Multi-scale simulation model of air system based on cross-dimensional data transmission method

The Secondary Air System (SAS) plays an important role in the safe operation and performance of aeroengines. The traditional 1D-3D coupling method loses information when used for secondary air systems, which affects the calculation accuracy. In this paper, a Cross-dimensional Data Transmission method (CDT) from 3D to 1D is proposed by introducing flow field uniformity into the data transmission. First, a uniformity index was established to quantify the flow field parameter distribution characteristics, and a uniformity index prediction model based on the locally weighted regression method (Lowess) was established to quickly obtain the flow field information. Then, an information selection criterion in 3D to 1D data transmission was established based on the Spearman rank correlation coefficient between the uniformity index and the accuracy of coupling calculation, and the calculation method was automatically determined according to the established criterion. Finally, a modified function was obtained by fitting the ratio of the 3D mass-average parameters to the analytical solution, which are then used to modify the selected parameters at the 1D-3D interface. Taking a typical disk cavity air system as an example, the results show that the calculation accuracy of the CDT method is greatly improved by a relative 53.88% compared with the traditional 1D-3D coupling method. Furthermore, the CDT method achieves a speedup of 2 to 3 orders of magnitude compared to the 3D calculation.     

大气环境监测卫星在生态环境行业应用分析

大气环境监测卫星是首颗生态环境领域大气环境监测专用卫星。卫星搭载了5台有效载荷，可实现CO2主动激光探测和大气细颗粒物的主被动结合探测，以及对气态污染物、云和气溶胶、水环境、自然生态等要素大范围、全天时综合监测，为生态环境遥感监管提供重要的数据支撑。本文从卫星载荷特点及数据获取能力出发，分析了其在生态环境行业的应用能力，并从大气环境、水环境和生态环境监测3个方面，结合在轨测试情况对卫星的应用能力进行详细阐述，可为开展大气环境监测卫星遥感应用提供参考。     

城市环境下北斗B-CNAV1电文RS-LDPC 级联编码方法

针对城市环境下卫星导航系统用户接收终端对电文编译码算法的低复杂度和抗衰落性能需求，以北斗导航系统B-CNAV1电文为改进对象提出了一种外码采用RS码、内码采用二进制LDPC码的电文级联编码方法。通过RS码提高电文对抗突发错误的能力，同时利用二进制LDPC码保证电文对抗随机错误的能力。采用LMS信道对城市接收环境建模，仿真结果验证了本文提出的RS-LDPC级联码与B-CNAV1电文64进制LDPC码具有相近的性能，同时大幅降低了算法复杂度，较好地实现了电文纠错性能和实现复杂度的平衡，提供了一种适用于城市环境的高性能、低复杂度电文编码方法。     

Transition control of a tail-sitter unmanned aerial vehicle with L1 neural network adaptive control

The main task of this work is to design a control system for a small tail-sitter Unmanned Aerial Vehicle(UAV) during the transition process. Although reasonable control performance can be obtained through a well-tuned single PID or cascade PID control architecture under nominal conditions, large or fast time-varying disturbances and a wide range of changes in the equilibrium point bring nonlinear characteristics to the transition control during the transition process, which leads to control prec...     

耐高温复合材料在火星探测器着陆器减速伞筒盖结构上的应用

针对火星探测器着陆巡视器减速伞筒盖结构在轨运行耐温度交变、辐照等空间环境和再入过程耐温度冲击性能需求,重点开展了筒盖复合材料耐温匹配性、力学性能、耐空间环境性能以及制件成型工艺研究。结果表明,选用J-168-1胶黏剂、J-245胶黏剂及T300/QY8911复合材料制备的试件通过各项性能试验考核,均能满足筒盖结构的设计指标要求。筒盖产品力学性能稳定,成型工艺可行性良好,最高瞬时使用温度可达200℃,经历空间环境模拟后力学性能保持率均在80%以上,耐高温、耐空间环境性良好。产品已成功装星发射,并在着陆巡视器落火阶段成功弹出分离,圆满完成使命。     

大气环境监测卫星紫外高光谱大气成分探测仪技术发展及应用

大气环境监测卫星是我国民用空间基础设施中长期发展规划中的科研卫星。本文介绍了搭载于该卫星的新一代紫外高光谱大气成分探测仪，通过发展紫外高光谱大幅宽高分辨超光谱成像技术，使紫外谱段高光谱大气观测空间分辨率提升一倍，大幅提升气态污染物监测能力，取得良好的应用效果。     

基于萤火一号技术的自主火星探测器方案

提出了基于萤火一号（YH-1）火星探测器技术的自主火星探测器方案,可携带多种有效载荷在准太阳同步圆轨道上对火星进行科学探测。该方案具有可实现性强、成本低、研制周期短等特点,并能满足火星探测后续工程中的环绕器设计要求,利于我国火星探测的长远发展。利用长征三号乙运载火箭,在西昌卫星发射中心就可实现2013/2016年的我国自主火星探测。     

Hardware qualification for scientific ballooning missions

The European Stratospheric Balloon Observatory (ESBO) initiative aims at simplifying the access to stratospheric balloon missions. We plan to provide platforms and support with instrument design in order to support scientists. During the design process, the inevitable question of qualification for the harsh flight conditions arises. Unfortunately, there is no existing standard for qualification of stratospheric ballooning hardware. Thus, we developed a qualification procedure for use within ESBO and similar projects.In this paper, we present our analysis of the environmental conditions in the stratosphere. While conditions at typical balloon float altitudes are similar to the space environment, there are also some relevant differences. For example, the thermal environment is dominated by radiation and thermal conduction, but the remaining atmosphere still supports a certain amount of convection. The remaining atmospheric pressure in the stratosphere also leads to reduced arcing distances. Vibrational loads are far less than for space missions, but quasi-static or shock loads may occur. The criticality of radiation increases with mission duration.Based on the environmental conditions, we present the qualification procedures for ESBO, which are based on the European Cooperation for Space Standardization (ECSS) standards for space systems. Overtesting against too high requirements leads to overengineering, driving mission cost and mitigating the advantages of balloons over space missions. Therefore, we modified the ECSS standards to fit typical scientific ballooning missions over several days at altitudes up to 40 km. Furthermore, we analyzed design rules for space systems with regard to their relevance for scientific ballooning, including material and component selection. We present the experience from the hardware qualification process for the ESBO prototype STUDIO (Stratospheric UV Demonstrator of an Imaging Observatory). Even though boundary conditions are different for each individual mission, we aimed for a broader approach: We investigated more general requirements for scientific ballooning missions to support future flights.     

Integration of Landsat-8 and Sentinel-1 dataset to extract geological lineaments in complex formations of Tepal mountain area,Shahrood, north Iran

Recently, the detection and extraction of geological lineaments have become an essential analytical technique to find relationships between the characteristics and occurrence of hydrogeology, and tectonic studies. The use of remote sensing, with the progressive development of image enhancement techniques, provides an opportunity to produce more reliable and comprehensive lineament maps. In this paper, semi-automatic approach based on Landsat 8 and Sentinel 1 radar data is proposed for lineaments extraction and validation. The combined method of linear filtering and automatic line module ensures a high degree of accuracy resulting in a lineament map. Based on identified lineaments, Sentinel1 is more capable of detecting edges than Landsat8, but the primary orientation lineaments extracted from Landsat8 and Sentinel1 were different. So, by combining band6 of Landsat8, and VV and VH polarization of Sentinel1, the area lineaments were extracted with high accuracy. Rose diagram showed the extracted lineaments' orientation is in good compliance with the region's existing faults. Also, the formations' lineament length density has good consistent with the density of the faults in the geological map.