自由飞行下基于航空器定位误差修正的碰撞风险研究

自由飞行能够提高空域容量从而缓解空域拥挤问题,在保障自由飞行安全性的基础上尽可能减小飞机的安全间距,需要研究自由飞行条件下飞机的安全评估问题。分析了所需CNS性能、防撞系统、风的因素等自由飞行下航空器定位误差的影响因素,考虑到航空器定位误差在短时间内具有累积性,提出采用INS、GPS数据融合算法对定位误差进行周期性修正。给出修正后的航空器定位误差分布在时间上的变化规律,并将其运用到自由飞行下碰撞风险评估中。结果表明,碰撞风险随安全间距增加呈下降趋势,以1.5×10-8次/飞行小时的目标安全水平为例,对航空器定位误差修正的最小安全间距为8 600 m,不对航空器定位误差进行修正的最小安全间距为9 100 m。

On the collision risk in rectification of the aircraft positioning error under the free flight condition

The paper is to deal with the problem on how to relieve the stress of the air traffic congestion in hoping to help the airport to display its airspace capacity fully in a more efficient way.To this purpose,we have made an exploration of the safety evaluation problem of the flights under the condition of free flight and analyzed the influential factors,such as the aircraft positioning errors,the CNS performance,the collision avoidance and prevention mechanism and operational system,in addition to wind and other meteorological factors,so as to establish a collision risk model based on the aircraft positioning errors.Since the effects of the different factors of the positioning error distribution can be various,it is also necessary to take into account the short-time cumulative characteristic features of the aircraft positioning errors when the analysis is done.Based on the above mentioned needs,we think it necessary to present an algorithm,which can combines the data of INS with those of GPS to correct the aircraft positioning error from time to time periodically,so as to dissolve the algorithm impacts imposed on the evaluation results.Nevertheless,the revised distribution of the aircraft positioning errors tends to vary with time,and such variation pattern can be given and then employed to the collision risk assessment of the free flight.Furthermore,according to the collision risk model based on the aircraft positioning errors,it would also be possible to establish a collision risk model based on the correction of the aircraft positioning errors.The results from our numerical simulation via a computer software show that as the separation increases,it would be possible for the collision risk liability between the two aircraft to drop down.Therefore,the above mentioned change of the aircraft positioning errors has been found in accord with the characteristic features of the collision risk under the illiberal flight condition or conditions.Taking the target safety level per flying hour for example,the statistics results show that,in terms of the time per flight hour,when set apart from the application of the presented algorithm,the minimum safety separation between the two aircraft can only be 9 100 m.And,in contrast,by correcting the aircraft positioning error with the application of the presented algorithm,this gap between the two has been further reduced to 8 600 m.This indicates that the correction of the aircraft positioning error can decrease the safety distance of the airplanes.Thus,it can be seen that the collision risk with corrected aircraft positioning error under free flight condition has been proved to be meaningful to some extent.