SO2 and NO2 are the most important pollution in atmosphere.An optimized long path(LP)differential optical absorption spectroscopy(DOAS)system of high light intensity at an ultraviolet(UV)wavelength is proposed and use...SO2 and NO2 are the most important pollution in atmosphere.An optimized long path(LP)differential optical absorption spectroscopy(DOAS)system of high light intensity at an ultraviolet(UV)wavelength is proposed and used to measure the concentration of SO2 and NO2 simultaneously.In contrast to the traditional DOAS,the system adopted a Y-type optical fiber structure instead of a combination of mirrors in the telescope.The UV light intensity test shows that the light intensity of UV can arrive to above 80% of the max measuring range when the light path reaches 135 m,and the integral time of the spectrograph is only 15 ms.The system is proved to be efficacious through laboratory calibration.The maximum error of SO2 calibration is 4.19%,and is 5.22% for NO2.The error of the SO2 and NO2 mixture calibration is within 10%.Field measurement is implemented in a wastewater treatment plant in winter.The measurement light path is 738 m.The concentration of SO2 varies from 6μg/m^3(2.26 ppb)to 20μg/m^3(7.52 ppb),and the concentration of NO2varies from 100μg/m^3(53.2 ppb)to 200μg/m^3(106.4 ppb)approximately.The results are in accordance with the data from a monitoring station nearby in magnitude order and variation tendency mostly.展开更多
针对复杂电磁环境中因低信噪比、快拍采样数据不足、非高斯杂波干扰及多径传播效应等导致的波达方向(Direction of Arrival,DOA)估计性能退化问题,本文提出了一种基于降维高阶累积量与低秩矩阵重构的多源相干信号的DOA估计算法。首先通...针对复杂电磁环境中因低信噪比、快拍采样数据不足、非高斯杂波干扰及多径传播效应等导致的波达方向(Direction of Arrival,DOA)估计性能退化问题,本文提出了一种基于降维高阶累积量与低秩矩阵重构的多源相干信号的DOA估计算法。首先通过构建四阶累积量矩阵扩展阵列孔径,抑制高斯噪声,提升欠定条件下的信号自由度;随后采用高效的降维策略,显著降低计算复杂度;最后通过交替方向乘子法求解低秩约束下的Toeplitz协方差矩阵重构问题,实现了复杂环境下多源相干信号的高精度定位。实验结果表明,本算法在低信噪比及少快拍数下对多源相干信号依然有出色的估计性能,兼具高精度和强抗干扰特性,有良好的工程实用价值。展开更多
针对水下目标方位(Direction of Arrival,DOA)估计准确性实时性的要求,理论分析了互质阵列模型、压缩感知DOA估计的原理,设计实现了基于FPGA的互质阵列压缩感知算法DOA估计系统。首先介绍了系统开发环境,包括平台选择、开发流程等;其次...针对水下目标方位(Direction of Arrival,DOA)估计准确性实时性的要求,理论分析了互质阵列模型、压缩感知DOA估计的原理,设计实现了基于FPGA的互质阵列压缩感知算法DOA估计系统。首先介绍了系统开发环境,包括平台选择、开发流程等;其次,介绍了硬件系统的整体框架,重点说明了PS与PL之间的数据传递流程和硬件各模块实现过程,并仿真验证了该系统的正确性。在Xilinx FPGA平台上进行了湖试数据的处理,完成了数据运算参数的统计收集,验证了DOA估计的有效性,并计算了运算耗时。结果表明,所设计的系统能够正确完成DOA估计并满足实时性要求。展开更多
基金supported by the National Natural Science Foundation of China(No.91741203)the Science and Technology Plan of Zhejiang Province(Nos.2018C03041 and 2018C03007).
文摘SO2 and NO2 are the most important pollution in atmosphere.An optimized long path(LP)differential optical absorption spectroscopy(DOAS)system of high light intensity at an ultraviolet(UV)wavelength is proposed and used to measure the concentration of SO2 and NO2 simultaneously.In contrast to the traditional DOAS,the system adopted a Y-type optical fiber structure instead of a combination of mirrors in the telescope.The UV light intensity test shows that the light intensity of UV can arrive to above 80% of the max measuring range when the light path reaches 135 m,and the integral time of the spectrograph is only 15 ms.The system is proved to be efficacious through laboratory calibration.The maximum error of SO2 calibration is 4.19%,and is 5.22% for NO2.The error of the SO2 and NO2 mixture calibration is within 10%.Field measurement is implemented in a wastewater treatment plant in winter.The measurement light path is 738 m.The concentration of SO2 varies from 6μg/m^3(2.26 ppb)to 20μg/m^3(7.52 ppb),and the concentration of NO2varies from 100μg/m^3(53.2 ppb)to 200μg/m^3(106.4 ppb)approximately.The results are in accordance with the data from a monitoring station nearby in magnitude order and variation tendency mostly.
文摘针对复杂电磁环境中因低信噪比、快拍采样数据不足、非高斯杂波干扰及多径传播效应等导致的波达方向(Direction of Arrival,DOA)估计性能退化问题,本文提出了一种基于降维高阶累积量与低秩矩阵重构的多源相干信号的DOA估计算法。首先通过构建四阶累积量矩阵扩展阵列孔径,抑制高斯噪声,提升欠定条件下的信号自由度;随后采用高效的降维策略,显著降低计算复杂度;最后通过交替方向乘子法求解低秩约束下的Toeplitz协方差矩阵重构问题,实现了复杂环境下多源相干信号的高精度定位。实验结果表明,本算法在低信噪比及少快拍数下对多源相干信号依然有出色的估计性能,兼具高精度和强抗干扰特性,有良好的工程实用价值。
文摘针对水下目标方位(Direction of Arrival,DOA)估计准确性实时性的要求,理论分析了互质阵列模型、压缩感知DOA估计的原理,设计实现了基于FPGA的互质阵列压缩感知算法DOA估计系统。首先介绍了系统开发环境,包括平台选择、开发流程等;其次,介绍了硬件系统的整体框架,重点说明了PS与PL之间的数据传递流程和硬件各模块实现过程,并仿真验证了该系统的正确性。在Xilinx FPGA平台上进行了湖试数据的处理,完成了数据运算参数的统计收集,验证了DOA估计的有效性,并计算了运算耗时。结果表明,所设计的系统能够正确完成DOA估计并满足实时性要求。
