自适应两级UKF算法及其在时变偏差估计中的应用

针对存在时变偏差的非线性系统状态估计问题,提出了一种新型的自适应两级UKF算法（ATUKF,adaptive two—stage unscented Kalman filter）．该算法利用衰减因子补偿模型的不确定性,对状态和偏差实施分离估计,并利用估计偏差对状态进行更新．将该算法用于存在随机时变偏差的近地卫星自主导航系统的状态估计问题中,仿真结果验证了其有效性,并利用可观测性分析方法对导航系统的可观测性进行了分析．     

Comparative analysis of global optical observability of satellites in LEO

With a growing number of resident space objects (RSOs), the facilities for near-Earth space surveillance have to cope with increasing workload. It also applies to low-cost small optical surveillance facilities which may present regional, national and global networks. Improved methods of planning and scheduling optical telescopes are required to use these instruments efficiently. Today, optical observations are only feasible if the following quite stringent requirements are met: the object should be illuminated by sunlight, and it should be above while the Sun is below the observer’s horizon. For different orbits, these preconditions result in varying degrees of the space object observability at various ground-based sites. Certainly, satellites in low Earth orbit (LEO) are particularly difficult to observe. This study aims at developing a new technique for assessing observability of a satellite in different types of orbits – namely, low, medium and high Earth orbits, imaging of the opportunity for its visibility in respective diagrams and their analysing for the existing near-Earth population of RSOs. Unlike other researches, wherein one or several observational stations have been chosen as target sites for in-depth analyses of visibility of all the satellites or just the selected ones, the present study focuses on examining the probability of optical surveillance of satellites in a certain orbit from any locations worldwide. It offers considerable scope for automation of surveillance planning and scheduling optical surveillance networks.     

重力传感器参数双轴旋转调制标定方法及实验验证

重力传感器参数的外场标定可充分发挥重力仪的测量潜力，提高重力测量的精度。利用全局可观性方法，对加速度计在静态条件下的参数可观性进行了分析，推导了静态多位置条件下加速度计参数可观的条件。根据理论推导的参数可观的条件，以双轴旋转重力仪为实验平台，设计了标定参数的编排方案。实验结果表明，该方法所测得的刻度因数对角线的最大偏差达到了10-8量级，利用对角线上的刻度因子修正了三轴转台的标定结果。2800s纯惯导解算结果证明，使用外场标定参数与实验室三轴转台标定参数的纯惯性导航精度相当。     

悬链面上的非线性控制系统

讨论了悬链面上的非线性控制系统的表示及性质     

单载机相位差无源定位系统可观测性分析(英文)

With a pair of antennas spaced apart, an airborne passive location system measures phase differences of emitting signals. Regarded as cyclic ambiguities, the moduli of the measurements traditionally are resolved by adding more antenna elements. This paper models the cyclic ambiguity as a component of the system state, of which the observability is analyzed and compared to that of the bear- ings-only passive location system. It is shown that the necessary and sufficient observability condition for the bearings-only passive location system is only the necessary observability condition for the passive location system with phase difference measurements, and that when the system state is observable, the cyclic ambiguities can be estimated by accumulating the phase difference measurements, thereby making the observer able to locate the emitter with high-precision.     

快速判断线性控制系统能控能观性的一种途径

介绍了判断线性控制系统能控性和能观性的一种方法,并提供了一种用 MATLAB 语言编写的快速准确判断线性控制系统能控能观性的软件。     

惯导系统初始对准的次优滤波算法

分析了惯导系统(INS)初始对准的动态误差向量方程及其动态误差向量的可观性问题,并研究了按动态误差向量的可观度划分观测子空间.在惯导系统初始对准问题中通过使用变量可观度的概念构造次优卡尔曼估计算法.并用C语言编程实现了初始对准的最优及次优卡尔曼滤波算法.从仿真结果可见次优卡尔曼滤波算法可用于INS初始对准的实用计算中.     

几种可观性分析方法及在惯导中的应用

建立了惯导系统（ＩＮＳ）的误差模型,研究Ｋузовков方法、奇异值判断法和状态解耦方法等３种可观性分析方法,并将这些方法用于惯导初始对准的可观性分析中。通过分析,用Кузовков方法和奇异值判断法相结合,可更有效地确定不可观状态。用状态解耦的方法,可以将状态分解到相应的子空间中,之后可以选择不可观的状态。     

基于扩展卡尔曼滤波的XPNAV-1卫星自主定轨算法研究

X射线脉冲星导航1号（XPNAV-1）是全球首颗脉冲星导航专用试验卫星。利用该卫星观测的单颗脉冲星数据,采用几何约束方法,能够有效抑制轨道误差增长,但存在长时间定轨发散问题。针对XPNAV-1卫星拓展试验任务及脉冲星导航后续发展需求,利用多颗脉冲星的观测数据,研究基于扩展卡尔曼滤波（EKF）的卫星自主定轨算法。首先,建立该卫星的轨道力学模型和观测方程;然后,详细论述EKF滤波算法和分段式定常系统（PWCS）的可观测性分析方法;最后,通过综合分析XPNAV-1卫星的观测数据、脉冲星对该卫星轨道的覆盖性以及系统状态的可观测性,进行自主定轨算法试验。试验结果表明,基于EKF的自主定轨算法滤波过程收敛,验证了该算法的合理性和有效性。     

四水箱控制系统的建模与解耦分析

控制系统的输入输出间的耦合严重影响控制效果,实现解耦成为控制研究的重要课题。四水箱液位控制系统是多输入多输出的非线性时变耦合系统,如何实现输入输出间解耦,对研究复杂过程控制具有指导意义。基于这种情况应用机理分析法建立四水箱液位控制系统的数学模型,并运用矩阵分析理论分析该系统的稳定性、能控性和能观测性,利用状态反馈对系统进行解耦,实现四水箱解耦控制系统。