【作者】 王凤娟；

【导师】 朱荣明；

【作者基本信息】 西安电子科技大学 ， 控制理论与控制工程， 2009， 硕士

【摘要】 图像导航是通过对机载传感器获得的图像进行分析和处理来获得导航定位参数的一种技术。信息丰富、成本低廉、完全自主等优越性使得图像导航已成为目前国内外导航技术的研究焦点。本文在了解了各种常用导航方法的基础上,对无人机图像导航领域的研究现状、算法原理及特点进行了深入分析。最成熟的研究成果是通过一幅实时图像得到多个地标点的同名点信息,然后根据摄影测量原理求解飞行器位置参数和姿态参数。该方法要求导航计算机能够存储大量的匹配地图,并且实时图像上的同名点个数要在三个及三个以上。针对以上问题,本文提出了基于图像跟踪的单点定位算法。若能利用激光测距仪测得无人机与地标点之间的距离量,利用主动式定位算法就可以解算出精度较高的无人机实时定位参数。但激光测距仪存在易暴露、易受干扰等缺点。鉴于测距仪使用的局限性,本文又提出了被动式单点定位算法。本算法先对地标点进行跟踪,然后利用实时的像点坐标、光轴平台角、无人机姿态角等信息,根据空间几何关系解算出无人机定位参数。将主动式和被动式单点定位方法相结合,可以扩宽无人机图像导航的范围。本文对基于图像跟踪的单点定位算法进行了算法推导,仿真结果表明了算法的有效性。最后,将本文提出的单点定位算法与捷联惯导系统一起构成组合导航系统,重点推导了适于该系统的集中式Kalman滤波器的状态方程和量测方程。更多还原

【Abstract】 Image navigation is the technology which gets navigational and location parameters by analysing and handling the image acquired from sensors carried by plane. Image navigation has been the focus of both home and abroad in the navigational field because of its advantages including abundant information, low cost and independence.Based on various common navigational methods, this paper deeply analyses the image navigational methods of UAV field, including the research status, algorithmic principles and characteristics. The most matured research result is to get the information of homonymous image points of multiple ground targets by a real-time image, and then solve the parameters of position and posture of UAV by camera and measure theory.This method requires the navigational computer could store a amount of matching maps, and the number of homonymous points on real-time image should be three or more. Aiming at above problems, this paper proposes a single point orientation algorithm, based on image track. If the distance from UAV to ground target can be measured by laser telemeter, we can get the precise UAV real-time location parameters by active orientation algorithm. However, laser telemeter has some disadvantages, including being exposed and interfered easily.Aiming at the limitation of laser telemeter,a passive single point orientation algorithm is proposed in this paper. The algorithm follows the trail of ground target, then makes use of informations including the coordinates of real-time image points, platform angles of optical axises and posture angels of UAV to solve the UAV location parameters according to the relationship of space geometry. The scope of image navigation of UAV can be expanded by combining active single point orientation algorithm and passive single point orientation algorithm. Besides, the single point orientation algorithm based on image track is deduced in this paper, the simulation results shows that the algorithm is effectual.Finally, the single point orientation algorithms proposed in this paper and the Strapdown Inertial Navigation System are united to constitute a navigation system. This paper focuses on the deduction of Kalman filtering state equations and the measurement equations of the system.更多还原