Accuracy Evaluation of GPS Broadcast Inter-signal Correction (ISC) Parameters and Their Impacts on GPS Standard Positioning

doi:10.11947/j.AGCS.2016.20150554

Abstract

Abstract: With the introducing of GPS (Global Positioning System) Block ⅡR-M satellites in 2005, a new civil signal (L2C) was transmitted on L2 frequency, and two new signals (L5I and L5Q) on a new frequency (L5) were also introduced as standard signals with Block ⅡF satellites beginning in 2010. In addition to the timing group delay (TGD) parameter contained in the legacy navigation (LNAV) message, four additional inter-signal correction (ISC) parameters are introduced in the new civil navigation (CNAV) message to provide corrections for L1C/A, L2C and L5 signals with respect to L1P(Y) signal. In this study, the ISC correction models are first developed for GPS single-and dual-frequency navigation users. Thereafter ISCs are validated with the differential code bias (DCB) products of different organizations, and several standard point positioning (SPP) schemes are also carried out to analyze the impact of ISCs on GPS standard positioning. The results indicate that the precision of broadcast ISC_C/A is about 0.2 ns, and those of TGD, ISC_L2C and ISC_L5Q are about 0.5 ns. The positioning accuracy of the SPP solution based on GPS L2C signals applying ISC corrections improves 30.6% and that based on L1C/A and L2C ionosphere-free combination improves 12.2% at 12 multi-GNSS experiment (MGEX) stations during day of year (DOY) 300-310 in 2014, compared to the solutions without the consideration of ISCs. For GPS dual-frequency users, the broadcast ISCs enable a level of accuracy that is competitive with ionosphere-free combination of the present L1P(Y) and L2P(Y) signals.

Key words: inter-signal correction (ISC), timing group delay (TGD), differential code bias (DCB), standard positioning

CLC Number:

P228

WANG Ningbo, YUAN Yunbin, ZHANG Baocheng, LI Zishen. Accuracy Evaluation of GPS Broadcast Inter-signal Correction (ISC) Parameters and Their Impacts on GPS Standard Positioning[J]. Acta Geodaetica et Cartographica Sinica, 2016, 45(8): 919-928.

References

[1] 袁运斌,欧吉坤.GPS观测数据中的仪器偏差对确定电离层延迟的影响及处理方法[J].测绘学报,1999,28(2):19-23.YUAN Yunbin,OU Jikun.The Effects of Instrumental Bias in GPS Observations on Determining Ionospheric Delays and the Methods of Its Calibration[J].Acta Geodaetica et Cartographica Sinica,1999,28(2):19-23.
[2] LI Zishen,YUAN Yunbin,FAN Lei,et al.Determination of the Differential Code Bias for Current BDS Satellites[J].IEEE Transactions on Geoscience and Remote Sensing,2014,52(7):3968-3979.
[3] MONTENBRUCK O,HAUSCHILD A,STEIGENBERGER P.Differential Code Bias Estimation Using Multi-GNSS Observations and Global Ionosphere Maps[J].Navigation,2014,61(3):191-201.
[4] 常青,张东和,萧佐,等.GPS系统硬件延迟估计方法及其在TEC计算中的应用[J].地球物理学报,2001,44(5):596-601.CHANG Qing,ZHANG Donghe,XIAO Zuo,et al.A Method for Estimating GPS Instrumental Biases and Its Application in TEC Calculation[J].Chinese Journal of Geophysics,2001,44(5):596-601.
[5] 张小红,李征航,蔡昌盛.用双频GPS观测值建立小区域电离层延迟模型研究[J].武汉大学学报(信息科学版),2001,26(2):140-143,159.ZHANG Xiaohong,LI Zhenghang,CAI Changsheng.Study on Regional Ionospheric Model Using Dual-frequency GPS Measurements[J].Geomatics and Information Science of Wuhan University,2001,26(2):140-143,159.
[6] 章红平,施闯,唐卫明.地基GPS区域电离层多项式模型与硬件延迟统一解算分析[J].武汉大学学报(信息科学版),2008,33(8):805-809.ZHANG Hongping,SHI Chuang,TANG Weiming.United Solution to Polynomial VTEC Modeling and DCB Analysis Using Ground-based GPS Observations[J].Geomatics and Information Science of Wuhan University,2008,33(8):805-809.
[7] 张宝成,欧吉坤,袁运斌,等.利用非组合精密单点定位技术确定斜向电离层总电子含量和站星差分码偏差[J].测绘学报,2011,40(4):447-453.ZHANG Baocheng,OU Jikun,YUAN Yunbin et al.Calibration of Slant Total Electron Content and Satellite-receiver's Differential Code Biases with Uncombined Precise Point Positioning Technique[J].Acta Geodaetica et Cartographica Sinica,2011,40(4):447-453.
[8] ZHANG Baocheng,TEUNISSEN P J G.Characterization of Multi-GNSS Between-Receiver Differential Code Biases Using Zero and Short Baselines[J].Science Bulletin,2015,60(21):1840-1849.
[9] MONTENBRUCK O,HAUSCHILD A.Code Biases in Multi-GNSS Point Positioning[C]//Proceedings of ION ITM 2013.San Diego:Institute of Navigation,2013:616-628.
[10] DACH R,BROCKMANN E,SCHAER S,et al.GNSS Processing at CODE:Status Report[J].Journal of Geodesy,2009,83(3-4):353-365.
[11] MONTENBRUCK O,STEIGENBERGER P,KHACHIKYAN R,et al.IGS-MGEX:Preparing the Ground for Multi-constellation GNSS Science[C]//Proceedings of the 4th International Colloquium on Scientific and Fundamental Aspects of the Galileo System.Galile:[s.n.],2013,9(1):42-49.
[12] SCHAER S.Differential Code Biases (DCB) in GNSS Analysis[C]//Proceedings of IGS Workshop 2008.Miami Beach:Swiss Federal Office of Topography Swisstopo,2008.
[13] 吴晓莉,平劲松,刘利,等.区域卫星导航系统硬件延迟解算[J].武汉大学学报(信息科学版),2011,36(10):1218-1221.WU Xiaoli,PING Jinsong,LIU Li,et al.Hardware Delay Solution of Regional Satellite Navigation System[J].Geomatics and Information Science of Wuhan University,2011,36(10):1218-1221.
[14] GUO Fei,ZHANG Xiaohong,WANG Jinling.Timing Group Delay and Differential Code Bias Corrections for BeiDou Positioning[J].Journal of Geodesy,2015,89(5):427-445.
[15] MICHAEL Rivers.The 2 SOPS User Range Accuracy (URA) Improvement and Broadcast Inter-frequency Bias (TGD) Updates[C]//Proceedings of the 13th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GPS 2000).Salt Lake City,UT:ION,2000:2551-2555.
[16] MONTENBRUCK O,LANGLEY R B,STEIGENBERGER P.First Live Broadcast of GPS CNAV Messages[J].GPS World,2013,24(8):14.
[17] FEESS W,COX J,HOWARD E,et al.GPS Inter-signal Corrections (ISCs) Study[C]//Proceedings of the 26th International Technical Meeting of the Satellite Division of the Institute of Navigation (ION GNSS 2013).Nashville,TN:[s.n.],2013:951-958.
[18] STEIGENBERGER P,MONTENBRUCK O,HESSELS U.Performance Evaluation of the Early CNAV Navigation Message[C]//Proceedings of the 2015 International Technical Meeting of the Institute of Navigation.Dana Point,California:Laguna Cliffs Marriott,2015:155-163.
[19] IS-GPS-200 Navstar GPS Space Segment/Navigation User Interfaces[S].Calif,USA:Revision G,GPS Directorate,2004.
[20] LI Zishen,YUAN Yunbin,LI Hui et al.Two-step Method for the Determination of the Differential Code Biases of Compass Satellites[J].Journal of Geodesy,2012,86(11):1059-1076.
[21] WANG Ningbo,YUAN Yunbin,LI Zishen,et al.Determination of Differential Code Biases with Multi-GNSS Observations[J].Journal of Geodesy,2016,90(3):209-228.
[22] 张宝成,欧吉坤,袁运斌,等.基于GPS双频原始观测值的精密单点定位算法及应用[J].测绘学报,2010,39(5):478-483.ZHANG Baocheng,OU Jikun,YUAN Yunbin,et al.Precise Point Positioning Algorithm Based on Original Dual-frequency GPS Code and Carrier-phase Observations and Its Application[J].Acta Geodaetica et Cartographica Sinica,2010,39(5):478-483.
[23] WILSON B D,YINGER C H,FEESS W A,et al.New and Improved:the Broadcast Inter Frequency Biases[J].GPS World,1999,10(9):56-66.
[24] LEANDRO R,SANTOS M,LANGLEY R.UNB Neutral Atmosphere Models:Development and Performance[C]//Proceedings of ION NTM 2006.Monterey,CA:Hyatt Regency Hotel,2006:18-20.