电缆网阻值测试仪的设计与实现

随着单片机技术的发展及其在测试领域的广泛应用,早期采用的人工作业对电缆网性能测定的方法已经不再适用。本文介绍了一种基于单片机技术的电缆网阻值测试仪。从电缆网阻值测试仪的功能与设计要求出发,阐述了总体设计方案,说明了该套设备的工作原理,描述了系统的硬件实施和软件设计,并对整套设备进行了实验验证。结果表明：设备满足了用户要求,提高了测试效率。     

A comprehensive numerical model investigating the thermal-dynamic performance of scientific balloon

The increase of balloon applications makes it necessary for a comprehensive understanding of the thermal and dynamic performance of scientific balloons. This paper proposed a novel numerical model to investigate the thermal and dynamic characteristics of scientific balloon in both ascending and floating conditions. The novel model consists of a dynamic model and thermal model, the dynamic model was solved numerically by a computer program developed with Matlab/Simulink to calculate the velocity and trajectory, the thermal model was solved by the Fluent program to find out the balloon film temperature distribution and inner Helium gas velocity and temperature field. These models were verified by comparing the numerical results with experimental data. Then the thermal and dynamic behavior of a scientific balloon in a real environment were simulated and discussed in details.     

On the observability of Mars entry navigation using radiometric measurements

A thorough observability analysis of the Mars entry navigation using radiometric measurements from ground based beacons is performed. This analysis involves the evaluation of the Fisher information matrix which is derived from the maximum likelihood estimation. A series of navigation cases with multiple beacons are investigated, and both range and range-rate measurements are considered. The determinant of Fisher information matrix is used to quantify the observability of navigation system, while the trace of Fisher information matrix is used to determine the lower-bound of estimation errors. For one and two beacon cases, the navigation system is unobservable. However, the eigenvectors of Fisher information matrix give the observable and unobservable component. When three or more beacon measurements are employed, the states of entry vehicle become observable. Some valuable analytic conclusions on the relationship between the geometric configuration of beacons and observability are obtained consequently. Finally, simulation results from two navigation examples indicate that our effort is useful for understanding and assessing the observability of the Mars entry navigation using radiometric measurements.     

Scientific objectives and payloads of Tianwen-1, China’s first Mars exploration mission

This paper describes the scientific objectives and payloads of Tianwen-1, China’s first exploration mission to Mars. An orbiter, carrying a lander and a rover, lifted-off in July 2020 for a journey to Mars where it should arrive in February 2021. A suite of 13 scientific payloads, for in-situ and remote sensing, autonomously commanded by integrated payload controllers and mounted on the orbiter and the rover will study the magnetosphere and ionosphere of Mars and the relation with the solar wind, the atmosphere, surface and subsurface of the planet, looking at the topography, composition and structure and in particular for subsurface ice. The mission will also investigate Mars climate history. It is expected that Tianwen-1 will contribute significantly to advance our scientific knowledge of Mars.     

混合电路仿真的新方法

实际的数字系统均由数字电路和模拟电路组成，分析数字电路的方法与分析模拟电路的方法是完全不同的。本文将给出一种仿真混合电路的新方法及相应的模拟器。ＭＣ－ＳＩＭ的主要原理如下：首先把被模拟电路划分成许多模拟模块和数字模块，模拟（数字）模块只有模拟（数字）输出；任一模拟输入均视一系列发生在离散的时间点上的事件；模拟模块在达到之前与数字模块一样参加排队；不论是数字模块还是模拟模块都在统一的时间轮下进行计算     

“田口式质量损失函数”的应用

利用质量损失函数，讨论产品质量波动给社会带来的损失，并将其应用于企业生产中，使企业改进了产品质量，提高了效益。这说明，在质量管理中，解决“质量”问题时，必须把改进质量的焦点移向产品的设计和开发阶段，即从以往的“产品出厂后的检查或加工过程中的控制”的质量观，推向“产品设计阶段的优化”，从“下游管理”转向“上游管理”，使产品设计或加工过程设计成为保证产品质量优化的关键。     

空空导弹模型参考变结构飞控系统设计

应用模型参考变结构最终滑态控制方案设计了某型中距拦射空空导弹变结构自动驾驶仪。理论分析证明，该方案有效地改善了系统的动态品质，并且对系统的不确定性因素具有较强的鲁棒性，数字仿真结果表明，所设计的变结构自动驾驶仪具有良好的指令跟踪性能，对于系统参数的变化不敏感。     

双臂机器人协调动力学及其优化

通过引入“虚铰”概念，将双臂机器人协调动力学问题统一归结为约束多体系统的动力学问题。利用子系统牛顿－欧拉递推法获得的单臂机器人的动力学方程以及静力传递与速度传递间的对偶关系，很方便地导出了双臂机器人的动力学方程与回路约束方程，回路约束方程的建立无需增加额外的计算。此外，文中还对双臂机器人协调动力学的求解及其优化问题进行了讨论，最后以一搬运双臂机器人为例进行了动力学的计算机辅助优化，获得了令人满意的结果。文中所得结论对双臂机器人的设计与控制均具有一定的参考价值。     

中值滤波的快速算法

提出了一种中滤波的快速算法，充分地利用相邻两次中值滤波窗口内数据的相关性。在运算过程中，通过对有序序列快速的对半查代和内插操作重构有序序列，从而得到各中值。本算法很大地提高了运算效率，计算机模拟表明该方法是有效的。     

弹载SAR信号处理及其硬件实现

针对空对舰导弹的情况，研究一种将合成孔径雷达技术用于弹戴制导雷达的方案，以提高其横向分辩率，实现对舰船目标的成象。弹载ＳＡＲ采用的一是一种聚束照射成象模式，通过站偿，可以转化为转台成象。