用PANDA对GPS和CHAMP卫星精密定轨

介绍了武汉大学自主研制的卫星导航系统综合处理软件PANDA；利用全球45个IGS站以及CHAMP卫星星载GPS数据．在不同条件下分别实现了GPS卫星的精密定轨．以及CHAMP卫星和GPS导航星座联合精密定轨。结果与IGS的最终精密星历以及GFZ提供的CHAMP卫星精密轨道的比较说明：PANDA软件求解的GPS导航星座和CHAMP卫星轨道精度处于同等水平。     

用Kaula线性摄动方法恢复CHAMP重力场模型

介绍了Kau la线性摄动方法的基本原理和算法,基于CHAMP几何法轨道和动力法轨道,给出了利用该方法恢复地球重力场模型的实现过程,分析了Kau la线性摄动方法在实际应用中需要注意的问题。基于德国慕尼黑技术大学提供的一个月的CHAMP几何法轨道和德国GFZ数据中心提供的快速科学轨道,计算出了50×50阶地球重力场模型CHAMP-Kau la1S,并与EIGEN-CG03C、EIGEN-CHAMP03S、EIGEN2、ENIGN1S、EGM96模型进行了比较。结果表明:X ISM-CHAMP1S模型精度明显优于相同阶次EIGEN1S模型,前40阶明显优于EGM96模型,而低于同阶次的EIGEN2和EIGEN-CHAMP03S模型精度。     

零次差分CHAMP卫星简动力定轨和SLR轨道验证

采用零次差分简化动力法对CHAMP卫星GPS相位观测资料进行精密轨道计算,并将计算结果与CHAMP快速轨道进行比对.结果表明X,Y、Z方向差值均方根为0.061 m,0.060 m与0.066 m,精度达到了厘米级;同时利用全球人卫激光观测数据对所求轨道进行验证,表明其精度优于20 cm.     

MGEX和iGMAS的多系统轨道和钟差产品精度分析

采用分析中心间互比、SLR残差检核、卫星钟差拟合以及阿伦方差等方法对MGEX和iGMAS提供的多系统轨道和钟差产品精度进行综合分析。结果表明,GPS和GLONASS卫星的轨道精度分别在1.0～1.3cm和2.0～3.6cm,其中iGMAS提供的轨道产品较优。Galileo卫星的轨道一致性在10～17cm,采用ECODE2模型或附加先验模型可有效提高轨道精度。BDS GEO卫星的轨道一致性在数m级,径向精度约为25cm;IGSO和MEO卫星的轨道一致性分别在21～40cm和11～18cm左右,且径向精度分别优于10cm和5cm。MGEX和iGMAS提供的GPS和GLONASS卫星的钟差精度较好,但稳定性和可靠性仍有待提升。Galileo卫星的钟差一致性约为0.2～0.4ns,且钟差产品中吸收了未被模型化的轨道误差。BDS GEO、IGSO和MEO卫星的钟差一致性分别在0.35～0.46ns、0.25～0.33ns和0.11～0.21ns,其中CODE提供的BDS IGSO/MEO卫星的钟差产品受偏航姿态模式影响较大。     

抗差方差分量估计在卫星定轨中的应用

针对卫星精密定轨过程中观测资料存在粗差以及观测资料的合理定权问题，将抗差方差分量估计引入到卫星精密定轨中。采用Lageos 2卫星1996年1月至2000年12月的全球SLR实测数据进行了卫星精密定轨计算，结果表明，抗差方差分量估计既可以有效地减弱观测资料中粗差的影响，又可以较好地解决观测资料的合理加权问题，从而可以提高卫星的定轨精度。     

基于运动学和简化动力学的SWARM卫星精密定轨研究

基于运动学和简化动力学方法,使用星载GPS观测数据,对SWARM卫星进行精密定轨,将轨道结果与ESA发布的事后科学轨道进行作差分析。结果表明：运动学轨道径向、切向和法向7 d平均RMS均小于3 cm,定轨精度达到cm级;简化动力学轨道径向平均RMS在0.65 cm左右,切向和法向在1.3 cm左右,高于预期要求。此外,使用IGS快速星历对SWARM卫星进行定轨,其精度与精密定轨精度近似相等,而在SWARM卫星近实时定轨研究中,使用IGS超快速星历确定的运动学轨道3D-RMS为9.68 cm,简化动力学轨道3D-RMS为3.61 cm,低于IGS快速星历的定轨精度。     

资源三号02星双频GPS快速精密定轨

采用资源三号02星双频GPS观测数据和CODE快速星历,利用非差简化动力学方法实现卫星精密定轨。通过卫星轨道重叠弧段检验,轨道径向精度优于3.90 cm,位置精度优于5.52 cm。利用SLR观测数据检核卫星轨道,精度优于4 cm。采用轨道外推和瞬时根数方法预报轨道,12 h内切向精度优于30 m。     

星载GPS实时定轨中重力场模型阶次的最优确定方法

分析重力场模型的截断误差及其影响因素,并用多颗不同轨道高度的低轨卫星GPS实测数据进行实时定轨仿真分析,提出实时定轨精度能够达到1.0 m(伪距法实时定轨)和0.5 m(相位法实时定轨)的重力场模型阶次的最优确定方法。使用CHAMP和TerraSAR-X 2颗卫星实测数据,验证了重力场模型阶次的最优确定方法的可行性和有效性。该方法不仅避免了传统经验法确定重力场模型阶次不准确的问题,而且不需要借助精密轨道进行精度评估,便于实时定轨系统的工程应用。     

基于IGU预报轨道实时估计精密卫星钟差

针对目前实时精密单点定位中,GPS卫星实时钟差服务所存在的精度问题,提出了一种基于IGU轨道的实时钟差估计方法。该方法基于IGU轨道,采用全球参考站非差载波相位观测值,进行实时钟差估计。数值结果表明：实时估计的卫星钟差与IGS最终产品的偏差大部分小于0.3 ns,平均优于0.2 ns;采用估计所得的实时钟差进行PPP静态定位,其精度可达1~2 cm,同时也可得到毫米级精度的天顶对流层延迟。     

利用SLR数据检核GLONASS卫星最终轨道

采用由EDC提供的2015-01-01～2015-12-31的SLR标准点观测数据进行GLONASS卫星最终轨道（CODE提供）检核,分别按照卫星PRN号和不同测站对检核结果进行统计分析。结果表明,不同卫星的检核效果参差不齐,跟卫星的服役年限有关,较新的卫星检核结果较好,第一轨道面的卫星检核结果最好;检核结果中存在一定的系统误差,且大部分的激光测距比最终轨道反算的站星距要短;利用SLR检核2015年全年GLONASS轨道精度总体优于3.3 cm,激光观测精度总体优于1.2 cm。     

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

Phylogenetic analysis of cultivable bacteria isolated from Arctic sea-ice

Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied     

Advances in Polar Science CONTENTS(Volume 25,2014)

正~~     

Guide to Authors： Journal of Mountain Science

<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet.     

Journal of Mountain Science(JMS)

<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by     

Relationship of Arctic sea ice and Northern Hemispheric 500 hPa Polar vortices

Using the NCEP/NCAR reanalysis monthly 500 hPa height data on a 2.5 latitude-longitude grid and 1°×1° sea ice data,the polar vortex area,intensity index and arctic sea ice area index are calculated respectively,and the meridional distribution,period variation and the abrupts in the long range trend are analyzed to study their relationship.The results show that the meridional distribution of sea ice and polar vortex h-ave distinctive difference,the relative positions of them are different in the eastern and western hemispheres,and exept they have periods of 4 months,quasi half year,quasi year,4-5 years and 10 years commonly,and each of them has its own respective variation as well.The sea ice area is decreasing apparently since 1980's,so is the polar vortex area,but their abrupt changge time are different totally.The area of sea ice and polar vortex has prominent positive correlation,but the relationship of sea ice intensity,polar vortex intensity,polar vortex area is complicated.     

Author Index for Journal of Mountain Science Volume 11,2014,pp 1-1656

<正>~~     

Information for Authors

<正>The Journal of Ocean University of China(Oceanic and Coastal Sea Research)is a comprehensive academic quarterly sponsored by the Ocean University of China,published one volume per year.This journal is devoted to the publication of the theoretical and applied research