在全球卫星导航系统(GNSS)中, 传统N中取M检测算法由于检测次数固定不变, 使得捕获时间变长, 而信号强度较强时并不需要执行完所有的检测次数。提出一种改进的N中取M检测算法, 借用唐检测的思想即N次中只要有M次检测到信号就可以判定信号存在而跳出检测。仿真结果表明: 当信号强度较弱为-135dB时, N中取M的平均检测次数为8, 改进算法的平均检测次数为7.3694; 信号强度较强为-131dB时, N中取M平均检测次数为8, 改进算法的平均检测次数为5.2234。因此改进算法可以提高捕获速度尤其是在一些信号强度较强的环境下, 同时改进算法的检测概率与虚警概率跟N中取M算法一致。

The detection number for the traditional MofN detection algorithm is fixed in global navigation satellite system(GNSS), thus the capture time becomes longer. But it is unnecessary to perform all the detections when the signal strength is strong. In order to resolve this problem, an improved MofN detection algorithm is presented, in which the idea of Tang detection is applied, that is, as long as the signal is detected M times in N times, the signal is decided to stop the detection. Simulation results show that the average detection number of the MofN detection algorithm and the improved algorithm is 8 and 7.3694 respectively when the signal strength is weaker as -135dB. And the average detection number of the MofN detection algorithm and the improved algorithm is 8 and 5.2234 respectively when the signal strength is stronger as -131dB. Therefore, the improved algorithm can improve the capture speed especially in some stronger signal environment. At the same time, the detection probability and the false alarm probability of the improved algorithm are consistent with those of the MofN detection algorithm.