期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
Gradient Descent Algorithm for Small UAV Parameter Estimation System
1
作者 Guo Jiandong Liu Qingwen Wang Kang 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2017年第6期680-687,共8页
A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and... A gradient descent algorithm with adjustable parameter for attitude estimation is developed,aiming at the attitude measurement for small unmanned aerial vehicle(UAV)in real-time flight conditions.The accelerometer and magnetometer are introduced to construct an error equation with the gyros,thus the drifting characteristics of gyroscope can be compensated by solving the error equation utilized by the gradient descent algorithm.Performance of the presented algorithm is evaluated using a self-proposed micro-electro-mechanical system(MEMS)based attitude heading reference system which is mounted on a tri-axis turntable.The on-ground,turntable and flight experiments indicate that the estimation attitude has a good accuracy.Also,the presented system is compared with an open-source flight control system which runs extended Kalman filter(EKF),and the results show that the attitude control system using the gradient descent method can estimate the attitudes for UAV effectively. 展开更多
关键词 gradient descent algorithm attitude estimation QUATERNIONS small unmanned aerial vehicle(UAV)
下载PDF
基于无人机航测获取高分辨率DEM数据的断层几何结构精细解译与分析——以海原断裂唐家坡为例 被引量:19
2
作者 孙稳 何宏林 +3 位作者 魏占玉 高伟 孙浩越 邹俊杰 《地震地质》 EI CSCD 北大核心 2019年第6期1350-1365,共16页
与断层活动相关的构造地貌是多次强震活动与长期地表过程共同作用的结果,其形态特征包含着丰富的强震活动信息。但由于测量手段和数据精度的限制,如何从形态复杂的构造地貌中准确识别这些信息一直是活动构造研究的难点。近年来,结合运... 与断层活动相关的构造地貌是多次强震活动与长期地表过程共同作用的结果,其形态特征包含着丰富的强震活动信息。但由于测量手段和数据精度的限制,如何从形态复杂的构造地貌中准确识别这些信息一直是活动构造研究的难点。近年来,结合运动重建模型(SfM,Structure from Motion)的小型无人机(sU AV,small Unmanned Aerial Vehicle)低空航测技术为研究者提供了一种低成本、高灵活性、快速获取高精度3D地形数据(DEM)和正射影像(DOM)的方法。文中利用该方法获得了海原断裂唐家坡西田埂位错区域的高精度、高分辨率DEM数据,然后基于DEM数据进行了构造地貌解译和断层陡坎形貌分析。通过地貌单元划分并对其与断层的切割关系进行解译,识别出一系列走滑断裂的伴生构造,并讨论走滑断层发育过程中的破裂类型及其样式。基于对冲沟水平位错量、断层陡坎垂直位错量的统计和断层陡坎坡度拐点的分析,认为研究区地貌面形成以来经历了2次地表破裂型地震事件。其中,最新一次事件的水平和垂直位移量分别为(4.3±0.4)m和(0.95±0.14)m,该位移量也代表了1920年海原地震的同震位移量;较老一次事件的水平和垂直位移量分别为(4.3±0.95)m和(0.85±0.22)m。 展开更多
关键词 构造地貌 精细结构 海原断裂 sUAV(small Unmanned Aerial vehicle) 水平位错垂直位错 坡折点
下载PDF
Bearing-only Visual SLAM for Small Unmanned Aerial Vehicles in GPS-denied Environments 被引量:6
3
作者 Chao-Lei Wang Tian-Miao Wang +2 位作者 Jian-Hong Liang Yi-Cheng Zhang Yi Zhou 《International Journal of Automation and computing》 EI CSCD 2013年第5期387-396,共10页
This paper presents a hierarchical simultaneous localization and mapping(SLAM) system for a small unmanned aerial vehicle(UAV) using the output of an inertial measurement unit(IMU) and the bearing-only observati... This paper presents a hierarchical simultaneous localization and mapping(SLAM) system for a small unmanned aerial vehicle(UAV) using the output of an inertial measurement unit(IMU) and the bearing-only observations from an onboard monocular camera.A homography based approach is used to calculate the motion of the vehicle in 6 degrees of freedom by image feature match.This visual measurement is fused with the inertial outputs by an indirect extended Kalman filter(EKF) for attitude and velocity estimation.Then,another EKF is employed to estimate the position of the vehicle and the locations of the features in the map.Both simulations and experiments are carried out to test the performance of the proposed system.The result of the comparison with the referential global positioning system/inertial navigation system(GPS/INS) navigation indicates that the proposed SLAM can provide reliable and stable state estimation for small UAVs in GPS-denied environments. 展开更多
关键词 Visual simultaneous localization and mapping(SLAM) bearing-only observation inertial measurement unit small unmanned aerial vehicles(UAVs) GPS-denied environment
原文传递
Implementation of a flexible Major Vacation Toll-free Program for small passenger vehicles in China
4
作者 Meng XU Ziyou GAO 《Frontiers of Engineering Management》 2017年第4期498-499,共2页
On July 24,2012,the State Council of the People’s Republic of China implemented'a toll-free program for small passenger vehicles during major vacations1).In the several months that followed,local governments issu... On July 24,2012,the State Council of the People’s Republic of China implemented'a toll-free program for small passenger vehicles during major vacations1).In the several months that followed,local governments issued implementation articles.The current Major Vacation Tollfree Program for small passenger vehicles(MVTP)pioneers the concept(Xu and Gao,2016),'Benefaction to People.'The current MVTP has received 展开更多
关键词 Implementation of a flexible Major Vacation Toll-free Program for small passenger vehicles in China FLEXIBLE
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部