遥感图象的半正交小波变换及数据压缩

本文利用Ｂ样函数构造半正交小波基，并利用对偶系设计了具有严格线性相位和精确重建特性的ＦＩＲ滤波器组，将其应用于遥感图象的数据压缩，取得了良好的成果     

Uncontrollable Rotational Motion of the Mir Orbital Station

The results of determining the rotational motion of the Mir orbital station are presented for four long segments of its unmanned uncontrolled flight in 1999–2000. The determination was carried out using the data of onboard measurements of the Earth's magnetic field intensity. These data, taken for a time interval of several hours, were jointly processed by the least squares method with the help of integration of the equations of station motion relative to its center of mass. As a result of this processing, the initial conditions of motion and the parameters of the mathematical model used were evaluated. The technique of processing is verified using the telemetry data on angular velocity of the station and its attitude parameters. Two types of motion were applied on the investigated segments. One of them (three segments) presents a rotation around the axis of the minimum moment of inertia. This axis executes small oscillations with respect to a normal to the orbit plane. Such a motion was used for the first time on domestic manned orbital complexes. The second type of motion begins with a biaxial rotation which, in a few weeks, goes over into a motion very similar to the rotation around the normal to the orbit plane, but around the axis of the maximum moment of inertia.     

遥感相机自动调焦的研究

本文介绍一种遥感相机自动调焦技术的实验研究结果，实验表明，差分式对比传递函数法调焦，具有调焦精度高，调焦速度快，受像移影响不明显，适应性好等优点。     

基于扩展卡尔曼滤波的GPS多径抑制技术

本文研究GPS系统中多径误差抑制技术。利用小范围多天线系统中多径对各天线之间伪距测量值影响的相关性，采用扩展卡尔曼滤波技术得到多径信号各参数，从接收信号中消去多径信号，以抑制多径信号影响。文章推导了多径信号对码环误差影响的闭合表达式，建立了采用当前统计模型的状态方程和观测方程。仿真表明该方法具备良好的抑制效果。     

一种不需要源个数估计的MUSIC算法

MUSIC方法是阵列高分辨测向子空间方法中的经典算法,该算法的一个缺点就是需要进行源个数估计,源个数估计不正确将会导致虚假峰和漏峰.提出一种不需要源个数估计的MUSIC方法,该方法首先将快拍分组,对每一组的自相关进行特征值分解,以最小特征值对应的特征向量作为噪声向量,然后将搜索向量在每一组噪声向量上的投影构成新的矩阵,DOA对应的新矩阵将缺秩,根据新矩阵的缺秩程度来估计DOA.仿真结果证明了该方法的有效性.     

丁羟推进剂粘接体系中的组分迁移

用浸泡增重法研究了衬层、绝热层对DOS和T27的吸收能力,用气相色谱仪研究了HTPB推进剂/HTPB衬层/EPDM绝热层粘接体系中DOS、T27和GFP的迁移。结果表明,HTPB衬层和EPDM绝热层对DOS和T27的吸收能力很强;粘合剂的极性增大或交联密度升高,衬层对DOS、T27的吸收能力下降,但粘合剂的极性增大,对衬层与HTPB推进剂的界面粘接性能不利;在HTPB推进剂/HTPB衬层/EPDM绝热层粘接体系中,DOS、T27或GFP的迁移平衡浓度为粘合剂相的平衡浓度。     

长征系列运载火箭航天发射总次数突破两位数

长征系列火箭为中国航天运载火箭的统称。文章讨论了该系列火箭的组成和航天发射情况。     

Low-Frequency Microaccelerations onboard the Foton-11 Satellite

We analyze the microacceleration measurements carried out onboard the Foton-11 satellite with the three-component accelerometer BETA. The microaccelerations were recorded virtually throughout the entire orbital flight of the Foton-11 satellite. The data obtained were analyzed in the following way. First they were used to determine the actual rotational motion of the satellite for several arbitrarily selected time intervals 4 h long. This problem was solved by constructing the approximation of the microacceleretation low-frequency component (previously determined from the data) by its calculated analog computed along the solutions to differential equations of rotational motion of the satellite. The approximation was made by the least squares method. As a result, those mathematical model parameters and the solutions to equations of motion were found that gave the best consistency of the microacceleretation low-frequency component and its calculated analog. Then the spectral analysis of the low-frequency component and its calculated analog was made. It was shown that, although basic harmonics of these functions coincided sufficiently well, some harmonics of the low-frequency component failed to be interpreted in terms of the satellite's rotational motion.     

复合固体推进剂燃气烟雾对激光透射的影响

建立了一套测定固体推进剂燃气烟雾对激光衰减的装置,研究了固体推进剂燃气对激光衰减的规律,由实验结果和理论分析得出,燃气烟雾对激光和可见光的透射率较好;能量较高的丁羟推进剂无烟化的最佳配方是Al粉含量应小于8%,硝胺(HR)的含量应大于30%。     

GPS／惯性组合导航系统导航性能的仿真与分析

本文从卡尔曼滤波的基本原理和几何精度因子GDOP的物理意义出发,并结合实例的仿真计算结果,讨论GPS/惯性组合导航系统的定位和测速精度。结果表明:由于位置和速度的双重组合,且由于卡尔曼滤波具有利用以前所有测量值的能力,以及综合利用GPS和惯导信息的能力,所以组合系统的精度虽仍与GDOP有关,但却高于单独利用GPS接收机点解法得到的定位和测速精度,其中定位精度的提高更为显著。