Reducing convergence time of precise point positioning with ionospheric constraints and receiver differential code bias modeling

2020 ◽  
Vol 94 (1) ◽  
Author(s):  
Yan Xiang ◽  
Yang Gao ◽  
Yihe Li
Keyword(s):  
Precise Point Positioning ◽  
Convergence Time ◽  
Differential Code Bias ◽  
Code Bias ◽  
Point Positioning

scholarly journals The Effect of BDS-3 Time Group Delay and Differential Code Bias Corrections on Positioning

2020 ◽  
Vol 11 (1) ◽  
pp. 104
Author(s):  
Peipei Dai ◽  
Jianping Xing ◽  
Yulong Ge ◽  
Xuhai Yang ◽  
Weijin Qin ◽  
...  
Keyword(s):  
Group Delay ◽  
Assessment System ◽  
Convergence Time ◽  
Single Frequency ◽  
Positioning Accuracy ◽  
Differential Code Bias ◽  
Receiver Clock ◽  
Code Bias ◽  
Point Positioning ◽  
The Impact

The timing group delay parameter (TGD) or differential code bias parameter (DCB) is an important factor that affects the performance of GNSS basic services; therefore, TGD and DCB must be taken seriously. Moreover, the TGD parameter is modulated in the navigation message, taking into account the impact of TGD on the performance of the basic service. International GNSS Monitoring and Assessment System (iGMAS) provides the broadcast ephemeris with TGD parameter and the Chinese Academy of Science (CAS) provides DCB products. In this paper, the current available BDS-3 TGD and DCB parameters are firstly described in detail, and the relationship of TGD and DCB for BDS-3 is figured out. Then, correction models of BDS-3 TGD and DCB in standard point positioning (SPP) or precise point positioning (PPP) are given, which can be applied in various situations. For the effects of TGD and DCB in the SPP and PPP solution processes, all the signals from BDS-3 were researched, and the validity of TGD and DCB has been further verified. The experimental results show that the accuracy of B1I, B1C and B2a single-frequency SPP with TGD or DCB correction was improved by approximately 12–60%. TGD will not be considered for B3I single-frequency, because the broadcast satellite clock offset is based on the B3I as the reference signal. The positioning accuracy of B1I/B3I and B1C/B2a dual-frequency SPP showed that the improvement range for horizontal components is 60.2% to 74.4%, and the vertical components improved by about 50% after the modification of TGD and DCB. In addition, most of the uncorrected code biases are mostly absorbed into the receiver clock bias and other parameters for PPP, resulting in longer convergence time. The convergence time can be max increased by up to 50% when the DCB parameters are corrected. Consequently, the positioning accuracy can reach the centimeter level after convergence, but it is critical for PPP convergence time and receiver clock bias that the TGD and DCB correction be considered seriously.

Performance Analysis of GPS/BDS Precise Point Positioning

2015 ◽  
Vol 713-715 ◽  
pp. 1123-1126
Author(s):  
Xiao Yu Li ◽  
Jun Wang ◽  
Ya Tao Liu
Keyword(s):  
Precise Point Positioning ◽  
Satellite Orbit ◽  
Gps Measurements ◽  
Differential Code Bias ◽  
Phase Offset ◽  
Antenna Phase ◽  
Offset Correction ◽  
Code Bias ◽  
Point Positioning ◽  
Processing Steps

Precise Point Positioning (PPP) with GPS measurements has achieved a level of success. In order to benefit from the multiple available constellations, research has been undertaken to combineGPS and BDS measurements in PPP processing.Mathematical models of GPS/BDS combined precise point positioning are introduced in this paper. GPS/BDS combined PPP models are developed based on the GPS-only PPP. The data pre-processing steps include applying satellite orbit and clock corrections, satellite antenna phase offset correction, receiver antenna phase offset correction, differential code bias corrections, troposphere delay corrections and the the Ionosphere-free observation combination is used. The results show that the positioning precision and convergence speed of GPS/BDS combined PPP are improved compared with GPS-only PPP.

Initial Performance Evaluation of Precise Point Positioning with Triple-Frequency Observations from BDS-2 and BDS-3 Satellites

2020 ◽  
Vol 73 (4) ◽  
pp. 763-775 ◽  
Author(s):  
Wenjie Zhang ◽  
Hongzhen Yang ◽  
Chen He ◽  
Zhiqiang Wang ◽  
Weiping Shao ◽  
...  
Keyword(s):  
Precise Point Positioning ◽  
Convergence Time ◽  
Asia Pacific ◽  
Basic Model ◽  
Triple Frequency ◽  
Ionosphere Model ◽  
Receiver Clock ◽  
Combined Solution ◽  
Code Bias ◽  
Point Positioning

This paper presents an investigation of the precise point positioning (PPP) performance of a combined solution from BDS-2 and BDS-3 satellites. To simultaneously process different BDS signal observations, i.e., B1/B1C, B2/B2a and B3C, undifferenced and uncombined observations with ionosphere delay constrained by the deterministic plus stochastic ionosphere model are used in the basic model. Special attention is paid to code bias and receiver clock parameters in the derivation of the observation model. The analysis is carried out using more than one-month data for BDS-2 and BDS-3 collected at the CANB, DWIN, KNDY and PETH stations in the Asia-Pacific region. The results suggest that compared with BDS-2 alone, the BDS-2 and BDS-3 solution provides significantly more accurate PPP, with increases of 28%, 21% and 5% in the up, north and east directions, respectively. In addition, the average root mean square error decreases to 0·21, 0·13 and 0·16 m for the three directions. Furthermore, the PPP convergence time for BDS-2 and BDS-3 is about 1·5 h and less than 1 h for the horizontal and vertical components, respectively, whereas that for BDS-2 alone is about 2·3 h for both directions.

Multi-GNSS triple-frequency differential code bias (DCB) determination with precise point positioning (PPP)

2018 ◽  
Vol 93 (5) ◽  
pp. 765-784 ◽  
Author(s):  
Teng Liu ◽  
Baocheng Zhang ◽  
Yunbin Yuan ◽  
Zishen Li ◽  
Ningbo Wang
Keyword(s):  
Precise Point Positioning ◽  
Differential Code Bias ◽  
Triple Frequency ◽  
Code Bias ◽  
Point Positioning

scholarly journals Advantages of Uncombined Precise Point Positioning with Fixed Ambiguity Resolution for Slant Total Electron Content (STEC) and Differential Code Bias (DCB) Estimation

2020 ◽  
Vol 12 (2) ◽  
pp. 304 ◽  
Author(s):  
Jin Wang ◽  
Guanwen Huang ◽  
Peiyuan Zhou ◽  
Yuanxi Yang ◽  
Qin Zhang ◽  
...  
Keyword(s):  
Total Electron Content ◽  
Ambiguity Resolution ◽  
Precise Point Positioning ◽  
Electron Content ◽  
Total Electron ◽  
Differential Code Bias ◽  
Ionosphere Modeling ◽  
Code Bias ◽  
Point Positioning ◽  
Slant Total Electron Content

The determination of slant total electron content (STEC) between satellites and receivers is the first step for establishing an ionospheric model. However, the leveling errors, caused by the smoothed ambiguity solutions in the carrier-to-code leveling (CCL) method, degrade the performance of ionosphere modeling and differential code bias (DCB) estimation. To reduce the leveling errors, an uncombined and undifferenced precise point positioning (PPP) method with ambiguity resolution (AR) was used to directly extract the STEC. Firstly, the ionospheric observables were estimated with CCL, PPP float-ambiguity solutions, and PPP fixed-ambiguity solutions, respectively, to analyze the short-term temporal variation of receiver DCB in zero or short baselines. Then, the global ionospheric map (GIM) was modeled using three types of ionospheric observables based on the single-layer model (SLM) assumption. Compared with the CCL method, the slight variations of receiver DCBs can be obviously distinguished using high precise ionospheric observables, with a 58.4% and 71.2% improvement of the standard deviation (STD) for PPP float-ambiguity and fixed-ambiguity solutions, respectively. For ionosphere modeling, the 24.7% and 27.9% improvements for posteriori residuals were achieved for PPP float-ambiguity and fixed-ambiguity solutions, compared to the CCL method. The corresponding improvement for residuals of the vertical total electron contents (VTECs) compared with the Center for Orbit Determination in Europe (CODE) final GIM products in global accuracy was 9.2% and 13.7% for PPP float-ambiguity and fixed-ambiguity solutions, respectively. The results show that the PPP fixed-ambiguity solution is the best one for the GIM product modeling and satellite DCBs estimation.

scholarly journals Precise Point Positioning Using the Regional BeiDou Navigation Satellite Constellation

2014 ◽  
Vol 67 (3) ◽  
pp. 523-537 ◽  
Author(s):  
Aigong Xu ◽  
Zongqiu Xu ◽  
Xinchao Xu ◽  
Huizhong Zhu ◽  
Xin Sui ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Asia Pacific ◽  
Satellite Orbits ◽  
Navigation Satellite ◽  
Asia Pacific Region ◽  
Point Positioning

On 27 December 2012 it was announced officially that the Chinese Navigation Satellite System BeiDou (BDS) was able to provide operational services over the Asia-Pacific region. The quality of BDS observations was confirmed as comparable with those of GPS, and relative positioning in static and kinematic modes were also demonstrated to be very promising. As Precise Point Positioning (PPP) technology is widely recognized as a method of precise positioning service, especially in real-time, in this contribution we concentrate on the PPP performance using BDS data only. BDS PPP in static, kinematic and simulated real-time kinematic mode is carried out for a regional network with six stations equipped with GPS- and BDS-capable receivers, using precise satellite orbits and clocks estimated from a global BDS tracking network. To validate the derived positions and trajectories, they are compared to the daily PPP solution using GPS data. The assessment confirms that the performance of BDS PPP is very comparable with GPS in terms of both convergence time and accuracy.

Improving Precise Point Positioning Convergence Time through TEQC Multipath Linear Combination

2018 ◽  
Vol 144 (2) ◽  
pp. 04018002 ◽  
Author(s):  
Mohammed Abou Galala ◽  
Mosbeh R. Kaloop ◽  
Mostafa M. Rabah ◽  
Zaki M. Zeidan
Keyword(s):  
Linear Combination ◽  
Precise Point Positioning ◽  
Convergence Time ◽  
Point Positioning

scholarly journals Multi-GNSS Combined Precise Point Positioning Using Additional Observations with Opposite Weight for Real-Time Quality Control

2019 ◽  
Vol 11 (3) ◽  
pp. 311 ◽  
Author(s):  
Wenju Fu ◽  
Guanwen Huang ◽  
Yuanxi Zhang ◽  
Qin Zhang ◽  
Bobin Cui ◽  
...  
Keyword(s):  
Quality Control ◽  
Real Time ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Convergence Time ◽  
Navigation Satellite ◽  
Positioning Accuracy ◽  
Global Navigation ◽  
Point Positioning ◽  
Global Navigation Satellite

The emergence of multiple global navigation satellite systems (multi-GNSS), including global positioning system (GPS), global navigation satellite system (GLONASS), Beidou navigation satellite system (BDS), and Galileo, brings not only great opportunities for real-time precise point positioning (PPP), but also challenges in quality control because of inevitable data anomalies. This research aims at achieving the real-time quality control of the multi-GNSS combined PPP using additional observations with opposite weight. A robust multiple-system combined PPP estimation is developed to simultaneously process observations from all the four GNSS systems as well as single, dual, or triple systems. The experiment indicates that the proposed quality control can effectively eliminate the influence of outliers on the single GPS and the multiple-system combined PPP. The analysis on the positioning accuracy and the convergence time of the proposed robust PPP is conducted based on one week’s data from 32 globally distributed stations. The positioning root mean square (RMS) error of the quad-system combined PPP is 1.2 cm, 1.0 cm, and 3.0 cm in the east, north, and upward components, respectively, with the improvements of 62.5%, 63.0%, and 55.2% compared to those of single GPS. The average convergence time of the quad-system combined PPP in the horizontal and vertical components is 12.8 min and 12.2 min, respectively, while it is 26.5 min and 23.7 min when only using single-GPS PPP. The positioning performance of the GPS, GLONASS, and BDS (GRC) combination and the GPS, GLONASS, and Galileo (GRE) combination is comparable to the GPS, GLONASS, BDS and Galileo (GRCE) combination and it is better than that of the GPS, BDS, and Galileo (GCE) combination. Compared to GPS, the improvements of the positioning accuracy of the GPS and GLONASS (GR) combination, the GPS and Galileo (GE) combination, the GPS and BDS (GC) combination in the east component are 53.1%, 43.8%, and 40.6%, respectively, while they are 55.6%, 48.1%, and 40.7% in the north component, and 47.8%, 40.3%, and 34.3% in the upward component.

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