Orbit-attitude-vibration coupled dynamics of tethered solar power satellite

A new orbit-attitude-vibration coupled dynamic model of the tethered solar power satellite (Tethered SPS) is established based on absolute nodal coordinate formulation. The Hamilton’s equation of the system is derived by introducing generalized momentum through Legendre transformation. The correctness of the proposed model is verified by an example. The dynamic characteristics of the Tethered SPS are studied using the symplectic Runge-Kutta method. Simulation results show that the orbital radius and the total energy of the system are well preserved. The attitude of the system is unstable when the mass of the bus system is small. However, the attitude stability is dependent on some other parameters of the system, which requires further studies. It is also found that the average tether force/deformation can be roughly estimated by simplifying the solar panel as a particle. The proposed model can be used to study the orbit-attitude-vibration coupled dynamics and control problems.     

调频激光干涉绝对距离测量技术及其信号处理

最最的绝对距离测量方法是非相干飞行时间测量法。随后，在小数重合法的基础上，产生了多波长干波绝对距离测量技术。随着半导体激光器的发展，８０年代又出现了调频干涉绝对距离测量方法，并很快成为一种新的测长技术。本文在综述绝对距离技术及方法的基础上，着重介绍了调频激光干涉绝对距离测量技术的一些新发展及其几种不同的信号处理。     

惯导平台式重力测量技术实现及应用

详细阐述了解析方位双轴惯导平台式重力测量的工作原理,并通过基于方位余弦积的惯导力学编排解决了极区工作问题。在常规平台式重力测量数据处理方法的基础上,针对高动态环境提出了基于Kalman滤波的运动扰动修正方法。在此基础上研制了ZL11-1A型国产惯导平台式海洋重力仪。通过与国外主流重力仪产品海上同船作业比对,结果表明,该型重力仪在高海况下测量精度依然优于1mGal,满足重力测量作业要求。     

406～920nm的绝对光谱响应高准确度标度

描述美国国家标准与技术研究院所建立的４０６￣９２０ｎｍ绝对光谱响应标度，该标度完全是建立在探测器测量基础上的，并可溯源到ＮＩＳＴ高准确度低温辐射计。硅光电二极管光吸收探测器被用来将光功率测量由ＨＡＣＲ传递到进行日常校准的单色仪装置。传递也包括建立硅光电二极管光吸收探测器的量子效率模型，最后给出了这些测量为基础的ＮＩＳＴ现有能力的简单介绍。     

Evaluation of SARAL/AltiKa performance using GNSS/IMU equipped buoy in Sajafi,Imam Hassan and Kangan Ports

Performance of SARAL/AltiKa mission has been evaluated within 2016 altimeter calibration/validation framework in Persian Gulf through three campaigns conducted in the offshore waters of Sajafi, Imam Hassan and Kangan Ports, while the altimeter overflew the passes 470, 111 and 25 on 13 Feb, 7 March and 17 June 2016, respectively. As the preparation, a lightweight buoy was equipped with a GNSS receiver/choke-ring antenna and a MEMS-based IMU to measure independent datasets in the field operations. To obtain accurate sea surface height (SSH) time series, the offset of the onboard antenna from the equilibrium sea level was predetermined through surveying operations as the buoy was deploying in the onshore waters of Kangan Port. Accordingly, the double-difference carrier phase observations have been processed via the Bernese GPS Software v. 5.0 so as to provide the GNSS-derived time series at the comparison points of the calibration campaigns, once the disturbing effects due to the platform tilt and heave have been eliminated. Owing to comparing of the SSH time series and the associating altimetry 1?Hz GDR-T datasets, the calibration/validation of the SARAL/AltiKa has been performed in the both cases of radiometer and ECMWF wet troposphere corrections so as to identify potential land contamination. An agreement of the present findings in comparison with those attained in other international calibrations sites confirms the promising feasibility of Persian Gulf as a new dedicated site for calibration/validation of ongoing and future altimetry missions.     

平台式重力仪航空重力测量数据后处理技术研究

针对航空重力测量对数据后处理的要求,结合平台式重力仪系统的组成与工作原理,在重力异常信号的频域特征基础上,设计出一套有严格频域规范的航空重力数据后处理流程,并对某海域实测数据进行了处理。结果表明,重力异常值内符合精度为12条东西测线达到0.43mGal/140s和0.84mGal/100s,4条南北测线达到0.39mGal/140s和0.79mGal/100s;以同测线GT-2A单次测量结果为标准值统计标准差,12条东西测线为0.72mGal/140s和0.98mGal/100s,4条南北测线为1.41mGal/140s和1.53mGal/100s。结果表明,设计的航空重力测量数据后处理方法可以实现重力异常信号的高精度提取。     

武汉上空钠层与钾层的同时激光雷达观测

简要介绍了(WIPM)双波长共振荧光激光雷达系统和数据处理方法, 并利用其对武汉上空钠层和钾层进行了多天的同时观测, 通过对钠层和钾层的绝对数密度、柱密度以及质心高度的计算, 同时与中纬度其他地区的相关参数进行比较,得出武汉上空钠层的绝对数密度、柱密度以及质心高度与其他中纬度地区十分相近的结论, 并且发现了一个钠层突发和钾层突发不同时出现的现象.      

H∞控制在飞行/推进综合控制系统中的应用

研究了多变量控制技术应用于飞行/推进一体化控制器的设计问题。对于耦合的飞行子系统和推进子系统,建立了飞行/推进综合模型,分析了对模型输出端乘性不确定性和对跟踪误差性能不确定性的飞行/推进综合多变量反馈控制系统转化为混合灵敏度函数整形问题设计的途径,提出了一种按时间加权的误差平方积分(ITAE)准则选择加权灵敏度函数的方法,应用混合加权灵敏度H∞控制器的设计方法对飞行/推进一体化模型进行了设计,并对所求的最优控制器进行了控制系统性能仿真验证。     

简析B757飞机RA故障的关联影响及维护建议

RA系统测量飞机到地面的真实高度。本文介绍了B757飞机RA系统的工作情况,对因RA系统故障引起其他飞机系统工作异常的典型现象进行了分析,介绍了排除故障过程,最后总结了在RA系统实际维护中需要注意的方面,并给出了维护建议。     

航天测绘发展现状与展望

航天测绘是全球基础测绘的主要手段,包括卫星地形测量、卫星重力测量、卫星磁力测量、卫星测高、卫星海洋测量等。航天测绘工程的发展经历了“返回型测绘卫星”工程、“传输型测绘卫星”工程和部分“集成型测绘卫星”工程。首先梳理了国际卫星测量的发展历史和现状,阐述了我国航天测绘各个阶段所发挥的作用,并分析了存在的问题,最后对航天测绘的未来发展提出了思路。