基于无人机载光电平台的目标定位技术

针对无人机目标定位问题,基于无人机载光电平台总结了无人机目标定位的典型工作流程,系统论述了无人机目标定位技术现状,阐述了包括基于视觉、地图匹配、空间前方交会和粒子滤波技术的主要目标定位方法.针对性地分析了4种技术的优缺点,对无人机目标定位技术的未来发展趋势进行了展望.     

A Terrain Referenced UAV Localization Algorithm Using Binary Search Method

This study focuses on localization of Unmanned Aerial Vehicles (UAV) since permanent navigation has vital significance to support position information and to avoid getting lost. Actually, there exist effective aeronautical navigation systems in use. Inertial Navigation System (INS) and Global Positioning System (GPS) are two representatives of the most common systems utilized in traditional aerial vehicles. However, an alternative supporter system for UAVs should be mentioned since INS and GPS have serious deficiencies for UAVs such as accumulated errors and satellite signal loss, respectively. Such handicaps are coped with integrating these systems or exploiting other localization systems. Terrain Referenced Navigation (TRN) could be a good alternative as a supporter mechanism for these main systems. This study aims to localize a UAV accurately by using only the elevation data of the territory in order to simulate a TRN system. Application of the methodology on a real UAV is also considered for the future. Thus assumptions and limitations are designed regarding the constraints of real systems. In order to represent terrain data, Digital Elevation Model (DEM) with original 30 meter-resolution (Eroglu and Yilmaz 2013) and also synthetically generated 10 meter-resolution maps are utilized. The proposed method is based on searching the measured elevation values of the flight within the DEM and makes use of simulation techniques to test the accuracy and the performance. The whole system uses sequences of elevation values with a predefined length (i.e. profile). Mainly, all possible profiles are generated and stored before the flight. We identify, classify and sort profiles to perform search operations in a small subset of the terrain. During the flight, a measured flight profile is searched by the Binary search method (Eroglu 2013) within a small neighborhood of corresponding profile set.     

Development of a GPU Accelerated Terrain Referenced UAV Localization and Navigation Algorithm

This study focuses on localization and navigation of Unmanned Air Vehicles (UAVs) based on digital terrain map data. The solution to the Terrain Referenced Localization and Navigation (TERELONA) or Terrain Referenced Navigation (TRN) is described by using particle filter. In many UAV applications one of the most important points is to provide accurate location information continuously. TERELONA system can supply the air vehicle with the accurate position information with a bounded error. In this paper, the particle filtering method as an implementation of Bayesian approach to the terrain referenced localization and navigation is described. The radar altimeter measurements are used as an implicit representation of aircraft position. Whenever new measurements are taken from radar altimeter, they are compared to the Digital Terrain Map (DTM) data in order to fix a position. The solution is represented, in a Bayesian framework, by a set of particles with their corresponding weights. We have developed the terrain referenced localization and navigation algorithm based on the particle approximation. The proposed algorithm, which is developed in CUDA^TM, is also tested on the GPU environment using GPUmat software architecture. Thus, we can cope with the computational load of the very large initial horizontal position errors. The proposed algorithm has been implemented in MATLAB^TM environment and evaluated on simulated data. Simulations are conducted over an ASTER GDEM product which belongs to a region in northwest of Turkey. The simulation results are provided.     

面向定位应用的无人机的悬停位置和飞行路径优化

无人机的一种典型应用是对地面目标进行定位.本文考虑,在无人机的飞行过程中,无人机在特定位置悬停,并广播信标信号.若地面节点与无人机悬停位置的距离满足通信范围,即可监测到无人机的信标信号,当地面节点监测到3个及以上不同悬停位置的信标信号时,即可使用多边定位法对自身进行定位.文中主要解决了如何选择悬停位置以及如何在悬停位置给定的情况下优化无人机飞行路径的问题,提出了两种无人机的悬停方案,并规划了两种方案下无人机的飞行路径,证明了两种悬停方案下提出的路径均为最短回路.通过模拟实验,验证了所提方案可以实现对待覆盖区域的完全覆盖,使任意地面节点均可实现定位;并且该方案可以通过调整无人机飞行高度和悬停方案中的网格大小,来提高定位精度.     

UAV Task Assignment

Unmanned aerial vehicles (UAVs) are becoming vital warfare and homeland security platforms because they have the potential to significantly reduce cost and risk to human life while amplifying warfighter and first-responder capabilities. This article builds on the very active area of planning and control for autonomous multiagent systems. This work represents a step toward enabling robust decision making for distributed autonomous UAVs by improving the team's operational reliability and capabilities through better system self-awareness and adaptive mission planning. The health-aware task assignment algorithm developed in this article was demonstrated to be effective both in simulation and flight experiments.     

Augmenting UAV autonomy

The addition of a camera to an unmanned aerial vehicle (UAV) allows the vehicle to perform a variety of tasks autonomously. This paper presents UAV vision systems that were developed and tested at the Georgia Institute of Technology to perform three of these tasks on the GTMax unmanned research helicopter. The first system demonstrates a vision-based navigation system. The second system demonstrates an automated search routine for stationary ground targets. The third system demonstrates a ground target tracking architecture for mobile targets.     

静态威胁下的无人机航迹规划

无人机（Uninhabited Air Vehicle,UAV）由于其自身优点,已经在军事以及民用领域取得广泛使用。无人机的航迹规划本质可归结为一个多目标多约束条件的最优化问题。简单介绍无人机航迹规划的基本理论。运用神经网络算法针对静态环境下的火力威胁和非火力分别建模。运用遗传算法对无人机进行航迹规划。通过建立不同环境的模型仿真验证算法的优越性。     

浅谈行向量引导的链表存储结构

本文通过对线性表、树和图三类基本结构的比较分析研究,提出了由行向量引导的链表存储结构采统一三种结构存储的设想和方法,使得某些问题的解决能建立在相对统一的存储结构上,试图降低算法的复杂程度.本文还给出了用行向量引导的链表存储结构来解决实际问题的一些算法.     

浅谈行向量引导的链表存储结构

本文通过对线性表、树和图三类基本结构的比较分析研究,提出了由行向量引导的链表存储结构来统一三种结构存储的设想和方法,使得某些问题的解决能建立在相对统一的存储结构上,试图降低算法的复杂程度。本文还给出了用行向量引导的链表存储结构来解决实际问题的一些算法。     

ITU Tailless UAV Design

Nowadays, mini Unmanned Aerial Vehicles (UAVs) are utilized in a wide range of reconnaissance and surveillance missions with an ever increasing need for endurance and range. Thus, a slight improvement on these two primary performance parameters is considered as a competitive advantage. In this work, a multi-functional tailless UAV concept and its design process is presented. In comparison to existing conventional UAV designs, the concept is shown to have superior aerodynamic and flight performance characteristics. In addition the detachable wing and body concept provides the much needed flexibility and multi-functionality for using the UAV for a range of operation concepts, in which each concept requires different payloads of distinct weight and size.     

辽宁省主要农作物转基因育种存在的问题及主攻方向

近年来,转基因育种在世界范围内已被广泛应用于农作物的改良,国内一些科研及教学机构转基因研究也取得了可喜进展。辽宁省农作物转基因育种研究起步相对较晚,目前已有一批转基因项目正在实施,解决辽宁省农作物转基因育种工作存在的问题,可使辽宁农业得到更大的发展。     

Localization in strain-rate-dependent solids

The localization of the deformation in strain-rate-dependent solids evolves through three distinct phases. Its onset is signalled by the first deviation from a homogeneous mode of deformation, which we propose to pinpoint by means of a linear perturbation analysis. The second stage, marked by a sharp increase of the effective strain rate in ‘shear bands’ of decreasing thickness, is analysed with a special finite element scheme that uses embedded shear-band modes of deformation. The third phase is entered with the long-term evolution of the localization and the question that arises here is whether or not stationary shear bands of finite thickness are to be expected as theoretically admissible solutions.     

无人机场景下尺度自适应的车辆跟踪算法

为解决传统相关滤波算法对无人机(UAV)拍摄视频中的车辆进行跟踪时,因目标车辆尺度变化而产生模型漂移的问题,提出了一种改进的尺度自适应的车辆跟踪算法.该算法基于核相关滤波,通过构建区分尺度的空间跟踪器,即利用两个滤波器分别对目标车辆的位置进行定位,对目标车辆的尺度进行估计,以此来快速确定目标相关信息,实现对目标车辆尺度...     

突发威胁情况下的无人机航迹重规划

为了提高Voronoi图在航迹规划方面的实用性,提出了一种改进型的Voronoi图构造模型。该模型通过引入威胁源的不可穿越区域边界,利用折中原理,在Delaunay三角网的基础上构建航迹拓扑空间。改进型的Voronoi图模型拓展了传统模型的航迹段数量,提高了航迹段对威胁的敏感性,使规划的航迹更为合理。其次,在分析突发威胁对于航迹拓扑空间影响的基础上,提出了一种基于改进型Voronoi图的航迹重规划模型,并结合D*算法对突发情况下的航迹重规划进行了研究,规划出了理想航迹。     

作物耐低钾营养研究进展

从作物对低钾反应遗传多样性及适应钾营养胁迫的生理特性两个方面综述了国内外作物耐1代钾营养研究状况，利用作物耐低钾的遗传特性，运用现代遗传育种技术，选育和推广耐低钾优良品种是缓解我国钾源短缺的最好途径，而且是高产、高效的生物学途径。     

利用内存行激活信息的DRAM行扰动问题研究

随着DRAM存储器制程的发展,存储单元尺寸更小,行扰动成为一个降低DRAM可靠性和暴露安全漏洞的关键性问题。提出一种基于内存行最近激活信息（RACPR）的解决DRAM行扰动问题的方法,主要思想是基于受害行的最近激活信息,利用被动激活操作与专用的主动刷新操作具有相同的防止行扰动的效果,减少不必要的主动刷新操作。提出最近激活计数器（RAC）来跟踪内存行的被动激活信息,并优化RAC的结构和操作,以降低其复杂性和开销。提出的RACPR方法性能开销可忽略,面积成本为0.006%。实验结果表明：与以往的概率方法相比,RACPR方法平均减少75%的主动刷新次数,并提供更好的平均内存访问性能。