中期冲突探测算法的研究与设计

综合考虑飞机实际飞行中存在多个航路转弯点及空中交通管制辅助系统需满足实时准确性的要求,设计了一种改进型的中期冲突探测算法.以雷达获取的飞机的当前位置和速度矢量作为初始状态,再结合航路飞行意图信息和转弯后的航迹误差积累方法,计算整合后的各航路分段冲突发生的概率来预测冲突发生的可能性.仿真实验结果表明,该算法能有效地用于中期冲突探测.     

基于航迹预测的飞行冲突探测

基于飞行器飞行途中的随机影响及观测仪器的误差影响,给出了常速模型的冲突探测模型。重点讨论2架飞行器靠近飞行的情况,采用卡尔曼滤波理论,预测2架飞行器的相对航迹。然后依据相对航迹,计算2架飞行器在各时刻的距离。最后根据冲突条件判断冲突是否存在。该方法不仅从模型上保证了更接近飞行器的实际飞行情况,而且计算机仿真结果表明该方法能有效地进行冲突探测。     

一种基于ADS-B信息的冲突告警算法

为了解决飞行流量持续快速增长导致的飞行安全问题,给出一种基于ADS-B信息的冲突告警算法。该算法的目的在于发现终端区或机场附近可能存在的飞行冲突,为飞行员采取避让措施提供足够的时间。算法主要由2个模型构成：第1个模型是飞行冲突区域划分模型,该模型包含保护空域(PAZ)和冲突空域(CAZ)2个区域;第2个模型是飞行冲突探测模型,该模型首先对冲突目标初选,然后对有可能发生飞行冲突的飞机从竖直和水平2个方向进行冲突探测并根据探测结果发出相应的告警信息。经大量的Monte-Carlo仿真实验表明该算法性能良好,能及时有效地发现飞行冲突,对确保终端区或者机场附近的安全有着重要意义。     

ADS-B信息的球状模型飞行冲突探测算法

随着空中飞行流量日趋增大,飞行器自由飞行过程中发生碰撞的可能性也越来越大,针对飞行器周围空域进行合理划分,给出了一种基于ADS-B信息的球状模型飞行冲突探测算法.该算法结合ADS-B的原理和特点,运用球状模型取代圆柱体模型对飞行器周围空域进行建模,然后进行冲突目标初选,对可能发生冲突飞行器的位置、航迹交叉点、距离进行计算并预估到达时间,与门限值比较判断能否发生碰撞,最后,对算法进行仿真.结果验证:算法能够更准确并且快速地完成冲突探测,并对驾驶员发出冲突告警,对防止飞行冲突的发生具有积极作用.     

适用于多航路的概率型中期冲突探测方法

通过分析飞机飞行过程中的航迹误差,提出了估计飞行冲突可能性大小的概率型中期冲突探测的思想。针对我国民航航路由多个航路段组成的特点,提出了改进的中期冲突探测算法。该方法参考飞行过程中的最小间距点,找出两飞机在整个预测时间内的5个极小间距点作为航迹误差的累积过程,从而更精确地描述了两机相遇几何中的联合航迹误差。最后实例仿真计算表明,该算法完全能满足空中交通管制对算法实时性的要求,可以应用于实际的空中交通管制系统中。     

飞行计划冲突预探测算法研究

对飞行计划冲突预探测进行了彻底的研究,给出了相应的预探测算法。在对各种冲突类型进行研究的同时,针对航迹交叉时横向间隔的冲突探测——预探测中最困难的问题,给出了相关的探测模型,结合严密的数学理论推导,得出相关的求解公式,全面地解决了该问题。当冲突存在时,该算法确定地给出冲突时间段和冲突的航路段。实践表明,该算法是非常有效的。     

基于球形边界的ATC飞行冲突概率预测

文章根据ICAO的飞行规则对飞行器的飞行冲突进行了较详细的理论分析,将该飞行冲突过程分成两个阶段即航路巡航阶段和离场起飞、进近着陆阶段,通过简化飞行边界条件和飞行冲突状态,分别推导给出了该两个阶段需要的三维飞行冲突预测解析运算模型。该飞行冲突预测解析运算模型运算量明显得到减少,并利用Monte-Carlo仿真算法验证了该算法的精确度和可行性。     

ATC系统中短期冲突探测方法的研究

飞行冲突探测是空中交通管制系统中的一个重要课题,本文结合我国空管的有关规定和飞行参数标准,介绍了在实践中探索并应用的一种冲突探测告警处理方法和运算步骤。     

改进蚁群算法在飞行冲突求解问题中的应用

改进的蚁群算法可以用于空中交通飞行冲突问题的求解.对空中交通飞行冲突问题的研究背景以及研究现状进行系统概述,简要介绍了人工势场法和蚁群算法.建立了相关的数学模型,将空中交通飞行冲突问题转化为有约束的非线性整数规划问题,并且把人工势场法和蚁群算法相结合,设计了将人工势场法的规划结果作为蚁群优化算法先验知识的求解思路.最后的仿真计算表明了该方法能加快蚁群算法的收敛速度,在短时间内提供理想的冲突解决方案.     

基于飞行姿态的潜在冲突预警算法

将冲突探测与飞行器的飞行姿态联系起来，将不同飞行姿态的不同取值标准应用于当前位置告警检测及高度与水平间距顶测的预推算法中，使得飞行器的飞行冲突探测算法更加合理、准确。算法在实际飞行检验中，取得了较好的效果。     

高阶Delaunay三角网及生成算法研究

Delaunay三角剖分是构建数字地形模型的有效方法,但是该方法会引起人工大坝和局部极值问题,使得地形模型不能很好地反映原始地形的真实面貌。在Delaunay三角网的基础上提出了一种高阶Delaunay三角网,并给出了高阶Delaunay三角网生成算法。实验结果表明,高阶Delaunay三角网能够有效地减少地形中局部极小的数量,因此,采用高阶Delaunay三角网建立的地形模型更接近于实际地形。     

Delaunay三角网构建方法比较研究

Delaunay三角网构建是3维场景可视化领域的一个热点也是难点问题。归纳总结了现有Delaunay三角网构建研究中的3类方法——逐点插入法、三角网生长法和分治法,以及在各自原理框架下的不同实现算法;比较分析了3种不同方法的优缺点和各自代表性算法的时间复杂度,并详细讨论了Delaunay三角网构建方法在大规模场景渲染和地形可视化领域中未来3个研究方向：混合算法研究、算法支撑技术研究和分布式并行算法研究。     

多边形单元网格自动生成技术

近年来兴起的多边形有限元方法,在有限元计算中采用多边形单元划分网格,不仅可以更好地适应求解区域的几何形状,而且增加了网格划分的灵活性。为了更方便有效地生成多边形单元网格,在Delaunay三角形的基础上,通过将共圆Delaunay三角形合并为一个圆内接多边形,首先提出了Delaunay多边形的概念,进而提出了一种多边形网格自动生成的Delaunay多边形化算法。利用该Delaunay多边形化技术,对工程中常见的几何形状进行网格划分的具体算例表明,Delaunay多边形化方法可以生成性质优良的多边形单元网格。     

航班滑行路径规划和停机位分配联合优化

针对机场的航班滑行路径规划和停机位分配的联合优化调度问题,构建基于冲突回避的滑行道与停机位联合调度模型,并提出改进的自适应差分进化算法求解问题.以最小化航班的滑行时间和旅客转机的行走时间为优化目标,建立非线性混合整数规划联合调度模型.设计考虑了滑行冲突的路径规划算法,完成航班的滑行路径分配,并通过自适应动态调整差分进化...     

Reconstruction of 2D polygonal curves and 3D triangular surfaces via clustering of Delaunay circles/spheres

A simple and efficient method is presented in this paper to reliably reconstruct 2D polygonal curves and 3D triangular surfaces from discrete points based on the respective clustering of Delaunay circles and spheres. A Delaunay circle is the circumcircle of a Delaunay triangle in the 2D space, and a Delaunay sphere is the circumsphere of a Delaunay tetrahedron in the 3D space. The basic concept of the presented method is that all the incident Delaunay circles/spheres of a point are supposed to be clustered into two groups along the original curve/surface with satisfactory point density. The required point density is considered equivalent to that of meeting the well-documented r-sampling condition. With the clustering of Delaunay circles/spheres at each point, an initial partial mesh can be generated. An extrapolation heuristic is then applied to reconstructing the remainder mesh, often around sharp corners. This leads to the unique benefit of the presented method that point density around sharp corners does not have to be infinite. Implementation results have shown that the presented method can correctly reconstruct 2D curves and 3D surfaces for known point cloud data sets employed in the literature.     

Conflict Detection and Resolution Method for Cooperating Unmanned Aerial Vehicles

This paper presents a Conflict Detection and Resolution (CDR) method for cooperating Unmanned Aerial Vehicles (UAVs) sharing airspace. The proposed method detects conflicts using an algorithm based on axis-aligned minimum bounding box and solves the detected conflicts cooperatively using a genetic algorithm that modifies the trajectories of the UAVs with an overall minimum cost. The method changes the initial flight plan of each UAV by adding intermediate waypoints that define the solution flight plan while maintaining their velocities. The method has been validated with many simulations and experimental results with multiple aerial vehicles platforms based on quadrotors in a common airspace. The experiments have been carried out in the multi-UAV aerial testbed of the Center for Advanced Aerospace Technologies (CATEC).     

Text region extraction in a document image based on the Delaunay tessellation

In this paper, Delaunay triangulation is applied for the extraction of text areas in a document image. By representing the location of connected components in a document image with their centroids, the page structure is described as a set of points in two-dimensional space. When imposing Delaunay triangulation on these points, the text regions in the Delaunay triangulation will have distinguishing triangular features from image and drawing regions. For analysis, the Delaunay triangles are divided into four classes. The study reveals that specific triangles in text areas can be clustered together and identified as text body. Using this method, text regions in a document image containing fragments can also be recognized accurately. Experiments show the method is also very efficient.     

三维任意区域中点集的三角剖分算法

本文在已有算法基础上，发展了一种三维任意区域中点集的三角剖分算法。该算法不仅可用于三维点集的标准Ｄｅｌａｕｎａｙ三角剖分，而且可用于带有约束表面及内部含有孔洞情况，可以处理非凸区域的三角剖分问题。算法对点在空间的位置滑任何限制。     

Anisotropic surface meshing with conformal embedding

This paper introduces a parameterization-based approach for anisotropic surface meshing. Given an input surface equipped with an arbitrary Riemannian metric, this method generates a metric-adapted mesh with user-specified number of vertices. In the proposed method, the edge length of the input surface is directly adjusted according to the given Riemannian metric at first. Then the adjusted surface is conformally embedded into a parametric 2D domain and a weighted Centroidal Voronoi Tessellation and its dual Delaunay triangulation are computed on the parametric domain. Finally the generated Delaunay triangulation can be mapped from the parametric domain to the original space, and the triangulation exhibits the desired anisotropic property. We compute the high-quality remeshing results for surfaces with different types of topologies and compare our method with several state-of-the-art approaches in anisotropic surface meshing by using the standard measurement criteria.     

A Delaunay Triangulation based method for wireless sensor network deployment

To obtain a satisfied performance of wireless sensor network, an adaptable sensor deployment method for various applications is essential. In this paper, we propose a centralized and deterministic sensor deployment method, DT-Score (Delaunay Triangulation-Score), aims to maximize the coverage of a given sensing area with obstacles. The DT-Score consists of two phases. In the first phase, we use a contour-based deployment to eliminate the coverage holes near the boundary of sensing area and obstacles. In the second phase, a deployment method based on the Delaunay Triangulation is applied for the uncovered regions. Before deploying a sensor, each candidate position generated from the current sensor configuration is scored by a probabilistic sensor detection model. A new sensor is placed to the position with the most coverage gains. According to the simulation results, DT-Score can reach higher coverage than grid-based and random deployment methods with the increasing of deployable sensors.