基于FFT的伪码快速捕获算法研究

Research on the PN Code Fast Acquisition Algorithm Based on FFT

扩频通信系统对信号捕获性能的要求不断提高,文中研究一种基于FFT的伪码快速捕获算法。应用易于硬件实现的基2-FFT算法。为了得到2~N长序列。讨论补零、线性内插、邻近取值、sinc函数内插四种重采样方法,分析比较他们在捕获过程中时相关峰值计算结果的影响。其中sinc函数内插法可以得到最好的捕获效果。针对微弱和高比特率信号,详细介绍并分析一种多数据住相关值整合算法。仿真证明这种捕获算法可以提高微弱信号的检测性能。

With the increasing demands on signal acquisition in direct spread spectrum system(DS-SS),an FFT-based strategy is studied.Badix-2 FFT,which is easier to be implemented on hardware is introduced and in order to get 2~N-long se- quence,four re-sampling methods are analyzed and compared.The simulation indicates that the application of sinc-interpolation could reach the best correlation performance.To acquire the signal on the low SNR(signal-noise ratio) and high bit rate environ- ment,the algorithm of PN code correlation power integrated in multiple periods and data bits is developed and simulated.And the result presents its contribution to better detection performance for weak signals.