摘要
针对短帧突发模式下,直接序列扩频(DSSS)系统短时间内以高检测概率捕获PN码相位这一矛盾,提出了一种数字匹配滤波器(DMF)非相干PN码快速捕获算法.在传统的择大判决法的基础上,用多码元累加单元取代逗留验证单元,从而不再需要估计信道,并提高了捕获速度.分析了该算法在QPSK-DSSS系统下的捕获性能以及频差、信噪比、扩频比等因素对检测概率的影响,实测结果证明了该算法可以在宽信噪比范围和一定频偏环境下实现PN码的快速捕获.
Pseudonoise （PN） code acquisition in a short period of time with high detection probability is required and challenging in short frame burst-mode direct-sequence spread-spectrum （DSSS） systems. A novel noncoherent approach to PN code acquisition, based on digital matched filters（DMFs）, is proposed to solve the problem. It is an improved mode of the traditional maximum-selection method. By using the method of multi-symbol accumulation cell instead of the dwell and verification cell, the proposed algorithm can increase the speed of code acquisition without channel estimation, and suggests itself as an attractive approach in high-speed applications. Its performance in QPSK-DSSS systems, as well as its impact on factors such as frequency shift, signal noise radio （SNR） and spreading factor on detection probability have also been shown. The in the presence of measurement results show that this algorithm is able to capture PN code fastly moderate frequency shift under the conditions of low SNR.
出处
《北京理工大学学报》
EI
CAS
CSCD
北大核心
2005年第8期730-733,738,共5页
Transactions of Beijing Institute of Technology
基金
教育部高等学校优教基金资助项目
关键词
码同步
码捕获
数字匹配滤波器
择大判决法
多码元累加
code synchronization
code acquisition
digital matched filter
maximum-selection method
multi-symbol accumulation
