共查询到20条相似文献,搜索用时 31 毫秒
1.
Kaminer I. Wei Kang Yakimenko O. Pascoal A. 《IEEE transactions on aerospace and electronic systems》2001,37(1):158-172
The problem of navigation system design for autonomous aircraft landing is addressed. New nonlinear filter structures are introduced to estimate the position and velocity of an aircraft with respect to a possibly moving landing site, such as a naval vessel, based on measurements provided by airborne vision and inertial sensors. By exploring the geometry of the navigation problem, the navigation filter dynamics are cast in the framework of linear parametrically varying systems (LPVs). Using this set-up, filter performance and stability are studied in an H∞ setting by resorting to the theory of linear matrix inequalities (LMIs). The design of nonlinear, regionally stable filters to meet adequate H∞ performance measures is thus converted into that of determining the feasibility of a related set of LMIs and finding a solution to them, if it exists. This is done by using-widely available numerical tools that borrow from convex optimization techniques. The mathematical framework that is required for integrated vision/inertial navigation system design is developed and a design example for an air vehicle landing on an aircraft carrier is detailed 相似文献
2.
无人机自动着陆中的机器视觉辅助技术 总被引:4,自引:0,他引:4
设计了一套辅助无人机自动着陆的机器视觉系统。该系统由机载硬件设备和用户开发软件共同组成,用以完成数字图像处理任务和无人机运动参数估计任务。系统传感器包括一个单目摄像机和机载惯性陀螺;数字图像处理使用的主要算法有图像的轮廓提取、角点检测和模版匹配。基于角点处各个方向上灰度差变化较大的特征,依据最小核值相似(SUSAN)算法和角点几何结构分析,提出一种改进的角点特征提取算法;根据任务开发的位置参数估计算法依据摄像机透视投影理论,运用摄像机成像标定方法导出了一种高精度的位置测量模型。通过计算机仿真表明,所提出的计算机视觉位置参数估计算法可以达到无人机着陆过程的精度要求。 相似文献
3.
低空无人机交通管理概览与建议综述 总被引:5,自引:2,他引:5
大量无序飞行的低空无人机运行会对地面设施、公共安全、空中载人飞行器等带来危害。然而,目前民航空中交通管理不能适应未来数以百万架的无人机。为了应对该挑战,世界各国针对低空无人机空中交通管理开发了新框架。低空无人机空中交通管理属于近几年出来的新事物。藉此聚焦于低空无人机交通管理,从4个方面进行概览:低空无人机相关的空中交通基本概念及现状、低空无人机交通管理介绍、低空无人机交通管理的关键技术和低空无人机交通管理相关科学问题,以期望对无人机产业健康发展有一定的建议意义。 相似文献
4.
In this paper, a model-based adaptive mobility control method for an Unmanned Aerial Vehicle(UAV) acting as a communication relay is presented, which is intended to improve the network performance in airborne multi-user systems. The mobility control problem is addressed by jointly considering unknown Radio Frequency(RF) channel parameters, unknown multi-user mobility, and non-available Angle of Arrival(AoA) information of the received signal. A Kalman filter and a least-square-based estimation algorithm are used to predict the future user positions and estimate the RF channel parameters between the users and the UAV, respectively. Two different relay application cases are considered: end-to-end and multi-user communications. A line search algorithm is proposed for the former, with its stability given and proven, whereas a simplified gradient-based algorithm is proposed for the latter to provide a target relay position at each decision time step, decreasing the two-dimensional search to a one-dimensional search. Simulation results show that the proposed mobility control algorithms can drive the UAV to reach or track the optimal relay position movement, as well as improving network performance. The proposed method reflects the properties of using different metrics as objective network performance functions. 相似文献
5.
无人驾驶飞行器的气动特点和设计 总被引:6,自引:6,他引:0
首先论述了发展无人驾驶飞行器(UAV)的重要性,集中介绍了2种UAV的平台,包括:高空长航时UAV和无人战斗机(UCAV)。讨论了这2种飞行器空气动力特点和气动设计的主要问题。对于高空长航时UAV设计中要重点发展的专用翼型的设计,介绍了一种新型的杂交设计思想和提出了基于CFD技术的多目标多点优化设计的工具。讨论了此类飞行器三维机翼设计的基本要求和三维后掠自然层流机翼的设计。UCAV设计中强调了气动/隐身综合设计的重要性,讨论了无尾布局时新型先进气动控制和矢量推进相结合的必要和难点。 相似文献
6.
7.
8.
单目机器视觉测距技术在无人机自动着舰中的应用 总被引:1,自引:1,他引:1
介绍了机器视觉的概念,探讨了机载单目机器视觉在无人机自动着舰方案中的应用。在对前方舰艇进行快速探测以及对摄像机进行预先标定的基础上,本文利用机器视觉理论与方法,以及摄像机内部参数和透视投影几何关系,计算无人机与前方舰艇相对距离。最后展望了机器视觉的发展及应用前景。 相似文献
9.
10.
11.
本文分析了新一代无人机动力的发展,针对小型无人机的活塞式动力装置的性能特点,提出了一种小型无人机二级增压系统匹配的高空实现方法。并对发动机的高空性能进行了初步分析,验证了方案的可行性,为高空无人机动力设计提供了设计依据。 相似文献
12.
13.
14.
针对UTM体制中无人机在地理围栏内的飞行监视问题,提出一种约束状态相关模态转换混合估计算法(CSDTHE)。采用随机线性混杂系统模型对无人机运动状态进行建模,利用CV、CT和CA三种模态描述无人机的飞行状态,以构建地理围栏内无人机运行的通用模态转换模型框架。利用飞行模态改变点(FMCP)定义相关模态转换参数,设计模态转换条件,生成模态转换概率矩阵,从而建立与状态相关的模态转换模型。运用约束卡尔曼滤波(CKF)方法对直线阶段和转弯阶段的无人机运动速度分别施加等式约束,并通过仿真实验验证了CSDTHE算法对无人机跟踪的有效性。 相似文献
15.
16.
《中国航空学报》2021,34(5):585-600
This article concentrates on ground vision guided autonomous landing of a fixed-wing Unmanned Aerial Vehicle (UAV) within Global Navigation Satellite System (GNSS) denied environments. Cascaded deep learning models are developed and employed into image detection and its accuracy promoting for UAV autolanding, respectively. Firstly, we design a target bounding box detection network BboxLocate-Net to extract its image coordinate of the flying object. Secondly, the detected coordinate is fused into spatial localization with an extended Kalman filter estimator. Thirdly, a point regression network PointRefine-Net is developed for promoting detection accuracy once the flying vehicle’s motion continuity is checked unacceptable. The proposed approach definitely accomplishes the closed-loop mutual inspection of spatial positioning and image detection, and automatically improves the inaccurate coordinates within a certain range. Experimental results demonstrate and verify that our method outperforms the previous works in terms of accuracy, robustness and real-time criterions. Specifically, the newly developed BboxLocate-Net attaches over 500 fps, almost five times the published state-of-the-art in this field, with comparable localization accuracy. 相似文献
17.
无人机自动着舰末段机器视觉导引方法研究 总被引:1,自引:0,他引:1
介绍了无人机的概念,以及目前舰载无人机的发展现状;主要讨论了在无人机自动着舰末段如何利用机器视觉导引无人机识别并跟踪舰艇,使其平稳、准确地飞入安装在舰艇尾部甲板上的拦截网中,实现撞网回收。 相似文献
18.
制空权是当代战争一切空中行动的前提条件,而承担空中优势重任的战斗机的研发工作长期以来为各军事大国所重视。数十年来,美军在空战理论、战斗机研发和空战实践等方面具有领先优势,已率先完成由能量机动制胜向信息机动制胜的空战能力转变。随着自主、人工智能、无人、通信、计算等技术的快速进步,美军正在塑造以下一代战斗机为核心,以复杂空战系统为基本空战单元的新空战形态,认知机动制胜将是未来空中对抗的制胜机理。本文将系统梳理空战制胜机理的演变历程,结合当前技术发展与布局,研判未来战斗机发展趋势。 相似文献
19.
无人机类脑吸引子神经网络导航技术 总被引:1,自引:0,他引:1
当前无人机在非结构化或未知环境下飞行主要采用SLAM进行导航与定位,存在如下突出问题:依赖高精度昂贵激光雷达等环境感知传感器;需要建立准确世界和无人机物理模型;受环境影响较大;自主智能水平较低,无法较好地满足无人机对导航系统的要求,需要发展自主智能的导航方式。基于吸引子神经网络的类脑导航技术,无需训练模型参数,不依赖高精度传感器,无需精确建模,且复杂环境下鲁棒性较强,具有解决上述问题的潜力。简要阐述了动物大脑导航机理,分析了吸引子神经网络和基于吸引子神经网络的类脑导航关键技术,最后讨论了吸引子类脑导航技术在无人机应用中的挑战。 相似文献
20.
低雷诺数平面叶栅试验方法研究 总被引:3,自引:0,他引:3
传统的叶型气动设计体系建立在高雷诺数基础上,UAV(无人飞行器)的发展对低雷诺数叶型气动设计和试验验证提出了新的要求。本文就降低叶型试验雷诺数的原理、实现的方法进行了分析,提出了在现有试验器基础上进行设备改造的方案和试验调节方法,并根据试验数据对改造后试验器的低雷诺数流场进行了初步分析,在国内首次通过试验手段获得了某高... 相似文献