Research Of Air Traffic Warning And Anti-collision Technology Based On ADS-B

Flight safety is the eternal theme in civil aviation, in order to reduce the risk of controllable hit ground and air collision, collision avoidance theory and collision avoidance system should be researched constantly by aviation industry. Traffic Alert and Collision Avoidance System II(TCASII) is equipped in civil aircrafts now. But TCASII can only provide traffic advisory(TA) and Resolution Advisory(RA) in the vertical direction, and still have some problems like false alarm. In order to solve the problems of TCASII, It is necessary to develop and research TCASIII which can provide RA in both horizontal and vertical directions, and also can provide low probability of false alarm. Communications,Navigation, Surveillance/Air Traffic Management(CNS/ATM) system(new voyage system)combined with satellite technology, data link technology and computer network technology guide the development of civil aviation into a new age. Automatic Dependent Surveillance-Broadcast(ADS-B) is an important part of the new voyage system which can replace some functions of S model responder. The positioning accuracy is higher, calculate reserve time more accurate and the realization of the collision avoidance much better if ADS-B is used by TCASIII.In order to improve the positioning accuracy of TCASII and provide a theoretical basis for TCASIII, this thesis based on the analysis of ADS-B air traffic alert collision avoidance technique. The main works are as follows:1)Take the stability of civil aviation flight into account, establish the state space model for the aircraft, and make analysis of data content and characteristics of the ADS-B and TCASII. Then study the critical problem of ADS-B and TCASII before data fusion, make data processing by using Kalman filter, and make data fusion with the scalar optima criterion in the sense of linear minimum variance.2) Combined with the principle of the TCASII, reasonable model around aircraft zone is established again, a deterministic conflict detection algorithm is presented based on ADS-B,which first eliminates threatening aircraft, and then detects aircraft conflict in horizontal and vertical directions respectively by making full use of the information such as longitude,latitude, velocity and heading of aircraft provided by ADS-B message and the ADS-B message characteristics including high-speed update rate.3) Integrated with the work manner of the TCASII, research the RA can provided in both horizontal and vertical directions is necessary, if there are two planes under the condition of conflict, propose two types of the collision avoidance strategy of“Keep speed is constant, and change direction” and “Keep direction is constant, and change speed” from horizontal direction and two kinds collision avoidance strategy of “climb” and “descend” from vertical direction. Using the horizontal velocity,direction and vertical speed as control variables, the conversion time of the control variable through the calculation of boundary conditions is obtained, thereby the feasible resolution method is founded.4) Faced with the many planes under the condition of conflict at same time, a collision resolution algorithm based on ADS-B and genetic algorithm is introduced in the condition of free flight. Firstly, the algorithm encoding the position of aircraft track points in the conflict sector, using GA to optimize the objective function in the route planning, guiding and realizing the plans and choices for the 2D track of aircraft. Then, planning the no conflict flight paths for each aircraft combined with TCP+1 report from the ADS-B information, to achieve the collision resolution between multi-aircrafts.