北斗卫星导航系统单频伪距绝对定位精度分析   总被引：1，自引：0，他引：1  

宗干  郭金运  李国伟  王书阳  胡志博 《全球定位系统》2013,38(3)

利用北斗卫星导航系统进行导航定位具有全天候、高精度、不受其他定位系统限制等优点.为验证目前系统定位精度,采用单频伪距绝对定位的方式,对系统试运行阶段和正式提供区域服务后两天的观测数据进行处理和分析.结果表明:北斗系统单频伪距绝对定位能够达到米级精度,可以满足基础测绘和日常生产的需要.  相似文献   

Ocean Crust Character and Spreading Age of Northwest Sub-sea, the South China Sea: Evidence from Sediment Strata and the Abnormity of Gravity and Magnetism     

WEI Xi  ZHU Yongjun  CHEN Yihan  HU Liguo  WU Jinyun  JIANG Jianqun  LI Zhenyuan 《地质学报》2012,86(3)

利用沉积地层被动超覆和基底重磁异常特征对南海西北次海形成时代和洋壳性质进行了探讨.推断南海西北次海初始扩张时间为早渐新世,结束扩张时间为晚渐新世早期.地层变形、被动超覆特征、洋壳基底形态及对称性特点反映出两期洋壳扩张事件.第一期发生在早渐新世.由于洋壳扩张,上始新统被拉断,在洋壳边界处上始新统突然终止现象明显.受洋壳横向扩张推挤和纵向沉降作用影响,上始新统明显变形,并向扩张中心倾覆.第二期洋壳扩张发生在晚渐新世早期.该期洋壳扩张持续时间短,扩张幅度小,下渐新统被拉开的距离有限.由于南海西北次海形成期间不同部位地壳伸展减薄程度不同,南海西北次海洋壳基底呈北东部较宽,向南西方向变窄,并逐渐尖灭的不规则三角形.根据盆地边缘上始新统向海盆中心方向的断点/线和重磁异常资料,推测西北次海南西侧洋壳边界位于海盆基底坡角处附近,洋壳较窄;而北东侧洋壳边界位于海底坡角处附近,洋壳相对较宽.另外,重磁异常表明,在洋壳基底中有陆壳残留块体存在.上述这些现象说明南海西北次海在洋壳萌芽阶段就先天天折,停止发育.  相似文献   

数字天顶摄影仪确定垂线偏差及其精度分析     

郭金运  宋来勇  常晓涛  刘新 《武汉大学学报(信息科学版)》2011,36(9):1085-1088,1101

给出了数字天顶摄影仪的基本结构和垂线偏差测量的基本算法,结合仪器和测量过程,分析了垂线偏差测量误差。数字天顶摄影仪的自动化程度和测量精度都高于传统的天文大地测量。  相似文献   

Flow resistance adjustments of channel and bars in the middle reaches of the Yangtze River in response to the operation of the Three Gorges Dam     

Hu  Yong  Deng  Jinyun  Li  Yitian  Liu  Congcong  He  Zican 《地理学报(英文版)》2022,32(10):2013-2035

Journal of Geographical Sciences - Since the Three Gorges Dam (TGD) was put into operation, the flood water level at an identical discharge rate has not displayed a decreasing trend along the...  相似文献   

Replacing fishmeal with soybean meal affects survival,antioxidant capacity,intestinal microbiota,and mRNA expression of TOR and S6K1 in Macrobrachium rosenbergii     

Zhili DING  Dongsheng ZHOU  Jinxian ZHENG  Xuefeng CHEN  Youqin KONG  Changle QI  Yan LIU  Qiongying TANG  Guoliang YANG  Jinyun YE 《海洋湖沼学报（英文）》2022,(2):805-817

Using alternative plant-derived dietary protein to replace fishmeal,combined with practical evaluation indexes,is a recent focus for aquaculture practices.An 8-...  相似文献   

一个双波地形重力波拖曳参数化方案   总被引：4，自引：0，他引：4  

王元  唐锦赟  伍荣生 《气象学报》2007,65(5):733-743

当地形次尺度强迫的作用与显式的经典动力作用效应相当时,地形重力波拖曳力对于环流的维持,以及动量和热量通量输送的动力效应变得十分显著。这种地形次尺度拖曳作用项可通过参数化的方法,在动力方程中加入额外的小项而引入数值模式。目前成熟的地形重力波拖曳参数化方法,如第1代基于线性单波理论的参数化方案;以及侧重考虑了临界层作用等因素对拖曳力的额外贡献的第2代参数化方案,都无法有效表达风速垂直变化引起的波动应力随高度变化的特征。基于上述考虑,本文给出了一个双波参数化方案用于计算地形重力波拖曳中由线性自由传播重力波造成的波动应力的垂直分布。通过二阶WKB近似,它对由风速垂直变化引起的对波动应力的选择性临界层吸收过程和经典的临界层吸收过程做了显式处理;而在不发生临界层吸收现象的地区,则用两个单波同时在垂直方向上进行应力的传播,并利用波饱和标准进行应力耗散。进一步地在真实地形(以大别山地区为个例)条件下的测试结果表明,通过在不同理想风速廓线以及北半球冬季中纬度纬向平均风廓线下对波动应力垂直分布的计算,证明该方案确实能有效地给出应力随高度变化的特征。  相似文献   

Applying energy theory to understand the relationship between the Yangtze River and Poyang Lake   总被引：1，自引：1，他引：0  

Mofei Chen  Jinyun Deng  Shaoying Fan  Yitian Li 《地理学报(英文版)》2018,28(8):1059-1071

The complex relationship between the Yangtze River and Poyang Lake controls the exchange of water and sediment between the two, and exerts effects on water resources, flooding, shipping, and the ecological environment. The theory of energy is applied in this paper to investigate the physical mechanisms that determine the nature of the contact between the Yangtze River and Poyang Lake and to establish an energy difference (F_e) index to quantify the interactions between the two systems. Data show that F_e values for this interaction have increased since the 1950s, indicating a weakening in the river effect while the lake effect has been enhanced. Enclosure of the Three Gorges Reservoir (TGR) has also significantly influenced the relationship between the river and the lake by further reducing the impacts of the Yangtze River. The river effect also increases slightly during the dry season, and decreases significantly at the end of the flooding period, while interactions between the two to some extent influence the development of droughts and floods within the lake area. Data show that when the flow of the five rivers within this area is significant and a blocking effect due to the Yangtze River is also clearly apparent, floods occur easily; in contrast, when the opposite is true and the flow of the five rivers is small, and the Yangtze River can accommodate the flow, droughts occur frequently. Construction and enclosure of the TGR also means that the lake area is prone to droughts during September and October.  相似文献   

山西省吕梁山秦家崖钨铜矿床地质特征及找矿前景北大核心CSCD     

裴进云 《地质与勘探》2022,58(5):954-964

山西省岩浆热液型矿床主要形成于中生代,与燕山期岩浆活动关系密切,在东部灵丘地区发育多个与次火山岩有关的铜铅锌银矿,近年来在吕梁山地区离石断裂东部也发现了多处钨铜多金属矿化,其中秦家崖钨铜矿床是工作程度最高、规模最大的矿床。本文在野外工作的基础上,对矿床地质、矿物组合、物化探异常体特征与成矿规律进行分析,研究认为:(1)钨矿体主要赋存于NE走向F_(1)断层破碎带中,矿体类型以石英脉型为主,另有少量蚀变岩型,矿物组合为黑钨矿+白钨矿+黄铜矿+黄铁矿,热液蚀变以硅化与绢云母化为主;(2)断裂破碎带中发育多条与矿体关系密切的长英质岩脉,激电测深剖面指示深部(~1000 m)存在隐伏的岩体;(3)秦家崖一带已发现的钨铜矿脉仍处于浅部细脉带,物探剖面揭示矿脉走向与延深位置均有高阻、中低极化的物探异常,指示矿体延深稳定,化探剖面与钻孔岩心元素组成证实矿体附近Cu、W异常明显,同时伴有Au、Mo异常,可作为找矿指标。综合分析认为,秦家崖钨铜矿床是与花岗岩类侵入有关的中、高温热液脉型矿床,进一步进行深边部勘查工作有望在研究区实现钨、铜、钼的找矿突破。  相似文献   

单自由度陀螺寻北仪寻北数学模型研究     

郭金运  李成尧 《四川测绘》1995,18(3):110-113

为了实现单自由度陀螺寻北仪自动寻北，通过分析寻北仅运动规律，本文建立了其寻北数学用到，分别为：模型Ⅰ——时间作为观测值，模型Ⅱ——角位置作为观测值，模型Ⅲ——时间及角位正同时作为观测值，楼四Ⅳ——最小二乘谱分析模型．通过模拟实验，认为自国对具有较强的抗干扰能力，适合单自由反陀螺寻北仪的数据采集和处理．  相似文献   

Coastal Gravity Anomalies from Retracked Geosat/GM Altimetry: Improvement, Limitation and the Role of Airborne Gravity Data   总被引：6，自引：0，他引：6  

Cheinway Hwang  Jinyun Guo  Xiaoli Deng  Hsin-Ying Hsu  Yuting Liu 《Journal of Geodesy》2006,80(4):204-216

We process geophysical and waveform data records of the Geosat/GM (geodetic mission) satellite altimeter mission for waveform retracking and applications. An improved threshold retracker is developed. The performances of the Beta-5, threshold and improved threshold retrackers are assessed over waters around Taiwan. The improved threshold retracker outperforms the other two. The improvement in the accuracy of sea surface height (SSH) is investigated according to marine zone and the distance of waters to the shore. The improvement rate increases closer to the land, with the largest improvement rate of about 20% in waters within 10 km of the shore. Over waters around islands and coasts, there are still retracked SSHs with large errors. Least-squares collocation is used to compute gravity anomalies from the Geosat/GM altimeter data. Use of retracked SSHs improves the accuracy of gravity anomalies by about 11%. Adding airborne gravity data further improves the accuracy, especially in the immediate vicinity of the coasts. Tide model errors over coastal waters remain a problem in altimetry applications, even if the waveforms are properly retracked.  相似文献