Spatial–temporal characteristic of BDS phase delays and PPP ambiguity resolution with GEO/IGSO/MEO satellites

GPS precise point positioning (PPP) ambiguity resolution (AR) can improve the positioning accuracy and shorten the convergence time. However, for the BeiDou Satellite Navigation System (BDS), the problems of satellite-induced code bias, imperfections in the error models and the inadequate accuracy of orbit products limit the applications of the BDS PPP AR system, which requires more than 6 h to achieve the first ambiguity-fixed solution. In this study, the accuracy of a wide-lane (WL) uncalibrated phase delay (UPD) is improved after careful consideration of the code bias and multipath. Meanwhile, the accuracy of the BDS float ambiguity is also improved by multi-GNSS fusion and improved precise orbit and clock products, which are critical for high-quality narrow-lane (NL) UPD estimations. With three tracking networks of different scales, including Hong Kong, the Crustal Movement Observation Network of China (CMONOC) and the multi-GNSS experiment (MGEX) networks, the spatial–temporal characteristics of WL and NL UPDs for BDS GEO/IGSO/MEO satellites are analyzed, and the PPP AR is performed. Numerous results show that WL and NL UPDs with a standard deviation (STD) of less than 0.15 cycles can be achieved for BDS GEO satellites, while a STD of less than 0.1 cycles can be obtained for IGSO and MEO satellites. With the precise UPD estimation, for the first time, the BDS PPP rapid ambiguity resolution for GEO/IGSO/MEO satellites is achieved. We found that the average time to first fix (TTFF) of the BDS PPP AR is shortened significantly, to approximately 40 min for Hong Kong and the CMONOC, while the TTFF was 57.4 min for the MGEX networks. With ambiguity resolution, the accuracy of the daily BDS PPP in the east, north and vertical directions improves from 1.74 cm, 1.08 cm, and 5.52 cm to 0.72 cm, 0.54 cm, and 3.21 cm for the Hong Kong network, 2.24 cm, 2.31 cm, and 5.64 cm to 1.18 cm, 0.79 cm, and 3.30 cm for the CMONOC, and 2.71 cm, 1.80 cm, and 6.00 cm to 1.58 cm, 1.15 cm, and 4.33 cm for the MGEX networks. Significant improvement is also achieved for kinematic PPP, with improvements of 40.41%, 34.33% and 37.17% in the east, north and vertical directions for the MGEX networks, respectively.

[1]  R. Hatch.  The synergism of GPS code and carrier measurements , 1982 .

[2]  Liu Jing-nan,et al.  PANDA software and its preliminary result of positioning and orbit determination , 2003, Wuhan University Journal of Natural Sciences.

[3]  Shaowei Han,et al.  Quality-control issues relating to instantaneous ambiguity resolution for real-time GPS kinematic positioning , 1996 .

[4]  Pierre Héroux,et al.  Precise Point Positioning Using IGS Orbit and Clock Products , 2001, GPS Solutions.

[5]  Guo Fei,et al.  Ambiguity resolved precise point positioning with GPS and BeiDou , 2016, Journal of Geodesy.

[6]  Paul Collins,et al.  Precise Point Positioning with Ambiguity Resolution using the Decoupled Clock Model , 2008 .

[7]  Y. Bock,et al.  Global Positioning System Network analysis with phase ambiguity resolution applied to crustal deformation studies in California , 1989 .

[8]  Lambert Wanninger,et al.  BeiDou satellite-induced code pseudorange variations: diagnosis and therapy , 2015, GPS Solutions.

[9]  Yidong Lou,et al.  Integrating GPS and BDS to shorten the initialization time for ambiguity-fixed PPP , 2017, GPS Solutions.

[10]  Peter Steigenberger,et al.  The Multi-GNSS Experiment (MGEX) of the International GNSS Service (IGS) - Achievements, prospects and challenges , 2017 .

[11]  O. Montenbruck,et al.  IGS-MGEX: Preparing the Ground for Multi-Constellation GNSS Science , 2013 .

[12]  G. Gendt,et al.  Resolution of GPS carrier-phase ambiguities in Precise Point Positioning (PPP) with daily observations , 2008 .

[13]  Xiaohong Zhang,et al.  Characteristics of systematic errors in the BDS Hatch–Melbourne–Wübbena combination and its influence on wide-lane ambiguity resolution , 2016, GPS Solutions.

[14]  Yidong Lou,et al.  Assessment of code bias variations of BDS triple-frequency signals and their impacts on ambiguity resolution for long baselines , 2016, GPS Solutions.

[15]  Xingxing Li,et al.  Improving the Estimation of Uncalibrated Fractional Phase Offsets for PPP Ambiguity Resolution , 2012 .

[16]  XiaoLi Wu,et al.  Multipath error detection and correction for GEO/IGSO satellites , 2012 .

[17]  C.C.J.M. Tiberius,et al.  Geometry-free ambiguity success rates in case of partial fixing , 1999 .

[18]  Alan Dodson,et al.  Ambiguity resolution in precise point positioning with hourly data , 2009 .

[19]  Hongzhou Chai,et al.  Performance analysis of BDS/GPS precise point positioning with undifferenced ambiguity resolution , 2017 .

[20]  Chengfa Gao,et al.  Improving Ambiguity Resolution for Medium Baselines Using Combined GPS and BDS Dual/Triple-Frequency Observations , 2015, Sensors.

[21]  Xingxing Li,et al.  Accuracy and reliability of multi-GNSS real-time precise positioning: GPS, GLONASS, BeiDou, and Galileo , 2015, Journal of Geodesy.

[22]  Jinling Wang,et al.  Assessment of precise orbit and clock products for Galileo, BeiDou, and QZSS from IGS Multi-GNSS Experiment (MGEX) , 2016, GPS Solutions.

[23]  R. Nerem,et al.  GPS Carrier phase Ambiguity Resolution Using Satellite-Satellite Single Differences , 1999 .

[24]  Maorong Ge,et al.  A method for improving uncalibrated phase delay estimation and ambiguity-fixing in real-time precise point positioning , 2013, Journal of Geodesy.

[25]  Jinling Wang,et al.  GPS RTK Performance Characteristics and Analysis , 2008 .

[26]  J. Zumberge,et al.  Precise point positioning for the efficient and robust analysis of GPS data from large networks , 1997 .

[27]  Qile Zhao,et al.  Multipath analysis of code measurements for BeiDou geostationary satellites , 2014, GPS Solutions.