基于光电成像的组合导航技术研究

【作者】 谢荣荣；

【导师】 冯培德；

【作者基本信息】 西北工业大学 ， 导航、制导与控制， 2006， 硕士

【摘要】 光电系统由于其较强的抗电子干扰能力和较高的自主性,在导航中起着越来越重要的作用。基于光电和SINS的组合导航系统可充分利用两子系统的优点,进行系统间的取长补短,提高系统的导航精度。通过使用高精度的光电传感器拍摄实时图像并进行特征识别并与SINS数据融合后,可提供一个具有较强抗电子干扰能力的自主式高精度组合导航系统。 本文研究了利用光电传感器拍摄地标点来校正SINS,从而实现高精度着陆引导或导航的方法。 首先,对飞机进行着陆引导时,距机场越近所需精度越高,而光电系统具有高分辨率和测量误差随着其相对目标距离减小而减小的优点,可提供一个具有抗电子干扰能力的自主式着陆引导系统。本文研究了基于光电成像的着陆引导系统方案。由于着陆引导过程中光电成像系统需要对准机场区域,文中设计了一种利用飞机姿态变化和机场区域中心偏离成像中心位置而进行光轴方向调整的算法,使成像系统光轴跟踪机场区域。为了保证着陆引导的精度,建立了Kalman滤波器估计系统位置和航向偏角。同时为了使飞机水平位置不偏离跑道中心,设计了飞机航迹控制,使飞机水平航迹收敛于机场中心线。仿真结果表明,此基于光电成像的着陆引导系统可满足飞机着陆的精度要求,使飞机安全着陆。 接着,提出了一种飞机拍摄地标点的实时图像与SINS系统进行组合导航的方法,可作为无线电等导航手段失效时辅助SINS系统进行高精度导航的手段。文中讨论了系统的结构,重点利用成像模型分析和建立了系统的Kalman量测方程并设计滤波器估计SINS系统误差。针对SINS长时间工作后的位置误差较大,其位置数据不适宜用作滤波器初值的情况,设计了滤波器初始位置算法估算高精度系统位置初值,加速滤波器收敛,使系统位置初始值较SINS位置的精度提高一个数量级,在滤波时间有限的情况下有利于系统精度的提高。 最后,对光电/SINS组合导航系统进行了仿真,并对影响系统精度的因素作了分析,探讨了地标点选择、摄像机参数和飞行航线选择等对精度的影响,得到一些有用结论,为光电成像系统的研制和性能指标的确定提供理论依据。仿真结果表明,使用这种光电/SINS组合导航系统可以较大程度的估算出SINS系统的误差,明显提高系统精度。更多还原

【Abstract】 With of the ability of anti-jamming and autonomous, electro-optical systems are playing more and more important part in the field of navigation. The integrated navigation system based on electro-optical system and SINS takes the full advantage of each system and is able to improve system performance greatly. By employing high-precision electro-optical sensor, the features are extracted and identified from real-time images to integrate SINS to provide a high-precision navigation system with the advantage of anti-jamming and autonomous ability.This dissertation investigates on the method of using electro-optical cameras to integrate SINS to realize high-precision navigation and landing guidance.First of all, in the procedure of aircraft landing guidance, the nearer the aircraft approaches the airport, the higher navigation precision is needed. The electro-optical system has high resolution and the advantage that measurement error decreases while the distance to objects is nearer, and as a result is suitable for Landing Guidance System. The research on the scheme of Landing Guidance System based on electro-optical sensors is carried on first. In the procedure of landing guidance, the camera must stare at the airport, so a rotation algorithm for electro-optical cameras using aircraft attitude and token deviation from the center of imaging plane is investigated. What’s more, the state equation and measurement equation for Kalman filters are constructed to estimate system position and azimuth angle. Also, the flight control module is made to make sure that horizontal trail of the aircraft converges at the center of airport runway. The simulation results indicate that the electro-optical landing guidance scheme proposed is able to satisfy the need for the precision of aircraft landing.Secondly, a method using real-time images of landmarks to integrate SINS and realize high precision navigation is proposed, which provides an autonomous navigation system in the situation of radio navigation system dropouts. The discussion of system architecture is brought forth first. Then it focuses on the construction of the measurement model and the Kalman filter in order to estimate SINS errors. Because SINS position errors are too large to satisfy the initial states of the filter, algorithm for estimating of the initial position for the Kalman filter is proposed to speed up the convergence of the filter, and simulations for the algorithm are done. The resultsindicate that the system position precision improves greatly and is able to satisfy Kalman filter.Finally, the system simulation and analysis of the factors that matter system results such as the selection of landmarks, the parameters of cameras and the trajectory of aircraft is done to improve navigation precision, and some useful conclusions are given to provide a standard for the development of electro-optical systems. The simulation results indicate that the proposal is able to estimate the errors of SINS and is useful to improve the precision of the integrated system.更多还原