Unbiased acceleration measurements with an electrostatic accelerometer on a rotating platform

The Gravity Advanced Package is an instrument composed of an electrostatic accelerometer called MicroSTAR and a rotating platform called Bias Rejection System. It aims at measuring with no bias the non-gravitational acceleration of a spacecraft. It is envisioned to be embarked on an interplanetary spacecraft as a tool to test the laws of gravitation.     

基于CAD模型的涡轮叶片误差检测系统

涡轮叶片型面误差检测是其制造过程中的重要环节.研究了涡轮叶片型面误差检测关键技术的实现方法,提出了基于测量数据的叶片截面关键参数的自动提取方法以及测量数据与计算机辅助设计(CAD)模型的坐标配准方法,制定了衡量叶片截面轮廓度、倾斜度、弯曲度和扭曲度的评估指标,并基于UG平台开发了叶片型面误差检测系统.应用实例表明,该系统可显著提高叶片的误差检测速度和分析质量.      

基于双投影策略的红外图像配准方法

图像配准是红外图像处理技术的前提,广泛应用于成像制导、光电侦查及工业实时监控等领域。考虑红外图像的实时配准需求,利用对数极坐标图像的尺度、转不变特性,将配准过程从直角坐标空间引入到对数极坐标空间,提出了基于双投影策略的配准算法,将二维空间的配准参数估计转换成两个一雏曲线的空间距离估计。此算法在保证尺度变化及旋转的匹配精度条件下,轴向投影统计大大降低匹配计算量。     

复杂背景下目标模板更新算法研究

在匹配跟踪算法中,模板更新策略是跟踪成败的关键。从复杂背景下的目标跟踪出发,指出固定模板和逐帧模板更新的不足之处,介绍几种性能较好的模板更新策略,并在此基础上提出改进的模板更新方法。同时,为了更好地克服背景光照带来的影响,对普通最小平均绝对差值函数MAD(M in imum Absolute D ifference)方法进行了改进。仿真实验结果表明,该算法能克服诸如烟尘干扰、背景光照变化、地貌起伏等不利因素,能在复杂背景中稳定和精确地进行目标跟踪。     

CBERS-O2热红外波段绝对辐射定标及其不确定性分析

文章介绍了2004年CBERS-O2星热红外波段绝对定标工作，结合野外试验情况和数据处理过程深入进行了不确定性因素分析（包括误差分析），并从亮温反演的角度分析定标精度，进而针对如何提高在轨卫星热红外波段绝对辐射定标的精度，进行了探讨。     

基于ECEF的误差配准与目标跟踪算法

考虑量测噪声和地球曲率对配准的影响,提出了一种基于地心坐标系(ECEF)的扩展卡尔曼滤波(EKF)配准与目标艰踪算法.根据坐标系转换关系,给出误差配准计算公式,建立目标的动态方程,用EKF方程进行估计.仿真结果表明:该法能同时有效估计目标运动状态和传感器配准误差,可用于远距离的传感器配准和目标跟踪.     

被动式车载光电系统的目标定位算法研究

阐述了被动式车载光电系统对目标的定位过程,给出了目标定位模型,并详细介绍了目标从车体坐标系到大地坐标系的坐标变换,实现了被动式车载光电系统对目标定位的坐标解算.     

基于光外差的光电探测器绝对频响测试技术研究

本文介绍了一种基于光外差的光电探测器绝对频响测试方法,通过对绝对频响的数学理论推导,得出光电探测器频响参数的计算公式;设计并研制了一套光外差测试系统,实现波长在1550nm对响应带宽高达67GHz的光电探测器频响测试;通过与高精度光波元件分析仪比对测试,验证了系统的准确性和可靠性,系统最大偏差不大于0.8dB,测量重复...     

Global empirical models of the density peak height and of the equivalent scale height for quiet conditions

Monthly average electron density profiles have been calculated from hourly electron density N(h) recorded in 26 digisonde stations distributed worldwide encompassing the time interval 1998–2006. The ionospheric electron density peak height of the F2 region, hmF2, and the effective scale height at the hmF2, Hm, deduced from average profiles have been analyzed to obtain the quiet-time behavior and have been analytically modeled by the spherical harmonic analysis (SH) technique using the modip latitude as the coordinate of the reference system. The coefficients of the SH models of hmF2 and Hm are bounded to the solar activity, and the temporal and seasonal variations are considered by Fourier expansion of the coefficients. The SH models provide a tool to predict hmF2 and Hm located anywhere in the range of latitudes between of 70°N and 70°S and at any time. The SH analytical model for hmF2 improves the fit to the observations by 10% in average compared to the IRI prediction, and it might improve the IRI prediction of hmF2 by more than 30% at high and low latitudes. The analytical model for Hm predicts the quiet behavior of the effective scale height with accuracy better than 15% in average which enables to obtain a good estimation of vertical profiles. These results could be useful to estimate information for the topside profile formulation.     

月球着陆探测器发动机推力线测量及标定

月球着陆探测器发动机推力线测量及标定是发动机装配与调整的关键环节.通过创建精测镜坐标系,实现发动机在对接面坐标系中的推力线平行量与偏斜的转换,得到热试车后标定推力线的方法.通过发动机热试车后数据分析,推力线测量及标定方法满足技术条件要求.