大多普勒环境下扩频信号快速捕获算法研究  

Research on Fast Acquisition Algorithm of Spread SpectrumSignal in Large Doppler Environment

作　　者：孙后印 贾方秀 SUN Houyin;JIA Fangxiu(School of Mechanical Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)

机构地区：[1]南京理工大学机械学院,江苏南京210094

出　　处：《测试技术学报》2023年第3期271-276,共6页Journal of Test and Measurement Technology

摘　　要：弹道参数回传系统中,由于弹丸与地面接收机之间较高的相对速度,使地面接收机收到的信号产生很大的多普勒频移,导致其对伪码的捕获难度和捕获时间增加,影响武器在战场中的实时反应能力和打击精度。为了在较大的多普勒频移情况下快速地完成对扩频码的捕获,针对部分匹配滤波结合快速傅里叶变换(Partially Matched Filtering combined with Fast Fourier Transform,PMF-FFT)捕获算法中由FFT运算而导致的扇贝损失现象,分别分析了补零和窗函数法对扇贝损失的改善效果,提出了改进的窗函数结构来对PMF-FFT算法进行改进,对进入FFT运算的数据加改进的布莱克曼窗(Blackman)函数,使得系统的扇贝损失几乎为0。利用MATLAB工具,对改进之后算法的性能进行仿真验证。结果表明,改进后的算法可以明显提高系统的检测概率,大幅降低了平均捕获时间,显著提升了算法的捕获性能。In the ballistic parameter return system,due to the high relative velocity between the projectile and the ground receiver,the signal received by the ground receiver has a large Doppler frequency shift,which leads to an increase in the acquisition difficulty and acquisition time of the pseudo code,and affects the real-time response ability and strike accuracy of the weapon in the battlefield.In order to quickly complete the acquisition of the spread spectrum code in the case of a large Doppler frequency shift,aiming at the phenomenon of scallop loss caused by FFT operation in Partially Matched Filtering combined with Fast Fourier Transform capture algorithm,the improvement effect of zero-padding and window function method on scallop loss is analyzed respectively,and an improved window function structure is proposed to improve the PMF-FFT algorithm,adding an improved Blackman window function to the data entering the FFT operation,so that the scalloping loss of the system is almost 0.Using the MATLAB tool,the performance of the improved algorithm is simulated and verified.The results show that the improved algorithm can significantly improve the detection probability of the system,greatly reduce the average capture time,and considerably improve the capture performance of the algorithm.

关 键 词：扩频信号 PMF-FFT 捕获算法 扇贝损失 窗函数 

分 类 号：TN914.42[电子电信—通信与信息系统]