一种能实现单频PPP-RTK的GNSS局域参考网数据处理算法  

A method for processing GNSS data from regional reference networks to enable single-frequency PPP-RTK

作　　者：张宝成[1,2] ODIJK Dennis 

机构地区：[1]中国科学院测量与地球物理研究所动力大地测量学国家重点实验室,武汉430077 [2]GNSS Research Centre,Department of Spatial Sciences,Curtin University

出　　处：《地球物理学报》2015年第7期2306-2319,共14页Chinese Journal of Geophysics

基　　金：国家自然科学重点基金(41231064);国家重点基础研究发展计划项目(2012CB825604);国家高技术研究发展计划(2012AA121803);国家自然科学基金(41374043);大地测量与地球动力学国家重点实验室开放基金(SKLGED2013-1-6-E);the Positioning Program Project 1.19 "Multi-GNSS PPP-RTK Network Processing" of the Cooperative Research Centre for Spatial Information(CRC-SI)联合资助

摘　　要：全球范围内大量布设的GNSS（Global Navigation Satellite System）参考网为精密定位、导航和授时等应用提供了丰富的数据资源.基于局域参考网,先后发展了若干侧重实现双频精密定位的技术,如NRTK（Network Real Time Kinematic）,PPP（Precise Point Positioning）和PPP-RTK等.其中,PPP-RTK融合了NRTK和PPP的技术优势,是目前相关研究的热点.本文改进了利用局域参考网提取各类改正信息的算法,以便于实现单频PPP-RTK,具体步骤包括：1）逐参考站实施非组合PPP,并固定已知站星距和卫星钟差,预估电离层延迟、浮点模糊度等参数;2）联合所有参考站的PPP模糊度预估值,通过重新参数化,形成一组双差整周模糊度和接收机、卫星相位偏差;3）固定双差整周模糊度,精化求解卫星相位偏差和各参考站PPP电离层延迟.基于网解中用到的卫星轨道和钟差,以及网解所提供的卫星相位偏差和（内插的）电离层延迟,参考网内的单频流动站即可实施PPP-RTK.基于澳大利亚某连续运行参考站网和流动站的实测数据,考察了：1）参考网数据处理中,双差模糊度的固定成功率（98.89%）和卫星相位偏差估值的时间稳定性（各连续弧段优于0.2周）;2）流动站处电离层延迟的内插精度（优于10cm）;3）单天内任一历元起算,固定静态（动态）单频PPP整周模糊度所需时长（均不超过10min）;4）模糊度固定前后,单频动态PPP的定位精度（模糊度固定后,平面和天顶RMS分别优于5cm和10cm;模糊度固定前,相应RMS仅为28～53cm）.Global Navigation Satellite System（GNSS）data from reference station networks deployed globally can facilitate positioning,navigation and timing applications.To enable precise positioning for dual-frequency users,several representative methods relying on GNSS referencenetworks have been developed,such as Network Real Time Kinematic（NRTK）,Precise Point Positioning（PPP）and PPP-RTK.The state-of-the-art PPP-RTK integrates the advantages of customary NRTK and PPP,and has become an important topic in current research.In this contribution,a network processing method is proposed to achieve single-frequency PPP-RTK.The elementary procedures are as follows：1）A Kalman-filter-based customary PPP is implemented station by station,with known geometric ranges and satellite clocks fixed.The estimable unknowns consist of,among others,the ionospheric delays and the float-valued carrierphase ambiguities.2）After measurement-update,the filtered PPP ambiguities of all stations are incorporated and reformulated into three sets of new parameters,namely,double-difference（DD）ambiguities,receiver and satellite carrier-phase biases.3）.The reformulated DD ambiguities are resolved into integers,and then the satellite carrier-phase biases as well as those filtered ionospheric delays are further updated.On the user side,by applying the satellite phase biases and（interpolated）ionospheric delays,the integer ambiguity resolution enabled single-frequency PPP-RTK is fulfilled.Numerical tests using daily GPS data collected by an Australian Continuous Operating Reference System（CORS）network and a single-frequency（u-blox）rover receiver show that success rate of CORS network ambiguity resolution is as high as 98.89%.In addition,the stability of estimated satellite carrier-phase biases is better than 0.2cycles over every continuous satellite arc.By confronting the ionospheric delays interpolated from the CORS with that determined from a dual-frequency receiver co-located with the rover receiver,interpolation error of 10

关 键 词：单频PPP-RTK 卫星相位偏差 电离层延迟 整周模糊度固定 

分 类 号：P223[天文地球—大地测量学与测量工程]