A comprehensive survey on the methods of angle of attack measurement and estimation in UAVs

Angle of Attack (AOA) is a crucial parameter which directly affects the aerodynamic forces of an aircraft. The measurement of AOA is required to ensure a safe flight within its designed flight envelop. This paper intends to summarise a comprehensive survey on the measurement techniques and estimation methods for AOA, specifically in Unmanned Aerial Vehicle (UAV) applications. In the case of UAVs, weight constraint plays a major role as far as sensor suites are concerned. This results in selecting a suitable estimation method to extract AOA using the available data from the autopilot. The most feasible and widely employed AOA measurement technique is by using the Multi-Hole Probes (MHPs). The MHP measures the AOA regarding the pressure variations between the ports. Due to the importance of MHP in AOA measurement, the calibration methods for the MHP are also included in this paper. This paper discusses the AOA measurement using virtual AOA sensors, their importance and the operation.     

基于模因算法的飞机装配序列规划

针对飞机制造的装配序列规划问题,提出一种基于模因算法的飞机部件装配序列规划方法。在装配优先约束矩阵和非正交干涉矩阵的基础上构建装配规划模型,以飞机零部件间的装配方向和装配工具的差异性来构建适应度函数。在非干涉解空间中进行全局搜索,获得较优的装配规划方案,通过二叉树中序遍历法将较优的方案转化为可行解,再经过交叉操作和变异操作后,在可行解空间内进行局部搜索,最终获取较优的装配方案。以某型号的飞机舱门装配为例,通过与传统遗传算法对比,证实模因算法在飞机装配序列规划中的可行性和有效性。     

基于DOA聚类算法的ARM抗有源诱偏技术研究

有源诱偏技术是雷达对抗反辐射导弹的一种重要手段,可以大大降低反辐射导弹的作战效能。为提高对敌目标的精确打击能力,在分析闪烁诱饵诱偏原理的基础上,针对有源诱偏干扰下被动雷达测角精度与稳定度不高的问题,通过对有源诱偏信号的时域特征进行分析,提出一种基于脉冲前沿检测的DOA聚类分选算法,找出前沿超前的辐射源信号,实现了高性能抗有源诱偏干扰和高精度抗干扰测向。仿真结果表明,该技术可以有效对抗四点源有源诱偏干扰。     

航天嵌入式软件数组越界缺陷特征研究

根据统计,数组越界是航天嵌入式软件开发过程中出现最多且最容易被遗漏的缺陷类型之一.目前自动化检测数组越界多基于抽象解释、符号执行、程序模型检验等方法,这些方法在误报、漏报、可扩展性等方面的表现依赖于软件及缺陷特征.分析了近三年航天嵌入式软件第三方测试中发现的94个数组越界问题,从缺陷模式和缺陷表现形式两方面分析得出10项航天嵌入式软件数组越界缺陷特征,并提出对设计具体检测方法关键的若干启示.进一步基于这些特征和启示探讨了数组越界检测算法针对中断驱动型程序的改进方向.     

一种基于OPTICS聚类的仅测角导航目标检测算法

仅测角自主导航方法具有设备简单、复杂度低，功耗低的优点，在空间任务中具有广泛的应用前景.针对中远距离下空间目标特征少的特点，提出了一种利用基于OPTICS聚类算法的空间目标检测方法，可用于仅测角导航过程中的目标检测.对原始星图进行预处理提取星点及目标点，并结合星图识别的结果选择部分帧，使用经过改进的OPTICS聚类方法获得目标运动轨迹.最后，使用本文中的算法对软件仿真出的含有目标的高精度星图进行处理验证了算法的可行性.在卫星相对于空间目标抵近过程中，目标检测的水平误差及垂直误差小于0.15°的帧数分别占到了85.4%以及99.6%.相比AVANTI实验中的目标检测方法，减少了在轨任务中相关参数的调节，进一步提升了算法的自主性.     

先进战斗机过失速机动大气数据融合估计方法

可控的过失速机动是先进战斗机超机动性能的重要标志，飞机飞行包线的扩大已超出传统的大气数据系统测量范围，可靠的迎角、侧滑角、总压、静压等飞行大气数据是制约先进战斗机过失速机动中飞行控制的关键因素。以中国推力矢量验证机为对象，基于过失速机动飞行试验的数据，开展大气参数估计与验证研究。结合过失速机动的时间与空间特性，研究了基于风速、地速、空速矢量和惯性姿态、导航参数的大气参数融合计算方法；针对过失速大迎角状态下飞机周围气流非定常、模型非线性导致的融合大气参数误差的复杂特性，进一步构建深度神经网络，对机动状态融合迎角、侧滑角的强非线性误差进行拟合。仿真和飞行试验表明：该方法可在大迎角飞行状态下实现主要大气参数的融合估计，过失速机动过程中融合迎角误差优于2.3°，融合得到的大气参数可为过失速大迎角机动飞行控制提供可靠的大气参数状态反馈。     

A survey of safety separation management and collision avoidance approaches of civil UAS operating in integration national airspace system

Recent years have witnessed a booming of the industry of civil Unmanned Aircraft System (UAS). As an emerging industry, the UAS industry has been attracting great attention from governments of all countries and the aviation industry. UAS are highly digitalized, informationized, and intelligent; therefore, their integration into the national airspace system has become an important trend in the development of civil aviation. However, the complexity of UAS operation poses great challenges to the traditional aviation regulatory system and technical means. How to prevent collisions between UASs and between UAS and manned aircraft to achieve safe and efficient operation in the integrated operating airspace has become a common challenge for industry and academia around the world. In recent years, the international community has carried out a great amount of work and experiments in the air traffic management of UAS and some of the key technologies. This paper attempts to make a review of the UAS separation management and key technologies in collision avoidance in the integrated airspace, mainly focusing on the current situation of UAS Traffic Management (UTM), safety separation standards, detection system, collision risk prediction, collision avoidance, safety risk assessment, etc., as well as an analysis of the bottlenecks that the current researches encountered and their development trends, so as to provide some insights and references for further research in this regard. Finally, this paper makes a further summary of some of the research highlights and challenges.     

Implementation of tactical maneuvers with maneuver libraries

This study creates and combines the general maneuver libraries for fixed-wing aircraft to implement tactical maneuvers. First, the generalized maneuver libraries are established by analyzing the characteristics of tactical maneuvers required in battlefields. The 7th order polynomial is applied to both the creation of the maneuver libraries and the generation of the trajectories or flight paths for modal inputs. To track the desired trajectory, we design the Attitude Command Attitude Hold (ACAH) system and the Rate Command Rate Hold (RCRH) system using Model Following Controller (MFC). Moreover, the Line-of-Sight (LOS) guidance law is designed. In particular, the CONDUIT® is employed to optimize the gains so that the control systems meet the aircraft Handling Qualities (HQ) criteria. Finally, flight simulations are performed for the longitudinal loop, immelmann-turn, and climb-slalom-descent maneuvers to verify that tactical aggressive maneuvers are realizable via the combination of maneuver libraries. This study can contribute to the development of flight techniques for aircraft tactical maneuvers and to the revision of air force operational manuals.     

太阳能飞机循环飞行的高度剖面能量策略

为满足设定的太阳能飞机多日连续飞行条件，依据飞行过程中当前时刻的飞行高度、光伏输出功率、动力电池组余量等系统状态参数，研究如何分配动力电池组充放电和电推进系统输入等功率。所用策略立足于实时功率平衡，充分利用正午前后的光伏峰值功率用于飞机爬升及充电，在午后下滑过程中利用全部光伏输出，以最大化利用光伏资源；在光伏有效输出不足时则以一定的维持功率下滑，使能量的综合损失最小。方法能够提高以预定夜间飞行高度连续多日续航的成功率，提升飞行高度、纬度、季节范围或搭载能力，或者拓展这几种飞行条件的组合域，优化太阳能飞机的适用性。     

上升段飞行器目标的视频图像跟踪

粒子滤波是一种基于贝叶斯估计理论和蒙特卡罗理论的实时目标跟踪方法，具有较为灵活的并行化跟踪方式，能够较好地维持跟踪目标的假设状态，具有较好的跟踪效果和鲁棒性。上升段飞行器目标飞行视频图像跟踪是火箭等目标飞行监控的重要阶段，但现阶段对飞行器上升段的视频图像跟踪主要依靠人工手动操作云台控制器，实现视频图像中的飞行器跟踪，跟踪图像存在跟踪滞后、画面抖动等现象，跟踪效果受人为因素影响较大。本文提出一种基于粒子滤波方法的上升段飞行器目标视频图像跟踪方法，建立飞行器目标粒子滤波跟踪模型实现对飞行器目标的识别和跟踪，在识别和跟踪的基础上建立云台控制模型，通过对云台的智能控制获得飞行器上升段的高质量图像。采用火箭发射的视频图像作为模型验证的实验数据，检验飞行器目标的跟踪效果。