无线光通信GPS辅助定点捕获实验研究

针对无线光通信对快速、精准的光束对准技术需求,为减小系统链路建立时间,增加捕获可靠性,提出将GPS技术应用于光通信实验系统中。以TMS320F2312为控制核心,可根据实时GPS坐标解算出需调整的方位及俯仰角,进而驱动二维转台完成初始捕获,据此进行了多次初始捕获实验。结果表明,采用GPS导航定位技术,可快速实现信标光的初始捕获,且具有较高的捕获成功概率。     

Experiment and analysis of the effect of fine tracking system on the unstable platform in laser communication

Atmospheric turbulence and platform vibration in the space optical communication can cause the offset and jitter of beam, which further result in the fluctuations of received optical power. To resist this effect, a communication system with fine tracking systems in the receiver and transmitter is designed. The system is used in the experiment of laser communication between high-rise buildings over a distance of 3.5 km. After adding a vibration source to the transmitter, the centroids of spots captured by the camera of the transmitter and the optical power of receiver are recorded for the purpose of analysis. When the vibration source works at the designated frequency, a peak appears at the corresponding frequency in the spectrum of the spot centroids and the optical power of receiver. Then the peak disappears once the fine tracking system begins to work. Compared with the condition without the fine tracking system, the minimum value of the optical power of receiver is increased by 5 dB, and the standard deviation is decreased by 30%.     

无线光通信ATP演示实验系统

针对空间无线光通信中捕获、瞄准和跟踪（ATP）技术的粗跟踪系统对信标光斑实时准确跟踪需求,为项目进一步工作提供基础,搭建了无线光通信ATP演示实验系统,分别对粗、精跟踪子系统进行了详细的介绍,利用该系统进行了运动目标的模拟跟踪实验。结果表明：粗跟踪可将运动误差控制在200μrad之内,使光目标始终维持在精跟踪视场内,精跟踪可将系统误差控制在15μrad,可满足通信需求。     

基于ATP系统的非机动目标跟踪实验

考虑到无线光通信的捕获、瞄准和跟踪(ATP)系统对信标光斑实时、准确跟踪的需求,采用具有高频、大幅度补偿能力的音圈电机作为精跟踪执行部件,以此搭建了基于PC机控制的无线光通信演示实验系统。进行了不同速度下的非机动模拟跟踪实验,分别采集、分析并评价了粗跟踪和精跟踪的跟踪误差,并实时采集了通信光光功率。实验结果表明:ATP系统的跟踪误差标准差随着模拟目标运动速度的增加而增大,误差变化范围却无较为明显的规律,系统可长时间保持通信链路;此外,粗跟踪误差曲线中多次出现的误差尖峰可能与粗大值有关。     

市内建筑间无线光通信GPS辅助单向捕获研究

为减小无线光通信链路建立时间及增加系统捕获可靠性,提出将GPS技术应用于光通信实验系统中。以TMS320F2812为控制核心,搭建了无线光通信定点单向捕获实验系统。系统采用用户界面统一控制,双方GPS坐标手工输入至用户界面,解算出需调整的方位及俯仰角后送于F2812,驱动二维转台完成初始捕获,据此选择多点进行了多次单向初始捕获实验。结果表明,采用GPS导航定位技术,可快速实现信标光的初始捕获,且具有较高的捕获成功概率。     

矿用电机车防撞系统的研究

为进一步加快井下大巷运煤速度,采用以AT89S52单片机作为系统控制核心,红外电路作为检测手段,设计了基于红外探测预警的智能防撞预警系统。此系统可提示司机采取相应的措施,必要时该系统具有自动制动功能,有效地防止事故发生。     

无线光通信粗跟踪一维模拟实验研究

针对空间无线光通信中捕获、瞄准和跟踪（ATP）技术的粗跟踪系统对信标光斑实时准确跟踪需求,为项目进一步工作提供基础,搭建了无线光通信的粗跟踪模拟实验系统,介绍了实验所需硬件的相关参数及实验方案,基于模糊PID控制策略进行了不同速度下的一维模拟跟踪实验。结果表明,跟踪误差随着模拟仿真台的运动速度的增加而增大,但始终满足于粗、精跟踪嵌套精度需求。     

自由空间光通信精跟踪系统设计及其通信实验

为了解决自由空间光通信对APT系统的高精度高带宽要求,设计研制了一种精跟踪系统。该系统以高帧频CMOS相机为探测机构,以音圈电机驱动的FSM(Fast Steering Mirror)为执行机构,由PC机进行控制和运算。在一维模拟运动平台中进行带粗跟踪的距离为2 km的激光通信实验时运用该系统,当模拟运动平台以不同角速度转动时,粗跟踪会有不同的跟踪残差,该残差以及大气湍流及平台振动引起的光斑抖动均由精跟踪系统来补偿。记录并分析了精跟踪补偿后的相机端光斑质心的变化以及光路中光功率的变化数据,得出结果:精跟踪残差受粗跟踪系统的影响,随模拟运动角速度的增大而增加,在1.2(°)/s时粗精跟踪系统联合能将光斑偏移量的标准差稳定在6μrad以内。     

Experiment study of ATP system for free-space optical communications

To meet the requirement of high tracking angular accuracy for the acquisition, tracking, and pointing (ATP) subsystem of the free-space optical communication, and provide the basis for the further optical communication between maritime mobile platforms, the experimental system, which executing part for the fine tracking is voice coil motor with high frequency and good performance for error compensation, is established, and the whole system can be controlled by personal computer. A series of experiments has been done for the simulation target of different uniform speed, and the data of tracking error for fine tracking and coarse tracking are collected, analyzed and evaluateds separately, and the real-time optical power of communication laser is also collected. The result shows that standard deviation for ATP system tracking error increases with the increase of target speed, while the range of tracking error appears to be no order. Furthermore, communication link can be hold for a long time.     

美军HAIPE加密技术原理与分析

HAIPE是美国国家安全局在美军全球信息栅格(GIG)中强制要求使用的加密方式,用以保障美军在IP化GIG中的通信安全,GIG中所有网络节点都必须遵循其规范。首先对HAIPE进行简介,然后进一步详细描述其要求的硬件架构和网络结构以及完整的通信流程,并介绍了其同侪发现与路由和密钥管理及交换等关键技术,最后分析了HAIPE技术的优势及缺点。