Bernoulli particle flter with observer altitude for maritime radiation source tracking in the presence of measurement uncertainty

For maritime radiation source target tracking in particular electronic counter measures（ECM）environment,there exists two main problems which can deteriorate the tracking performance of traditional approaches.The frst problem is the poor observability of the radiation source.The second one is the measurement uncertainty which includes the uncertainty of the target appearing/disappearing and the detection uncertainty（false and missed detections）.A novel approach is proposed in this paper for tracking maritime radiation source in the presence of measurement uncertainty.To solve the poor observability of maritime radiation source target,using the radiation source motion restriction,the observer altitude information is incorporated into the bearings-only tracking（BOT）method to obtain the unique target localization.Then the two uncertainties in the ECM environment are modeled by the random fnite set（RFS）theory and the Bernoulli fltering method with the observer altitude is adopted to solve the tracking problem of maritime radiation source in such context.Simulation experiments verify the validity of the proposed approach for tracking maritime radiation source,and also demonstrate the superiority of the method compared with the traditional integrated probabilistic data association（IPDA）method.The tracking performance under different conditions,particularly those involving different duration of radiation source opening and switching-off,indicates that the method to solve our problem is robust and effective.     

多天线/GPS光纤陀螺IMU组合车载定姿系统研究

利用GPS多天线定姿系统与低成本光纤陀螺IMU组合,以PC104作为组合导航计算平台,采用重调式松散组合算法,构建了低成本、高精度、高可靠性的车载航姿保持系统,并成功应用于移动卫星通讯系统。经测试,组合系统静态初始化时间小于2min,动态定姿精度优于0.1度,更新率为100Hz。该项技术可进一步拓展应用于舰载、机载等运动平台,前景可观。     

航空器海上飞行空域规划方法

为充分利用海上空域资源,提供海上飞行有效空域活动范围,针对海上空域可用资源问题进行了研究,主要目的是寻找一种有效的海上空域可用资源规划方法。一方面,分析了我国周边海域的海上空域资源,并基于岸基军、民航已规划使用空域的环境数据,结合周边空管雷达监视能力服务范围信息,设计了一种基于图形栅格化法的海上空域资源智能规划方法。另一方面,基于协同区域随机搜索算法,分析计算出适合航空器飞行的海上空域数据,可为航空器海上飞行空域规划提供可靠依据。     

海上目标雷达与 AIS航迹时空匹配方法

针对海上目标的雷达与船舶自动识别系统(Automatic Identification System,AIS)中,航迹之间存在的时空不匹配现象,提出了在空间对准之后结合海上航迹运动特点,对 AIS航迹数据进行插值对准雷达目标航迹的方法,在解决雷达与 AIS航迹之间时空不匹配问题的同时,最大程度减小插值误差。该方法根据船舶航向变化率,结合航速航向法和内插外推法的优势,针对不同航迹特点自动选择最佳的插值配准方法,实现海上目标的雷达与 AIS航迹点的自动插值和时空对齐。仿真实验结果表明,所提方法针对海上目标复杂运动,可以自动匹配选择最佳插值方法,有效降低误差,实现雷达与 AIS航迹之间的时空匹配。     

Maritime Communications via Satellites Employing Phased Arrays

This paper examines the feasibility of providing maritime mobile telecommunications as a new service via satellites. A global system with a capacity of 10 duplex voice/data channels (plus an interrogation/reply channel) per satellite is described. The capability is achieved with a 0-dB gain UHF antenna in the ship and a UHF phased array in the satellite, which produces 11 steerable beams, each with 30-dB peak gain. The links between satellite and shore are assumed to be at SHF. A dedicated satellite weighs 320 kg, which can be launched with an up-rated Thor-Delta. The prime power requirement of 730 watts is provided by an oriented solar array.     

BDS-3 PPP模糊度固定实现及精度评估

精密单点定位(PPP)模糊度固定(AR)能够显著提升精密定位的收敛速度和精度。通过在BDS-2和BDS-3之间添加系统间偏差的方法实现BDS-3的模糊度固定,并基于全球MGEX测站静态、仿动态数据和车载实验数据全面评估了BDS-3模糊度固定的效果。结果表明,相对于浮点解,BDS-3 PPP模糊度固定能够显著提升PPP的精度,在东北天3个方向上静态解算精度提升依次为37.4%、26.2%和20.1%;仿动态解算精度提升依次为38.3%、27.2%和11.1%;车载动态实验BDS-3模糊度固定精度在三维方向上综合提升为40.4%。此外,模糊度固定后,以浮点解稳定后的两倍定位精度为基准,在东北天方向上,静态定位时间提升程度依次为63.5%、64.0%和40.3%;仿动态定位时间提升程度依次为58.7%、56.8%和25.4%;车载实验在三维方向的收敛时间为30.0 min。以上结果证明了所提方法的有效性及BDS-3模糊度固定的性能提升。     

Anti-aircraft artillery simulator

Air defense systems protect land and maritime resources from air attack. Depending on the regional characteristics and type of conflicting forces, air defense threats vary considerably. In regional conflicts, where forces with similar capabilities are involved and no air-superiority can be achieved, the role of air defense systems becomes critical. In combat terrains containing mountains (in mainland or in small islands), the man-operated or computer-controlled (using passive sensors) anti-aircraft artillery can be highly effective. The simulator presented in this work aims to exploit the capabilities provided by current commercial-off-the-shelf (COTS) communication and multimedia technologies for providing a training environment that improves the personnel capability for effective use of man-controlled anti-aircraft weapons.     

空间站工程海上应急救援保障新模式研究

载人空间站工程阶段,载人飞船发射任务呈现出高频度、常态化的特点,对上升段海上应急救援提出了新的要求。通过对国内外载人飞船海上应急搜救的现状分析,设计并提出了我国空间站工程海上应急救援保障新模式：在组织实施上,将交通运输部救捞系统纳入载人航天任务指挥系统,实现快速的应急响应和平战转换;在装备保障上,返回舱打捞、搜索定位、医疗救护系统、通信系统与船舶平台一体化设计,核心装备随船使用,尽量做到不拆不卸。最后,对现有模式和新模式进行了综合效益比较。     

EGNOS: project status overview

The European Geostationary Navigation Overlay System (EGNOS) is being developed in Europe to provide GPS and GLONASS satellite-based augmentation services to aviation, maritime and land users. EGNOS is a major element of the European Satellite Navigation Programme which is jointly being implemented by the European Union, the European Space Agency (ESA) and EUROCONTROL.     

GPS/GLONASS/GALILEO实时服务（RTS）产品性能评估分析

目前,不同机构提供的GNSS实时服务产品性能存在差异。为了全面揭示实时服务产品的性能，为系统服务和用户应用提供参考，统计了各实时服务产品的历元完整率及卫星数量，基于实时轨道和钟差恢复方法，比较分析了产品精度，并评估了产品定位性能。研究结果表明：正常情况下，实时服务产品的历元完整率较高，基本可保持在95%以上，所提供系统的卫星数量保持稳定且充足。对于GPS，各机构卫星实时轨道平均精度基本一致，约为3cm，实时钟差精度略有差别。对于其他GNSS，不同机构产品精度存在差别。利用实时服务产品进行GPS实时精密单点定位的平面精度优于10cm，高程精度优于20cm。相对于GPS单系统，多系统联合定位精度基本一致，但收敛速度明显提升。     

复合材料层合板装配精度影响因素研究

受制造能力的限制,零件加工和装配过程难免存在误差,因此产品的装配精度难以保证。不同于金属材料,复合材料具有各向异性的特性。因此,复合材料产品的装配精度更加难以控制。针对复合材料产品装配精度难以保证的问题,分析了复合材料层合板装配精度影响因素。采用有限元仿真分析方法,通过将同一批零件进行编号并重新配对组合,分析不同零件配对组合方式对装配精度的影响;对于由多个零件组装而成的装配顺序可调整的产品,分析不同装配顺序对装配精度的影响。研究表明,零件的不同配对组合方式和装配顺序都会对装配精度产生影响,因此,在实装前进行装配精度预判,选择最优的零件配对组合方式和装配顺序对提高复合材料产品的装配精度是非常必要的。     

FADS/INS组合法迎角、侧滑角测量方法研究

嵌入式大气数据传感(FADS)系统比传统迎角、侧滑角传感器在测量精度、可靠性、隐身性能上都具有较大的优势,因此该系统可被应用于各型飞行器上。但由于该系统在获得大气参数方面存在延时,所以,它在飞行器机动飞行状态下,迎角和侧滑角的测量精度会下降。针对这一问题,本文提出了以FADS测量结果为基础,采用惯性导航系统(INS)测量的迎角、侧滑角变化量进行修正的FADS/INS组合法迎角、侧滑角测量方法。理论分析和仿真结果表明,该组合系统在飞行器处于平稳和机动飞行时,对迎角、侧滑角的测量均能获得较高精度。     

基于 GPS 和电子海图的落水人员搜救定位系统

现阶段我国的海上搜救工作仍然采用救生衣方式的被动求救和大面积搜索的模式,搜救效率较低.为了解决了这个问题,本文设计实现了基于全球定位系统(GPS)和电子海图的落水人员搜救定位系统.该系统将 GPS、地理信息系统(GIS)、数据库同步、无线传输技术有机结合,有效保障了落水人员的精确定位,为救援船舶及时追踪落水人员提供了可靠的依据     

若干周期性复合材料结构数学均匀化方法的计算精度

数学均匀化方法(MHM)一般需要通过有限元方法(FEM)来实现,摄动阶次和单元阶次直接影响计算结果。在解耦格式中,各阶摄动位移是相应阶次的影响函数和均匀化位移导数的乘积。单元阶次的选取取决于影响函数和均匀化位移的精度要求,而摄动阶次的选取则主要依赖于虚拟载荷的性质和均匀化位移各阶导数的计算精度;针对周期性复合材料杆的静力学问题,在施加不同阶次的载荷时,通过选择合适阶次的单元和摄动阶次得到了精确解。使用类似的方法研究了2D周期性复合材料静力学问题,指出了四边固支作为周期性单胞边界条件以及宏观位移求导精度对计算结果将有很大的影响。强调了二阶摄动对数学均匀化方法计算精度的作用;在数值结果中,应用最小势能原理评估了各阶摄动数学均匀化方法的计算精度,数值比较结果验证了结论的正确性。     

一种远程维护发布系统的设计与实现

为了满足高密度测控任务需求,有效缩短软件维护发布周期,提高工作效率,加强任务软件的有效配置、管理及控制,提供海上测控软件远程支持,研究了一种海上测控软件远程维护发布系统,该系统可实现测控软件的统一维护发布、安装、使用和更新等远程管理。文章详细阐述了该系统的体系结构、C/S模式的软件组成（包括服务器端系统发布管理软件和客户端更新代理软件）、主要功能模块及客户端工作流程,分析阐述了该系统的安全机制等技术。     

High-Resolution Frequency Measurement by Linear Prediction

The efficacy of linear prediction spectrum analysis (LPSA) (also called autoregressive or maximum entrophy spectrum analysis) for problems concerning narrowband signals in noise is examined by means of Monte Carlo simulation. For the case of pure tones (sinusoids) in white noise, both frequency estimation accuracy and resolution of two closely spaced tones with the linear prediction approach are discussed. In addition, estimation of the carrier frequency of a narrowband random (fading) Gaussian signal in noise is considered. The results are compared with standard fast Fourier transform (FFT) methods. These comparisons indicate that there is no significant advantage to using the linear prediction approach with real (bandpass) data. It is concluded that these experiments should be repeated with complex (baseband) data before a complete assessment of the LPS approach can be made.     

半球谐振陀螺发展综述

首先阐述了半球谐振陀螺工作原理及技术优势,后着重对其在美国、俄罗斯、法国的发展历程、应用场景、技术发展、精度指标及进行了综述,同时概述了国内的发展历程、现阶段达到水平。其后,针对海上领域武器系统的特点及需求,在借鉴国外已有应用的基础上,论述半球谐振陀螺在海上应用的可能性及优势。最后对半球谐振陀螺的未来发展进行了展望。     

基于电子海图的船舶动态信息显示系统

随着全球经济发展、海事活动的迅猛增加,我国建立了船舶交通管理系统(VTS)、船舶自动识别系统(AIS)等诸多应用于海事管理工作的信息系统.然而这些系统之间彼此独立、数据分散,且通过纸质海图进行标绘,不能为海事工作提供全面、快速、统一的信息支持.针对这一现状,本文设计了一套基于电子海图的船舶动态信息显示系统.该系统融合了VTS、AIS等现有信息资源,通过电子海图显示平台实现船舶动态信息的可视化,并且能够实时查询综合应急信息,有利于海岸、港湾的船舶管理及海上船舶的安全航行,提高了应急指挥的效率.     

国外机载海面监视雷达发展现状与趋势

首先对目前西方国家装备的较先进的机载海面监视雷达进行了介绍,总结了它们的技术特点。现役机载海面监视雷达具有多功能和多工作模式的特点,除增强了对高海况下的小目标检测能力外,还新增了气象探测、SAR/ISAR和HRRP等先进功能。最后指出了机载海面监视雷达未来发展趋势。     

Radar Altimeter Optimization for Geodesy Over the Sea

The optimum processor and its accuracy limit for radar altimetry for geodetic use over the sea are studied with a model accounting for random surface reflectivity, sea height variation, additive noise, and pointing errors, and allowing for arbitrary antenna patterns, signal modulations, and other system parameters. The ?threshold? case solution (which can have any specified accuracy) dictates a signal modulation bandwidth just shy of resolving the sea height variation and/or illuminated sea area (as scaled into time delay and ?smeared? by pointing errors). For such a modulation a relatively complete solution is obtained. These results are used to determine practical radar altimeter designs, additionally accounting for antenna size, stability, and peak power restraints. Conditions allowing neglecting of limiting or complicating effects due to temporally varying reflectivity, sea height, and vehicle position are given and shown to be satisfied for a typical satellite.