浙江省水利基础数据标准研究

针对现有国家、行业标准规范有关水利基础数据的内容无法满足当前浙江省智慧水利建设和数字化改革的问题，该文将水利地理实体与浙江水利业务充分融合，提出了一种全水利对象分类、全关系时空表达的多层次水利基础数据模型，讨论了水利基础数据质量目标和编制技术流程，重点阐述了水利基础数据标准编制的核心内容，包括水利对象分类颗粒度划分、水利对象编码和水利知识图谱构建等，通过浙江省级地方标准《水利对象分类规范》(DB33/T 2512—2022)、《河湖基础数据规范》(DB33/T 2442—2022)、《水库基础数据规范》(DB33/T 586—2022)的实践，构建了浙江省水利基础数据标准体系，为省级水利基础数据采集、处理、管理和服务提供支撑，为其他行业在基于本行业地理实体编制基础数据标准提供经验。     

数字测绘产品生产过程中数据质量的控制

数据质量是一个相对的概念，是指数据对特定用途的分析和操作的适用程度。数据具有不确定性,衡量数据质量的标准会随着具体应用的特点和要求而变化，因此，在数据质量问题中，有可以战小甚至消除的因素，也有难以检测和控制的因素。因此，我们在生产过程中既要对哪些可以控制的因素进行有效地控制．同时对存在的不确定的因素采取相应对策。     

沈阳地铁四号线一期GPS平面控制网的建立

以实际案例的形式阐述了GPS平面控制网建立的全过程,规定了该网的控制点点位选择原则及埋设标准,简单描述了该项工程的数据采集要求,利用基线解算和平差软件对采集的数据进行最终的处理,对数据处理结果进行精度评定,并得出结论:该网各项精度指标均满足设计和规范要求,数据成果质量优异,可作为该工程的首级平面控制基准。     

三级GPS大地控制网中GPS观测数据质量检测方法研究

本文在分析影响GPS观测数据质量和GAMIT／GLOBK数据处理质量评价标准的基础上,介绍了TEQC数据质量检测软件和基线解算质量控制指标,探讨了三级GPS大地控制网数据质量的检测方法,并对实测数据进行了检测和评定。实践表明,该检测方法是有效和切实可行的。     

地质图空间数据库建设质量控制方法研究

针对地质数据库建设的质量控制问题,本文依托1：50 000区域地质图空间数据库建设成果数据质量控制,通过对区域地质图空间数据库建设过程中可能产生的质量问题进行总结和分析,系统阐述了空间数据库成果数据质量控制的基本理论与方法技术。实践证明,通过该方法,很好地规范了空间数据生产和数据库建设,实现数据库建设整体质量控制,保证了数据质量。通过成果数据的应用效果分析,证实了该质量控制方法的有效性、实用性和可操作性,具有广泛的推广意义。     

数字影像地图的编制

本文介绍了利用原始遥感影像数据、DEM数据、空三加密数据和地形矢量数据通过定向、纠正、镶嵌、编辑、复合和整饰等工序编制数字影像地图的方法，并讨论了数字影像地图的质量评估标准以及在编制过程中的质量控制方法，最后简要叙述了数字影像地图的应用现状并对其前景作了展望。     

空间数据的误差分析与处理

土地信息系统中最有价值的部分莫过于具有可靠质量的数据，包括空间数据和非空间数据。但目前数据库中的数据缺少精度标准和数据质量的控制。针对这种情况，本文对空间数据进行了误差分析，提供了消除数据错误、改正系统误差和处理偶然误差的一些方法。采用这些方法，在很大程度上改善了空间数据的质量，输出的产品在精度和图面美观方面基本符合规范的要求。     

TEQC软件用于GPS控制网数据质量检测的研究

在分析影响GPS观测数据质量和GAMIT/GLOBK数据处理质量评价标准的基础七,通过TEQC数据质量检测软件和基线解算质量控制指标,研究三级GPS大地控制网数据质量的检测方法,并以三级GPS大地控制网观测数据为例对观测数据进行检测和评定.     

交通图出版前的数据质量控制研究

数据质量控制一直以来都是地理信息系统(GIS)的一个关键环节,随着GIS在地图出版领域的应用,地图出版前的数据质量控制也成为了目前需要迫切解决的问题。本文研究了交通图编制的基本要求以及编制规范,通过GIS数据和交通图出图数据的比较,总结了在交通图出版前有可能存在的数据质量问题,并提出了相应的控制措施。     

公开地图成果质量分析与控制方法

从公开地图的市场走向、设计与制作方法、质量控制等方面,研究了公开地图成果质量存在的数据安全性、数据准确性、数据现势性、数据标准性、工作程序性、用户认可度等常见性问题和影响因素,摸索出一套行之有效的质量控制方法。     

GPS虚拟参考站原理及实测精度验证分析

首先介绍GPS RTK技术的局限性,然后分析基于GPS连续运行参考站网络虚拟参考站的基本原理、数学模型,根据综合误差线性内插原理计算虚拟参考站的综合原始观测数据,求出流动站的定位结果;然后就某市建立的虚拟参考站网络的实测数据进行动态、静态精度分析;最后得出结论：虚拟参考站技术扩大GPSRTK的使用范围,提高动态测量的精度,其开放式的数据服务使VRS技术成为Net Work RTK的主要发展方向之一。     

CORS基准站周跳探测与修复方法研究

在高精度GNSS测量中,周跳的存在直接影响到整周模糊度的解算及最终定位精度。针对目前各省市连续运行基准站网多系统观测数据的获取导致周跳探测工作量增加,该文基于甘肃省卫星定位连续运行基准站网(GSCORS)双频观测值提出了一种满足普遍条件的多系统周跳探测方法。采用相位减伪距结合电离层残差法分别对GPS和BDS原始观测值进行周跳探测与修复,通过对相应载波的模拟周跳探测发现,BDS较大的卫星钟差和伪距噪声影响了数据质量,其周跳检测量时间序列波动大于GPS,对7周以上周跳探测的精度较GPS会有1周的偏差,但电离层残差法能对BDS相位减伪距法探测残留的1周小周跳进行二次探测并修复。实验最终证实该方法能够有效探测并且正确分离GPS和BDS每个频率1周以上的周跳。     

New global positioning system reference station in Brazil

Co-located very long baseline interferometry (VLBI) and global positioning system (GPS) reference stations were installed near Fortaleza, Brazil, in 1993. Both have been important in the realization and maintenance of the International Terrestrial Reference Frame. A new-generation GPS system was installed in 2005 to replace the original station. Experience gained in the prior 12 years was used to improve the design of the GPS antenna mount. Preliminary indications are greatly improved data quality from the new station. Simultaneous observations from the nearly half-year of overlapping operation have been used to determine the local tie between the new and old GPS reference points to about 1 mm accuracy. This can be used to update the 1993 survey tie between the original GPS and the VLBI points, although there are questions about the accuracy of that measurement based on a comparison with space geodetic data. A test of removing the conical radome over the old GPS antenna indicates that it has biased the station height by about 16 mm downward, which probably accounts for most of the previous survey discrepancy.     

A new combined European permanent network station coordinates solution

The EUREF [International Association of Geodesy (IAG) Reference Frame Sub-Commission for Europe] network of continuously operating GPS stations (EPN) was primarily established for reference frame maintenance, and also plays an important role for geodynamical research in Europe. The main objective of this paper is to obtain an independent homogeneous time series of the EPN station coordinates, which is also available in SINEX format. A new combined solution of the EPN station coordinates was computed. The combination was performed independently for every week, in three steps: (1) the stated constraints on the coordinates were removed from the individual solutions of the Analysis Centers; (2) the de-constrained solutions were aligned to ITRF2000; (3) the resulting solutions were combined using the Helmert blocking technique. All the data from GPS weeks 900 to 1302 (April 1997–December 2004) were used. We investigated in detail the behavior of the transformation parameters aligning the new combined solution to ITRF2000. In general, the time series of the transformation parameters show a good stability in time although small systematic effects can be seen, most likely caused by station instabilities. A comparison of the new combined solution to the official EUREF weekly combined solution is also presented.     

双基准站RTK测量代替等级控制测量的方法

提出了RTK测量的改进措施,基于双基准站RTK测量误差分析,推导了其测量限差,探讨了RTK测量代替等级控制测量的问题,并以试验数据进行了验证。     

浅析城市参考站网络建设通讯方案

城市数字化和数字城市是现代化城市的发展趋势,连续运行GPS参考站系统是实现地理空间数据采集实时化、处理自动化、服务网络化和社会化的先进技术手段之一,是城市地理空间基础设施的重要组成部分.通讯技术是参考站系统的关健技术,通讯质量及速度是参考站稳定运行的重要条件.本文就参考站的通讯问题进行讨论.     

超站式集成测绘系统STGPS的研究

介绍了超站式集成测绘系统STGPS的研究思想、研究目标、系统构成和功能;讨论了坐标转换和测绘基本服务问题;提出了无需作加密控制的即用即测作业模式。     

Instantaneous BDS + GPS undifferenced NRTK positioning with dynamic atmospheric constraints

As the Chinese BeiDou Navigation Satellite System (BDS) has become operational in the Asia-Pacific region, it is important to better understand and demonstrate the benefits of combining triple-frequency BDS with dual-frequency GPS observations for network-based real-time kinematic (NRTK) services. Undifferenced NRTK is a new NRTK service mode, it extends the concept of NRTK by not requiring reference station and specified reference satellite at the rover processing. In order to realize the undifferenced NRTK service, a strategy for real-time modeling the undifferenced (UD) augmentation information is given, in which the fixed double-differenced ambiguities are transformed into UD ones with the help of datum settings. Since this strategy is insensitive to existing ephemeris products, it is applicable to the services of current BDS regional reference networks. Furthermore, a processing scheme for ambiguity resolution (AR) with arbitrary-frequency observations is also presented in detail. An instantaneous and reliable BDS + GPS positioning service can be provided to the rovers in undifferenced NRTK processing mode. With the data collected at 31 stations from a continuously operating reference station network in Guangdong Province (GDCORS) of China, the efficiency of the proposed approaches using combined BDS and GPS observations is confirmed. For three rover stations during days 327–329, a total of 12,960 1-min tests were performed separately to demonstrate the performance of AR. Thanks to the dynamically refined priori information of residual tropospheric and ionospheric error, and the availability of more satellites and observations, the AR fixing rates of combined BDS and GPS systems improve by 13 to 65%, compared with those of the GPS-only system using the traditional WL-L1-IF scheme. The positioning accuracy has also significantly improved.     

Generation of differential GPS corrections along with performance of quality control

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Generation of differential GPS corrections along with performance of quality control

The DGPS technique can provide considerably better relative positioning accuracy than the stand-alone GPS positioning, but the improvement depends on the distance between the user and the reference station (spatial correlation), the latency of differential corrections (temporal correlation), and the quality of differential corrections. Therefore, how to correctly generate differential corrections as well as their pricision is very important to the DGPS positioning technique. This paper presents a new algorithm for generating differential GPS corrections. This algorithm directly uses code and carrier observations in the measurement model of a Kalman filter, so that it is possible to use a simple stochastic model and to use the standard algorithm of the Kalman filter. The algorithm accounts for biases like multipath errors and instrumental delays in code observations and it shows how differential corrections are differently affected by code biases when dual or single frequency data is used. In addition, the algorithm can be integrated with a real time quality control procedure. As a result, the quality of differential corrections can be guaranteed with a certain probability.