# Anti-Collision System for Small Civil Aircraft
## 1 Introduction  
The aviation development affects the growth of air traffic density which may lead to mutual aircraft collisions. In cooperation with ICAO and FAA, European organizations have been dealing with the problems deriving from both the increase and safety of air traffic. NextGen (the USA) and SESAR (the EU) programs together with the ATM/CNS conception have become cornerstones of the future communication infrastructure. The given programs assume that global navigation satellite systems (GNSS) will have a dominant position in all flight phases. Simultaneously, appropriate alternatives are being sought that might serve as a backup in case of GNSS malfunction or breakdown. Great attention is paid to the issue of anti-collision systems (ACS). Most of the published works are devoted to the anti-collision systems of autonomous unmanned aircraft. Very few published works are devoted to the anti-collision system for the category of small aircraft. Some research results in the field of anti-collision systems are presented in [1]. The basic premise of creating an anti-collision system is that all flying objects (FO) work in the aviation communications network and each of the flying objects transmits their location information. An important condition for the operation of the proposed anti-collision system is a synchronous communication network. The design of an onboard anti-collision system for unmanned aerial vehicles (UAVs) is presented in the work [2]. There is an assumption that all UAV work in the communication network and each of the UAVs communicate their location information. It is mentioned in the work, that the basic condition for the operation of the proposed anti-collision system is to work in a common communication network for UAVs. Using the algorithms mentioned in this thesis, it is possible to design the architecture of the anti-collision system for UAV, which can determine its position against other users of the aviation communication network. The operational economic aspects of detection and anti-collision systems used in helicopters are analyzed in [3]. They listed their helicopter protection anti-collision systems with high voltage wires in the Wire Strike Protection System (WSPS). There is basic information about the Powerline detector provided. Comparing current generations of OASys radar systems (Amphitech Systems) and LOAS (Goodrich Sensor Systems) in terms of their detection performance and financial demands is done to implement them into different types of helicopters. The analyzed accident shows the balance that is directly related to the use of these specific devices on civil helicopters. In the article, we deal with a proposal for an anti-collision system for the small aircraft category. The aircraft of this category essentially perform flights outside of the controlled airspace and their activity is subject to VFR regulations. However, in some instances, a sudden change of weather conditions or an unexpected increase in air traffic may occur. In such situations, it may be difficult for the pilot to see and avoid other airplanes in time as required by the VFR regulations. The pilot would probably appreciate having access to information on the positions of flying objects in the proximity. It would significantly reduce both the time of other aircraft detection and the reaction time needed to take appropriate measures to avoid dangerous situations or collisions. Most small aircraft are equipped with a GPS, nevertheless, their pilots are unable to identify the position of other flying objects in their proximity. As a rule, the anti-collision system is not installed in small aircraft. Only some of them make use of the new ADS-B technology for the monitoring of other aircraft positions in the surroundings. An autonomous system for other aircraft detection in the proximity of a small civil airplane would contribute to the increase of aviation safety. The goal was to propose an anti-collision system for small aircraft capable of providing timely information necessary for effective and safe flights.