The Research On Ground Collision Avoidance Algorithm Based On High-precision Terrain Data For General Aviation

With the opening of China's low altitude,the development of the general aviation industry has ushered in new opportunities.In recent years,however,frequent flight accidents have occurred in China,including a large number of accidents caused by human factors,which also severely limits the healthy development of the general aviation industry.In order to improve the flight safety factor and reduce the tragic accidents,make the general aviation perform tasks such as rescue,forest protection,and transportation safely,it is urgent to establish a reliable and effective ground collision avoidance algorithm.So the purpose of this paper is to solve the collision avoidance problem when the aircraft encounters terrain obstacles.In order to make the algorithm more accurate and practical,the article will be based on high-precision terrain data expansion algorithm.Firstly,by analyzing the advantages and disadvantages of different terrain data structures,the data structure used in the research was established.The geodetic datum and projection methods used in the terrain data were introduced.The transformation methods between geographic coordinates and projected coordinates were given.Secondly,this paper studied the collision definition of the aircraft by constructing the collision model of the aircraft,and then combined it with the alarm method in the enhanced ground proximity warning system,to establish a corresponding warning method,including alarm method based on radio and alarm method based on terrain in front.Afterwards,the aircraft collision avoidance algorithm was studied,including vertical and horizontal collision avoidance algorithm.The research of the algorithm followed the principle from easy to difficult.So the research established an algorithm in the standard static atmosphere environment at first,and then established an existing horizontal wind algorithm.Considering the relevant regulatory requirements and aircraft performance limitations,basic flight constraints were established to make the algorithm more feasible.Finally,simulation was performed to test the algorithm.The software used was matlab7.0.Terrain data came from eastern Sichuan.Aircraft parameters came from Cessna172 R.Through simulation and verification,it can be seen that the algorithm can effectively send out alarms and give a reasonable avoidance plan.When selecting a larger collision model,the alarm will be triggered earlier and the safety status will be reached earlier in the process of vertical collision avoidance;the alarm will be triggered earlier but need to change a larger angle to reach safe course in the process of horizontal collision avoidance.In summary,this paper conducts a comprehensive study of ground collision avoidance algorithm.The result of simulation show that the algorithm is effectiveness and has a certain and reference value.