星载SAR的信号模型与性能分析

阐述星载合成孔径雷达（ＳＡＲ）信号的数学模型，涉及点目标和扩展目标的回波响应函数的一维和二维表示，以及目标场的重构问题。进一步分析了回波信号的多普勒特性，给出了严格的和近似的表示式。对星载ＳＡＲ系统的性能，主要是对分辨率和覆盖特性进行了定量分析，给出了具有速度比值修正的计算公式，对模糊性问题也有所涉及。     

卫星信号和数据质量监测算法研究

结合卫星导航系统的实际应用,对卫星播发的导航信号和观测数据的质量监测算法进行了研究,可以满足卫星定轨和用户定位精度的要求。文中首先分析了卫星信号出现异常的原因,并有针对性地给出了用于卫星信号质量监测的宽窄相关伪距比较和码-载偏离度计算方法,然后又对用户伪距和载波相位这两个主要测量值的数据突变问题的实时监测方法展开了分析和探讨,最后进行了仿真研究。结果表明,这些算法是可行、实用并且有效的。     

电子角跟踪导引头技术及其应用前景

对电子角跟踪在反辐射导引头中的应用进行了研究。介绍了导引头的组成、电子角跟踪的工作原理和特点。研究了如灵敏度、角跟踪误差、制导信号提取、弹体扰动去耦、角搜索模糊，以及单目标跟踪等关键技术，最后分析了电子角跟踪技术在雷达、单机无源定位、反辐射、救生和机器人等技术领域的应用前景。     

Impaired T-wave amplitude adaptation to heart-rate induced by cardiac deconditioning after 5-days of head-down bed-rest

The study of QT/RR relationship is important for the clinical evaluation of possible risk of acquired or congenital ventricular tachyarrhythmias. In the hypothesis that microgravity exposure could induce changes in the repolarization mechanisms, our aim was to test if a short 5-days strict 6° head-down bed-rest (HDBR) could induce alterations in the QT/RR relationship and spatial repolarization heterogeneity. Twenty-two healthy men (mean age 31±6) were enrolled as part of the European Space Agency HDBR studies. High fidelity (1000 Hz) 24 h Holter ECG (12-leads, Mortara Instrument) was acquired before (PRE), the last day of HDBR (HDT5), and four days after its conclusion (POST). The night period (23:00–06:30) was selected for analysis. X, Y, Z leads were derived and the vectorcardiogram computed. Selective beat averaging was used to obtain averages of P–QRS–T complexes preceded by the same RR (10 ms bin amplitude, in the range 900–1200 ms). For each averaged waveform (i.e., one for each bin), T-wave maximum amplitude (Tmax), T-wave area (Tarea), RTapex, RTend, ventricular gradient (VG) magnitude and spatial QRS-T angle were computed. Non-parametric Friedman test was applied. Compared to PRE, at HDT5 both RTapex and RTend resulted shortened (−4%), with a decrease in T-wave amplitude (−8%) and area (−13%). VG was diminished by 10%, and QRS-T angle increased by 14°. At POST, QT duration and area parameters, as well as QRS-T angle were restored while Tmax resulted larger than PRE (+5%) and VG was still decreased by 3%. Also, a marked loss in strength of the linear regression with RR was found at HDT5 in Tmax and Tarea, that could represent a new dynamic marker of increased risk for life-threatening arrhythmias. Despite the short-term HDBR, ventricular repolarization during the night period was affected. This should be taken into account in astronauts for risk assessment during space flight.     

基于特征提取与统计的信号类型识别

针对空间电子对抗领域的截获信号类型识别问题,提出了一种基于特征提取与统计的非合作信号类型识别方法。首先,通过对瞬时频率和复包络模值特征进行统计,实现了信号类型的粗分类,接着,基于细微特征提取和比对,实现了信号类型的精确识别。仿真结果表明,当处理器输入信噪比高于11dB时,所提方法对8类信号的正确识别概率均超过90%。本方法处理复杂度较低,易于星上工程实现。     

专用捷变频信号源校准系统研制

捷变频末制导雷达可有效提高武器系统的抗干扰能力,但是作为其专用测试设备的捷变频信号源的计量检定问题却难以得到有效解决。通过分析现有的测试技术,使用通用仪器设备构建测试平台,可实现专用捷变频信号源的自动计量校准。系统采用两路差频形成中频频差的检测方法进行瞬时频率测量,采用单脉冲引频激励测试技术,利用通用测试仪器实现捷变频参数的校准,将捷变频计量技术推向工程应用阶段,可避免通过研制生产专用的计量设备造成其本身难以计量的问题。     

伽利略系统的当前频率和信号设计方案

本文简要介绍伽利略系统最新提出的频率和信号设计方案,涉及方案设计基本要求、频率和信号基本方案、各种导航信号的调制体制、所用扩频测距伪码、性能参数、时间与坐标参考系等。     

时变微弱扩频信号检测

提出了一种解决微弱高动态扩频信号捕获的新方法,利用分数阶域滤波设计了伪码—时频联合匹配滤波的框架,最后进行了相关计算并给出了应用实例。     

基于轴角转换芯片AD2S1210的圆感应同步器信号处理方法研究

设计了一套用于圆感应同步器测角系统的信号处理算法,并详述了其过程。在测角系统对感应同步器信号的解算中,该方法仅通过对轴角转换芯片AD2S1210输出的数字信号进行纯软件分析和处理来获得角位置信号的整数值。从而简化了测角系统的硬件电路,提高了测角实时性。     

脉冲雷达探测中高轨道目标方法及试验

通过分析中高轨目标雷达回波信号特性,给出一种基于空间目标动力学约束的回波信号相参积累方法,介绍了信号积累模式下中高轨道目标的参数测量方法。通过对国内某型号雷达进行中高轨目标探测支路改造及相关试验,获取试验数据并对其进行分析,验证了原理的正确性和方法的可行性。