高动态链路中折叠PMF-FFT快速捕获方法

Folded PMF-FFT fast acquisition method for high dynamic scenarios

在高动态链路中存在大多普勒频偏,直接序列扩频(direct-sequence spread spectrum,DSSS)接收机必须具有大捕获带宽。现今广泛使用的部分匹配滤波加快速傅里叶变换运算(partial matching filter-fast Fourier transform,PMF-FFT)方法的捕获带宽受限于其FFT运算点数,难以适应高动态场景。因此,提出一种低复杂度大带宽的折叠PMF-FFT捕获方法。该方法首先对接收信号和本地伪码分别作折叠,即分段求和,然后再按照PMF-FFT方法处理。理论分析和仿真结果表明,在更低计算复杂度下,折叠长度为F的折叠PMF-FFT方法的捕获带宽能够达到PMF-FFT方法的F倍。

Due to the big Doppler shift in high dynamic scenarios,it requires extremely large receiver bandwidth to acquire the direct-sequence spread spectrum（DSSS）signal.Nowadays,the partial matching filter-fast Fourier transform（PMF-FFT）acquisition method is widely used for the receiver of the DSSS signal.However,its acquisition bandwidth is limited by FFT points,which brings challenges in high dynamic scenarios.Thus,this paper proposes a low-complexity high-bandwidth folded PMF-FFT method.Firstly,it folds incoming signal,and local pseudo-noise code,as preprocessing.Then,the folded data are processed by the PMF-FFT method.Theoretical analysis and numerical results demonstrate the proposed method with Ffolding times is able to achieve F times bandwidth of that of PMF-FFT.Moreover,it costs even less computational complexity.