针对非圆相干信号的解相干问题,给出了一种新的特征空间算法(eigenspace-direction of arrival,ES-DOA)。利用信号源的非圆特性,虚拟地扩展了阵元个数,使阵列信息增至扩展前的两倍,对信号源数目的估计突破了M-1(M为阵元数)的限制;将信...针对非圆相干信号的解相干问题,给出了一种新的特征空间算法(eigenspace-direction of arrival,ES-DOA)。利用信号源的非圆特性,虚拟地扩展了阵元个数,使阵列信息增至扩展前的两倍,对信号源数目的估计突破了M-1(M为阵元数)的限制;将信息量加倍后的协方差矩阵加以重构,给出一种新的特征空间算法进行解相干,最大限度地利用了噪声子空间与信号子空间的信息,避免了空间平滑思想的阵列孔径损失及最大似然算法运算量过大的问题;该方法还对信号源功率进行了估计,提高了对小能量信号的估计成功概率。仿真结果表明,该方法对波达方向估计具有很好的鲁棒性。展开更多
The onset times of acoustic signals with spikes,heavy bodies and unclear takeoffs are difficult to be picked accurately by the automatic method at present.To deal with this problem,an improved joint method based on th...The onset times of acoustic signals with spikes,heavy bodies and unclear takeoffs are difficult to be picked accurately by the automatic method at present.To deal with this problem,an improved joint method based on the discrete wavelet transform(DWT),modified energy ratio(MER)and Akaike information criterion(AIC)pickers,has been proposed in this study.First,the DWT is used to decompose the signal into various components.Then,the joint application of MER and AIC pickers is carried out to pick the initial onset times of all selected components,where the minimum AIC position ahead of MER onset time is regarded as the initial onset time.Last,the average for initial onset times of all selected components is calculated as the final onset time of this signal.This improved joint method is tested and validated by the acoustic signals with different signal to noise ratios(SNRs)and waveforms.The results show that the improved joint method is not affected by the variations of SNR,and the onset times picked by this method are always accurate in different SNRs.Moreover,the onset times of all acoustic signals with spikes,heavy bodies and unclear takeoffs can be accurately picked by the improved joint method.Compared to some other methods including MER,AIC,DWT-MER and DWT-AIC,the improved joint method has better SNR stabilities and waveform adaptabilities.展开更多
文摘针对非圆相干信号的解相干问题,给出了一种新的特征空间算法(eigenspace-direction of arrival,ES-DOA)。利用信号源的非圆特性,虚拟地扩展了阵元个数,使阵列信息增至扩展前的两倍,对信号源数目的估计突破了M-1(M为阵元数)的限制;将信息量加倍后的协方差矩阵加以重构,给出一种新的特征空间算法进行解相干,最大限度地利用了噪声子空间与信号子空间的信息,避免了空间平滑思想的阵列孔径损失及最大似然算法运算量过大的问题;该方法还对信号源功率进行了估计,提高了对小能量信号的估计成功概率。仿真结果表明,该方法对波达方向估计具有很好的鲁棒性。
基金Project(2015CB060200) supported by the National Basic Research Program of ChinaProject(41772313) supported by the National Natural Science Foundation of ChinaProject(2018zzts736) supported by the Independent Innovation Exploration Project of Central South University,China
文摘The onset times of acoustic signals with spikes,heavy bodies and unclear takeoffs are difficult to be picked accurately by the automatic method at present.To deal with this problem,an improved joint method based on the discrete wavelet transform(DWT),modified energy ratio(MER)and Akaike information criterion(AIC)pickers,has been proposed in this study.First,the DWT is used to decompose the signal into various components.Then,the joint application of MER and AIC pickers is carried out to pick the initial onset times of all selected components,where the minimum AIC position ahead of MER onset time is regarded as the initial onset time.Last,the average for initial onset times of all selected components is calculated as the final onset time of this signal.This improved joint method is tested and validated by the acoustic signals with different signal to noise ratios(SNRs)and waveforms.The results show that the improved joint method is not affected by the variations of SNR,and the onset times picked by this method are always accurate in different SNRs.Moreover,the onset times of all acoustic signals with spikes,heavy bodies and unclear takeoffs can be accurately picked by the improved joint method.Compared to some other methods including MER,AIC,DWT-MER and DWT-AIC,the improved joint method has better SNR stabilities and waveform adaptabilities.
