Design and Analysis of Terminal Guidance Law for Kinetic Interceptors based on Pulse Engine

A new terminal guidance law is proposed based on a solid propellant pulse engine and an improved proportional navigation method to address the terminal guidance issue for kinetic interceptors.On this basis,the start-stop curve of the pulse motor during the terminal guidance process is designed,along with its start-up logic.The effectiveness of the proposed guidance strategy is verified through simulation.

Anti-Jamming Algorithm Based on Spatial Blind Search for Global Navigation Satellite System Receiver

A novel subspace projection anti-jamming algorithm based on spatial blind search is proposed,which uses multiple single-constrained subspace projection parallel filters.If the direction of arrival(DOA)of a satellite signal is unknown,the traditional subspace projection anti-jamming algorithm cannot form the correct beam pointing.To overcome the problem of the traditional subspace projection algorithm,multiple single-constrained subspace projection parallel filters are used.Every single-constrained anti-jamming subspace projection algorithm obtains the optimal weight vector by searching the DOA of the satellite signal and uses the output of cross correlation as a decision criterion.Test results show that the algorithm can suppress the jamming effectively,and generate high gain toward the desired signal.The research provides a new idea for the engineering implementation of a multi-beam anti-jamming algorithm based on subspace projection.

A Spatio-temporal Data Model for Road Network in Data Center Based on Incremental Updating in Vehicle Navigation System

The technique of incremental updating,which can better guarantee the real-time situation of navigational map,is the developing orientation of navigational road network updating.The data center of vehicle navigation system is in charge of storing incremental data,and the spatio-temporal data model for storing incremental data does affect the efficiency of the response of the data center to the requirements of incremental data from the vehicle terminal.According to the analysis on the shortcomings of several typical spatio-temporal data models used in the data center and based on the base map with overlay model,the reverse map with overlay model (RMOM) was put forward for the data center to make rapid response to incremental data request.RMOM supports the data center to store not only the current complete road network data,but also the overlays of incremental data from the time when each road network changed to the current moment.Moreover,the storage mechanism and index structure of the incremental data were designed,and the implementation algorithm of RMOM was developed.Taking navigational road network in Guangzhou City as an example,the simulation test was conducted to validate the efficiency of RMOM.Results show that the navigation database in the data center can response to the requirements of incremental data by only one query with RMOM,and costs less time.Compared with the base map with overlay model,the data center does not need to temporarily overlay incremental data with RMOM,so time-consuming of response is significantly reduced.RMOM greatly improves the efficiency of response and provides strong support for the real-time situation of navigational road network.

Jamming and spoofing interferences suppression technique for satellite navigation receiver

A satellite navigation receiver that can suppress jamming interference and spoofing interference simuhaneously is designed in this paper. An anti-jamming improved constrained spacial adaptive processing algorithm in signal processing and an anti-spoofing M-estimator based extended Kalman filter algorithm in information processing are proposed respectively. Simulations of the integral designed anti-interferences satellite navigation receiver demonstrate that the designed anti-interferences receiver can suppress jamming signals efficiently （ above 40 dB） and ensure the normal reception of satellite signals while satellite signals and jamming signals have the similar direction of arrival （ almost 10° ）. The designed anti-interference receiver can effectively eliminate the influence of spoofing signals on the navigation solution accuracy and maintain high accuracy of position and velocity estimation, which improves the anti-jamming and anti-spoofing capability of the satellite navigation receiver.

低成本GNSS终端多普勒平滑伪距定位算法

随着低成本全球卫星定位(GNSS)终端硬件性能的不断提升,其在定位领域的应用也更加广泛,然而低成本GNSS终端在数据采集中常受观测环境的影响,使得载波相位观测值的高精度定位较为困难。伪距定位算法因其定位模型简单且实时性好的优势被广泛使用,因此本文利用多普勒平滑伪距方法,充分利用了多普勒观测值的作用,通过多普勒平滑伪距噪声来提升观测值的测量精度,利用多普勒平滑伪距模型对静态与多种动态环境下的平滑效果进行测试和分析。实验结果表明:在静态情况下,采用多普勒平滑伪距算法,伪距单点定位与伪距实时差分定位模型定位中平面精度较平滑之前分别提高了25%与31%;在动态环境下,有遮挡动态实验其精度提升30%以上,空旷情况下定位精度提升15%以上,快速运动过程中其提升能达到20%左右。表明通过多普勒平滑伪距算法可以显著提高低成本GNSS终端的定位精度。

基于GDCORS的北斗终端高精度定位算法实现及性能分析

为了提升广东省卫星导航定位基准服务系统(以下简称“GDCORS”)的社会化应用范围,扩充GDCORS的服务对象,提出了基于时间差分和卡尔曼滤波的实时高精度定位方法,利用该方法开发了高精度定位APP,并且研制了与之配套的外接北斗定位模块,然后基于GDCORS提供的实时差分产品数据使用多种智能手机在广州市内开展了静态和动态定位测试。测试结果表明,提出的高精度定位算法实现了基于手机观测数据的米级北斗伪距差分定位,基于单频外接设备的分米级、基于多频外接设备的厘米级北斗载波相位差分定位,以上基于GDCORS的北斗终端高精度定位算法具备应用推广价值。

导航终端标准体系的构建

导航终端细分专业多,行业需求多、应用广泛,构建协调统一的导航终端标准体系是对国家关于加快构建高质量发展国家标准体系要求的积极响应。本文从国家对健全各领域标准体系需求出发,分析了导航终端标准体系建设的需求特点,从导航终端各子体系着手,自顶向下提供了一种标准体系构建方法,为导航终端研制单位核心产品的标准体系构建提供指导,为其他技术领域标准体系构建提供参考。

卫星导航终端小型化开口缝隙螺旋天线

研究了一种小型化卫星导航终端开口缝隙螺旋天线。天线主体为四条宽度渐变的开口缝隙螺旋臂,蚀刻在外表面覆铜的介质基板围成的方型结构上,由印制于介质基板内表面的微带线结构馈电网络进行耦合馈电;馈电网络由底面回形结构和侧面逐渐向上变宽的折形结构组成,使用同轴线接头在天线底部对其馈电。天线总体尺寸为26 mm×26 mm×29 mm,实测结果表明:|S_(11)|≤-10 dB的阻抗带宽为7.88%(1.523 GHz~1.648 GHz),轴比≤3 dB的圆极化带宽为20.26%(1.490 GHz~1.826 GHz),在北斗B1频段中心频率(1.561 GHz)、GPS L1频段中心频率(1.575 GHz)和GLONASS L1频段中心频率(1.602 GHz)处增益分别达到3.33 dBi、3.18 dBi和2.79 dBi。该天线采用开口缝隙螺旋结构,通过简单的馈电网络串行耦合馈电实现天线的圆极化,在较小尺寸情况下实现了较宽的带宽和较好的增益。

交叉耦合馈电的小型化八臂缝隙螺旋天线

研究了一种应用于卫星导航终端的小型化交叉耦合馈电八臂缝隙螺旋天线。八条缝隙螺旋臂作为天线的辐射单元,蚀刻在FR4介质基板构成的方形柱状结构的外表面。馈电网络为上、下相互正交四分之三圆环的交叉偶极子微带线结构,延伸至了外表面且实现了交叉耦合馈电。天线尺寸为0.082λ0×0.082λ0×0.130λ0(λ0为中心频率1.561 GHz对应的自由空间波长),实测结果显示,|S11|≤-10 dB的阻抗带宽为1.554 GHz~1.591 GHz,3 dB轴比带宽为1.535 GHz~1.594 GHz。在北斗卫星导航系统B1频段中心频率(1.561 GHz)和全球定位系统L1频段中心频率(1.575 GHz)处的增益分别达到了2.56 dBi和2.75 dBi。该天线采用八臂缝隙螺旋和交叉偶极子臂耦合馈电相结合的结构,实现了较好的圆极化性能,同时具备宽频带和小型化的特点。

北斗三号新型船载终端设计

针对北斗二代卫星导航系统终端在精度、可靠性和智能化程度等方面存在缺陷,提出采用北斗三号卫星导航系统新技术,设计出新型船载终端。采用北斗三号卫星导航系统的定位技术和通信技术,对终端的硬件结构和软件系统进行设计和实现。结果表明,结合物联网等通信技术,采用高精度北斗定位结合GIS地理信息技术,将北斗+物联网通信技术相互兼容,结合计算机数据库管理和电子海图技术,利用北斗三号卫星导航系统特点可以设计出新型船载终端。终端设计能提高海上船舶实时动态监管和应急救助处置能力,构建快捷高效的应急救助体系。

L/S频段一体化高集成SiP模块设计

为解决系统小型化、轻量化的设计需求,设计了一款支持北斗RNSS、RDSS一体化SiP收发模块,工作频段支持北斗B3/L/S三频点。该SiP模块采用一体化陶瓷封装架构,通过异质异构集成方式集成了多种射频无源器件和数模芯片。采用金属腔体屏蔽与多排交叉金属通孔结构实现了隔离屏蔽,并对滤波器、多工器、巴伦以及传输结构等无源器件进行了仿真设计,最终实现尺寸为24.0 mm×24.0 mm×4.3 mm,性能良好。文中介绍了SiP收发模块的工作原理、关键技术以及最终实现形式,设计结果满足定位及导航终端等相关应用需求。

基于北斗卫星导航技术的配电自动化 通信终端设计

为了提高配电自动化通信终端的通信可靠性和抗干扰性,设计了基于北斗卫星导航技术的配电自动化通信终端。具体设计配电自动化通信终端总体架构、通信终端载体和通信终端运行主程序,在北斗控制单元中编写信息传入速率控制程序,调控终端功率大小,实现信号传入速率控制,采用射频信号处理程序对射频信号进行滤波和放大。测试结果表明:设计的配电自动化通信终端通信收发损失程度均在5以下,信噪比均大于10,说明该终端的通信可靠性较高、通信抗干扰性较强。

Combined algorithm of acquisition and anti-jamming based on SFT

A communication and navigation receiver is required to remove hostile jamming signals and synchronize receiving signals effectively especially for satellite communication and navigation whose resources are becoming more and more limited. This paper proposes a novel signal receiving method by combining the pro- cesses of anti-jamming and synchronization to reduce the overall computationa~ complexity at the expense of slightly affecting the detection probability, which is analyzed in detail by derivations. Furthermore, this paper introduces sparse Fourier transformation （SFT） into the proposed algorithm to replace fast Fourier transfor- mation （FFT） so as to further reduce the calculation time especially in large frequency offset environments.

终端区点融合进场程序运行安全和效率仿真评估

为解决繁忙终端区运行效率低下的问题,提出了一种基于点融合进场程序的终端区运行安全和效率评估方法。首先考虑空域结构、障碍物和下降梯度等限制条件,以成都终端区为研究对象,设计点融合进场程序并对其进行安全性评估。使用SIMMOD软件对传统区域导航(Remote Area Navigation, RNAV)进场程序和点融合系统(Point Merge System, PMS)进场程序进行模拟仿真,对比了两种运行模式下、不同交通流场景下的航班冲突次数和运行时间。结果表明:正常流量情况下,PMS程序较RNAV程序的冲突次数和总运行时间分别减少了80.92%和6.79%;极限流量情况下,PMS程序较RNAV程序的冲突次数和总运行时间分别减少了17.31%和1.21%。研究表明,点融合程序对于正常流量情况下终端区运行安全和效率提升效果较好,极限流量情况下效果不明显。

终端区进场航空器管制效率量化分析

终端区航空器的飞行密度和复杂度较高,此管制区域的处理能力是制约航空体系效率的瓶颈,对进场航空器管制效率进行量化研究,有助于提高管制工作处理能力和质量。首先,提出以区域导航(RNAV,regional area navigation)标准仪表进场程序的标称里程为计算基准量化进场管制效率,通过随机搜索聚类算法的结果得到航空器使用的RNAV标准仪表进场程序,选用在北京首都国际机场着陆的航空器为分析对象,计算航空器的进场管制效率,结合航迹讨论不同RNAV标准仪表进场程序下航空器的运行方式及特点。其次,对进场管制效率的影响因素进行分析,并采用灰色关联分析法量化各影响因素的影响程度与权重,结果显示:雷达引导度和航行三要素改变次数对进场管制效率具有显著影响,飞行流量和RNAV标准仪表进场程序的标称里程对进场管制效率的影响相对较小。继而,从影响因素角度出发评估整体进场管制效率,得到更为全面客观的整体进场管制效率。最后,尝试从RNAV进场程序路径以及优良管制行为模式两方面寻求进场管制效率的提升途径和方法。

基于Winform的农机导航终端监控系统设计与试验

农机自动导航是实现精细农业的关键,随着导航技术的日益发展,终端监控作为导航系统的核心受到了广泛的关注。为了实现对农机作业时导航定位信息的有效监控,在Windows平台上采用VS2019开发环境、Winform软件开发技术和C#语言,设计了一种农机自动导航车载终端系统。系统主要包括硬件平台的搭建以及软件系统的设计,具有数据实时通讯、数据分析处理、文件读写、虚拟场景显示、百度地图显示和历史作业轨迹查看等功能。将该导航终端监控系统搭载到洋马插秧机上进行试验,结果表明:软件系统界面友好,通讯稳定,功能较为齐全,满足农机田间辅助作业的需求。

基于EasyAR的聂荣臻元帅陈列馆导览系统研究

针对移动终端增强现实导览系统开发难度大、自然特征识别数据量大、计算耗时长、标志物识别准确率较低、受光照、遮挡影响大、易于导致跟踪失败等问题,提出一种基于EasyAR的增强现实导览方法。采用3DsMax对场景进行三维建模仿真,采用Unity开发交互设计程序,采用EasyAR检测和跟踪标识物特征点,叠加显示对应的增强现实仿真模型、播放视频、动画、音效。借助这一方法,开发了聂荣臻元帅陈列馆导览系统。实验表明,上述方法降低了开发导览系统的难度、高效易用、识别自然特征数据块速度快、准确率高、降低了光照及遮挡影响跟踪问题,为AR仿真提供一个最佳解决方案。

空间云锚点在博物馆移动端信息导览中的应用研究

文章针对博物馆移动端信息导览的现状进行分析,探讨了空间云锚点技术在移动端导览系统中的应用可能性,并根据应用策略进行原型测试。以南京云锦博物馆为设计对象,根据空间云锚点技术的应用特征,优化博物馆的信息导览功能,为数字技术在博物馆智能导览系统中的应用实践提供设计参考。

开敞岛礁海域环境大型LNG码头规划布置关键问题

舟山群岛海域规划有多个LNG重要港址,对于保障长三角天然气供应具有关键作用。LNG码头具有自身建设要求高和对外排他性强的特性,在舟山群岛海域为代表的开敞岛礁海域建设具有较大技术难度。以舟山六横和上海洋山LNG码头为例,系统分析开敞岛礁海域对LNG码头规划布置的影响,分析码头和航道布置关键问题,论证多个大型LNG泊位联合布置的安全间距,研究LNG船舶通航安全和通航效率影响,提出LNG码头规划布置方案。结果表明,开敞环境下布置多个大型LNG泊位时,与掩护条件较好时相比应适当增加安全间距,注意横风、横流以及斜顶流的影响,确保船舶通航安全,要控制LNG合理运输规模,采取通航优化措施,提升区域船舶通航效率。

Research on FMC analytic algorithm of PBN track transition coding

Airborne navigation database(NavDB)coding directly affects the result of analysis on the instrument flight procedure by the modern aircraft flight management computer(FMC).A reasonable flight track transition mode can improve the track tracking accuracy and flight quality of the aircraft.According to the path terminator(PT)and track transition characteristics of the performance based navigation(PBN)instrument flight procedure and by use of the world geodetic system(WGS)-84 ellipsoidal coordinate system,the algorithms for“fly by”and“fly over”track transition connections are developed,together with the algorithms for coordinates of fix-to-altitude(FA)altitude termination point and heading-to-an-intercept(VI)track entry point and for track transition display of the navigation display(ND).According to the simulation carried out based on the PBN instrument approach procedure coding of a certain airport and the PBN route data at a high altitude,the algorithm results are consistent with the FMC-calculated results and the actual ND results.