摘要
随着通信技术的发展,视频监控在水库系统管理中所起的作用越来越明显,安全巡视、实时水位数据采集和监测等以往需要由现场人员亲自操作的工作,现在可借助高科技让现场人员足不出户即可在中央控制室中完成,这是水库自动化的一个体现。水库视频监控系统中,往往由于地理因素的限制,传统的电缆或光纤布线成本极高,施工难度极大。与此同时,考虑到安全性问题,水库系统通信不宜在公网上进行,因此新兴的无线通信方式3G、VPN也不适用。而作为水库无线通信领域中常被人忽视的方式——无线数字微波通信,则可以很好地解决上述问题。
论文以无线数字微波通信技术为研究对象,在理论分析和实物搭建上进行了研究,介绍了微波在不同环境下的传播情况,针对球形地表、大气折射对微波传播的影响,修正了相应的参数;针对课题技术需求,对相关的频段、无线局域网标准、传输带宽、接收点位置等进行了分析和选择;比较了直扩技术和跳频技术的优劣,结合课题实际情况确定直扩技术来实现系统的抗干扰;应用Matlab/Simulink软件平台设计了基于直扩技术的无线数字微波通信系统模型;基于无线网桥模式设计和搭建了无线数字微波通信实物系统,配置了相应的软件参数;通过仿真和调试验证了无线数字微波通信系统在远距离无线通信、抗干扰、远程监控等方面是行之有效的。
论文的成果有:1、采用无线数字微波通信技术来实现视频信号传输、水库系统远程监控、系统抗干扰,解决了有线传输和无线公网传输可行性不高的问题。2、在传统的无线数字微波通信系统基础上加入直扩技术模块来抗干扰。3、对通信系统硬件平台的搭建和软件平台的配置,提出了具体的方法,并调试成功。4、搭建水库系统无线局域网,实现局域网互连。
本论文设计的通信系统虽然可以解决远距离无线通信、抗干扰、远程监控等问题,但还可在更高速传输、直扩技术和跳频技术结合(混频技术)、多普勒频移修正等方面做进一步改善。
With the development of communication technology, video surveillance has played a more important role in reservoir system. Site personnel can do work which they dealt with outside before in central control room by means of video surveillance, such as patrol, monitoring of realtime water level and so on. Because of geographical restriction and high cost, it isn't feasible for us to carry out wired video surveillance by cable or optical fiber in the reservoir system. Meanwhile, network security problem will be caused in public network by rising wireless communication technology which we should not apply, such as 3G, VPN, and so on. However, wireless digital microwave communication technology which is neglected by us can solve those problems above.
This paper introduces wireless digital microwave communication technology as object of study, describes microwave propagation in different conditions, and revises relevant parameters because of the negative impact on microwave communication which is caused by spherical earth surface, atmospheric refraction and so on; According to the request for technology, it analyses and chooses relevant frequency range, standard of wireless local area network (WLAN), transmission bandwidth, location of receiver and so on; It compares direct sequence spread spectrum (DSSS) with frequency hopping spread spectrum (FHSS) and chooses DSSS to carry out anti-jamming; It designs wireless digital microwave communication system based on DSSS in Matlab/Simulink software platform, sets up real communication system based on wireless bridge mode and configurates relevant parameters in software platform. Finally, it proves that the wireless digital microwave communication system is achievable in long-distance communication, anti-jamming and remote video surveillance, after simulation in Matlab/Simulink and debugging in the campus.
The achievement of this paper are as follow:1. It applies wireless digital microwave communication technology to carry out information communication, remote video surveillance and anti-jamming and solve problems of difficulties of wired transmission and communication in the public network.2. It applies DSSS to achieve anti-jamming based on traditional wireless digital microwave communication system.3. It presents solutions to hardware platform construction and software platform configuration and makes successful debugging.4. It constructs wireless local area network to work out interconnection in the reservoir system.
Although the designed communication system can carry out wireless information communication, remote video surveillance and anti-jamming, we could make improvement in the faster transmission, combination of DSSS and FHSS (frequency mixing technology), revise of Doppler frequency shift and so on.
引文
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