基于相干累积的跳频扩频信号的捕获方法  

Acquisition method of frequency hopping spread spectrum signal based on coherent accumulation

作　　者：王研 鲁金昆 韩航程[2] WANG Yan;LU Jinkun;HAN Hangcheng(Communication Brigade of General Staff,Beijing Armed Police Corps,Beijing 100027,China;College of Information and Electronics,Beijing Institute of Technology,Beijing 100081,China)

机构地区：[1]武警北京总队参谋部通信大队,北京100027 [2]北京理工大学信息与电子学院,北京100081

出　　处：《计算机应用》2021年第S02期187-191,共5页journal of Computer Applications

摘　　要：为解决高动态低信噪比环境下信号捕获质量差、通信性能弱的问题,提出了一种基于相干累积的跳频扩频信号的捕获算法。该算法首先对中频信号的2倍重采样信号做快速傅里叶变换(FFT);然后与PN码的FFT的共轭相乘,再做快速傅里叶逆变换(IFFT)完成一次相关,最后对多路相关的结果按照行存列取的方式做FFT,进行相干累积,并通过峰均比来判断是否捕获成功。相较于时域相关运算,频域相关运算在码相位上,只需经过2次FFT与1次IFFT运算,算法复杂度低。由于高斯白噪声的特性,相干累积能实现对信号能量的累积,而不累积噪声能量,可实现对微弱信号的捕获。实验结果表明,该算法在信噪比为-21 dB的情况下,可实现对6 000 m/s高动态下3.8 GHz频段附近的信号的捕获,具有较高运算效率和灵敏度。In order to solve the problem of poor signal capture quality and weak communication performance in a high dynamic and low signal-to-noise ratio environment,a frequency hopping spread spectrum signal capture algorithm based on coherent accumulation was proposed. First,Fast Fourier Transform(FFT)was performed on the 2 times resampled signal of the intermediate frequency signal,which was then multiplied with the conjugate of the PN(Pseudo-Noise)code FFT,then an inverse Fast Fourier Transform(IFFT)was performed to complete a correlation,and finally FFT was performed on the results of the multi-path correlation according to the row storage and column fetching method,and the coherent accumulation was performed,and the peak-to-average ratio was used to determine whether the capture was successful. Compared with time-domain correlation operations,frequency-domain correlation operations only need two FFT and one IFFT operations on the code phase,so that the algorithm complexity is low. Due to the characteristics of Gaussian white noise,coherent accumulation realized the accumulation of signal energy,without the accumulation of noise energy,so that weak signals could be captured. Experimental results show that the algorithm can capture signals near the frequency band of 3. 8 GHz under high dynamics at 6 000 m/s when the signal-to-noise ratio is-21 dB,and it has high computational efficiency and sensitivity.

关 键 词：跳频扩频 相干累积 捕获 频域相关 快速傅里叶变换 

分 类 号：TN918[电子电信—通信与信息系统]