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Transceiving protocol designc for a free space optical communication system (EI CONFERENCE) 会议论文  OAI收割
2008 International Conference on Optical Instruments and Technology: Optical Systems and Optoelectronic Instruments, November 16, 2008 - November 19, 2008, Beijing, China
Hualong W.; Wanxin S.; Zhongbao X.
收藏  |  浏览/下载:58/0  |  提交时间:2013/03/25
A new transceiving protocol is demonstrated for a Free Space Optical (FSO) communication system  and it's discussed in two parts: the transmitting protocol and the receiving protocol. During the discussion of these two parts  the cooperation of them is also discussed. Different from wired communication  an FSO system modulates the data on a narrow beam of laser transmitting through the free space or the atmosphere  and the protocol presented in this paper is mainly optimized for terrestrial Free Space Optical links  in which the signal channel of the system is mainly the atmosphere. Due to the complex composition and activity of the atmosphere  this signal channel brings in great influence on the transmitting laser in it  for example  the absorption and scattering of the atmosphere molecules and aerosols  the scintillation of received laser power caused by the turbulence of the atmosphere  all of which results in a much higher Bit Error Rate (BER) of the communication system. Thus in designing a protocol for an FSO system  more effort should be taken in the encoding of the data stream  the synchronization of the data stream  error checking and exception handling. The main function of the transmitting protocol includes interfacing the outer input data with a parallel port  buffering the input data  encoding the input data stream  serializing the parallel data and output the serialized data. It also has an output management unit to manage the activity of each part of the transmitting protocol. The main function of the receiving protocol includes filtering and synchronizing the input serial data stream  paralleling the serial data stream  decoding the input data  error checking  exception handling and interfacing the outer receiver with a parallel port. The entire transceiving protocol could be programmed into a single FPGA chip to improve system integrity and reduce the system cost. The presented protocol could be taken as "protocol transparent" for outer interfaces  meaning that when interfacing the presented system to an outer system  you don't have to consider what protocol the outer system transceiving data stream is under  for example  the TCP/IP protocol or anything else  in the case that its I/O interface is a parallel port. Simulation and final experiment prove that the protocol presented is working fine at a certain bit rate scale. 2009 SPIE.  
Design of GPS/INS integrated navigation system based on multisensor information fusion (EI CONFERENCE) 会议论文  OAI收割
6th World Congress on Intelligent Control and Automation, WCICA 2006, June 21, 2006 - June 23, 2006, Dalian, China
Chunmei H.; Yantao T.; Wanxin S.; Mao L.
收藏  |  浏览/下载:38/0  |  提交时间:2013/03/25
Two kinds of design methods of GPS/INS integrated navigation system are presented  that is GPS/INS integrative system and integrated navigation system based on information fusion. By analyzing mathematics model of the first system error  we found that inertia velocity error would cause code loop track error. Consequently  the pseudo range meterage error is interrelated with inertia velocity error  which is complex to calculate. If this relativity is ignored in the state equation and observation equation of this system  it must affect the estimated precision of the kalman filter and maybe the system is unstable. Therefore  the second integrated navigation method is introduced. It adopts information fusion  federal kalman filter and covariance. And consider the above pertinence to analyze the navigation performance of the integration system. Then it gives the flow of federal kalman filter algorithm. By analyzing  the conclusion is that velocity error of integrated navigation system drops from 0.5m/s to below 0.05m/s  and improves the precision and reliability of the navigation system effectively  well continuity and real-time capability. It provides an effective way for data analysis and process of fusion navigation system. 2006 IEEE.