【作者】 金智慧；

【导师】 荆武兴；

【作者基本信息】 哈尔滨工业大学 ， 飞行器设计， 2007， 硕士

【摘要】 近年来,天文导航以其自主性强、精度高、成本低廉等特点在航天领域得到越来越广泛的应用,成为航天器自主导航的一种重要方法。本文以近地轨道卫星为研究对象,着重研究了基于多姿态敏感器的卫星自主天文导航方法及非线性滤波方法在卫星自主导航系统中的应用,并对自主导航算法的DSP实现、DSP计算结果的实时图形显示等问题进行了研究。本文研究的主要内容有:(1)针对近地轨道卫星,在J2000.0地心赤道惯性坐标系下,综合考虑地球形状摄动、大气阻力摄动、日月引力摄动和太阳光压摄动等因素,建立了较为精确的卫星轨道动力学模型。(2)针对卫星上同时配备有太阳敏感器、地球敏感器和星敏感器的情况,研究了利用姿态敏感器测量信息进行自主天文导航的方法,分别基于扩展卡尔曼滤波和Unscented卡尔曼滤波两种非线性滤波算法设计了导航滤波器以确定卫星在轨的位置和速度。为验证导航方案的可行性及导航算法的性能,本文进行了数学仿真,对两种滤波算法的性能进行了比较分析,并着重讨论了采样周期和敏感器测量精度对导航系统定轨精度的影响。(3)研究了自主导航算法的DSP实现问题。采用C语言和汇编语言混合编程的方法将自主导航算法从PC机移植到DSP集成开发环境CCS中,通过JTAG接口将算法程序加载到TMS320C6713芯片。仿真实验时,一台PC机以固定的采样周期通过RS232接口向DSP芯片传输敏感器测量数据,DSP在接收到所需数据后驱动导航算法进行实时的解算处理。仿真实验证实了该方案的可行性,其结果表明使用DSP芯片实现自主导航算法具有运算速度快、计算精度高等特点,能够很好的满足导航计算机的要求。最后,使用LabVIEW软件编程解决了DSP计算结果以图形化的方式实时显示的问题。更多还原

【Abstract】 In recent years, celestial navigation has been applied much more widely in astronautic fields because of its high precision, high self-determination and low cost. It has become an important method of spacecraft autonomous navigation.This dissertation taking near earth satellite as research object, systematically studied the method of satellite autonomous celestial navigation based on multi-sensors, the application of nonlinear filtering method in satellite autonomous navigation system and its DSP realization. In addition, this dissertation also studied the display of DSP calculation results in graphics mode. The main work of this dissertation is summarized as follows:Firstly, a precise orbital dynamic model of near earth satellite is established in J2000.0 equatorial inertial coordinate system, considering the perturbation influence of earth shape perturbation, atmospheric drag, lunisolar perturbation and solar radiation pressure, etc.Secondly, the autonomous celestial navigation method is studied using measurement information of attitude sensors on the assumption that the near earth satellite has sun-sensor, earth-sensor and star-sensor simultaneously. The navigation filters based on EKF(Extended Kalman Filter) and UKF(Unscented Kalman Filter) are designed in order to determine the satellite’s position and velocity. Numerical simulations are made in order to validate the feasibility of navigation scheme and evaluate the performance of navigation algorithms. In simulation section, this dissertation compare and analyze the performance of EKF and UKF algorithm, discuss the effects of sampling period and sensor precision on positioning accuracy.Thirdly, this dissertation studied the DSP realization of autonomous navigation algorithm. Transform the navigation algorithm program from computer into CCS(Code Composer Studio, TI’s DSP IDE) using C and assembly language, and load the program into TI’s TMS320C6713 chip through JTAG interface. When simulation experimentation is in operation, one computer transmit sensor data to DSP chip through RS232 interface in fixed sampling period. After receiving the needed data, DSP run on-board program and do real-time navigation operation. The simulation validated the feasibility of this navigation scheme and its results showed that using DSP chip to realize autonomous navigation algorithm has many merits, such as: high speed, high precision, etc. It can commendably meet navigation computer’s requirements. At last, applying the LabLEW software resolve the question which is described as to display the DSP calculation results in graphics mode.更多还原