北斗卫星导航系统/美国全球定位系统载波相位相对定位全球精度分析

文章推导了载波相位相对定位精度的计算公式;分析了影响载波相位相对定位精度的各项因素;提出了频率精度衰减因子的概念,用以表达不同频率组合对定位精度的定量影响;在此基础上,计算并绘制了美国全球定位系统(GPS)、北斗二号(BDS2)、北斗三号(BDS3)及其融合系统的单天解、半小时解和单历元解的相对定位精度因子全球分布图;利用自主知识产权的处理软件(GCN和VENUS/ARSNet)解算了实测数据,检验了GPS和BDS2的单天解和单历元解的定位精度.分析表明:BDS的B1/B2频率定位精度优于GPS L1/L2频率; BDS2在其服务区内精度总体上与GPS相当; BDS3在亚太地区定位精度高于GPS.根据上述结论,文章在导航系统信号频率和全球定位系统(GPS)测量规范方面提出了优化建议,可为系统性能优化和制定标准提供参考.     

GPS数据解算过程中相关问题研究

基于2011和2012年陆态网GPS连续观测数据,分析了GPS水平速度场数据解算过程中,不同对流层延迟参数个数与初始坐标偏差对解算精度的影响;利用重采样方法模拟生成多组不同时间间隔的流动数据,分析了不同时间间隔的流动观测模式下的解算精度。通过实验证实,为了得到高精度的GPS单日松弛解,必须进行对流层延迟估计,对流层参数个数设置为2,7,13时解算精度存在少量差别,表现为随着参数增多解算精度有所提高;初始坐标误差在10m时可以得到精度较高的时间序列结果,误差在30m及50m时不能得到可用的时间序列;当流动观测时间间隔大于1年时,可以获得较为可靠的水平速度场结果;时间间隔短于1年时,水平速度场解算精度较低。     

CORS观测网络地壳运动监测系统研制及应用

以四川CORS观测网络为数据基础,结合GPS高精度数据处理技术及B／S技术架构,设计并实现了一套地壳运动在线监测系统。该地壳运动监测系统以GAMIT／GLOBK为数据处理引擎,实现各CORS站数据的高精度自动化解算,并通过WEB技术实现测站信息、基线序列以及坐标序列等的信息可视化表达。试验结果表明,该系统具备较好的运行稳定性和友好的人机交互性,可实现自动化的区域地壳运动监测。     

结合欧拉矢量的反演算法构建青藏高原东北缘地壳运动速度场模型

探讨地壳运动速度场模型的构建方法,提出结合欧拉矢量的维多样性动态权重粒子群算法构建地壳运动速度场模型。通过模拟算例验证该算法的稳定性和有效性,建立的速度场模型与线性权重粒子群算法和非线性权重粒子群算法的计算结果相比具有较高的精度,且收敛速度较快。利用青藏高原东北缘1999—2013年中国地壳运动观测网络观测到的GPS水平速率结果,在块体划分和模型辨识的基础上,建立青藏高原东北缘地壳运动速度场模型,并将其与最小二乘配置法的计算结果进行比较,结果表明改进的粒子群算法建立的地壳运动速度场模型具有较高的精度。     

汶川地震前后区域地壳形变场及孕震特征研究

利用中国地壳运动观测网络GPS区域网1999、2001、2004、2007年观测资料及中国大陆构造环境监测网络区域网2009、2011年观测资料,解算了南北地震带相对华南地块的GPS速度场,并用最小二乘配置方法解算了南北地震带南、北部地区应变率场的多期次结果,通过分析汶川地震前、后地壳运动速度场和应变率场的动态变化,进一步研究了汶川地震前区域地壳形变和应变积累背景与孕震异常的形变场主要特征及其形成机制.     

高频GNSS实时地震学与地震预警研究现状

为实现从注重灾后救助向注重灾前预防转变,如何提高地震灾害监测预警和风险防范能力成为我们关注的重点.本文给出了国际上GNSS位移记录、强震动加速度记录、测震速度记录在地震预警中的应用现状,并总结了各自的特点,归纳出围绕高频GNSS地震学在震级与破裂过程实时反演中的几个需要进一步研究的关键问题：（1）引入北斗系统,基于高频GNSS（GPS/BDS）双系统的实时位移解算方法来提高实时单站位移解算精度,使实时解算精度达到厘米级;（2）开展强震仪加速度记录基线偏移校正研究,弥补地震近场GNSS站密度不足问题;（3）强震仪加速度记录与GNSS位移记录特点不同,开展强震仪加速度数据与GNSS位移数据实时融合处理研究,快速获得包含丰富地震形变和速率的波形数据;（4）测震学方法可快速估算震级,但是在强震发生时会出现震级饱和现象,造成震级估算偏低.需要开展基于GNSS位移时间序列的多种方法相结合的实时震级估算方法研究,通过与地震学方法比较和结合,来得到精度高、计算快的震级估值算法;（5）基于高频GNSS、断层初始模型快速选取、断层尺度、参数自适应调整是快速判断断层破裂方向的基础,在断层破裂过程自适应准实时反演算法方面需要进一步加强.通过国内外研究现状调研、分析,表明基于高频GNSS地震学的震级快速确定、震源破裂过程准实时反演算法的发展将对我国地震预警系统从"二网融合"到"三网融合"提供坚实的技术支撑.     

山东地壳运动监测及管理信息系统的设计与研发

全面介绍了山东GPS地壳运动监测及管理信息系统的设计思路和框架以及软件开发方法,该系统以VC++、Matlab和WebGIS为开发基础,集成了设备监控、高精度数据解算、结果分析及应用,以及信息网络发布等功能,可为同类GPS观测网管理系统的研发提供良好的借鉴。     

2000国家GPS大地控制网的数据处理和精度评估

2000国家GPS大地控制网集合了各类GPS网近10年的观测数据, 提供GPS点在全球参考框架下20000历元的绝对位置.文中简要介绍GPS数据处理的方法,给出数据处理的精度统计;以部分点的实测速度为基础,建立中国大陆地壳运动速度场;基于GPS测量的动态系统状态,选择序贯卡尔曼滤波的广义测量平差方法,对GPS点做顾及地壳运动的整网平差,并给出整网平差结果的精度统计和外部检核.一系列的手段和措施保证了平差结果的合理性和可靠性.     

GPS在我国地震监测中的应用现状与发展展望

回顾了GPS技术应用于我国地震监测中的发展历程,重点从GPS数据处理与时间序列、中国大陆构造变形速度场与应变率场、中国大陆活动地块运动定量化和地震研究等方面,介绍了GPS在我国地震监测中的应用现状,并针对当前面临的问题与挑战,进行了讨论,从地震预测研究、基础研究、GPS台网监测布局和GPS解算精度与时效4个方面,对GPS在我国地震监测中的发展进行了展望。     

北斗区域卫星导航系统基本导航定位性能初步评估

北斗区域卫星导航系统(也称北斗2代1期)于2012年12月27日正式开始运行,系统由14颗卫星组成,包括5颗地球静止轨道卫星、5颗倾斜地球同步轨道卫星和4颗中圆地球轨道卫星.本文初步评估了北斗区域卫星导航系统建成运行后的基本导航定位性能,包括卫星可见性、位置精度衰减因子、伪距和载波相位观测量精度、单点定位和差分定位精度以及模糊度解算性能等.通过实验分析可知:北斗伪距和载波相位测量精度已与GPS处在同一水平,伪距测量精度约为33 cm,载波测量精度约为2 mm;北斗伪距单点定位水平精度优于6 m,高程精度优于10 m,已满足设计要求;北斗区域卫星导航系统已具备独立的双频RTK定位能力,其单历元双频模糊度解算成功率几乎与GPS相当;北斗载波相位差分定位精度与GPS相位差分定位处在同一水平,超短基线情况下,定位精度优于1 cm,而在短基线情况下优于3 cm;北斗与GPS组合定位时,模糊度解算的固定率和可靠性均显著提高;在短基线情况下,北斗/GPS组合载波相位差分动态定位精度相对于单一的GPS定位的改善可达20%以上;北斗单频伪距差分定位精度优于2.5 m,与GPS相比仍存在较大差距,其主要原因可能为北斗GEO卫星伪距多路径误差较大.     

Preliminary assessment of the navigation and positioning performance of BeiDou regional navigation satellite system

BeiDou regional navigation satellite system(BDS)also called BeiDou-2 has been in full operation since December 27,2012.It consists of 14 satellites,including 5 satellites in Geostationary Orbit(GEO),5 satellites in Inclined Geosynchronous Orbit(IGSO),and 4 satellites in Medium Earth Orbit(MEO).In this paper,its basic navigation and positioning performance are evaluated preliminarily by the real data collected in Beijing,including satellite visibility,Position Dilution of Precision(PDOP)value,the precision of code and carrier phase measurements,the accuracy of single point positioning and differential positioning and ambiguity resolution(AR)performance,which are also compared with those of GPS.It is shown that the precision of BDS code and carrier phase measurements are about 33 cm and 2 mm,respectively,which are comparable to those of GPS,and the accuracy of BDS single point positioning has satisfied the design requirement.The real-time kinematic positioning is also feasible by BDS alone in the opening condition,since its fixed rate and reliability of single-epoch dual-frequency AR is comparable to those of GPS.The accuracy of BDS carrier phase differential positioning is better than 1 cm for a very short baseline of 4.2 m and 3 cm for a short baseline of 8.2 km,which is on the same level with that of GPS.For the combined BDS and GPS,the fixed rate and reliability of single-epoch AR and the positioning accuracy are improved significantly.The accuracy of BDS/GPS carrier phase differential positioning is about 35 and 20%better than that of GPS for two short baseline tests in this study.The accuracy of BDS code differential positioning is better than 2.5 m.However it is worse than that of GPS,which may result from large code multipath errors of BDS GEO satellite measurements.     

Global precision analysis of carrier phase relative positioning in BeiDou navigation satellite system and United States global positioning system

In this paper, we derived a high-efficiency formula for calculating the precision of carrier phase relative positioning,analyzed the various factors that affect the positioning accuracy using the carrier phase, and proposed the concept of using a frequency dilution of precision to describe the quantitative effect of different frequency combinations on the positioning precision. To this end, we computed and plotted the global spatial distribution map of the relative positioning dilution of precision for single-day solution, half-hour solution, and single-epoch solution of the global positioning system(GPS), regional Beidou navigation satellite system(BDS2), future global Beidou navigation satellite system(BDS3), and their fusion systems.Using processing software with autonomous intellectual property rights(GCN and VENUS/ARSNet), we solved the measurement data and examined the positioning precision of the single-day solution and single-epoch solution of GPS and BDS2.The analysis demonstrated that the B1/B2 frequency positioning precision of BDS2 was better than that of L1/L2 frequency positioning of GPS, but the positioning precision of the BDS2 is worse than that of GPS over most of the service region of the BDS2. Further, the positioning precision of BDS3 is better than that of GPS in the Asia-Pacific region, while it is the opposite in other regions. Based on these conclusions, we put forth some optimization recommendations regarding the signal frequency of the navigation system and GPS measurement standards to serve as references for optimizing the system performance and formulating standards.     

GPS监测的中国及其周边现时地壳形变

利用多个全国性的GPS监测网、中国地壳运动主要活动带的区域性GPS监测网以及亚太地区大地测量计划(APRGP)的GPS监测网自1991年以来近10年的GPS资料,通过旋转变换将不同方法得出的各个子网的速度解进行统一,给出一个自恰的、完整的ITR一7框架下的速度场综合解.为了研究中国现时地壳运动在欧亚板块内形变的特征,基于一个现时板块运动模型ITRF97VEL,给出了3类网共260多个站的形变速度场.结果表明中国地壳运动有明显的不均匀性,以南北地震带为界,西强东弱;中国西部受印度板块强烈的冲挤,地壳运动由南向北逐渐减慢,呈现南北向缩短,东西向伸展,有明显的块体特征;喜马拉雅和天山西部分别提供了约15mm/a和9-13mm/a的汇聚速率;拉萨块体有(20.2±1.2)mm/a的伸长;喀喇昆仑一嘉黎断裂的右旋走滑速率和阿尔金断裂的左旋走滑速率分别为2-3mm/a和4-6mm/a,穿过龙门山断裂带的缩短速率小于7mm/a,这些都支持地壳增厚学说;沿阿尔金断裂带到喜马拉雅存在一个NNE弥散带,它是形变速度有东和西分量的分界线,是一个有特殊意义的动力学带.中国东部以走滑为主,东北块体是中国最稳定的地区,华北块体具有较大走滑性,是东部较易变形区.     

Establishment of the GPS Monitoring Network in North China, the Relation of Horizontal Crustal Movement to Stress Field and Seismicity

In the paper, the establishment, measurement, data-processing program and monitoring accuracy of the GPS seismic monitoring network in North China, especially in the Capital-Circle area, have been presented briefly. The relation of horizontal crustal deformation to tectonic movement, stress-field variation and seismicity has been analyzed in detail. The results indicate that the accuracy of GPS measurement has reached the order of 10-9 and the annual rate of horizontal crustal deformation in North China is about 4 ~5 mm. Horizontal crustal movement is a direct indication of the regional stress field. Therefore, by monitoring the time-sequence variation of horizontal crustal motion, it would be possible to investigate the change in the stress field, to analyze the tendency of seismicity and to determine the seismogenic zones.     

Current crustal movement in Chinese mainland

The quantification of tectonic deformation in the Eastern and Central Asia is of great significance for the study on global plate motion and lithospheric dynamics. In the past four years, the velocity field of horizontal crustal movement for the Chinese mainland has been established for the first time thanks to the intensified GPS measure-ments and its improved accuracy. The velocity field derived from GPS measurements delineates the patterns of tectonic deformation in the Chinese mainland in the unprecedented detail, and thus reveals the new features of the ongoing tectonic process resulted from the collision of Indian plate to Eurasian plate. Meanwhile, the surface offset induced by two strong earthquakes occurred in Chinese mainland was sampled precisely using InSAR technique.     

中国大陆现今地壳运动研究

GPS结果十分清晰地刻画出中国大陆地区块体运动及内部变形特征，提供了认识印度欧亚碰撞引起的活动构造的新视角．本文回顾了4年来中国学者在利用GPS研究现今地壳运动方面所取得的成就，以及在利用InSAR技术研究强震破裂方面的进展情况．这些研究成果，标志着中国大陆构造变形的定量化研究进入了一个新阶段.      

Geodetic Measurements of Crustal Deformation in the Western Mediterranean and Europe

—Geodetic measurements of crustal deformation over large areas deforming at slow rates (<5 mm/yr over more than 1000 km), such as the Western Mediterranean and Western Europe, are still a challenge because (1) these rates are close to the current resolution of the geodetic techniques, (2) inaccuracies in the reference frame implementation may be on the same order as the tectonic velocities. We present a new velocity field for Western Europe and the Western Mediterranean derived from a rigorous combination of (1) a selection of sites from the ITRF2000 solution, (2) a subset of sites from the European Permanent GPS Network solution, (3) a solution of the French national geodetic permanent GPS network (RGP), and (4) a solution of a permanent GPS network in the western Alps (REGAL). The resulting velocity field describes horizontal crustal motion at 64 sites in Western Europe with an accuracy on the order of 1 mm/yr or better. Its analysis shows that Central Europe behaves rigidly at a 0.4 mm/yr level and can therefore be used to define a stable Europe reference frame. In that reference frame, we find that most of Europe, including areas west of the Rhine graben, the Iberian peninsula, the Ligurian basin and the Corsica-Sardinian block behaves rigidly at a 0.5 mm/yr level. In a second step, we map recently published geodetic results in the reference frame previously defined. Geodetic data confirm a counterclockwise rotation of the Adriatic microplate with respect to stable Europe, that appears to control the strain pattern along its boundaries. Active deformation in the Alps, Apennines, and Dinarides is probably driven by the independent motion of the Adriatic plate rather than by the Africa-Eurasia convergence. The analysis of a global GPS solution and recently published new estimates for the African plate kinematics indicate that the Africa-Eurasia plate motion may be significantly different from the NUVEL1A values. In particular, geodetic solutions show that the convergence rate between Africa and stable Europe may be 30–60% slower than the NUVEL1A prediction and rotated 10–30° counterclockwise in the Mediterranean.     

福建沿海、台湾海峡GPS观测分析及地球动力学特征研究

利用 3期GPS联测结果所获得的福建沿海地壳水平运动信息 ,采用ITRF94全球框架为基础的GPS测站地壳运动模型及其处理软件 ,对所获得的观测数据进行处理和精度分析。得到福建省高精度的GPS测站大地坐标、边长及其位移矢量 ,其精度达到 1 7×10 - 8。计算了福建地壳运动速率、主应变率 ,东西与南北向线应变率、面应变率、剪应变率、大地转动率和最大剪应变率等值线并给出了它们的分布图象。根据多年形变和现今GPS观测资料 ,分析福建地壳垂直运动与水平运动 ,显示区域应力场优势分布特征。最后 ,对福建沿海及台湾海峡地壳动力学特征作了初步的探讨     

Correlated Crust and Mantle Strain Field in China

INTRODUCTION Moststudiesonactiveblockshavebeenfocusedonidentificationofblockboundariesandtheiractivity;inotherwords,mostoftheworkwaslimitedtothehorizontalmovementoftheblocks.Inreality,theblocksarenotonlysurroundedbyactivefaultsofhorizontalmotion,butalsoco…