Assessment of code bias variations of BDS triple-frequency signals and their impacts on ambiguity resolution for long baselines     

Lou  Yidong  Gong  Xiaopeng  Gu  Shengfeng  Zheng  Fu  Feng  Yanming 《GPS Solutions》2017,21(1):177-186

GPS Solutions - Carrier phase ambiguity resolution over long baselines is challenging in BDS data processing. This is partially due to the variations of the hardware biases in BDS code signals and...  相似文献   

A new model for the vibration isolation via pile rows consisting of infinite number of piles     

Jian‐Fei Lu  Dong‐Sheng Jeng  Jian‐Wei Wan  Ji‐Sheng Zhang 《国际地质力学数值与分析法杂志》2013,37(15):2394-2426

In this study, on the basis of the Floquet transform method, a numerical model for the simulation of the vibration isolation via multiple periodic pile rows with infinite number of piles is established. By means of the fictitious pile method due to Muki and Sternberg, the second kind of Fredholm integral equations for the pile rows are developed by using the fundamental solutions for the half‐space and the compatibility conditions between the piles and half‐space. Employing the Floquet transform method, integral equations for the pile rows in the wavenumber domain are then derived. Solution of the integral equations yields the wavenumber domain solution for the pile rows. The space domain solution can then be retrieved by inversion of the Floquet transform. Numerical results show that the proposed model with the Floquet transform method is in a good agreement with those of the conventional direct superposition method. On the basis of the new model, influences of the spacing between neighboring piles, the Young's modulus of the piles, and the pile length on the vibration isolation effect of the pile rows are investigated. Numerical simulations conducted in this study show that compared with the direct superposition method, the efficiency of the proposed model for simulation of the vibration isolation via pile rows is very high. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

地震动力分析的经典方法与现代计算技术     

万召侗  姚运生 《大地测量与地球动力学》2004,24(1):111-116

回顾了体系地震动力分析的历史过程，并对地震动力分析的传统理论方法、近似方法和现代计算技术从新的角度加以阐述，同时给出体系地震动力分析的应用前景，以促进经典的传统理论方法、近似方法和现代计算技术的综合和在实际工程中的应用，形成系统而完整的地震动力分析体系。  相似文献   

青藏高原500hpa暖性高压生成的热成风适应机制     

李国平  万军  邓思华 《成都信息工程学院学报》1991,(Z1)

本文利用热成风适应原理,采取分解分析法对青藏高原500hpa暖性高压的生成机制作了一些定性和定量的讨论。结果表明:在扰动的水平尺度大于热成风适应的特征尺度的条件下,当源地有明显的负值非热成风涡度出现时,流场将向温度场适应,而温度场由于高原的加热作用存在暖中心或暖脊,则适应的结果在高原大气500hpa形成暖性高压,并伴随高层辐合,低层辐散及下沉运动。  相似文献   

Southern high latitude climate anomalies associated with the Indian Ocean dipole mode     

刘娜贾贞  陈红霞华锋 《中国海洋湖沼学报》2006,24(2):125-128

1 INTRODUCTION In southern high latitudes, recent observations have shown a standing mode of ACW (Antarctic Circumpolar Wave) with eastward propagation across the Southern Ocean of the Antarctic in co- varying SST (sea surface temperature) and SLP (sea le…  相似文献   

用地基GPS资料分析大气可降水汽总量   总被引：16，自引：5，他引：11  

杜瑞林  乔学军  王琪  万蓉  王伟  杨少敏  谭凯 《大地测量与地球动力学》2005,25(3):121-124

利用“中国地壳运动监测网络”和三峡监测网的地基GPS资料，通过Bernese软件以及根据Bevis等和Rocken等水汽解算原理编制的水汽解算软件。获得了武汉、巴东、兴山、泸州等长江流域测站大气可降水汽总量分布和时间间隔为2小时的GPS遥感大气可降水汽序列，并与站点雨量及区域面雨量进行对比分析，结果表明：地基GPS遥感水汽量变化与地面降水有很好的相关性。而且GPS遥感水汽变化序列峰值对应于强降水提前了8～22小时。有助于强降水特别是突发性强降水的预测；多个站点的GPS遥感水汽总量联合分析，对于区域水汽总量变化研究有一定意义。  相似文献   

西南极菲尔德斯半岛白垩纪晚期和第三纪早期岩石的古地磁学及其大地构造意义          下载免费PDF全文

刘椿  朱日祥  郑祥身  刘小汉  金增信  冯宇 《极地研究》1991,3(2):136-143

采自菲尔德斯半岛白垩纪晚期和第三纪早期五个岩层单位的12个采点109块定向岩芯标本进行了系统的古地磁学测定,从中得知,55～45Ma时期,该区极位置与澳大利亚的同时期结果不同,它经历了大约20°～30°的南向水平移动与70°～80°的西向旋转,逐渐地构成了今日彼此相对位置的格架。文章绘制出南极洲的视极移曲线。  相似文献   

Study on methods of land use dynamic monitoring at county level     

Lin-yi Li  Fang Huang  Zhao-li Liu  En-pu Wan 《中国地理科学(英文版)》2001,11(2):181-185

Remote sensing technique has played an important role in land use dynamic monitoring, but as for the land use dynamic monitoring at county level, traditional remote sensing methods such as satellite imagery visual interpretation and computer classification can not meet its demand for accuracy. The result of 1: 10 000 land use investigation map has high accuracy, but this method can not be used to dynamically monitor the land use because of its big expenses, long period and difficulty in updating data. In this paper, the characteristics of physiognomy, climate and the status of land use in Dehui County are taken into consideration and a set of method, which takes use of 3S techniques and applies to Northeast China Plain, is come up with. When the land use type of a land parcel changed as a whole, the date updating can be make by changing its land type ID in the attribute table in a GIS. When the land use type of an irregular area changed, GPS receivers are used to position its border. This set of method is characteristic of high accuracy and low expenses. It gets the information of land use change timely and can be used to dynamically monitor the land use. Foundation item: Under the auspices of the key project of the National Ninth Five-year Plan (96-B02-01-07). Biography: LI Lin-yi (1968 —), female, a native of Jilin, Ph. D. candidate of Changchun Institute of Geography, the Chinese Academy of Sciences. Her research interest includes land use change monitoring and crop yield estimation using “3S” techniques.  相似文献   

ON THE BEHAVIORS OF OCEAN BOTTOM EDDY     

吴德星  冯土 《中国海洋湖沼学报》1994,12(4):343-350

On the basis of scaling analysis,this paper presents a frontal geostrophic dynamic system which canbe used to describe the dynamics of an isolated bottom eddy and shows that five possible dynamicsubregimes are included in the system.A particle-in-cell method is used to investigate the behavior of the eddy in the two dynamic subregimes,with 1)nonlinear effect(ε)relevant to the sloping bottom-inducedbeta effect(β_1)and 2)seamount-induced beta effect(β_2)dominant.In the dynamic subregime of β_1～ ε～10~(-2)and β_2=0,the eddy can keep as a whole for a long time and migrates for a long distance.Inthe dynamic subregime where the seamount-induced beta effect (β_2～10~(-1))is dominant,the seamounttraps the water particles,causing the eddy to break up into a discrete set of eddies moving around the seamount.  相似文献   

用区域重力资料确定的华北地台南缘地缝合线及其地质意义     

张晓春  冯凤雪  王正晓 《河南国土资源》1997,(4)

利用１∶２０万区域重力资料，结合航磁，电磁测深、遥感、天然地震等丰富的地质、地球物理资料，根据断裂的地质、地球物理标志，在华北地台南缘发现并确定了控制火山喷发的裂隙—中心式古火山通道，即隐伏的北西西向的上戈—铁炉坪—付店超壳断裂带。该断裂属华北地台南缘不同时代、不同性质的近东西向的地缝合线。研究认为：该断裂及其次级断裂不仅是重要的长期多次活动的控岩、导矿和容矿构造，而且也为矿床的多次改造、叠加和再富集提供了热源。它的发现，对重新认识豫西地区大地构造的演化特征，建立新的成矿模式，拓宽该区的找矿前景具有重要意义。  相似文献