隐身技术对飞机作战效能影响研究

采用较完善的飞机，火控和武器系统模型以及详实的数据，应用分布式仿真原理的可视化仿真平台，进行了隐身飞机对实规第三代战斗机作战效能的仿真研究以及常规第三代战斗机采用隐身技术降低RCS指标后对作战效能的影响研究，仿真结果表明，未来的隐身飞机较常规第三代战斗机在 超视距作战中具有相当大的优势，第三代战斗机采用隐身技术降低RCS指标后可以提高其超视距作战能力。     

Integrated Entry Guidance for Reusable Launch Vehicle

A method for the implementation of integrated three-degree-of-freedom constrained entry guidance for reusable launch vehicle is presented. Given any feasible entry conditions, terminal area energy management interface conditions, and the reference trajectory generated onboard then, the method can generate a longitudinal guidance profile rapidly, featuring linear quadratic regular method and a proportional-integral-derivative tracking law with time-varying gains, which satisfies all the entry corridor constraints and meets the requirements with high precision. Afterwards, by utilizing special features of crossrange parameter, establishing bank-reversal corridor, and determining bank-reversals according to dynamically adjusted method, the algorithm enables the lateral entry guidance system to fly a wide range of missions and provides reliable and good performance in the presence of significant aerodynamic modeling uncertainty. Fast trajectory guidance profiles and simulations with a reusable launch vehicle model for various missions and aerodynamic uncertain-ties are presented to demonstrate the capacity and reliability of this method.     

高速摄影技术在三维位移测量中的应用

提出了用高速摄影技术准确测量三维位移的新方法。该方法利用一只测量基准，使两台高速摄影机的拍摄方向相互垂直或成一定角度，并使所有的测点都在拍摄范围内。从摄影胶片上点的运动求出测点的三维坐标。实验结果表明：该方法的测量精度较高，适用于测量大梦位移的时间历程。     

Effects of eccentricity of the reference orbit on multi-tethered satellite formations

The paper discusses the relevance of eccentric reference orbits on the dynamics of a tethered formation, when a massive cable model is included in the analysis of a multi-tethered satellite formation. The formations examined in this study are hub-and-spoke (HAS) and closed-hub-and-spoke (CHAS) configurations for in-plane and Earth-facing spin planes. Stability of the formations is studied by means of numerical simulation, together with the evaluation of the effects of eccentricity on tether elongation, agents relative position, and formation orientation and shape.     

一个高性能单反射面紧缩场

介绍了一个单反射面紧缩场,其反射面实体由多块面板拼装而成.单块面板成形基于"点阵钉模、真空负压、金属蜂窝"精密成形工艺,平均精度达到25μm(rms),拼装后总体形面精度达到40μm(rms).通过优化电气布局、边缘设计和馈源设计,该紧缩场具有优良电性能.给出了该紧缩场在39GHz时电性能实测曲线.      

一种超高分辨率机载聚束SAR两维自聚焦算法

受运动参数测量误差和大气扰动等因素影响,合成孔径雷达(SAR)图像通常会发生散焦,利用自聚焦对散焦的SAR图像进行后处理是一种有效的重聚焦手段。传统的自聚焦算法都只是针对方位一维相位误差的估计和补偿。随着成像分辨率的提高,自聚焦时残留距离徙动的校正成为SAR成像面临的一个新挑战。本文推导得到了极坐标格式算法处理后残留距离徙动和方位相位误差的解析表达式,分析了两者之间的内在关系,并利用该关系,提出了一种能够同时进行残留距离徙动和方位相位误差补偿的两维自聚焦算法。实测数据处理结果表明,在残留距离徙动效应不可忽略的条件下,该方法能够极大地改善原有自聚焦算法的聚焦性能。     

Deramp range migration processing for space-borne spotlight synthetic aperture radar

The deramp range migration algorithm (DRMA) for space-borne spotlight synthetic aperture radar (SAR) is presented, which is based on the two-step algorithm and range migration algorithm. The presented algorithm combines the advantages of SPECAN algorithm and range migration algorithm. Firstly, the presented algorithm performs a bulk azimuth raw data compression to achieve a pixel spacing no larger than the expected azimuth resolution of the fully focused image. Therefore, the azimuth spectral folding phenomenon is overcome. Secondly, the residual and precise focusing of the synthetic aperture radar data is achieved by applying the range migration algorithm. The space-borne SAR focusing parameters’ computation is also described in the paper. At the end of this paper, results are presented which confirm the validity of the presented algorithm.     

发动机零部件稳态应力计算的状态函数法

An opti mization process is used to redesign blades of a high-pressure compressor.An artificial neural network (ANN) method is coupled to Navier-Stokes solvers and is applied to three different redesigns.A newrotor blade of a transonic compressor is designed by modifying thick, stacking line andinlet angle using a 3Dapproach, with a significant efficiencyi mprovement at the design point.The off-design behavior of this new compressor is also checked afterwards, which shows that the whole performance of the inlet stage is improved over a wide range of mass flow.The losses are reduced, proving the good performance of the opti mum.The whole results indicate that the opti mization method can find i mproved design and can be integrated in a design procedure.      

海南地区强磁暴期间强区域扩展F事件研究

利用2004年海南DPS-4数字测高仪观测到的强区域扩展F(SSF)数据,分析研究了5个强磁暴(Dst＜-100 nT)事件期间海南SSF的响应特征.结果发现,在海南地区,5个强磁暴事件中有3个磁暴Dst最小值位于2200-0200 LT之间,在磁暴主相及恢复相初期均出现了SSF现象,这种触发作用可能源于磁层直接渗透电场的作用,而另两个磁暴Dst最小值均发生在白天,一个SSF现象出现在磁暴的恢复相晚间,另一个SSF现象出现在超强磁暴的初相晚间,后者可能由该超强磁暴的急始造成的直接渗透电场所触发;5个强磁暴期间发生的SSF现象或者仅出现在午夜前,或者先出现在午夜前并持续到午夜后;同时,还就这些观测结果与Dabas等人有关磁暴对ESF影响的结论进行对比和讨论.      

一种圆极化天线极化特性的幅度精测方法

文章介绍了一种圆极化天线极化特性的测试方法。该方法仅利用幅度测量得到圆极化天线极化椭圆相关数据,就可获得圆极化天线主极化、交叉极化、圆极化轴比等全部信息。该方法简单可行且可获得精确的极化特性测试结果。应用该测试方法,结合使用时域硬件门测试技术,在紧缩场成功实现了星载大型UHF螺旋天线的测试,获得了理想的测试结果,使得大型紧缩场双反射面系统在UHF频段的应用成为可能。