一种新的通用航空机载防撞逻辑设计方法

A New Approach to Design Airborne Collision Avoidance Logic for General Aviation

由于机载防撞系统(TCAS)是针对具有较大垂直高度变化率的大型飞机设计的,系统设定条件和与之相关的解脱建议并不能适用于通航飞机。针对通用航空的防撞问题,提出了一种基于马尔可夫决策过程(MDP)的防撞逻辑设计方法。首先,将飞机空中相遇过程的动态模型转换为离散转移函数;然后,基于防撞系统结果事件末端效用函数进行MDP建模,采用动态规划方法导出了最优防撞逻辑的迭代方程;最后,给出了通航飞机最优化防撞逻辑的设计流程并对最优防撞逻辑进行了计算机仿真。仿真结果表明,通过调整效用比参数可以在保证安全性能的同时有效降低系统告警率。在垂直相遇高度小于30 m的相遇过程占比高达18%的情况下,当告警率大于0.85时系统的碰撞概率仅为2.88×10-4左右。该设计方法对我国在低空空域通用飞机防撞系统的研究具有一定的参考价值。

Since the traffic alert and collision avoidance system（ TCAS） was designed for large aircraft that can achieve greater vertical rates,the assumptions made by the system and the associated resolution advisories were not always appropriate for general aviation aircraft. In view of the collision avoidance system for general aviation,an approach based on the Markov decision process（ MDP） to design the collision avoidance logic is proposed. Firstly,the dynamics of the aircraft involved in the encounter is discretized into a discrete transition function,and then the collision avoidance system is modeled with MDP based on the end-state utility function of its outcomes,the iterating equation for the optimal collision avoidance logic is derived by using dynamic programming. Finally,the design process of the optimal collision avoidance logic for general aviation is presented,and also the optimized logics are evaluated in computer simulation. The simulation results show that the collision avoidance logic can meet the current safety level while lowering the alert rate by adjusting the utility ratio parameters. In the circumstance that a significant fraction of encounters（ about 18%） has a vertical miss distance of less than 30 m,the collision probability is approximately 2.88×10-4 providing that the alert probability is greater than 0.85. The method has certain reference value for research on the collision avoidance system in low altitude airspace general aviation aircraft in China.