The schemes and effects of electronically jamming GPS’s C/A code receivers are studied by using CW as the narrow band jamming signal and BPSK signal modulated by Gold code which is incoherent to that adopted by GPS ...The schemes and effects of electronically jamming GPS’s C/A code receivers are studied by using CW as the narrow band jamming signal and BPSK signal modulated by Gold code which is incoherent to that adopted by GPS as the wide band one. By simulating with Monte Carlo method and programming in Matlab language, the various jamming results in terms of bit error rate under several jamming scenarios are obtained. Through analyzing the simulation results and quantitative dependences of jamming effects on the distance from jammer to GPS receiver and the jammer’s height over ground, it is concluded that jamming with wide band jammer is much more effective than that with narrow band one.展开更多
The ionospheric time delay is one of the main error sources in C/A code GPS navigation and positioning applications. In this paper, a method is proposed for real-time dual-frequency ionospheric time-delay correcting u...The ionospheric time delay is one of the main error sources in C/A code GPS navigation and positioning applications. In this paper, a method is proposed for real-time dual-frequency ionospheric time-delay correcting using a C/A code GPS receiver, and the principle of the circuit block diagram for this method is analyzed with its feasibility theoretically demonstrated.展开更多
This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（...This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（FFT） correlation through hyper code technique and the amount of points in every FFT correlation by using an averaging correlation method. To validate the proposed acquisition performance, the paper applies this algorithm to the real L2C signal collected by the global positioning system（GPS） L2C intermediate frequency（IF） signal sampler—SIS100L2C. The acquisition results show that the proposed modified algorithm can acquire the code phase accurately with less calculation and its acquisition performance is better than the single hyper code method.展开更多
We generalized an constructing method of noncoherent unitary space time codes (N-USTC) over Rayleigh flat fading channels. A family of N-USTCs with T symbol peroids, M transmit and N receive antennas was constructed b...We generalized an constructing method of noncoherent unitary space time codes (N-USTC) over Rayleigh flat fading channels. A family of N-USTCs with T symbol peroids, M transmit and N receive antennas was constructed by the exponential mapping method based on the tangent subspace of the Grassmann manifold. This exponential mapping method can transform the coherent space time codes (C-STC) into the N-USTC on the Grassmann manifold. We infered an universal framework of constructing a C-STC that is designed by using the algebraic number theory and has full rate and full diversity (FRFD) for t symbol periods and same antennas, where M, N, T, t are general positive integer. We discussed the constraint condition that the exponential mapping has only one solution, from which we presented a approach of searching the optimum adjustive factor αopt that can generate an optimum noncoherent codeword. For different code parameters M, N, T, t and the optimum adjustive factor αopt, we gave the simulation results of the several N-USTCs.展开更多
目的:设计国际疾病分类(international classification of diseases,ICD)国际疾病编码管理信息系统,以为医疗机构提供高效、准确、安全的编码管理服务。方法:该系统基于客户端/服务器(Client/Server,C/S)模式设计,使用Oracle数据库,通过...目的:设计国际疾病分类(international classification of diseases,ICD)国际疾病编码管理信息系统,以为医疗机构提供高效、准确、安全的编码管理服务。方法:该系统基于客户端/服务器(Client/Server,C/S)模式设计,使用Oracle数据库,通过Dapper对象关系映射(object-relational mapping,ORM)技术实现与Oracle数据库的数据交互,采用C#编程语言开发。整个系统包括用户权限管理、疾病编码管理、患者信息管理、疾病统计分析和系统管理5个功能模块。结果:采用该系统可以高效地进行ICD编码的查询、审核及数据统计分析,显著提高了ICD编码管理的效率和准确性。结论:该系统为医疗机构提供了一种有效的疾病编码管理工具,有助于医疗服务质量和管理效率的提升。展开更多
At present, there are some static code analyses and optimizations that can be applied to Concurrent C programs to improve their performance or verify their logical correctness. These analyses and optimizations are int...At present, there are some static code analyses and optimizations that can be applied to Concurrent C programs to improve their performance or verify their logical correctness. These analyses and optimizations are inter-process. In order to make their implementation easy, we propose a new method to construct an optimizing compiling system CCOC for Concurrent C. CCOC supports inter-process code analysis and optimization to Concurrent C programs and does not affect the system's portability and separate compilation of source programs. We also discuss some implementation details of CCOC briefly.展开更多
文摘The schemes and effects of electronically jamming GPS’s C/A code receivers are studied by using CW as the narrow band jamming signal and BPSK signal modulated by Gold code which is incoherent to that adopted by GPS as the wide band one. By simulating with Monte Carlo method and programming in Matlab language, the various jamming results in terms of bit error rate under several jamming scenarios are obtained. Through analyzing the simulation results and quantitative dependences of jamming effects on the distance from jammer to GPS receiver and the jammer’s height over ground, it is concluded that jamming with wide band jammer is much more effective than that with narrow band one.
文摘The ionospheric time delay is one of the main error sources in C/A code GPS navigation and positioning applications. In this paper, a method is proposed for real-time dual-frequency ionospheric time-delay correcting using a C/A code GPS receiver, and the principle of the circuit block diagram for this method is analyzed with its feasibility theoretically demonstrated.
基金supported by the Fundamental Research Fund for the Central Universities(NS2013016)
文摘This paper provides a direct and fast acquisition algorithm of civilian long length（CL） codes in the L2 civil（L2C） signal. The proposed algorithm simultaneously reduces the number of fast Fourier transformation（FFT） correlation through hyper code technique and the amount of points in every FFT correlation by using an averaging correlation method. To validate the proposed acquisition performance, the paper applies this algorithm to the real L2C signal collected by the global positioning system（GPS） L2C intermediate frequency（IF） signal sampler—SIS100L2C. The acquisition results show that the proposed modified algorithm can acquire the code phase accurately with less calculation and its acquisition performance is better than the single hyper code method.
文摘We generalized an constructing method of noncoherent unitary space time codes (N-USTC) over Rayleigh flat fading channels. A family of N-USTCs with T symbol peroids, M transmit and N receive antennas was constructed by the exponential mapping method based on the tangent subspace of the Grassmann manifold. This exponential mapping method can transform the coherent space time codes (C-STC) into the N-USTC on the Grassmann manifold. We infered an universal framework of constructing a C-STC that is designed by using the algebraic number theory and has full rate and full diversity (FRFD) for t symbol periods and same antennas, where M, N, T, t are general positive integer. We discussed the constraint condition that the exponential mapping has only one solution, from which we presented a approach of searching the optimum adjustive factor αopt that can generate an optimum noncoherent codeword. For different code parameters M, N, T, t and the optimum adjustive factor αopt, we gave the simulation results of the several N-USTCs.
文摘目的:设计国际疾病分类(international classification of diseases,ICD)国际疾病编码管理信息系统,以为医疗机构提供高效、准确、安全的编码管理服务。方法:该系统基于客户端/服务器(Client/Server,C/S)模式设计,使用Oracle数据库,通过Dapper对象关系映射(object-relational mapping,ORM)技术实现与Oracle数据库的数据交互,采用C#编程语言开发。整个系统包括用户权限管理、疾病编码管理、患者信息管理、疾病统计分析和系统管理5个功能模块。结果:采用该系统可以高效地进行ICD编码的查询、审核及数据统计分析,显著提高了ICD编码管理的效率和准确性。结论:该系统为医疗机构提供了一种有效的疾病编码管理工具,有助于医疗服务质量和管理效率的提升。
文摘At present, there are some static code analyses and optimizations that can be applied to Concurrent C programs to improve their performance or verify their logical correctness. These analyses and optimizations are inter-process. In order to make their implementation easy, we propose a new method to construct an optimizing compiling system CCOC for Concurrent C. CCOC supports inter-process code analysis and optimization to Concurrent C programs and does not affect the system's portability and separate compilation of source programs. We also discuss some implementation details of CCOC briefly.
