最大熵谱估计及其在电子战中的应用

介绍了最大熵谱估计的原理，与快速傅里叶变换相比，它有低的旁瓣和高的分辩力。同时讨论了在电子战方面的应用。     

一种激光多普勒测速仪辅助捷联惯导在线标定方法

针对惯组长期贮存过程中陀螺和加速度计零偏漂移的问题, 提出了一种利 用激光多普勒测速仪辅助捷联惯导的在线标定方案。给出了包括激光多普勒测速仪安装 误差角和惯组安装误差角的航位推算误差方程。基于航位推算误差方程建立了闭环卡尔 曼滤波器,对惯组零偏误差、激光多普勒测速仪安装误差角和惯组方位安装误差角进行 在线标定。仿真结果表明,加速后激光多普勒测速仪安装误差角和惯组方位安装误差角 得到估计;方位角改变后惯组零偏误差也得到估计。该方法允许跑车前不用综合标定, 直接装订前一次的安装角参数,缩短了准备时间。     

载人航天任务测速雷达双通道数据融合方法

针对载人航天任务中高精度测速雷达在实时多主站外弹道融合时仅能采用单通道应答数据参与处理,获得的弹道精度较差,且测速雷达数据利用率仅有50%的问题,提出利用多普勒效应和应答机遥测参数两种方法对测速雷达跟踪模式进行实时准确识别,首先得到测速雷达双通道的应答数据,然后通过改进的非线性滤波+机动模型算法对火箭上升段外弹道测量数据进行高精度融合。最后采用仿真数据对传统方法和新方法的外弹道融合精度进行了比对分析。该方法的应用可有效提高测速雷达测元利用率和载人航天任务火箭上升段外弹道精度,具有较强的工程应用价值。     

一种基于协方差矩阵重构的相干信源DOA估计算法

针对空间相干信源的波达方向估计问题,提出了一种基于协方差矩阵重构的TSVD-ESPRIT算法。它利用包含所有信源信息的特征向量构造Toeplitz协方差矩阵,避免了阵列有效孔径的损失,分辨率高且稳定性好;并且利用ESPRIT算法代替MUSIC算法进行DOA估计,避免了谱峰搜索,大大降低了计算量。数据仿真和分析证明了该算法的正确性和有效性。     

Evaluation of Characteristics of Non-Metallic Inclusions in P/M Ni-Base Superalloy by Automatic Image Analysis

Non-metallic inclusions,especially the large ones,within P/M Ni-base superalloy have a major influence on fatigue characteristics,but are not directly measurable by routine inspection.In this paper,a method,automatic image analysis,is proposed for estimation of the content,size and amount of non-metallic inclusions in superalloy.The methodology for the practical application of this method is described and the factors affecting the precision of the estimation are discussed.In the experiment,the characteristics of the non-metallic inclusions in Ni-base P/M superalloy are analyzed.     

Navigation Accuracy Category-Position Models and Estimate Position Uncertainty Calculations for TIS-B System

Navigation accuracy category-position (NACp) is an important parameter for system accuracy of traffic information service-broadcast (TIS-B), which is determined by estimate position uncertainty (EPU). Centered about the problems that the existing EPU calculation based on noise measurement is low in accuracy and unfit for describing uncorrected biases in target reports, this article analyses the traditional NACp model, and uses the least square estimation (LSE) in EPU calculation. Furthermore, it proposes an extended NACp model, which considers both noise and biases and acquires EPU estimation with the help of approximate multiplex Taylor expression. Analysis and simulation show that the proposed method not only leads to significant improvement of the accuracy of EPU calculation, but is fit for EPU calculation with tracking biases in TIS-B system as well. As such it can find application in practice to depict different kinds of error models in TIS-B system.     

机载设备外场数据的可靠性增长分析

对我国航空机载设备外场数据的性质进行分析后,提出该种数据是变动母体混合数据,不同于通常用于可靠性估计的不变母体数据。提出外场数据中含有可靠性增长信息。 为利用外场数据来分析和评估航空机载设备的可靠性增长和可靠性状态,提出一个数学模型。模型的基本原理是最小二乘法。为说明模型的使用提供了一个实例。     

Assessment of the consequences of the Fengyun-1C breakup in low Earth orbit

On 11 January 2007, the People’s Republic of China conducted a successful anti-satellite test against one of their defunct polar-orbiting weather satellites. The target satellite, called Fengyun-1C, had a mass of 880 kg and was orbiting at an altitude of about 863 km when the collision occurred. Struck by a direct-ascent interceptor at a speed of 9.36 km/s, the satellite disintegrated, spreading the cataloged fragments between 200 and 4000 km, with the highest concentration near the breakup height. By the end of April 2008, 2377 pieces of debris, including the original payload remnant, had officially been cataloged by the US Space Surveillance Network. Of these, nearly 1% had reentered the Earth’s atmosphere. This deliberate act is the largest debris-generating event on record, and its consequences will adversely affect circumterrestrial space for many years.     

卫星转动条件下APS星敏感器星像目标中心提取精度分析

 目前对星敏感器星像定位的研究多限于静态情况,而卫星转动过程中,在曝光期间星像在像平面不断移动,从而影响星像定位的精度,重点分析动态情况下APS星敏感器星像目标中心的提取精度。首先分析采用质心法计算星像目标中心的误差源,提出动态精度的估计方法,并推导相应的计算公式;进而以给定的APS星敏感器参数为基础,研究了计算窗口、曝光时间等精度影响因素的选择方法;最后通过仿真进行了验证。     

高动态下基于DMF的伪码捕获频差估计研究

基于数字匹配滤波器（DMF）的PN码捕获电路具有较快的捕获速度,但其输出主相关峰值对频差较为敏感。为了消除频差对捕获性能的影响,文章提出了一种基于FFT的频差估计算法。首先构造一个载波频差的希尔波特复矢量,然后对其进行快速傅里叶变换。该算法能够精确检测出载波频偏的绝对值大小和方向,可以有效地改善大频差下的伪码捕获性能。