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基于亚采样点级别的TDOA时延估计 被引量:1
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作者 杨建辉 王逸轩 刘玉红 《无线电工程》 2017年第1期23-26,31,共5页
针对无源时延定位技术中时延的估算受系统采样率影响较大的问题,提出一种基于亚采样点的时延估计算法,在采样点最小单位的基础上,利用2个基准监测站信号点的几何特征计算时延。在Matlab仿真程序中,模拟1个信号辐射源和2个基准监测站,以... 针对无源时延定位技术中时延的估算受系统采样率影响较大的问题,提出一种基于亚采样点的时延估计算法,在采样点最小单位的基础上,利用2个基准监测站信号点的几何特征计算时延。在Matlab仿真程序中,模拟1个信号辐射源和2个基准监测站,以2个监测站信号及其瞬时相位作为算法输入部分,对比二者时延估计的精度,证明算法的有效性。试验结果表明,基于亚采样点的时延估计算法计算精度与信号点数及采样周期有关,且在相同采样率下,该算法估计的时延精度高于采样点级别的时延估计方法。 展开更多
关键词 TDOA 时延估计 亚采样点 瞬时相位法 精度分析
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Divergence of tree-ring-based drought reconstruction between the individual sampling site and the Monsoon Asia Drought Atlas: an example from Guancen Mountain 被引量:3
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作者 Qiang Li Yu Liu +2 位作者 Huiming Song Yinke Yang Boyang Zhao 《Science Bulletin》 SCIE EI CAS CSCD 2015年第19期1688-1697,共10页
To evaluate the applicability of the Standardized Precipitation-Evapotranspiration Index (SPEI) and the self-calibrated Palmer Drought Severity Index (scPDSI) to paleoclimate reconstructions in the east Asian summ... To evaluate the applicability of the Standardized Precipitation-Evapotranspiration Index (SPEI) and the self-calibrated Palmer Drought Severity Index (scPDSI) to paleoclimate reconstructions in the east Asian summer monsoon region, we used a 194-year tree-ring width chronology from Guancen Mountain, Shanxi Province, China, to investigate its correlation with SPEI and scPDSI, respectively. The results indicated scPDSI as a robust drought index that could be reconstructed from tree-ring width on Guancen Mountain other hydroclimate-related Significant correlations with series illustrated that our reconstruction captured common variations of hydroclimate in the surrounding areas. Additionally, our reconstruction showed significant correlation with nearby grid points of the Monsoon Asia Drought Atlas (MADA). However, while unprecedented drying trend existed during the past several decades in MADA, it was not represented in our reconstruction or in instrumental scPDSI/Dai-PDSI. This may imply that MADA overestimated drought severity during the past several decades in our study area; this overestimation was probably caused by an insufficient spatiotemporal distribution of the tree-ring network used by MADA. Therefore, more drought reconstructions based on individual sampling sites in eastern Asia are necessary to gain a thorough understanding of the Asian Monsoon climate variability. 展开更多
关键词 Tree tings Drought reconstruction Individual sampling site Monsoon Asia Drought Atlas Guancen Mountain
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