An improved quaternion Gauss–Newton algorithm for attitude determination using magnetometer and accelerometer

For the vector attitude determination, the traditional optimal algorithms which are based on quaternion estimator(QUEST) measurement noise model are complicated for just two observations. In our application, the magnetometer and accelerometer are not two comparable kinds of sensors and both are not small field-of-view sensors as well. So in this paper a new unit measurement model is derived. According to the Wahba problem, the optimal weights for each measurement are obtained by the error variance researches. Then an improved quaternion Gauss–Newton method is presented and adopted to acquire attitude. Eventually, simulation results and experimental validation employed to test the proposed method demonstrate the usefulness of the improved algorithm.     

Cleaning space debris with a space-based laser system

High-energy pulsed laser radiation may be the most feasible means to mitigate the threat of collision of a space station or other valuable space assets with orbital debris in the size range of 1–10 cm. Under laser irradiation, part of the debris material is ablated and provides an impulse to the debris particle. Proper direction of the impulse vector either deflects the object trajectory or forces the debris on a trajectory through the upper atmosphere, where it burns up. Most research concentrates on ground-based laser systems but pays little attention to space-based laser systems.There are drawbacks of a ground-based laser system in cleaning space debris. Therefore the placement of a laser system in space is proposed and investigated. Under assumed conditions,the elimination process of space debris is analyzed. Several factors such as laser repetition frequency, relative movement between the laser and debris, and inclination of debris particles which may exercise influence to the elimination effects are discussed. A project of a space-based laser system is proposed according to the numerical results of a computer study. The proposed laser system can eliminate debris of 1–10 cm and succeed in protecting a space station.     

低温动态加载下老化HTPB推进剂强度准则研究

为获得低温动态加载下老化后HTPB推进剂强度准则,开展了低温动态加载下不同热老化时间后HTPB推进剂单轴与准双轴拉伸试验,根据试验结果获得的力学性能参数,基于双剪强度理论构建了推进剂强度极限线及故障包络线。研究发现:随着温度的降低和热老化时间的延长,HTPB推进剂强度极限线范围变大,即推进剂强度增强;随着热老化时间的延长,HTPB推进剂故障包络线缩小,即推进剂抵抗破坏能力逐渐减弱。研究结果可为低温点火条件下战术导弹药柱结构完整性分析提供数据支持。     

Precision analysis of autonomous orbit determination using star sensor for Beidou MEO satellite

This paper focuses on the autonomous orbit determination accuracy of Beidou MEO satellite using the onboard observations of the star sensors and infrared horizon sensor. A polynomial fitting method is proposed to calibrate the periodic error in the observation of the infrared horizon sensor, which will greatly influence the accuracy of autonomous orbit determination. Test results show that the periodic error can be eliminated using the polynomial fitting method. The User Range Error (URE) of Beidou MEO satellite is less than 2?km using the observations of the star sensors and infrared horizon sensor for autonomous orbit determination. The error of the Right Ascension of Ascending Node (RAAN) is less than 60?$\mathrm{\mu }\text{rad}$ and the observations of star sensors can be used as a spatial basis for Beidou MEO navigation constellation.     

基于波长调制谐波信号主峰拟合的气体浓度测量方法

为了提高激光波长调制光谱法(WMS)测量气体浓度的速度和准确度,首次提出了一种通过对吸收光谱谐波信号的主峰进行拟合的气体浓度测量方法。在该方法中,只扫描吸收光谱谐波信号的主峰部分来获得谐波信号(WMS-2f/1f)的峰值点。因为缩减了吸收光谱的扫描范围,所以扫描速度得到了提高。通过对吸收光谱谐波信号(WMS-2f/1f)的主峰部分进行多项式拟合,进一步提高了测量精度。详细讨论了多项式阶数的确认方法,以及拟合数据长度对测量结果的影响。通过测量不同情况下的二氧化碳浓度验证了该方法的有效性。     

面向一体化测试与运管的航天器指令技术研究

现有的航天器测试与运管程序通过word文档采用自然语言的方式进行描述,需要人工录入、集成、整合和校验,既浪费人力、时间,又容易因人为原因出错,不利于测试与运管程序在多用户间的快速交互,且存在安全隐患。针对该问题,借鉴NASA及ESA的PLEXIL、PLUTO、Timeliner-TLX、SCL等航天器指令设计经验,研究了面向航天器地面测试与在轨运管的航天器指令技术,该指令架构具备层次化、模块化、抽象化等高级程序特点,且具备对航天器进行工作过程监测与异常状态处置能力,便于航天器测试与运管程序的人机交互、数字化设计、交换共享与解译执行,可作为国内航天器测试与运管程序一体化设计的技术参考。     

大气层外多拦截器协同跟踪与制导算法

针对大气层外多弹头多诱饵的进攻场景,采用多拦截器全拦截策略,提出了带故障诊断的协同跟踪算法、时间协同中制导律以及消除脱靶量的末制导律。首先,基于最小二乘算法以及误差传播理论,实现了局部信息融合以及测量方程的线性化,简化了非线性跟踪滤波算法的设计;并依托滤波算法,设计了传感器故障诊断算法,以排除其对跟踪效果的影响。然后,基于对拦截器和目标受力的合理简化,给出了相对运动解析解,设计了有限推力下的多拦截器时间协同中制导律以及末制导律,实现对多个目标的同时击毁。仿真结果显示,本文设计的协同跟踪与制导算法,可以有效估计目标的状态并排除故障传感器的干扰,实施对多个目标的时间协同拦截。     

滚控式变质心飞行器动力学特性分析与控制

为明确滚控式变质心飞行器的控制机理,为其工程实践提供相应的理论参考,建立包含滑块运动的滚控式变质心飞行器七自由度完整动力学模型,并分析讨论其运动特性以及动力学系统的特点。其次结合频域分析法对滑块运动与载体姿态运动之间的耦合影响以及动态响应过程进行分析研究,揭示了滚控式飞行器的控制机理。同时针对其通道间的耦合效应以及执行机构参数设置对控制能力的影响分析提出了对飞行器结构设计和控制系统设计的相关要求,为滚控式变质心飞行器的工程实践提供一些理论参考。     

高精度液浮陀螺仪在双轴转台上的标定方法与误差分析

为提高液浮陀螺仪在双轴转台上的标定精度,将双轴转台的误差,陀螺仪的安装误差以及陀螺仪自身的静态误差建立在陀螺仪的标定模型中,在1g重力场中分别建立了16位置和20位置陀螺仪的标定方案。采用误差分离技术与最小二乘法来标定液浮陀螺仪的误差模型系数。与传统的8位置标定方法相比,本文所提出的两种多位置标定方法可以自动规避或补偿双轴转台误差,也可消除不易测量的陀螺仪安装误差对标定结果的影响,以此来提高液浮陀螺仪的标定精度。最后对提出的多位置标定方法进行误差分析,验证了方法的有效性。     

突片形状对气膜冷却效率的影响

气膜冷却广泛应用于航空发动机热端部件的热防护,为了提高气膜冷却效果,设计了3种突片型式,采用实验的方法对其冷却效果进行了对比研究,结果表明：突片的存在强化了气膜冷却效率,使得气膜冷却效率远高于无突片的气膜冷却效率。吹风比对不同突片作用有所不同,存在一最佳吹风比,但该值随着突片的型式变化。突片的堵塞比对气膜冷却效率有很大的影响,3种突片作用下的气膜冷却效率均随堵塞比的增加而增大。梯形突片的冷却效率明显优于三角形突片和椭圆突片。但突片亦增大了气膜孔的流动阻力,降低了流量系数。