Enhancing real-time precise point positioning time and frequency transfer with receiver clock modeling

GPS Solutions ◽  
2018 ◽  
Vol 23 (1) ◽  
Author(s):  
Yulong Ge ◽  
Feng Zhou ◽  
Tianjun Liu ◽  
WeiJin Qin ◽  
Shengli Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Receiver Clock ◽  
Frequency Transfer ◽  
Point Positioning ◽  
Positioning Time

scholarly journals Real-Time Orbit Determination of Korean Navigation Satellite System based on Multi-GNSS Precise Point Positioning

2019 ◽  
Vol 94 ◽  
pp. 03008 ◽  
Author(s):  
Gimin Kim ◽  
Hyungjik Oh ◽  
Chandeok Park ◽  
Seungmo Seo
Keyword(s):  
Real Time ◽  
Orbit Determination ◽  
Precise Point Positioning ◽  
Satellite System ◽  
Navigation Satellite ◽  
Receiver Clock ◽  
Point Positioning ◽  
Clock Offset ◽  
Monitoring Stations

This study proposes real-time orbit/clock determination of Korean Navigation Satellite System (KNSS), which employs the kinematic precise point positioning (PPP) solutions of multiple Global Navigation Satellite System (multi-GNSS) to compensate for receiver clock offset. Global visibility of KNSS satellites in terms of geometric coverage is first analyzed for the purpose of selecting optimal locations of KNSS monitoring stations among International GNSS Service (IGS) and Multi-GNSS Experiment (MGEX) network. While the receiver clock offset is obtained from multi-GNSS PPP clock solutions of real observation data, KNSS measurements are simulated from the dynamically propagated KNSS reference orbit and the receiver clock offset. The offset and drift of satellite clock are also generated based on two-state clock model considering atomic clock noise. Real-time orbit determination results are compared with an artificially generated true or bit, wihch show 0.4m and 0.5m of 3-dimensional root-mean-square (RMS) position errors for geostationary (GEO) and ellitically-inclined-geosynchronous-orbit (EIGSO) satellites, respectively. The overall results show that the real-time precise orbit determination of KNSS should be achievable in meter level by installing KNSS-compatible multi-GNSS receivers on the IGS and/or MGEX network. The overall process can be also used to verify integrity of KNSS monitoring stations.

scholarly journals Performance of Multi-GNSS Precise Point Positioning Time and Frequency Transfer with Clock Modeling

2019 ◽  
Vol 11 (3) ◽  
pp. 347 ◽  
Author(s):  
Yulong Ge ◽  
Peipei Dai ◽  
Weijin Qin ◽  
Xuhai Yang ◽  
Feng Zhou ◽  
...  
Keyword(s):  
White Noise ◽  
Precise Point Positioning ◽  
Noise Model ◽  
Single System ◽  
Time Transfer ◽  
Receiver Clock ◽  
Maximum Improvement ◽  
Frequency Transfer ◽  
White Noise Model ◽  
Point Positioning

Thanks to the international GNSS service (IGS), which has provided multi-GNSS precise products, multi-GNSS precise point positioning (PPP) time and frequency transfer has of great interest in the timing community. Currently, multi-GNSS PPP time transfer is not investigated with different precise products. In addition, the correlation of the receiver clock offsets between adjacent epochs has not been studied in multi-GNSS PPP. In this work, multi-GNSS PPP time and frequency with different precise products is first compared in detail. A receiver clock offset model, considering the correlation of the receiver clock offsets between adjacent epochs using an a priori value, is then employed to improve multi-GNSS PPP time and frequency (scheme2). Our numerical analysis clarify how the approach performs for multi-GNSS PPP time and frequency transfer. Based on two commonly used multi-GNSS products and six GNSS stations, three conclusions are obtained straightforwardly. First, the GPS-only, Galileo-only, and multi-GNSS PPP solutions show similar performances using GBM and COD products, while BDS-only PPP using GBM products is better than that using COD products. Second, multi-GNSS time transfer outperforms single GNSS by increasing the number of available satellites and improving the time dilution of precision. For single-system and multi-GNSS PPP with GBM products, the maximum improvement in root mean square (RMS) values for multi-GNSS solutions are up to 7.4%, 94.0%, and 57.3% compared to GPS-only, BDS-only, and Galileo-only solutions, respectively. For stability, the maximum improvement of multi-GNSS is 20.3%, 84%, and 45.4% compared to GPS-only, BDS-only and Galileo-only solutions. Third, our approach contains less noise compared to the solutions with the white noise model, both for the single-system model and the multi-GNSS model. The RMS values of our approach are improved by 37.8–91.9%, 10.5–65.8%, 2.7–43.1%, and 26.6–86.0% for GPS-only, BDS-only, Galileo-only, and multi-GNSS solutions. For frequency stability, the improvement of scheme2 ranges from 0.2 to 51.6%, from 3 to 80.0%, from 0.2 to 70.8%, and from 0.1 to 51.5% for GPS-only, BDS-only, Galileo-only, and multi-GNSS PPP solutions compared to the solutions with the white noise model in the Eurasia links.

scholarly journals Simulation case study of deformations and landslides using real-time GNSS precise point positioning technique

2016 ◽  
Vol 7 (6) ◽  
pp. 1856-1873 ◽  
Author(s):  
Raquel M. Capilla ◽  
José Luis Berné ◽  
Angel Martín ◽  
Raul Rodrigo
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Positioning Technique ◽  
Point Positioning

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.

scholarly journals Examining the Accuracy of Network RTK and Long Base RTK Methods with Repetitive Measurements

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Tamer Baybura ◽  
İbrahim Tiryakioğlu ◽  
Mehmet Ali Uğur ◽  
Halil İbrahim Solak ◽  
Şeyma Şafak
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
High Accuracy ◽  
Base Station ◽  
Network Rtk ◽  
Real Time Kinematic ◽  
Study Results ◽  
Point Positioning

Real-time kinematic (RTK) technique is important for mapping applications requiring short measure time, the distance between rover and base station, and high accuracy. There are several RTK methods used today such as the traditional RTK, long base RTK (LBRTK), network RTK (NRTK), and precise point positioning RTK (PPP-RTK). NRTK and LBRTK are popular with the advantage of the distance, the time, and accuracy. In the present study, the NRTK and LBRTK measurements were compared in terms of accuracy and distance in a test network with 6 sites that was established between 5 and 60 km. Repetitive NRTK and LBRTK measurements were performed on 6 different days in 2015-2017-2018 and additionally 4 campaigns of repetitive static measurements were carried out in this test network. The results of NRTK and LBRTK methods were examined and compared with all relevant aspects by considering the results of the static measurements as real coordinates. The study results showed that the LBRTK and NRTK methods yielded similar results at base lengths up to 40 km with the differences less than 3 cm horizontally and 4 cm vertically.

Performance of Real-Time Precise Point Positioning

2013 ◽  
Vol 36 (1) ◽  
pp. 98-108 ◽  
Author(s):  
Junping Chen ◽  
Haojun Li ◽  
Bin Wu ◽  
Yize Zhang ◽  
Jiexian Wang ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Point Positioning

GPS inter-frequency clock bias modeling and prediction for real-time precise point positioning

GPS Solutions ◽  
2018 ◽  
Vol 22 (3) ◽  
Author(s):  
Lin Pan ◽  
Xiaohong Zhang ◽  
Xingxing Li ◽  
Jingnan Liu ◽  
Fei Guo ◽  
...  
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Modeling And Prediction ◽  
Point Positioning

scholarly journals Real-Time Precise Point Positioning Using Orbit and Clock Corrections as Quasi-Observations for Improved Detection of Faults

2018 ◽  
Vol 71 (4) ◽  
pp. 769-787 ◽  
Author(s):  
Ahmed El-Mowafy
Keyword(s):  
Real Time ◽  
Precise Point Positioning ◽  
Exclusion Process ◽  
Satellite Orbit ◽  
Satellite System ◽  
Navigation Satellite ◽  
System Service ◽  
Point Positioning ◽  
Predicted Values ◽  
Global Navigation Satellite

Real-time Precise Point Positioning (PPP) relies on the use of accurate satellite orbit and clock corrections. If these corrections contain large errors or faults, either from the system or by meaconing, they will adversely affect positioning. Therefore, such faults have to be detected and excluded. In traditional PPP, measurements that have faulty corrections are typically excluded as they are merged together. In this contribution, a new PPP model that encompasses the orbit and clock corrections as quasi-observations is presented such that they undergo the fault detection and exclusion process separate from the observations. This enables the use of measurements that have faulty corrections along with predicted values of these corrections in place of the excluded ones. Moreover, the proposed approach allows for inclusion of the complete stochastic information of the corrections. To facilitate modelling of the orbit and clock corrections as quasi-observations, International Global Navigation Satellite System Service (IGS) real-time corrections were characterised over a six-month period. The proposed method is validated and its benefits are demonstrated at two sites using three days of data.

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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