某型飞机进气道对发动机性能和台架点的影响

对某双转子涡喷发动机装与不装飞机进气道进行了台架对比实验，测量了发动机的状态参数和进口压力场。根据实验结果，分析了飞机进气道引起发动机的进气畸变和对发动机台架性能及台架点的影响，并讨论了造成变化的原因。实验结果对于正确使用该类型双转子涡喷发动机具有重要的现实意义。     

螺旋桨气流斜吹对飞行影响的分析

简要论述了螺旋桨气流斜吹的理论，重点分析了螺旋桨气流斜吹对飞行的影响。最后结论飞行实例，进一步分析了螺旋桨气流斜吹给飞行带来的偏差。结果表明，飞机在大迎角或大侧滑角下飞行时，螺旋桨气流斜吹使同产生了附加的拉力力矩和侧力力矩，对飞机俯仰和方向平衡有明显影响，给飞行员的操纵带来不利影响。所以，在分析螺旋桨副作用对飞行的影响时，必须考虑螺旋桨气流斜吹的作用。     

Identification of uncatalogued LEO space objects by a ground-based EO array

A ground-based electro-optical (EO) array, deployed at the Jilin Space Tracking Base of Changchun Observatory, China, has been in operation since April 2017. The array has 8 small telescopes, each has an aperture of 15 cm and a field of view of 14° × 14°. On average, the array can collect angles data over 3–4 thousand Very Short Arcs (VSAs) of Low Earth Orbit (LEO) space objects each night. Correlation of the VSA angles data with the NORAD catalogue objects results in about 85% of all the VSAs being correlated to NORAD objects. The remaining 15% VSAs angles data could be supposed from uncatalogued objects. The Initial Orbit Determination (IOD) solutions of the VSAs with the range-search method and the association results of the IODs with the geometrical method are presented. The mean IOD success rate is about 91% and the True Positive (TP) rate is more than 86%. In addition, the classical Gauss, Laplace, Gooding and Double-r angles-only IOD methods are applied to process VSA angles data and their performance is assessed. The CBTA method is used to associate the IOD tracks and compared with the geometrical method. A set of procedures for identifying the uncatalogued objects based on the VSA angles data is designed. Processing of the VSA angles data from Aug 4 to Sep 30, 2017 reveals there are possibly 415 uncatalogued LEO objects.     

Hyperspectral imaging—An advanced instrument concept for the EnMAP mission (Environmental Mapping and Analysis Programme)

In the upcoming generation of satellite sensors, hyperspectral instruments will play a significant role. This payload type is considered world-wide within different future planning.Our team has now successfully finalized the Phase B study for the advanced hyperspectral mission EnMAP (Environmental Mapping and Analysis Programme), Germans next optical satellite being scheduled for launch in 2012. GFZ in Potsdam has the scientific lead on EnMAP, Kayser-Threde in Munich is the industrial prime.The EnMAP instrument provides over 240 continuous spectral bands in the wavelength range between 420 and 2450 nm with a ground resolution of 30 m×30 m. Thus, the broad science and application community can draw from an extensive and highly resolved pool of information supporting the modeling and optimization process on their results. The performance of the hyperspectral instrument allows for a detailed monitoring, characterization and parameter extraction of rock/soil targets, vegetation, and inland and coastal waters on a global scale supporting a wide variety of applications in agriculture, forestry, water management and geology. The operation of an airborne system (ARES) as an element in the HGF hyperspectral network and the ongoing evolution concerning data handling and extraction procedures, will support the later inclusion process of EnMAP into the growing scientist and user communities.     

Validation of an active transponder for KOMPSAT-5 SAR image calibration

This paper describes the development and validation of a transportable active transponder designed for the image calibration of Korea Multi-Purpose Satellite-5 (KOMPSAT-5) with a synthetic aperture radar (SAR). Ground targets are essential in SAR image calibration. The environment for the deployment of ground targets for SAR image calibration should provide uniformity and minimum interference. The Amazon or deserts are regarded as desirable environments. However, such environments for SAR image calibration are difficult to find in Korea. Thus, it will be advantageous to have an active transponder whose performance will not be severely limited by the absence of such uniform environment. We have therefore developed an active transponder which has an adjustable internal delay and into which the orbit data of an arbitrary satellite can be loaded. The stored obit data with the aid of an internal global positioning system (GPS) receiver and gyroscope enables the active transponder to point to a selected satellite. In addition, a virtual deployment of the active transponder is possible due to its adjustable internal delay. Thus, the developed active transponder can be deployed at any place without environmental constraint. The performance of the developed active transponder is validated using the satellite TerraSAR-X, which is already in operation. The test results show that the active transponder is successfully compliant with the requirements for KOMPSAT-5 image calibration.     

Ce元素含量和铸造方法对AZ91-2Ca合金微观组织与力学性能的影响

在AZ91-2Ca合金中分别添加0.5%,1.0%和1.5%的Ce元素,采用重力铸造制备合金并结合组织性能分析,优化出最佳Ce含量。对最佳成分合金进行不同浇铸温度的压力铸造,对比研究Ce含量和铸造方法对AZ91-2Ca合金微观组织和力学性能的影响。研究表明:在重力铸造条件下,随Ce含量提高,合金组织明显细化,强化相Al_4Ce含量逐渐增加,进而改善了力学性能。当Ce含量为1.5%时,强度和延伸率均达到最大值。在压力铸造条件下,随浇铸温度由640℃提高到700℃,压铸AZ91-2Ca-1.5Ce合金微观组织不断细化,Al_4Ce相分布均匀,700℃压铸合金综合性能最高,抗拉强度、屈服强度和延伸率分别为191 MPa,157 MPa和1.7%。相比于重力铸造,压力铸造可进一步提高该合金的强度,从而为解决高Ca阻燃镁合金阻燃效果和力学性能之间的矛盾提供了新思路,促进了该合金在航空航天和汽车领域的应用。     

Accurate orbit predictions for debris orbit manoeuvre using ground-based lasers

Orbit manoeuvre of low Earth orbiting (LEO) debris using ground-based lasers has been proposed as a cost-effective means to avoid debris collisions. This requires the orbit of the debris object to be determined and predicted accurately so that the laser beam can be locked on the debris without the loss of valuable laser operation time. This paper presents the method and results of a short-term accurate LEO (<900 km in altitude) debris orbit prediction study using sparse laser ranging data collected by the EOS Space Debris Tracking System (SDTS). A main development is the estimation of the ballistic coefficients of the LEO objects from their archived long-term two line elements (TLE). When an object is laser tracked for two passes over about 24 h, orbit prediction (OP) accuracy of 10–20 arc seconds for the next 24–48 h can be achieved – the accuracy required for laser debris manoeuvre. The improvements in debris OP accuracy are significant in other applications such as debris conjunction analyses and the realisation of daytime debris laser tracking.     

Equivalent ARMA model representation for RLG random errors

It is shown that a mixture of random noises can be represented by a single equivalent ARMA (autoregressive moving average) model that is simple to implement. We applied the scheme to model RLG (ring laser gyroscope) random errors. An identification result from real test data confirms the validity of this approach     

仿真一体化技术在飞行管理系统中的应用

本文介绍新近研制的FMS仿真一体化软件的基本结构及其功能,并以飞行管理系统侧向制导为例,探索了仿真一体化方法的实现及应用问题。实践表明,利用仿真一体化方法来研究飞行管理系统是很灵活和方便的,并且更接近于实际系统的工作情况。     

关于压力容器法兰标准若干问题的建议

本文对我国现行压力容器法兰标准的五个问题提出建议性处理意见,供讨论。