基于恒虚警准则的伪码并行捕获门限设置  

Threshold Setting Rule for Parallel PN Code Acquisition Based on Constant False Alarm Rate Criteria

作　　者：杨颖[1] 陈培[1] 王云[1] 陈杰[1] 

机构地区：[1]中国科学院微电子研究所,北京100029

出　　处：《数据采集与处理》2010年第2期234-238,共5页Journal of Data Acquisition and Processing

基　　金：国家"八六三"高技术研究发展计划(2007AA12Z344)资助项目

摘　　要：对含有非相干累加处理的伪码并行捕获算法,其检验量服从中心χ2分布,难以获得门限的闭合表达式。常见的门限设置方法存在无法保证虚警概率的问题。本文提出一种基于恒虚警率(Constant false alarm rate,CFAR)准则的门限设置方法。在分析检验量统计特性的基础上,利用高斯分布合理地近似真实分布,得到高斯近似门限,并对不同虚警概率和非相干累加次数组合下的真实门限与高斯近似门限之间的误差进行分析和归纳,得到了参考门限的闭合表达式。仿真结果表明使用该门限设置法进行捕获判决,得到的虚警概率符合恒虚警概率准则,并能保证系统要求的虚警概率指标。For pseudo noise （PN） code acquisition of the direct sequence spread spectrum receivers, the threshold is crucial for the false alarm probability performance. The decision variables from those acquisition algorithms containing non-coherent integrations are central Chisquare distributed. It is difficult to obtain the closed-form expression for the threshold. Based on constant false alarm rate （CFAR） criteria, a new threshold setting rule is proposed to solve the problem i. e. , the false alarm probability cannot be guaranteed when the conventional methods are applied. By analyzing the statistical property of the decision variable, the rule applies a reasonable Guassian approximation to the true distribution. Then, the expression for the threshold on different false alarm probabilities and non-coherent integrations is given by the theoretical analysis of the error between the Guassian approximate threshold and the true one. Simulation results show that the rule has a good performance in guaranteeing the false alarm probability.

关 键 词：恒虚警准则 伪码并行捕获 门限设置 

分 类 号：TN914.42[电子电信—通信与信息系统]