基于时频联合的长PN序列快速捕获算法

Fast Sequential Acquisition Method Based on Time and Frequency Combined Domain

针对低信噪比下长周期PN序列捕获中存在的捕获速度慢、捕获效率低等问题,从直接捕获角度出发,提出一种基于时频联合的长PN序列快速捕获算法。首先,对部分频域捕获进行研究,提出了频域分段和频域采样两种频域捕获方案。将部分频域捕获与时域均值捕获算法结合,利用本地均值序列和接收均值序列进行频域采样捕获,有效提高了捕获效率。仿真结果表明,在信噪比-10dB、捕获相位范围221的条件下,该算法捕获速度较时域快速算法提高约15倍,能够较好地适用于低信噪比下长PN序列快速捕获。

To solve sequential acquisition problems with long pseudo-noise code, such as low speed and poor efficiency in the environment of few received sequences, a fast sequential acquisition meth- od based on time and frequency combined domain is proposed from the perspective of direct acquisi- tion（TFSA）. Firstly, frequency intersecting and frequency sampling frequency subset schemes are designed by the study of acquisition model based on frequency subset. And then the sampling meth- od in frequency domain and average algorithm in time domain are combined to improve capture effi- ciency, where the local average sequences and received average sequences are effectively used. The simulation results show that the acquisition speed of TFSA is 15 times faster than time domain fast acquisition methods when the sequence SNR is - 10dB and the capture range is 22t. TFSA is quite suitable for long PN sequence acquisition in low SNR environment.