P code direct acquisition is an important technology in satellite navigation system. As the P code has a long period, it is hard to directly acquire. The traditional average method can process multiple code phases in ...P code direct acquisition is an important technology in satellite navigation system. As the P code has a long period, it is hard to directly acquire. The traditional average method can process multiple code phases in a time to shorten the acquisition time. But with the increase of average phase error of the input signal and the local code, the correlation signal-to-noise ratio （SNR） loss increases. To reduce the SNR loss, an improved average method is introduced. A new sequence is generated with a summation of phase shifting sequences to decrease correlation peak loss. Simulation results show that compared with direct average method, the improved average method effectively increases correlation SNR.展开更多
以磁盘冗余阵列(Redundant Array of Inexpensive Disks,RAID)技术中新出现的P-code编码为主要对象,进行了其构造方法、编码及译码算法的详细分析,并首次运用位矩阵(Binary Distribution Matrix,BDM)的方法分析和研究了P-code码。在此...以磁盘冗余阵列(Redundant Array of Inexpensive Disks,RAID)技术中新出现的P-code编码为主要对象,进行了其构造方法、编码及译码算法的详细分析,并首次运用位矩阵(Binary Distribution Matrix,BDM)的方法分析和研究了P-code码。在此基础上,对当前主要RAID-6编码的扩展即更多磁盘数量的容错问题进行了总结与探讨,提出了P-code等垂直最大距离可分码(Maximum Distance Separable,MDS)的扩展将是该领域未来研究的新方向和难点。展开更多
According to the signal-to-noise ratio （SNR） loss of average algorithms in direct P-code acquisition method, this paper analyzes the SNR performance of the overlap average algorithm quantitatively, and derives the r...According to the signal-to-noise ratio （SNR） loss of average algorithms in direct P-code acquisition method, this paper analyzes the SNR performance of the overlap average algorithm quantitatively, and derives the relationship of SNR loss with overlap shift value and initial average phase difference in the overlap average algorithm. On this basis, the bidirectional overlap average algorithm based on optimal correlation SNR is proposed. The algorithm maintains SNR consistent in the entire initial average phase difference space, and has a better SNR performance than the overlap average algorithm. The effectiveness of the algorithm is verified by both theoretical analysis and simulation results. The SNR performance of the bidirectional overlap average algorithm is 5 dB better than that of the direct average algorithm, and 2 dB better than that of the overlap average algorithm, which provides the support for direct P-code acquisition in low SNR.展开更多
文摘P code direct acquisition is an important technology in satellite navigation system. As the P code has a long period, it is hard to directly acquire. The traditional average method can process multiple code phases in a time to shorten the acquisition time. But with the increase of average phase error of the input signal and the local code, the correlation signal-to-noise ratio （SNR） loss increases. To reduce the SNR loss, an improved average method is introduced. A new sequence is generated with a summation of phase shifting sequences to decrease correlation peak loss. Simulation results show that compared with direct average method, the improved average method effectively increases correlation SNR.
文摘以磁盘冗余阵列(Redundant Array of Inexpensive Disks,RAID)技术中新出现的P-code编码为主要对象,进行了其构造方法、编码及译码算法的详细分析,并首次运用位矩阵(Binary Distribution Matrix,BDM)的方法分析和研究了P-code码。在此基础上,对当前主要RAID-6编码的扩展即更多磁盘数量的容错问题进行了总结与探讨,提出了P-code等垂直最大距离可分码(Maximum Distance Separable,MDS)的扩展将是该领域未来研究的新方向和难点。
基金supported by the National Natural Science Foundation of China(61102130)the Innovative Program of the Academy of Opto-Electtronics,Chinese Academy of Sciences(Y12414A01Y)
文摘According to the signal-to-noise ratio （SNR） loss of average algorithms in direct P-code acquisition method, this paper analyzes the SNR performance of the overlap average algorithm quantitatively, and derives the relationship of SNR loss with overlap shift value and initial average phase difference in the overlap average algorithm. On this basis, the bidirectional overlap average algorithm based on optimal correlation SNR is proposed. The algorithm maintains SNR consistent in the entire initial average phase difference space, and has a better SNR performance than the overlap average algorithm. The effectiveness of the algorithm is verified by both theoretical analysis and simulation results. The SNR performance of the bidirectional overlap average algorithm is 5 dB better than that of the direct average algorithm, and 2 dB better than that of the overlap average algorithm, which provides the support for direct P-code acquisition in low SNR.
