The root multiple signal classification（root-MUSIC） algorithm is one of the most important techniques for direction of arrival（DOA） estimation. Using a uniform linear array（ULA） composed of M sensors, this metho...The root multiple signal classification（root-MUSIC） algorithm is one of the most important techniques for direction of arrival（DOA） estimation. Using a uniform linear array（ULA） composed of M sensors, this method usually estimates L signal DOAs by finding roots that lie closest to the unit circle of a（2M-1）-order polynomial, where L 〈 M. A novel efficient root-MUSIC-based method for direction estimation is presented, in which the order of polynomial is efficiently reduced to 2L. Compared with the unitary root-MUSIC（U-root-MUSIC） approach which involves real-valued computations only in the subspace decomposition stage, both tasks of subspace decomposition and polynomial rooting are implemented with real-valued computations in the new technique,which hence shows a significant efficiency advantage over most state-of-the-art techniques. Numerical simulations are conducted to verify the correctness and efficiency of the new estimator.展开更多
The contents of As, Cd, Hg and Pb in root tubers of annual and biennial plants of Polygonum multiflorum Thunb. in Jiangsu Province were 0.32, 0.24, 0, 1.25 and 0.20, 0.26, 1.67×10 -4, 1.32 mg·kg -1 respectiv...The contents of As, Cd, Hg and Pb in root tubers of annual and biennial plants of Polygonum multiflorum Thunb. in Jiangsu Province were 0.32, 0.24, 0, 1.25 and 0.20, 0.26, 1.67×10 -4, 1.32 mg·kg -1 respectively, which totally met the standards of GTSIEMPP (WM2—2001). Biology concentration factors (BCF) of Cd is 2.4-2.6, which indicates that the root tuber of P. multiflorum has a strong accumulative action to Cd. While the accumulative action to As, Hg and Pb is not strong, BCF are 0.025-0.015, 0-6.40×10 -4 and 0.06 respectively.展开更多
传统的波达方向(direction of arrival,DOA)估计算法在独立信号和相干信号同时存在时往往失效或者性能下降;因而寻求可以同时估计独立信号和相干信号的测向算法具有重要意义。基于均匀线阵接收到信号的特点,提出了一种简单有效的独立信...传统的波达方向(direction of arrival,DOA)估计算法在独立信号和相干信号同时存在时往往失效或者性能下降;因而寻求可以同时估计独立信号和相干信号的测向算法具有重要意义。基于均匀线阵接收到信号的特点,提出了一种简单有效的独立信号和相干信号DOA估计新方法。该方法首先利用求根多重信号分类(root-mutiple signal classification,root-MUSIC)算法进行DOA估计,并根据相干源对应根的特点来消除相干信号的干扰,从而获得独立信号的波达方向;然后利用阵列接收数据协方差矩阵中独立信号的托普利兹(Toeplitz)特性,从中去除独立信号的数据分量,再利用改进矢量重构和总体最小二乘-旋转不变子空间(total least square-estimation of signal parameters via rotational invariance technique,TLS-ESPRIT)算法来估计相干信号的波达方向。理论分析和实验仿真结果表明,所提方法具有一定的阵列扩展能力,且计算量小、估计性能好。展开更多
基金supported by the National Natural Science Foundation of China(61501142)the Shandong Provincial Natural Science Foundation(ZR2014FQ003)+1 种基金the Special Foundation of China Postdoctoral Science(2016T90289)the China Postdoctoral Science Foundation(2015M571414)
文摘The root multiple signal classification（root-MUSIC） algorithm is one of the most important techniques for direction of arrival（DOA） estimation. Using a uniform linear array（ULA） composed of M sensors, this method usually estimates L signal DOAs by finding roots that lie closest to the unit circle of a（2M-1）-order polynomial, where L 〈 M. A novel efficient root-MUSIC-based method for direction estimation is presented, in which the order of polynomial is efficiently reduced to 2L. Compared with the unitary root-MUSIC（U-root-MUSIC） approach which involves real-valued computations only in the subspace decomposition stage, both tasks of subspace decomposition and polynomial rooting are implemented with real-valued computations in the new technique,which hence shows a significant efficiency advantage over most state-of-the-art techniques. Numerical simulations are conducted to verify the correctness and efficiency of the new estimator.
文摘The contents of As, Cd, Hg and Pb in root tubers of annual and biennial plants of Polygonum multiflorum Thunb. in Jiangsu Province were 0.32, 0.24, 0, 1.25 and 0.20, 0.26, 1.67×10 -4, 1.32 mg·kg -1 respectively, which totally met the standards of GTSIEMPP (WM2—2001). Biology concentration factors (BCF) of Cd is 2.4-2.6, which indicates that the root tuber of P. multiflorum has a strong accumulative action to Cd. While the accumulative action to As, Hg and Pb is not strong, BCF are 0.025-0.015, 0-6.40×10 -4 and 0.06 respectively.
文摘传统的波达方向(direction of arrival,DOA)估计算法在独立信号和相干信号同时存在时往往失效或者性能下降;因而寻求可以同时估计独立信号和相干信号的测向算法具有重要意义。基于均匀线阵接收到信号的特点,提出了一种简单有效的独立信号和相干信号DOA估计新方法。该方法首先利用求根多重信号分类(root-mutiple signal classification,root-MUSIC)算法进行DOA估计,并根据相干源对应根的特点来消除相干信号的干扰,从而获得独立信号的波达方向;然后利用阵列接收数据协方差矩阵中独立信号的托普利兹(Toeplitz)特性,从中去除独立信号的数据分量,再利用改进矢量重构和总体最小二乘-旋转不变子空间(total least square-estimation of signal parameters via rotational invariance technique,TLS-ESPRIT)算法来估计相干信号的波达方向。理论分析和实验仿真结果表明,所提方法具有一定的阵列扩展能力,且计算量小、估计性能好。
