摘要
用相干平均法进行周期性弱信号检测,要求对信号有一定的先验知识,或通过计算能够确定信号周期,在GPS信号捕获应用中有一定的局限性。基于此,首先改进了传统的相干平均法,不用确定信号周期,直接对中频信号进行频率补偿,使周期满足一定条件,提高了信噪比;然后结合FFT和平均相关算法各自在频谱分析中的优点,分别将其应用于多普勒频移和伪码相位的确定。通过对GPS实测数据和高动态模拟数据进行仿真实验验证,结果表明该算法运算量与传统的快捕算法相比大大减少,并且在较低信噪比的环境下是有效的。
Detecting periodical weak signals by coherent average algorithm requires that the transcendental knowledge of the signal is known, or the period of the signal can be confirmed by proper calculation. So there will be some restriction when this algorithm is used for GPS signal acquisition. Based on this point, the traditional coherent average algorithm was improved at first. Directly by compensating the frequency of the intermediate frequency signal, the period of the signal was changed to satisfy the requirement without confirming the period, and the SNR was raised. Then common FFT algorithm and Averaging Correlation algorithm were respectively used to determine the Doppler shift and the initial phase of PN. Sampled data from GPS Receiver and simulated high dynamic GPS signals were used for simulation experiments. Simulation results indicate that the computational cost is decreased a lot, compared with that of the traditional algorithm＇s, and this algorithm will work in order under low SNR conditions.
出处
《系统仿真学报》
CAS
CSCD
北大核心
2013年第3期474-479,共6页
Journal of System Simulation
基金
国家"863"课题项目(2009AA7050411)
关键词
相干平均
高动态
弱信号
快速捕获
平均相关
coherent average
high dynamic
weak signal
fast acquisition
averaging correlation
