Global GPS data analysis at the National Geodetic Survey

NOAA’s National Geodetic Survey (NGS) has been one of the Analysis Centers (ACs) of the International GNSS Service (IGS) since its inception in 1994. Solutions for daily GPS orbits and Earth orientation parameters are regularly contributed to the IGS Rapid and Final products, as well as solutions of weekly station positions. These solutions are combined with those of the other ACs and then the resultant IGS products are distributed to users. To perform these tasks, NGS has developed and refined the Program for the Adjustment of GPS EphemerideS (PAGES) software. Although PAGES has continuously evolved over the past 15 years, recent efforts have focused mostly on updating models and procedures to conform more closely to IGS and the International Earth Rotation Service (IERS) conventions. Details of our processing updates and demonstrations of the improvements will be provided.     

First results of DORIS data analysis at Geodetic Observatory Pecný

In a cooperation between the Astronomical Institute, University of Bern (AIUB), the Geodetic Observatory Pecný (GOPE), and the Institut Géographique National (IGN), DORIS data analysis capabilities were implemented into a development version of the Bernese GPS software. The DORIS Doppler observables are reformulated such that they are similar to global navigation satellite system (GNSS) carrier-phase observations, allowing the use of the same observation models and algorithms as for GNSS carrier-phase data analysis with only minor software modifications. As such, the same algorithms may be used to process DORIS carrier-phase observations. First results from the analysis of 3 weeks of DORIS data (September 2004, five DORIS-equipped satellites) at GOPE are promising and are presented here. They include the comparison of station coordinates with coordinate estimates derived by the Laboratoire d’Etudes en Géophysique et Océanographie Spatiale/Collecte Localisation Satellites analysis centre (LCA) and the Institut Géographique National/Jet Propulsion Laboratory (IGN/JPL), and the comparison of Earth orientation parameters (EOPs) with the International Earth Rotation and Reference Frames Service (IERS) C04 model. The modified Bernese results are of a slightly lower, but comparable, quality than corresponding solutions routinely computed within the IDS (International DORIS Service). The weekly coordinate repeatability RMS is of the order of 2–3 cm for each 3D station coordinate. Comparison with corresponding estimates of station coordinates from current IDS analysis centers demonstrates similar precision. Daily pole component estimates show a mean difference from IERS-C04 of 0.6  mas in X _p and  ? 0.5  mas in Y _p and a RMS of 0.8  mas in X _p and 0.9  mas in Y _p (mean removed). An automatic analysis procedure is under development at GOPE, and routine DORIS data processing will be implemented in the near future.     

Geodetic results from ISAGEX data

Laser and camer data taken during the International Satellite Geodesy Experiment (ISAGEX) have been used in dynamical solutions to obtain center-of-mass coordinates for the Astro-Soviet camera sites at Helwan, Egypt and Oulan Bator, Mongolia and East European camera sites at Potsdam, German Democratic Republic and Ondrejov, Czechoslovakia. The results are accurate to about 20 m in each coordinate. The orbit of PEOLE (i=15^o) has also been determined from ISAGEX data and mean Kepler elements suitable for geodynamic investigations are presented.     

空间大地直角坐标与大地坐标反算的非迭代法

介绍一种国外提出的由空间直角坐标 X ,Y,Z不需迭代 ,直接求解大地坐标 B,L,H的算法 ,给出了具体计算公式     

Geodetic sensitivity to surface meteorological data: 24-h and 6-h observing sessions

Tests have been performed to assess the utility of surface meteorological measurements for improved geodetic performance. Three types of a priori met data are considered: a default global, seasonal model; local met measurements collected at a subset of the test network; output values from a NOAA Forecast Systems Lab assimilation model. A variety of configurations for handling tropospheric parameters in the geodetic solutions is also considered. We find no geodetic advantage in using the measured met data under any test scenario. Differences among the three types of a priori information are generally insignificant, although biases can be introduced when some troposphere parameters are not adjusted. Even when using only a relatively small network (<100 km) the differences remain minor. When observing sessions are reduced from 24 h to 6 h the increased error due to measurement noise obscures all other effects except for the shortest baselines where some advantage may be achieved by not adjusting troposphere parameters for very close station pairs.     

Log-cumulants of the finite mixture model and their application to statistical analysis of fully polarimetric UAVSAR data

Since its first flight in 2007, the UAVSAR instrument of NASA has acquired a large number of fully Polarimetric SAR (PolSAR) data in very high spatial resolution. It is possible to observe small spatial features in this type of data, offering the opportunity to explore structures in the images. In general, the structured scenes would present multimodal or spiky histograms. The finite mixture model has great advantages in modeling data with irregular histograms. In this paper, a type of important statistics called log-cumulants, which could be used to design parameter estimator or goodness-of-fit tests, are derived for the finite mixture model. They are compared with log-cumulants of the texture models. The results are adopted to UAVSAR data analysis to determine which model is better for different land types.     

统计信息与空间信息按地理格网集成的方法研究

统计信息是区域可持续发展中的重要信息资源,涵盖了人口、农业、工业、经济等各类数据。采用GIS技术,有效地实现统计信息与空间信息的集成管理是区域可持续发展的重要保证。本文在分析了GIS中常用的集成方法基础上,提出了通过统计信息的“空间化”实现两者集成的方法,并以人口为例,详细论述了通过“空间化”实现人口数据与空间数据的集成过程。通过这种集成,可以高效地利用GIS的分析功能实现统计信息的管理、分析、显示。     

统计数据空间可视化方法分析

随着地理信息系统技术的发展,统计数据空间可视化的实现变得方便、快捷、即时和动态。但利用GIS软件和现有的专题地图编制软件处理一个研究区域大量繁复的统计数据仍有一定难度,大量的数据处理和图型设计工作还需要依靠经验和平面设计软件来完成,本文试图从统计数据空间可视化的基础原理出发,分析数据关系、图型构成及实现流程,提出相应的设计原则和方法。     

永久性潮汐与大地测量基准

社会、经济和科技的发展,对大地测量基准的精度、历元、框架等方面的要求愈来愈高,因此必须顾及具有同等精度量级的地球动力现象如潮汐、极移、地壳运动、冰后期反弹等对大地测量基准的影响。本文仅讨论永久性潮汐对重力基准、高程基准、大地水准面、垂线偏差等方面的影响。对大地测量基准中使用的无潮汐、平均湖汐和零潮汐等概念和相关计算进行了推导和讨论。     

Geodetic applications of eclipses and occultations

If in imagination we viewed a solar eclipse or the occultation of a star from a point outside the earth, we would see the shadow of the moon advancing across the face of the earth, the earth meanwhile turning on its axis beneath the shadow. When some point on the advancing edge of the shadow overtook a given point on the surface of the earth, an observer at that point would note the beginning of the eclipse or occultation. When the trailing edge of the shadow uncovered that point again, the observer there would note the end of the eclipse or occultation. The universal time (as distinguished from the local time) of the beginning or ending would depend on the position of the observer with reference to the body of the earth, that is, on his ideal geodetic coordinates. These universal times would not depend in the least on the direction of the observer’s vertical. This fact is the key to the usefulness of eclipses and occultations for geodetic purposes. Suppose that the prediction for the times of beginning or ending had been made on the basis of the astronomical latitude and longitude of the observer. Since there would be in general deflections of the vertical in latitude and longitude, Δπ and Δλ, these would bring about, even in the absence of any other source of discrepancy, diffe- This article is at once a condensation and an expansion. It is a condensation of a series of lectures delivered in the winter and spring of 1947 to members of the U. S. Coast and Geodetic Survey and of the Army Map Service. It is an expansion of a very informal lecture given before Section III of the International Association of Geodesy, meeting in General Assembly at Oslo in August, 1948.     

大地水准面数值计算及结构分析

针对大地水准面精化问题,该文提出了基于大地水准面起伏几何性质构建精确大地水准面的方法。相对传统方法根据经验公式设计精化大地水准面分辨率,该文提出了一种顾及区域性特点的大地水准面分辨率设计方法,推导了构建厘米级大地水准面需要达到的空间分辨率计算公式。采用Alltrans EGM2008Calculator 1.00软件计算不同区域的大地水准面高程,并用坡度方法分析大地水准面的精细结构。最后以江西省大地水准面起伏为基础,采用该方法进行计算。结果表明:构建厘米级大地水准面需要达到的空间分辨率为7″,可为大地水准面精化研究提供参考。     

Geodetic aspects of seismological phenomena

Seismology is related to many problems of geodesy. The energy production of our planet is rather close to energy consumption of the Earth so that the energy balance can be disturbed significantly by minor processes acting on global scale. From this point of view the effect of tidal triggering of earthquakes is discussed by the study of tidal stress tensor components expressed in spherical system of coordinates. Tidal friction influences through the despinning of the axial rotation the geometrical flattening. This flattening variation causes stresses along the longitude and this phenomenon is closely related to the seismic energy release. Until now there is no unambiguous success to relate changes of the Earth orientation parameters with seismicity. Present-day accuracy of the length of day variations is not sufficient yet to detect spin variation generated by the greatest earthquakes. The polar motion is probably more sensitive to earthquakes and then there is a chance to detect the polar displacements generated by seismic events. In the last section of the present contribution, the strain rates derived from the static seismic moments and from space geodetic observations are compared. Future geodetic strain rate data will be useful in earthquake prediction.     

大地测量专家程鹏飞研究员

程鹏飞研究员于1964年生于黑龙江省,1980年考入同济大学测量系,分别于1984年和1987年获工学学士学位和硕士学位,1987年毕业后在中国测绘科学研究院工作,主要从事卫星导航与定位的研究和应用工作,曾任中国测绘科学研究院大地测量与地球动力学研究所助理研究员、副研究员、国家光电测距仪检测中心副主任、院长助理;1995年赴奥地利格拉茨技术大学应用大地测量与摄影测量研究所攻读博士学位,于1998年获博士学位后回到中国测绘科学研究院大地测量与地球动力学研究所工作,同年被评为研究员,1999年至2002年任该所所长,2002年获清华大学MPA证书,同年任中国测绘科学研究院副院长至今.     

新疆大地控制网点2000国家大地坐标系成果应用分析

利用GPS相关技术,通过对比,分析了新疆大地控制网点2000国家大地坐标系成果在新疆测绘领域应用情况,验证了相关的数学精度,并提出了相关的应用分析结论。     

文莱大地基准与坐标格网

介绍了文莱大地基准及其对应的坐标格网发展的过程与现状,给出了文莱各个基准间的关系与转换参数。可为我国南海护渔、人道主义救援提供地理空间信息,同时为了解文莱大地测量发展历程、促进我国与文莱的测绘技术交流提供参考。     

大地测量反演中参数可辨识性问题

大地测量反演是进行大地测量物理解释研究的重要手段。在反演中,参数选择及求解（参数辨识）的正确性必须确保。本文根据有代表性的准则函数推演出大地测量反演参数可辨识条件,给出其适用范围;在概括了典型的大地测量力学模型基础上,讨论了其反演参数可辨识性问题;利用有限元数值反演算例验证了参数可辨识性的结论。表明：大地测量反演参数可辨识条件及其可辨识性的结论,体现了确定大地测量反演参数（种类和个数）理论上的必要性。     

大地测量数据共享环境的建立

探讨现代大地测量技术体系及其对大地测量生产、应用和服务模式的冲击,提出大地测量数据共享环境的概念,并构建大地测量数据共享体系结构。