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Hybrid TDOA/FDOA and track optimization of UAV swarm based on A-optimality

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Journal of Systems Engineering and Electronics 2023年第1期34卷 149-159页

作者： LI Hao sun hemin ZHOU Ronghua ZHANG Huainian Department of Intelligence Air Force Early Warning AcademyWuhan 430019China

The source location based on the hybrid time difference of arrival(TDOA)/frequency difference of arrival(FDOA) is a basic problem in wireless sensor networks, and the layout of sensors in the hybrid TDOA/FDOA positioning will greatly affect the accuracy of positioning. Using unmanned aerial vehicle(UAV) as base stations, by optimizing the trajectory of the UAV swarm, an optimal positioning configuration is formed to improve the accuracy of the target position and velocity estimation. In this paper, a hybrid TDOA/FDOA positioning model is first established, and the positioning accuracy of the hybrid TDOA/FDOA under different positioning configurations and different measurement errors is simulated by the geometric dilution of precision(GDOP) factor. Second, the Cramer-Rao lower bound(CRLB) matrix of hybrid TDOA/FDOA location under different moving states of the target is derived theoretically, the objective function of the track optimization is obtained, and the track of the UAV swarm is optimized in real time. The simulation results show that the track optimization effectively improves the accuracy of the target position and velocity estimation.

关键词： unmanned aerial vehicle(UAV)swarm time difference of arrival(TDOA) frequency difference of arrival(FDOA) A-optimality track optimization

Regional Frequency Analysis of Observed Sub-Daily Rainfall Maxima over Eastern China

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Advances in Atmospheric Sciences 2017年第2期34卷 209-225页

作者： hemin sun Guojie WANG Xiucang LI Jing CHEN Buda SU Tong JIANG Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Institute of Geography and Remote SensingNanjing University of Information Science and TechnologyNanjing 210044China State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesOriimqi 830011China National Climate Center China MeteorologicaI AdministrationBeijing 100081China

Based on hourly rainfall observational data from 442 stations during 1960-2014, a regional frequency analysis of the annual maxima （AM） sub-daily rainfall series （1-, 2-, 3-, 6-, 12-, and 24-h rainfall, using a moving window approach） for eastern China was conducted. Eastern China was divided into 13 homogeneous regions： Northeast （NE1, NE2）, Central （C）, Central North （CN1, CN2）, Central East （CE1, CE2, CE3）, Southeast （SE1, SE2, SE3, SE4）, and Southwest （SW）. The generalized extreme value performed best for the AM series in regions NE, C, CN2, CE1, CE2, SE2, and SW, and the generalized logistic distribution was appropriate in the other regions. Maximum return levels were in the SE4 region, with value ranges of 80-270 mm （1-h to 24-h rainfall） and 108-390 mm （1-h to 24-h rainfall） for 20- and 100 yr, respectively. Minimum return levels were in the CN1 and NE1 regions, with values of 37-104 mm and 53-140 mm for 20 and 100 yr, respectively. Comparing return levels using the optimal and commonly used Pearson-III distribution, the mean return-level differences in eastern China for 1-24-h rainfall varied from -3-4 mm to -23-11 mm （- 10%-10%） for 20-yr events, reaching -6-26 mm （-10%-30%） and -10-133 mm （-10%-90%） for 100-yr events. In view of the large differences in estimated return levels, more attention should be given to frequency analysis of sub-daily rainfall over China, for improved water management and disaster reduction.

关键词： sub-daily rainfall annual maxima regional frequency analysis return level eastern China

Changes in Extreme Maximum Temperature Events and Population Exposure in China under Global Warming Scenarios of 1.5 and 2.0°C: Analysis Using the Regional Climate Model COSMO-CLM

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Journal of Meteorological Research 2018年第1期32卷 99-112页

作者： Mingjin ZHAN Xiucang LI hemin sun Jianqing ZHAI Tong JIANG Yanjun WANG Chinese Academy of Meteorological Sciences Beijing 100081 University of ChineseAcademy of Sciences Beijing 100049 Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/School of Geography and Remote Sensing Nanjing University of Information Science & Technology Nanjing 210044 National Climate Center China Meteorological Administration Beijing 100081 Jiangxi Provincial Climate Center Nanchang 330046

We used daily maximum temperature data（1986–2100） from the COSMO-CLM（COnsortium for Small-scale MOdeling in CLimate Mode） regional climate model and the population statistics for China in 2010 to determine the frequency, intensity, coverage, and population exposure of extreme maximum temperature events（EMTEs） with the intensity–area–duration method. Between 1986 and 2005（reference period）, the frequency, intensity, and coverage of EMTEs are 1330–1680 times yr^–1, 31.4–33.3℃, and 1.76–3.88 million km^2, respectively. The center of the most severe EMTEs is located in central China and 179.5–392.8 million people are exposed to EMTEs annually. Relative to 1986–2005, the frequency, intensity, and coverage of EMTEs increase by 1.13–6.84, 0.32–1.50, and15.98%–30.68%, respectively, under 1.5℃ warming; under 2.0℃ warming, the increases are 1.73–12.48, 0.64–2.76,and 31.96%–50.00%, respectively. It is possible that both the intensity and coverage of future EMTEs could exceed the most severe EMTEs currently observed. Two new centers of EMTEs are projected to develop under 1.5℃ warming, one in North China and the other in Southwest China. Under 2.0℃ warming, a fourth EMTE center is projected to develop in Northwest China. Under 1.5 and 2.0℃ warming, population exposure is projected to increase by 23.2%–39.2% and 26.6%–48%, respectively. From a regional perspective, population exposure is expected to increase most rapidly in Southwest China. A greater proportion of the population in North, Northeast, and Northwest China will be exposed to EMTEs under 2.0℃ warming. The results show that a warming world will lead to increases in the intensity, frequency, and coverage of EMTEs. Warming of 2.0℃ will lead to both more severe EMTEs and the exposure of more people to EMTEs. Given the probability of the increased occurrence of more severe EMTEs than in the past, it is vitally important to China that the global temperature increase is limited within 1.5℃.

关键词： extreme maximum temperature events population exposure 1.5 and 2.0℃ global warming COSMO-CLM regional climate model China

Synchronous Characteristics of Precipitation Extremes in the Yangtze and Murray–Darling River Basins and the Role of ENSO

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Journal of Meteorological Research 2021年第2期35卷 282-294页

作者： Yu GONG Tong JIANG Buda SU Jinlong HUANG Zbigniew WKUNDZEWICZ Cheng JING hemin sun State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China Institute for Disaster Risk Management/School of Geographical Science Nanjing University of Information Science&Technologyy Nanjing 210044China National Climate Center China Meteorological AdministrationBeijing 100081China Beijing Meteorological Observation Center(Beijing Observatory) Beijing 100089China National Meteorological Center China Meteorological AdministrationBeijing 100081China University of Chinese Academy of Sciences Beijing 100049China Institute of Agricultural and Forest Environment Polish Academy of Sciences y Bukowska 1960-809PoznanPoland

The floods caused by the extreme precipitation in the Yangtze River basin(YRB)and Murray–Darling River basin(MDRB),the largest basins in China and Australia,have significant impacts on the society and regional *** on the spatial–temporal analysis of the daily precipitation extremes(DPEs)during 1982–2016,we found that for both basins,the whole-basin-type DPEs have the highest proportion and a synchronous DPE interannual variation characteristic exists in the two basins,with the 3-yr running correlation coefficient of the annual DPE days(DPEDs)reaching almost 0.7(significant at the 0.01 level).The El Ni?o–Southern Oscillation(ENSO),which is one of the most significant climate disturbance factors in the world,plays an important role in modulating the variability of the DPEs in the two *** value decomposition(SVD)analysis revealed that both the YRB and the MDRB’s whole-basin-type DPEs are closely coupled with the procedure that the preceding winter eastern Pacific(EP)-type El Ni?o faded to a central Pacific(CP)-type La *** means that the DPEs in the YRB and MDRB may synchronously occur more frequently when the above process *** to the atmosphere–ocean interaction from the east–west dipole sea surface temperature(SST)anomaly pattern,the atmospheric circulation disturbance exhibits a pattern in which the equatorial eastern Pacific region is a mass source anomaly with a higher pressure,drier air,and weaker convection,while the equatorial western Pacific region is a mass sink anomaly with a lower pressure,wetter air,and stronger ***,two wave trains that originated from the tropical western Pacific were found to extend to the YRB and *** interaction between the wave train’s interphase dynamics and water vapor transport disturbance results in the ascent conditions and enhanced water vapor transport,which leads to the synchronous occurrence of DPEs in the YRB and MDRB on an interannual scale.

关键词： precipitation extreme El Ni?o–Southern Oscillation(ENSO) Yangtze River basin(YRB) Murray–Darling River basin(MDRB)

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频率编码脉冲信号性能分析

系统工程与电子技术 2001年第5期23卷 102-104,F003页

作者：谭贤四武文孙合敏王红空军雷达学院雷达装备研究所武汉430010

使用大时宽带宽信号是提高雷达距离、速度及其联合分辨性能的最常用方法之一。频率编码脉冲是一种大时宽带信号 ,具有良好的距离分辨性能和较窄的瞬时带宽。推导了频率编码脉冲信号及步进频率脉冲信号的模糊函数 ,分析了其距离、速度分... 详细信息

使用大时宽带宽信号是提高雷达距离、速度及其联合分辨性能的最常用方法之一。频率编码脉冲是一种大时宽带信号 ,具有良好的距离分辨性能和较窄的瞬时带宽。推导了频率编码脉冲信号及步进频率脉冲信号的模糊函数 ,分析了其距离、速度分辨性能及其相应关系 ,并就有效解决其距离 -速度联合测量问题进行了讨论。

关键词：编码脉冲干扰模糊函数信号分析分辨率雷达

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大型望远镜拼接弧线永磁电机电流谐波抑制

红外与激光工程 2021年第S2期50卷 114-121页

作者：宋晓莉孙何敏汪达兴张驰中国科学院国家天文台南京天文光学技术研究所江苏南京210042 中国科学院天文光学技术重点实验室(南京天文光学技术研究所) 江苏南京210042 中国科学院大学北京100049 南京信息工程大学江苏南京210044

望远镜口径的增加使得其轴系驱动电机越来越大,近年来拼接电机成为国际上研究的热点。拼接弧线永磁电机的电流谐波影响大型天文望远镜目标观测轴系跟踪精度,文中根据拼接弧线电机的数学模型及谐波分析,提出了一种基于准比例-谐振控制器... 详细信息

望远镜口径的增加使得其轴系驱动电机越来越大,近年来拼接电机成为国际上研究的热点。拼接弧线永磁电机的电流谐波影响大型天文望远镜目标观测轴系跟踪精度,文中根据拼接弧线电机的数学模型及谐波分析,提出了一种基于准比例-谐振控制器的电流谐波抑制算法,并设计了单元拼接弧线电机相应的电流控制器。仿真和实验分别对比了PI和准比例谐振控制器对电流谐波的影响。实验结果表明,采用准比例谐振控制器时,拼接弧线电机定子电流中的5次谐波分量削弱了63.3%,7次谐波分量削弱了34.4%,11次谐波分量削弱了51%,13次谐波分量削弱了59.2%,大大降低了拼接弧线电机电流谐波,有助于提高望远镜跟踪精度。

关键词：电流谐波抑制拼接弧线永磁电机准比例谐振控制器 PI控制器望远镜

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气候变化对水文循环的影响

气象 2020年第3期46卷 289-300页

作者：姜彤孙赫敏李修仓苏布达南京信息工程大学地理科学学院/灾害风险管理研究院南京210044 北京市气象探测中心北京100089 国家气候中心北京100081

水文循环是地球上海洋、陆地和大气之间相互作用中最活跃且最重要的枢纽,受气候变化影响最为显著。本文回顾了气候变化对全球水文循环的影响,并对20世纪60年代以来中国降水、蒸散发、地表径流及大气水汽含量等陆地水文循环要素变化进行... 详细信息

水文循环是地球上海洋、陆地和大气之间相互作用中最活跃且最重要的枢纽,受气候变化影响最为显著。本文回顾了气候变化对全球水文循环的影响,并对20世纪60年代以来中国降水、蒸散发、地表径流及大气水汽含量等陆地水文循环要素变化进行了评估。气候变暖使得全球水文循环加强,观测数据表明自1970年以来,全球对流层和地表水汽含量呈现增加趋势,但由于监测网络在空间覆盖和时间响应的限制,热带水汽增加与环流减弱之间相互影响,使得气候变化对区域水文循环的影响不确定性较大。在全球气候变化背景下,中国水文循环符合全球水循环变化的特征,又表现出更为复杂的区域特征,各个流域间空间差异增大。大气水汽含量在80年代后呈现上升的趋势;60年代以来,中国降水平均态虽然无明显变化但空间差异显著增加,实际蒸散发平均值微弱增加,空间差异增大,地表径流空间差异增大,某些流域呈现减少趋势。21世纪以来,由蒸散发再凝结形成的降水量增加,大气内循环活跃程度加大。

关键词：水文循环气候变化中国全球

UWB-HPM脉冲辐照下抛物面天线耦合特性研究

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兵器装备工程学报 2022年第11期43卷 141-146页

作者：胡欣杨江平孟藏珍孙合敏空军预警学院武汉430019 中国人民解放军93498部队石家庄050000

针对超宽带高功率微波脉冲辐照下雷达前门耦合特性进行探索,通过理论分析、软件仿真、辐照实验,对抛物面雷达天线的响应特性进行了研究。实验结果表明:由于天线的带通滤波作用,与窄带信号辐照相比,在接收超宽带脉冲信号过程中,会导致输... 详细信息

针对超宽带高功率微波脉冲辐照下雷达前门耦合特性进行探索,通过理论分析、软件仿真、辐照实验,对抛物面雷达天线的响应特性进行了研究。实验结果表明:由于天线的带通滤波作用,与窄带信号辐照相比,在接收超宽带脉冲信号过程中,会导致输出信号频谱变窄、时域延拓、峰值电压变小,并伴有振荡衰减的尾瓣,耦合输出信号表现为非线性失真。由于在耦合过程中丢失部分能量,毁伤效果降低。

关键词：超宽带高功率微波脉冲抛物面天线耦合特性

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珠江流域旱涝变化及其与大气环流关系研究

干旱区资源与环境 2017年第4期31卷 142-147页

作者：罗岚心姜彤孙赫敏景丞苏布达中国气象科学研究院北京100081 中国气象局国家气候中心北京100081 南京信息工程大学气象灾害预报预警与评估协同中心/地理与遥感学院南京210044

基于珠江流域57个气象站1960-2014年逐日降水量资料,选用标准降水指数(SPI)为旱涝指标,讨论旱涝时空变化特征,研究与极端旱涝相关的大气环流成因。结果表明:(1)珠江流域旱涝严重程度主要受降水量影响,SPI能有效反映流域的旱涝特征;(2)自... 详细信息

基于珠江流域57个气象站1960-2014年逐日降水量资料,选用标准降水指数(SPI)为旱涝指标,讨论旱涝时空变化特征,研究与极端旱涝相关的大气环流成因。结果表明:(1)珠江流域旱涝严重程度主要受降水量影响,SPI能有效反映流域的旱涝特征;(2)自1980s起,流域有干旱趋势,西北部干旱化趋势显著;(3)流域春旱减缓,秋旱加重,夏季洪涝频发;(4)极端的旱涝变化与大气环流关系密切,西太平洋副热带高压与东亚大槽是两个主要影响珠江流域旱涝变化的环流系统。

关键词：旱涝变化标准降水指数大气环流背景珠江流域