基于双机身和斜拉杆的大展弦比无人机机翼弯矩减小措施

为了减小临近空间大展弦比无人机机翼的弯矩和挠度,采用双机身和斜拉杆两种方案,对弯矩和挠度沿展向的分布进行计算与分析;同时还对斜拉杆方案下机翼受压力时的失稳特性进行研究.结果表明：两种方案均可较大程度地减小机翼弯矩和挠度;双机身方案可使最大弯矩减小为原来的24％,斜拉杆方案可使最大弯矩减小为原来的20％;且采用斜拉杆方案,在给定参数下机翼不会发生失稳现象.     

A real-time GNSS-R system based on software-defined radio and graphics processing units

Reflected signals of the Global Navigation Satellite System (GNSS) from the sea or land surface can be utilized to deduce and monitor physical and geophysical parameters of the reflecting area. Unlike most other remote sensing techniques, GNSS-Reflectometry (GNSS-R) operates as a passive radar that takes advantage from the increasing number of navigation satellites that broadcast their L-band signals. Thereby, most of the GNSS-R receiver architectures are based on dedicated hardware solutions. Software-defined radio (SDR) technology has advanced in the recent years and enabled signal processing in real-time, which makes it an ideal candidate for the realization of a flexible GNSS-R system. Additionally, modern commodity graphic cards, which offer massive parallel computing performances, allow to handle the whole signal processing chain without interfering with the PC’s CPU. Thus, this paper describes a GNSS-R system which has been developed on the principles of software-defined radio supported by General Purpose Graphics Processing Units (GPGPUs), and presents results from initial field tests which confirm the anticipated capability of the system.     

基于数字包络检波的RNSS通道时延标定方法

提出一种采用数字处理的时延测试方法,用于对导航卫星导航信号发射通道分数码片时延的精确测量。该方法是通过高速A/D（模/数）转换器,对导航卫星下行的BPSK（二进制相移键控）信号和卫星导航秒脉冲进行双通道采样,读取采样数据并进行数据处理。根据秒脉冲信号触发门限上升沿确定时延测量起点,对BPSK采样数据进行平方律检波,获取码片换相点,计算换相点和秒脉冲之间的分数码片时延,并进行滤波器时延校准,从而得到导航卫星发射链路的分数码片时延,该方法不需要进行伪随机信号的捕获和跟踪,测量精度主要取决于采样器采样率。通过在测试中使用一根校准电缆对该方法进行验证,验证结果表明,采用本文提出测试方法的测量误差优于0.3ns。     

极小展弦比背鳍气动特性研究

对极小展弦比背鳍进行了风洞实验和CFD分析。研究表明：亚声速大迎角下背鳍涡破裂影响不严重,且涡破裂迎角较大;正侧滑通常使背鳍法向力增加,负侧滑使法向力降低;CFD分析证实了大负侧滑条件下翼片法向力会变成负值,从而引起十字翼在倾斜条件下滚转力矩发生突变。     

空空导弹仿真环境的构建

导弹的仿真试验是导弹挂飞和靶试前的关键性试验,是判断导弹是否具备试飞条件的重要工程依据.本文介绍的空空导弹仿真试验环境,可以在试验室条件下完成导弹的工作流程,为雷达型空空导弹的半实物仿真提供了重要的支撑平台     

基于相推法的空间光载射频链路绝对延时测量

空间光载射频链路利用空间光链路实现射频信号的传输.由于采用大气信道传输光载射频信号,链路绝对延时受到大气湍流和温度等因素影响,产生延时抖动.本文采用相推法对1 km空间光载射频链路的绝对延时进行了高精度测量,测量结果与理论模型吻合,测量精度优于0.1 ps.该测量方法采用电光调制和射频鉴相实现了链路绝对延时测量,与光载...     

无线电引信的电磁脉冲效应

强电磁脉冲对武器装备电子系统具有很强的干扰和破坏作用。通过超宽带电磁脉冲对无线电引信的辐照实验,研究了无线电引信在超宽带电磁脉冲作用下的效应。实验表明：无线电引信在超宽带电磁脉冲照射下,会产生早炸现象。在介绍无线电引信工作原理的基础上,分析了无线电引信产生早炸的原因,得出超宽带电磁脉冲直接作用无线电引信点火电路从而引起旱炸的结论。     

空间TDICCD相机动态信噪比计算方法研究

信噪比是空间光学相机系统的主要设计指标之一,可用于表征相机的辐射性能。文章通过建立遥感卫星轨道模型,分析计算一年中任意时刻用太阳高度角和卫星观测角描述太阳、卫星、地面目标点之间的相对位置关系,并将计算得到的卫星观测角和太阳高度角等参数导入大气传输软件MODTRAN,输出在相机入瞳处的地面目标光谱辐亮度,再根据信噪比的计算方法,最后完成TDICCD相机动态的信噪比计算值。通过该方法,可以计算任一时刻任一观测目标的信噪比,这将有利于判断在某一时刻的能量是否满足观测要求,以随时改变TDICCD的探测器级数,使得成像像质达到最佳。     

SLUCUBE: Innovative high performance nanosatellite science and technology demonstration mission

The Space Systems Research Laboratory (SSRL) at Saint Louis University is developing SLUCUBE nanosatellite as part of the space mission design program. The objective of the mission is to demonstrate space capability of high performance nanosatellite components that has been developed at SSRL for the past three years. The objective of the program is to provide extremely low-cost and rapid access to space for scientists and commercial exploitation using commercial-off-the-shelf components. SLUCUBE is a double CubeSat with dimensions 10×10×20 cm and a mass of 2 kg. This nanosatellite features suite of technology demonstration components to enlarge the capability of space mission for such class of spacecrafts. The primary mission of SLUCUBE is to test and demonstrate several enabling technologies by flying a number of university developed high performance components. This paper describes the new developed technologies by providing details of specific components developed along with the R&D efforts and laboratory facilities. A brief discussion about the student involvement and educational benefits will also be presented.     

球型收敛调节片喷管红外特性数值研究

通过数值模拟的方法,研究了喉部宽高比、下俯和偏航矢量作动角等3个结构参数对球型收敛调节片喷管(SCFN)后半球红外辐射空间分布的影响规律。结果表明：①喉部宽高比的增大使得铅垂对称面内(zOx)的红外辐射得到很好的抑制,当二元喷管喉部宽高比达到3.5时,尾向0°方向的红外辐射强度相对于基准圆形喷口降低了17.6%,水平对称面(yOz)内部分探测角度则出现了红外辐射增强的现象;②喷管调节片下俯作动角在zOx对称面310°~350°范围以及偏航作动角在yOz对称面330°~350°范围,红外辐射强度呈现增强趋势,而在无矢量作动的对称面内,红外辐射强度则得到有效抑制。