针对军校学生课业多、训练多、任务多,可利用的课余时间少且零碎的现状,为提高"军事卫星通信系统"课程的教学效果,以课程第四教学单元"信道资源规划与分配"为例,分别从课前在线课程设计、课中线下课程设计及课后教学评价设计3个方面进行线上线下混合式教学模式研究,探索适合军校学生学习的教学模式,使学生能够真正掌握理论知识,并将其运用到后续课程"军事卫星通信设备"中,为打造符合军校特点的混合式教学模式提供参考.

为全面提升高校本科教育质量水平,教育部要求各高校淘汰"水课"、打造"金课",合理提升课程的深度、难度和挑战度.通过将科研实践与教育教学深度融合,提出一种科研嵌入式教学模式,并基于此模式,以"卫星通信"课程为例,从教学准备、教学实施和教学评价3个方面对符合"金课"要求的教学设计进行了探讨,为打造"金课"提供了参考思路.

Considering the spatial possibility of opportunistic spectrum sharing, sensing-based spectrum sharing method ws applied in the satellite-terrestrial network.The sensing-throughput tradeoff problem was studied, and the throughput is a concave function of the sensing duration was proved.In order to further improved the satellite uplink throughput, the multi-slots sensing method and the cooperative sensing method were proposed.Computer simulations showed that the optimal sensing duration could maximized the uplink throughput, and the multi-slot sensing method or the cooperative sensing method could further improved the throughput of satellite network.

如何科学、有效地整合科研实践和教学这两种基本活动,是高校人才培养和教师队伍建设中亟须解决的问题.对目前高校教育科研实践与教学活动的现状进行了分析,总结了当前二者相互结合与转化的形式和特点,提出科研实践嵌入式教学模式.从教学准备、教学实施及评价机制3个方面对提出的教学模式进行了探讨,为高等教育提高教师综合能力、进一步培养创新型人才提供了新的发展思路.

由于全球卫星导航系统兼容互操作进程不断推进,设计实现具有兼容互操作性能的卫星导航接收终端是接收机领域的又一方向.针对CDMA导航信号设计实现了一种双频兼容互操作接收终端,利用终端控制软件设置终端参数,以通用的数字前端模块、基于时域多通道并行捕获、多相位的相关器实现数字接收处理模块,进一步实现定位解算.该终端具有通用性强、捕获速度快、定位精度高等特点,为提高服务的连续性、完好性和可用性奠定了硬件基础.

针对LT码在采用高斯消元算法时性能分析方法计算复杂且性能较差这一问题,提出了基于概率转移函数的性能分析方法。首先,对两种均匀度分布下的LT码进行了分析并给出了性能的定量表达式;其次,研究了一般性度分布下LT码,给出了一种简单有效的性能衡量的指标参数,并给出了参数的计算表达式;最后,对提出的性能分析方法进行了仿真验证分析。仿真结果表明,与基于生成矩阵满秩上下界计算方法相比较,基于概率转移函数方法对于均匀度分布码字的性能衡量最大误差降低到0.012 4,一般码字计算复杂度降低到O(k~2)。理论分析表明,基于概率转移方法能够更有效地指导通信领域LT码的优化设计。

为满足岗位任职对人才培养需求,日常教学中,需要完成教学目标从“知识为本”向“能力为本”的转变;教学过程从“知识传授”向“知识获取”为主的转变;老师角色从教学主演者向激发学生探索创新的主导者的转变;考核评价方式从传统单一向灵活多样的转变,以期为学生适应岗位任职打下良好基础.笔者依据多年积累的本科生教学经验,对应用牵引、原理映射式教学模式改革设计与实践创新进行了探讨.

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针对北斗二号系统中AS(Authorized Service,授权服务)采用的BPSK(10)、BOC(14,2)、BOC(15,2.5)信号,研究如何抑制多径效应对AS信号跟踪的影响,提高定位精度.对3种信号的自相关特性及功率谱密度进行比对,并在对基于码跟踪环的EML(Early Minus Late,早减迟)和HRC(High Resolution Correlator,高精度相关器)技术进行分析的基础上,将这2种技术用于北斗二号AS信号的多径抑制.仿真表明:EML和HRC均适用于北斗二号AS信号,采用EML时,对BOC(14,2)、BOC(15,2.5)的多径抑制性能优于对BPSK(10)的;采用HRC时,对BPSK(10)的多径抑制性能优于对BOC(14,2)、BOC(15,2.5)的;对于BPSK(10),HRC较EML在误差包络面积上多径抑制性能提高约89.7％;对于BOC(14,2)、BOC(15,2.5),HRC和EML多径抑制性能相当,而EML的计算量相对较小因而整体性能更优;通过减小相关器间隔和增大带宽,可提高多径抑制性能,对BPSK(10)的效果比对BOC(14,2)、BOC(15,2.5)的更为明显.

本文首先介绍了南太平洋大学卫星远程教育网络USPnet的发展历史及现状,重点分析了网络由最初只能提供单向语音通信到目前支持交互式多媒体通信的发展历程;然后分析了USPnet的VSAT网络架构,主校区作为主站,各分校区作为远端站;最后介绍了USPnet提供的应用,包括交互式数据、语音通信和视频会议等。

本文简要介绍了印度"教育卫星"计划以及教育星EDUSAT的发展现状,详细分析了其组网结构、实际应用及下一步发展计划等.

Traffic prediction plays an important role for congestion control and resource allocation of network management. For self-similar network traffic,in virtue of aggregated burstiness on all time scales,the prediction accuracy of traditional traffic prediction methods is generally low.In order to deal with the burstiness in traffic data,a burst decomposition based traffic prediction method is proposed in this paper.More specifically,before performing traffic prediction,the burst will be separated from the traffic by control chart,which leads to the decomposition of original traffic into the burst part and non-burst part.Then Artificial Neural Network(ANN) based method and adaptive template matching based method are used for the prediction of non-burst part and burst part respectively.Finally,the prediction results of original traffic are obtained through combining the predictions of the two parts.The real traffic based experimental results show that the prediction accuracy of the proposed method is higher than that of traditional methods.

本文对墨西哥Satmex系列通信卫星及政府计划组建的新一代端到端卫星通信系统Mexsat系列卫星进行了简要介绍．并对基于“互动教育卫星系统“远程教育典型应用——虚拟大学的应用现状进行阐述；最后指出我国应大力发展基于卫星的远程教育事业。

本文简要介绍了印度。教育卫星。计划以及教育星EDUSAT的发展现状．详细分析了其组网结构、实际应用及下一步发展计划等。

<正>引言音频接收设备已经是日常生活、学习、工作中不可缺少的工具,但是在使用过程中由于某些原因,如切换频道、播放广告等,信号输出时会出现音量大小不一的情况,严重影响用户的收听效果。产生这种音量相差较大的主要原因是音频信号输入的幅度不一致,解决办法就是进行增益控制。

A-GNSS(Assisted Global Navigation Satellite System) is an important technology for navigation in weak signal environments.The principle of the A-GNSS was presented.The structure and mode of typical system AGPS(Assisted Global Positioning System) were discussed.The advantages and disadvantages were analyzed in the end.

To cope with the positioning problem of navigation receiver in weak signal condition,a strapdown inertial navigation platform was built to assist satellite navigation system.In this platform,we selected the ADXL345 which is the three-axis digital accelerometer produced by Analog Devices,Inc.,its digital output data can be accessible through either SPI or I2C digital interface.The ADXL345 outputed data under the control of the CPLD,and it was used to frame together with the gyro output data in the MCU.The data frame was sent through the RS232 serial port to the navigation computer where the strapdown inertial calculation was completed and the ancillary information was provided for satellite navigation system.As a key component of inertial measurement unit,ADXL345 is stable and easy to use.Its 10Hz output rate and about 3.9mg/LSB scale factor in full-resolution mode meets the need of the platform design.And the experimental results show that the horizontal accuracy of coarse alignment of SINS is 0.15°.