基于MATLAB的卫星导航信号仿真和验证平台

提出了一种GPS/Galileo卫星导航信号仿真和验证平台的软件实现方法,给出了基于MATLAB软件的GPS/Galileo卫星导航信号仿真和验证平台的体系架构,详细描述了卫星导航信号仿真和验证平台主要模块的功能,并给出了实现方法.仿真结果和接收机定位结果验证了基于MATLAB的GPS/Galileo卫星导航信号仿真和验证平台的有效性.     

中央苏区图书出版物研究

从图书出版年度分布、出版部门分布、类别分布等方面，对土地革命战争时期中央苏区出版的446种图书进行统计分析。     

为《无线电导航原理》设计GPS／北斗综合实验平台

现代高科技战争对导航信息的需求越来越大，针对传统导航课程教学模式的不足，从需求分析、平台功能设计和系统架构实现几方面阐述了用于实践教学的GPs／北斗综合实验平台的设计和实现，并对该平台的部分功能进行了展示。该平台的建设和使用，极大的激起了学员学习导航课程的兴趣，收到了良好的教学效果。     

Vector tracking loops in GNSS receivers for dynamic weak signals

Vehicle positioning with the global navigation satellite system(GNSS) in urban environments faces two problems which are attenuation and dynamic.For traditional GNSS receivers hardly able to track dynamic weak signals,the coupling between all visible satellite signals is ignored in the absence of navigation state feedback,and thermal noise error and dynamic stress threshold are contradictory due to non-coherent discriminators.The vector delay/frequency locked loop(VDFLL) with navigation state feedback and the joint vector tracking loop(JVTL) with coherent discriminator which is a synchronization parameter tracking loop based on maximum likelihood estimation(MLE) are proposed to improve the tracking sensitivity of GNSS receiver in dynamic weak signal environments.A joint vector position tracking loop(JVPTL) directly tracking user position and velocity is proposed to further improve tracking sensitivity.The coherent navigation parameter discriminator of JVPTL,being able to ease the contradiction between thermal noise error and dynamic stress threshold,is based on MLE according to the navigation parameter based linear model of received baseband signals.Simulation results show that JVPTL,which combines the advantages of both VDFLL and JVTL,performs better than both VDFLL and JVTL in dynamic weak signal environments.     

Endocrine and environmental aspects of sex differentiation in fish

This paper reviews the current knowledge concerning the endocrine and environmental regulations of both gonadal sex differentiation in gonochoristic and sex inversion in hermaphroditic fish. Within the central nervous system, gonadotropins seem to play a role in triggering sex inversion in hermaphroditic fish. In gonochorists, although potentially active around this period, the hypothalamo-pituitary axis is probably not involved in triggering sex differentiation. Although steroids and steroidogenic enzymes are probably not the initial triggers of sex differentiation, new data, including molecular approaches, have confirmed that they are key physiological steps in the regulation of this process. Environmental factors can strongly influence sex differentiation and sex inversion in gonochoristic and hermaphroditic fish, respectively. The most important environmental determinant of sex would appear to be temperature in the former species, and social factors in the latter. Interactions between environmental factors and genotype have been suggested for both gonochoristic and hermaphroditic fish.     

内蒙古城镇经济区划的研究

为协调城市与其周围地区的经济发展，更好地发挥中心城市的辐射作用，在注重现有区际联系、城镇之间经济技术联系，以及自然环境条件相似性的原则下，把内蒙古城镇划分为蒙东北部、蒙东部、蒙中东部、蒙中部和蒙西部５ 个城镇经济区，内包括１０ 个城镇经济亚区     

基于“精明增长理论”的中部六省会城市发展的比较

20世纪90年代，美国为抑制城市的无序蔓延现象提出精明增长理念，从它被提出至今，相关的研究逐步深化．本文在精明增长视角下构建指标体系，对中部六省会城市进行对比，通过对各城市建设中土地的利用．城市化发展，自然资源与环境状况，公共交通发展及住房现状等问题的研究，发现各省会城市发展中普遍存在的问题．     

基于船舶领域的珠江口通航风险评估

针对珠江口通航水域的交通安全状况,基于动态船舶领域及相关计算模型,建立船舶航行密度、交通冲突和矢量动能风险子模型,并且通过挖掘分析事故数据和船舶动态数据,对载运易发生事故的特殊货物船舶进行附加风险加权;然后,对四项风险因子进行耦合,建立系统性的珠江口通航风险评估模型;最后,针对水域内船舶实时营运状态,率定相关计算参数,运用该耦合模型计算得出"珠江口通航风险综合指数",并将风险指数分为4级.验证分析表明,该通航风险评估模型比较客观实际,可为海事监管提供技术支撑.     

北斗导航辅助移动机器人同时定位和地图构建研究

针对未知环境下移动机器人实时构图和导航问题,将基于激光的环境特征提取和地图构建技术与北斗卫星导航相结合,设计了一种基于特征地图的移动机器人自主导航系统。利用激光提取环境信息,采用点和直线段进行环境表示,结合里程计进行定位,同时进行地图构建。然后在地图上关联北斗坐标,丰富地图信息,根据路径规划方法实现移动机器人自主导航。在Poineer3-AT机器人上实验表明:该方法能够快速提取直观的表示环境信息,并实现自主导航功能,有效提高了移动机器人导航能力。     

厦门港船舶航行环境系统的安全分析

以厦门港海上交通事故资料为基础,从理论上探讨了安全系统工程方法在船舶航行环境系统安全分析中的应用,提出了厦门港船舶航行环境的主要潜在危险,并在事故树分析的基础上,获得了厦门港海上交通事故的航行环境原因及其重要度,这对该水域的系统安全分析和采取安全措施具有一定的意义。