综合通信导航识别系统的故障注入方法研究

针对综合通信导航识别系统的综合化、模块化特点，在综合分析系统故障检测诊断机制、构建系统故障信息库的基础上，设计了一种面向综合通信导航识别系统的软件故障注入方案，可提高综合通信导航识别系统故障诊断软件的效能。通过利用此方案进行故障注入试验，验证了综合通信导航识别系统故障诊断软件的功能和性能。     

Dual smoothing ionospheric gradient monitoring algorithm for dual-frequency BDS GBAS

In this study, a Dual Smoothing Ionospheric Gradient Monitor Algorithm (DSIGMA) was developed for Code-Carrier Divergence (CCD) faults of dual-frequency Ground-Based Augmentation Systems (GBAS) based on the BeiDou Navigation Satellite System (BDS). Divergence-Free (DF) combinations of the signals were used to form test statistics for a dual-frequency DSIGMA. First, the single-frequency DSIGMA was reviewed, which supports the GBAS approach service type D (GAST-D) for protection against the effect of large ionospheric gradients. The single-frequency DSIGMA was used to create a novel input scheme for the dual-frequency DSIGMA by introducing DF combinations. The steady states of the test statistics were also analysed. The monitors were characterized using BDS measurement data, whereby standard deviations of 0.0432 and 0.0639 m for the proposed two test statistics were used to calculate the monitor threshold. An extensive simulation was designed to assess the monitor performance by comparing the Probability of Missed Detection (PMD) according to the differential error with the range domain PMD limits under different fault modes. The results showed that the proposed algorithm has a higher integrity performance than the single-frequency monitor. The minimum detectable divergence with the same missed probability is less than 50% that of GAST-D.     

Modeling and analysis of solar Doppler difference bias with arbitrary rotation axis

The solar rotation causes the solar Doppler difference bias, which leads to the decline of the velocity measurement accuracy. Modeling and compensation are an effective solution. The limited model with specific geometric direction, where the solar rotation axis is perpendicular to the plane through the Sun, the Earth and Mars, was established. However, in fact, the geometric relationship among the Sun, Mars and the spacecraft is not fully in line with the hypothesis of the model due to the spacecraft orbital angle and the solar rotation axis drift. Thus, this model is not consistent with the fact. In order to solve this problem, a universal solar Doppler difference bias model, which provides the expression with arbitrary rotation axis, is established in this paper. In this method, for any point at the solar surface, four variables including the direction of the solar rotation linear velocity at this point, the distance from this point to the rotation axis, the vector from this point to Mars, and the vector from this point to the spacecraft are calculated. Based on these four variables, the solar Doppler difference bias corresponding to this point is obtained. The theoretical analysis and simulation results demonstrate that the solar Doppler difference bias model with the actual rotation axis is different from that with one of the specific rotation axes. Therefore, it is indispensable to build the proposed model for compensation. Besides, the direction of the solar rotation axis, the spacecraft-Mars-Sun angle and the spacecraft-to-Mars distance are important impact factors for the proposed model.     

飞机保障设备发展现状及建议

航空保障设备是综合保障要素之一,是战斗能力形成的重要支撑。本文介绍了国外保障设备发展趋势,分析了我军面临的主要问题:保障设备需求论证不充分,研制流程不规范,"通用化、系列化、模块化"程度低,缺乏全寿命周期的数据信息分析共享等,提出了飞机保障设备发展措施与建议,可作为我军保障设备未来发展的参考。     

Concurrent image-based visual servoing with adaptive zooming for non-cooperative rendezvous maneuvers

An image-based servo controller for the guidance of a spacecraft during non-cooperative rendezvous is presented in this paper. The controller directly utilizes the visual features from image frames of a target spacecraft for computing both attitude and orbital maneuvers concurrently. The utilization of adaptive optics, such as zooming cameras, is also addressed through developing an invariant-image servo controller. The controller allows for performing rendezvous maneuvers independently from the adjustments of the camera focal length, improving the performance and versatility of maneuvers. The stability of the proposed control scheme is proven analytically in the invariant space, and its viability is explored through numerical simulations.     

基于预测模型迭代优化的改进比例导引律

为了提高对加速度时变机动目标的制导精度,将预测决策理论与传统比例导引(PN)相结合,提出了一种通过泰勒级数预测模型迭代控制加速度修正项的改进比例导引律。首先,以预设的低阶泰勒级数预测模型预测特定时间的位移,并计算位移预测值与测量值的差值;然后,通过迭代方法逐阶增加泰勒级数预测模型阶数,直至满足精度要求;最后,计算泰勒级数预测模型的二阶导数,修正比例导引律的加速度指令。仿真结果表明,传统PN和APN的脱靶量分别约为195 m和95 m,提出的改进比例导引律的脱靶量约为8.3 m,极大地提高了制导精度。     

卫星状态智能诊断知识库设计方法

及时准确地发现并处理卫星出现的异常,对卫星运控管理非常重要,关系到卫星在轨使用寿命。设计卫星状态智能诊断知识库,基于该知识库构建的卫星在轨状态自动化报警诊断系统,能够辅助卫星管理人员进行运控管理,这对提高工作效率、降低管理成本、提高卫星安全性具有重要意义。     

UKF稳定性研究及其在相对导航中的应用

讨论了UKF应用于状态方程为线性,测量方程为非线性对象时的稳定性问题。文中 给出了一个UKF保持稳定的充分条件,指出适当增加过程噪声和测量噪声方差阵的设置值, 有利于保证UKF的稳定性。本文还将UKF应用于航天器相对导航滤波器设计,通过数学仿真和 理论分析证实了文中有关UKF稳定性结论的正确性。本文所得到的结论为将UKF应用于实际工 程,特别是航天器相对导航滤波器设计,提供了理论参考。
     

一种单子样旋转矢量姿态算法

旋转矢量姿态算法可有效抑制高动态环境下捷联惯导系统(SINS)产生的圆锥误差。当 直接应用多子样旋转矢量姿态算法时,会降低系统姿态更新频率;若要保持姿态更新频率, 则需要提高采样频率,从而增加了导航计算机的硬件负担,并导致量化误差突出。针对上述 不足,提出了一种利用当前及前N个姿态更新周期角增量的单子样旋转矢量姿态算 法,并在典型圆锥运动条件下推导了算法补偿项系数。此外,由于陀螺输出经过数字滤波处 理后其幅频特性的改变会影响圆锥误差的补偿效果,根据滤波器特性推导了单子样旋 转矢量姿态算法的修正算法,以便于在工程中推广应用。该算法在不降低姿态更新频率 的同时,可获得较高的解算精度,适于高动态环境应用,实验结果验证了上述算法的正确性 和有效性。
     

基于比例分配的过驱动碟形飞行器滑模控制

为了避免一些执行机构提前出现饱和,针对具有位置约束的过驱动碟形飞行器,按照执行机构的约束范围,提出了一种比例分配策略.基于该策略,可以使双输入系统简化成单输入系统,并避免有执行机构提前出现饱和.考虑执行机构具有一阶动态特性和系统气动参数的不确定性,设计了滑模控制律.通过比例分配和伪逆分配的比较,得出了一种确定伪逆分配权矩阵的方法.仿真结果表明了该方法的正确性和有效性.