针对短突发信号捕获计算复杂度高的问题,提出了一种基于复杂度和性能联合优化的卫星导航信号捕获方法,推导分析采用并行频率搜索的分段相关-视频积累捕获算法的捕获性能和计算复杂度构建联合捕获优化因子.对不同频率搜索间隔、不同接收机灵敏度和不同相关器个数三种情况分别进行了优化设计,得到其计算复杂度和捕获性能联合最优的分段数,并与传统单一捕获性能优化方法对比,仿真实验结果表明:该设计值与载噪比(CNR)、频率搜索间隔等因素相关,可以有效控制捕获算法的计算复杂度;在输入CNR为 45 dB-Hz、相关器个数为 8、多普勒搜索间隔为 2000 Hz的情况下,相比于传统捕获优化方法,可降低 21.2％的计算复杂度.

为了弥补有关低轨导航功率增强信号的兼容性分析相关研究的不足,提出一种基于等效载噪比和谱分离系数的兼容性评估方法:该分析方法类比干扰信号评估方法,计算原信号的等效载噪比损耗和谱分离系数,信号等效载噪比损耗绝对值越大,谱分离系数越大,增强信号兼容性越差;并对不同调制方式的信号分别作兼容性评估,筛选适合低轨导航功率增强信号调制方式.实验结果表明,二相移相键控体制(BPSK)功率增强信号兼容性较差,可以采用二进制偏置载波(BOC)(6,4)信号作为低轨导航功率增强信号;等效载噪比损耗低,谱分离系数小.

针对导航出站信号易被恶意用户利用来获取定位信息的问题,在保证区域外导航服务正常使用的前提下,分析卫星功率增强信号在压制模式下的阻断效果及实施条件:分析通过低轨卫星(LEO)增强实现区域定位阻断的模型,并研究区域定位阻断的评估方法;然后将用户接收等效载噪比做为评估定位阻断性能的核心指标;最后给出相应的载噪比门限的计算方法,用最小星上天线增益评价阻断实施条件.分别对二进制偏置载波(BOC)(1,1)、四相移相键控(QPSK)(10)和二相移相键控(BPSK)(5)调制信号进行阻断仿真.结果表明,对于低轨卫星实施的增强信号,至少需要 15.69 dB的最小星上天线增益;星上增益大小与信号体制、播发干扰类型有关,也取决于信号的抗干扰能力;对于QPSK(10)调制信号,带限白噪声干扰需要 27.93 dB的最小星上天线增益.

随着人们对定位安全和定位准确性要求的提升,仅仅依赖卫星导航系统已经不能满足用户在各种复杂环境下的个性化定位需求,在此背景下,通信导航一体化技术应运而生.移动通信网络具有覆盖广、用户数量大和安全保密性好等优点,将通信系统作为卫星导航系统的有效补充,可以有效提升导航系统的性能.导航通信融合技术已经成为导航领域未来发展的重要技术热点,但目前缺乏清晰的导通融合架构和导通融合方式.从导通融合的技术层面进行划分,提出了波形融合、信息融合、硬件融合三种导通融合方式,分析了通信系统的辅助信息对导航系统精度和抗干扰能力的影响,以及两种典型的导通融合系统的优缺点,并对其未来的发展进行了展望,补充了导航通信融合技术的基础理论,对导通融合技术的发展具有重大意义.

为了优化卫星转发信道饱和条件下信号的接收性能,分析透明转发器饱和状态下互调噪声的产生原因,削弱互调噪声对转发信道载噪比(CNR)恶化的影响.本文通过建立信道模型、计算信道参数、仿真优化分析的方法对问题进行研究.分别研究转发器增益调整对接收端CNR的直接影响与互调信号对CNR的间接影响,并进行了理论计算与仿真分析.仿真结果表明:在饱和条件下,转发器增益回退可以改善CNR损耗.当干扰信号发射功率为45 dBW时,转发器回退?1 dB可以达到最小的CNR损耗为?1.55 dB.随着干扰增强,最优的增益回退值会逐渐增长,同时最小的CNR损耗也会增加,研究成果可应用于卫星转发信道中,为饱和条件下转发器增益调整优化提供指导借鉴.

A jamming technique aiming at phase-coded stepped-frequency radar is proposed.The modulation characteristic of phase-coded stepped-frequency signal and multi-carrier phase-coded signal is analyzed.On the basis of the above,a new jamming technique of multi-carrier phase-coded repeater is presented.The new jamming effectiveness is analyzed theoretically.This method can make phase-coded stepped-frequency radar form several precede and lag lifelike false targets.The relativity of m series in equal length is studied.The opt principle of jamming signal sub-carrier and phase-coded series are presented.The conclusion is proved by simulation experiment.The studied result indicates that this jamming technique is superior to jamming technique of intermittent-sampling predictive repeater.

For group experts' argumentation problem in war design engineering,according to argumentation's topic and goal,group experts' argumentation was divided into three kinds:information-seeking argumentation,inquiry argumentation,deliberation argumentation.Under this classification,this paper built an argumentation model for war design engineering.This model was to construct models for real-world practices of argumentation.It was convenient for experts to see argumentation process.Finally,the paper discussed the application of model in war design engineering.

Data provenance is a hot research issue these years. This paper introduced its concept and profile of this field first based on related works. Then divided it into two parts,one was the model in open world which including two typical formal model,the other was the model in closed world,which including database provenance models and workflow provenance models. After this,it compared over ten provenance systems in technical side. At last proposed some promising aspects of this field.

At present,methods of non-integrity dynamic systems design mainly include adaptive control,predictive control,optimal control,intelligence control and so on.Based on analyzing the recent results in modeling of WMR dynamics,a survey on motion control of WMR based on dynamic models was given.In addition,future research directions on related topics were also discussed.