基于PMF-FFT的低信噪比突发扩频捕获方案设计  

Design of Burst Spread Spectrum Acquisition Scheme Based on PMF-FFT With Low SNR

作　　者：魏鑫程 李晓亮 马荣 任欢 平续斌[1] WEI Xincheng;LI Xiaoliang;MA Rong;REN Huan;PING Xubin(Xidian University,Xi'an 710071,China;Beijing Research Institute of Telemetry,Beijing 100076,China)

机构地区：[1]西安电子科技大学,西安710071 [2]北京遥测技术研究所,北京100076

出　　处：《遥测遥控》2025年第2期48-55,共8页Journal of Telemetry,Tracking and Command

摘　　要：卫星的快速相对运动会导致突发扩频信号产生多普勒频移。在低信噪比环境下,信号受噪声干扰严重,传统捕获算法对大范围多普勒频移的捕获能力受限。针对上述问题,本文设计了一种导频加部分匹配滤波和快速傅里叶变换(Partial Match Filter-Fast Fourier Transform,PMF-FFT)的并行突发扩频信号捕获算法。该算法利用导频信息以及多路并行处理实现对多普勒频移和码相位的快速捕获,大幅降低突发信号的捕获时间。通过对捕获算法的数学模型和捕获损耗进行详细分析,并对FFT进行补零以降低捕获系统的扇贝损失,本文最后设计了一种基于恒虚警率和指定检测概率的最短同步段的设计方案。仿真结果表明:虚警概率为10-6下,捕获算法对信噪比为-31 dB的突发信号捕获概率达到99%,验证了设计方案的可行性。The rapid relative motion of satellites causes the burst spread-spectrum signals to produce a Doppler frequency shift.In low signal-to-noise ratio(SNR)environments,the traditional acquisition algorithms are limited in their abilities to capture large Doppler frequency shift when signals are seriously disturbed by noise.In view of the above problems,this paper designs a parallel burst spread spectrum signal acquisition algorithm based on pilot information and Partial Match Filter-Fast Fourier Transform(PMFFFT).The algorithm utilizes pilot information and multi-path parallel processing method to achieve fast acquisition of Doppler frequency shift and PN code,which greatly reduces the acquisition time of burst signal.Firstly,the mathematical model and the acquisition loss of the algorithm are analyzed in detail.Then,the scallop loss of the acquisition system is reduced by zeroing the FFT.Finally,a method of the shortest synchronization segment based on a constant false-alarm rate and a specified detection probability is designed.The simulation results show that the acquisition probability of the proposed algorithm reaches 99%for burst signals under the-31 dB signal-to-noise ratio when the false alarm probability is 10-6,which verifies the feasibility of the design method.

关 键 词：突发信号 信号捕获 捕获损耗 PMF-FFT 

分 类 号：TN914.42[电子电信—通信与信息系统]