基于有限维种子累积序贯估计的PN码快捕算法

提出了一种基于有限维种子累积序贯估计（FSASE，Finite Seed Accumulation of Sequential Estimation）的直接扩频序列快速捕获算法。该算法既能解决SASE算法只能工作在理想情况（不能有多普勒频移，PN码偏等影响）的问题，又能克服RASE算法不能在低信噪比下工作的缺陷。文中采用生成函数流图法推导出了衰落信道下FSASE算法平均捕获时间的闭式解。理论分析和计算机模拟表明，该算法即使在很低的信噪比下也具有优良的性能，并且实现复杂度低，具有工程实用价值。

Fast Acquisition of Pseudonoise Sequence Based on Finite Seed Accumulation of Sequential Estimation

This paper presents a method for fast acquisition of pseudonoise(PN) sequence based on finite seed accumulation of sequential estimation.It solves not only the problem of that SASE method must work in the ideal environment(there is no effect of Doppler frequency shift,PN chip offset),but also the problem of that RASE method can not work well at low signal-to-noise ratios(SNR).The mean acquisition time of the FSASE method is derived by the generating function flow graph technique for the fading channel.Analysis in theory and numerical results show that the proposed FSASE works well even at low SNR.And it can be designed by simple hardware and used in the engineering.