为降低水下通信中出现的多径和多普勒效应,提高水下目标探测精度,采用双曲调频信号作为探测信号,利用双曲调频信号(hyperbolic modulation frequency,HFM)时频变化具有双曲线的特征,通过建立HFM信号时间-尺度级联原子库模型,在原子库中寻找最优解,进而对HFM信号的两个频率变化因子进行估计。计算机仿真和水池实验的结果均证明,相较于现在常用的小波-拉东变换(wavelet-Radon)估计方法,本方法的均方根误差小于1%,因此在水下目标探测中有较大的应用价值。To reduce the multi-path and Doppler effects occurring in underwater communications and to increase the precision of underwater target detection,we employ a modulation frequency signal as the detection signal. A hyperbolic modulation frequency( HFM) signal is hyperbolic in the time-frequency domain. In view of this feature,we establish a time-scale cascade dictionary model to find the optimal solution; furthermore,two frequency variation factors of the HFM signal are estimated. The simulation results and the pool trials show that the proposed algorithm performs well,and its accuracy is superior to that of the commonly used wavelet-Radon transform. The root mean square error of the frequency variation factors is 1% lower than that achieved using the wavelet Radon transform.This demonstrates the potential of the suggested algorithm for underwater target detection.国家自然科学基金项目(61471309,61107023);; 国家教育部博士点基金项目(20110121120020);; 福建省自然科学基金项目(2013J01258);福建省自然科学基金项目(2010J01344);; 福建省重点基金项目(2012H1012
