict detection (e.g., ACAS and STCA), visual lookout remains an important defense against loss of separation for all classes of aircraft. This is particularly true for pilots of light aircraft, many of which are single-pilot operated, are not equipped with ACAS or transponders, and frequently operate VFR outside ATC radar cover and at low altitudes. These pilots must develop sound visual scanning techniques. To avoid collisions, you must scan effectively from the moment the aircraft moves until it comes to a stop at the end of the flight. Collision threats are present on the ground, at low altitudes in the vicinity of aerodromes, and cruising levels [18]. Researchers at NASA's Armstrong Flight Research Center have dramatically improved upon existing ground collision avoidance technology for aircraft.