SUPREME: an open-source single-frequency uncombined precise point positioning software

Performance of Open Source Precise Point Positioning Software Using Single-Frequency GPS Data This research aims to assess the performance of GPS Precise Point Positioning (PPP) with code and carrier phase observations from L1 signal collected from geodetic GPS receiver around the world. A simple PPP software developed for processing the single frequency GPS data is used as a main tool to assess a positioning accuracy. The precise orbit and precise satellite clock corrections were introduced into the software to reduce the orbit and satellite clock errors, while ionosphere-free code and phase observations were constructed to mitigate the ionospheric delay. The remaining errors (i.e. receiver clock error, ambiguity term) are estimated using Extended Kalman Filter technique. The data retrieved from 5 IGS stations located in different countries were used in this study. In addition, three different periods of data were downloaded for each station. The obtained data were then cut into 5-min, 10-min, 15-min and 30-min data segments, and each data segment was individually processed with the developed PPP software to produce final coordinates. Results indicate that the use of 5-min data span can provide a horizontal positioning accuracy at the same level as a pseudorange-based differential GPS technique. Furthermore, results confirm effects of station location and seasonal variation on obtainable accuracies.

Download Full-text

Multi-GNSS (GPS/Galileo) single-frequency precise point positioning: a case study over Victoria

Earth Science Informatics ◽

10.1007/s12145-021-00663-w ◽

2021 ◽

Author(s):

Fereydoun Nobakht-Ersi ◽

Abdolreza Safari

Keyword(s):

Precise Point Positioning ◽

Single Frequency ◽

Point Positioning

Download Full-text

Precise Point Positioning Using Dual-Frequency GNSS Observations on Smartphone

Sensors ◽

10.3390/s19092189 ◽

2019 ◽

Vol 19 (9) ◽

pp. 2189 ◽

Cited By ~ 27

Author(s):

Qiong Wu ◽

Mengfei Sun ◽

Changjie Zhou ◽

Peng Zhang

Keyword(s):

Precise Point Positioning ◽

Frequency Mode ◽

Single Frequency ◽

Dual Frequency ◽

Static Mode ◽

Position Errors ◽

Point Positioning ◽

Similar Accuracy ◽

Positioning Algorithm ◽

Gnss Observations

The update of the Android system and the emergence of the dual-frequency GNSS chips enable smartphones to acquire dual-frequency GNSS observations. In this paper, the GPS L1/L5 and Galileo E1/E5a dual-frequency PPP (precise point positioning) algorithm based on RTKLIB and GAMP was applied to analyze the positioning performance of the Xiaomi Mi 8 dual-frequency smartphone in static and kinematic modes. The results showed that in the static mode, the RMS position errors of the dual-frequency smartphone PPP solutions in the E, N, and U directions were 21.8 cm, 4.1 cm, and 11.0 cm, respectively, after convergence to 1 m within 102 min. The PPP of dual-frequency smartphone showed similar accuracy with geodetic receiver in single-frequency mode, while geodetic receiver in dual-frequency mode has higher accuracy. In the kinematic mode, the positioning track of the smartphone dual-frequency data had severe fluctuations, the positioning tracks derived from the smartphone and the geodetic receiver showed approximately difference of 3–5 m.

Download Full-text

Performance Analysis of Static Precise Point Positioning Using Open-Source GAMP

Artificial Satellites ◽

10.2478/arsa-2020-0004 ◽

2020 ◽

Vol 55 (2) ◽

pp. 41-60

Author(s):

Jabir Shabbir Malik

Keyword(s):

Performance Analysis ◽

Open Source ◽

Observational Data ◽

Precise Point Positioning ◽

Three Dimensional ◽

Satellite System ◽

International Gnss Service ◽

Positioning Accuracy ◽

Position Accuracy ◽

Point Positioning

AbstractIn addition to Global Positioning System (GPS) constellation, the number of Global Navigation Satellite System (GLONASS) satellites is increasing; it is now possible to evaluate and analyze the position accuracy with both the GPS and GLONASS constellation. In this article, statistical analysis of static precise point positioning (PPP) using GPS-only, GLONASS-only, and combined GPS/GLONASS modes is evaluated. Observational data of 10 whole days from 10 International GNSS Service (IGS) stations are used for analysis. Position accuracy in east, north, up components, and carrier phase/code residuals is analyzed. Multi-GNSS PPP open-source package is used for the PPP performance analysis. The analysis also provides the GNSS researchers the understanding of the observational data processing algorithm. Calculation statistics reveal that standard deviation (STD) of horizontal component is 3.83, 13.80, and 3.33 cm for GPS-only, GLONASS-only, and combined GPS/GLONASS PPP solutions, respectively. Combined GPS/GLONASS PPP achieves better positioning accuracy in horizontal and three-dimensional (3D) accuracy compared with GPS-only and GLONASS-only PPP solutions. The results of the calculation show that combined GPS/GLONASS PPP improves, on an average, horizontal accuracy by 12.11% and 60.33% and 3D positioning accuracy by 10.39% and 66.78% compared with GPS-only and GLONASS-only solutions, respectively. In addition, the results also demonstrate that GPS-only solutions show an improvement of 54.23% and 62.54% compared with GLONASS-only PPP mode in horizontal and 3D components, respectively. Moreover, residuals of GLONASS ionosphere-free code observations are larger than the GPS code residuals. However, phase residuals of GPS and GLONASS phase observations are of the same magnitude.

Download Full-text

Multi-GNSS Single Frequency Precise Point Positioning

2018 IEEE International Workshop on Metrology for the Sea; Learning to Measure Sea Health Parameters (MetroSea) ◽

10.1109/metrosea.2018.8657857 ◽

2018 ◽

Author(s):

Anna Innac ◽

Salvatore Gaglione ◽

Antonio Angrisano

Keyword(s):

Precise Point Positioning ◽

Single Frequency ◽

Point Positioning

Download Full-text

Single-Frequency Precise Point Positioning Using Multi-Constellation GNSS: GPS, GLONASS, Galileo and BeiDou

GEOMATICA ◽

10.5623/cig2016-203 ◽

2016 ◽

Vol 70 (2) ◽

pp. 113-122 ◽

Cited By ~ 1

Author(s):

Mahmoud Abd Rabbou ◽

Ahmed El-Rabbany

Keyword(s):

Urban Areas ◽

Precise Point Positioning ◽

Cost Effective ◽

Convergence Time ◽

Single Frequency ◽

Dual Frequency ◽

Positioning Accuracy ◽

Point Positioning ◽

Beidou Satellites ◽

Gnss Observations

Single-frequency precise point positioning (PPP) presents a cost-effective positioning technique for a large number of users. However, it possesses low positioning accuracy and convergence time compared with the dual-frequency PPP. Single-frequency PPP commonly employs GPS satellite systems that suffer from poor satellite geometry, especially in dense urban areas. We develop a new single-frequency PPP model that combines the observations of current GNSS constellations, including GPS, GLONASS, Galileo and Beidou. The MGEX IGS final precise products are utilized to account for the orbital and clock errors, while the IGS final global ionospheric maps (GIM) model is used to correct for the ionospheric delay. The GNSS inter-system biases are treated as additional unknowns in the estimation process. The con tri bution of the additional GNSS observations to single-frequency PPP is assessed through solution comparison with its traditional GPS-only counterpart. Various GNSS combinations are considered in the assessment, including GPS/GLONASS, GPS/Galileo, GPS/BeiDou and all-constellation GNSS. It is shown that the additional GNSS observations enhance the PPP solution accuracy and convergence time in comparison with the tra di tional GPS-only solution. Except for stations with a sufficient number of tracked BeiDou satellites, both Galileo and BeiDou have marginal effects on the positioning accuracy due to their limited number of satel lites. However, for stations with a sufficient number of visible BeiDou satellites, an average of 40% PPP accuracy improvement is obtained. The major contribution to the PPP accuracy enhancement is obtained from GLONASS satellite observations.

Download Full-text

Real-Time Global Ionospheric Map and Its Application in Single-Frequency Positioning

Sensors ◽

10.3390/s19051138 ◽

2019 ◽

Vol 19 (5) ◽

pp. 1138 ◽

Cited By ~ 7

Author(s):

Liang Zhang ◽

Yibin Yao ◽

Wenjie Peng ◽

Lulu Shan ◽

Yulin He ◽

...

Keyword(s):

Real Time ◽

Total Electron Content ◽

Precise Point Positioning ◽

Single Frequency ◽

Electron Content ◽

Vertical Total Electron Content ◽

Total Electron ◽

Time Service ◽

Point Positioning ◽

Raw Observations

The prevalence of real-time, low-cost, single-frequency, decimeter-level positioning has increased with the development of global navigation satellite systems (GNSSs). Ionospheric delay accounts for most errors in real-time single-frequency GNSS positioning. To eliminate ionospheric interference in real-time single-frequency precise point positioning (RT-SF-PPP), global ionospheric vertical total electron content (VTEC) product is designed in the next stage of the International GNSS Service (IGS) real-time service (RTS). In this study, real-time generation of a global ionospheric map (GIM) based on IGS RTS is proposed and assessed. There are three crucial steps in the process of generating a real-time global ionospheric map (RTGIM): estimating station differential code bias (DCB) using the precise point positioning (PPP) method, deriving slant total electron content (STEC) from PPP with raw observations, and modeling global vertical total electron content (VTEC). Experiments were carried out to validate the algorithm’s effectiveness. First, one month’s data from 16 globally distributed IGS stations were used to validate the performance of DCB estimation with the PPP method. Second, 30 IGS stations were used to verify the accuracy of static PPP with raw observations. Third, the modeling of residuals was assessed in high and quiet ionospheric activity periods. Afterwards, the quality of RTGIM products was assessed from two aspects: (1) comparison with the Center for Orbit Determination in Europe (CODE) global ionospheric map (GIM) products and (2) determination of the performance of RT-SF-PPP with the RTGIM. Experimental results show that DCB estimation using the PPP method can realize an average accuracy of 0.2 ns; static PPP with raw observations can achieve an accuracy of 0.7, 1.2, and 2.1 cm in the north, east, and up components, respectively. The average standard deviations (STDs) of the model residuals are 2.07 and 2.17 TEC units (TECU) for moderate and high ionospheric activity periods. Moreover, the average root-mean-square (RMS) error of RTGIM products is 2.4 TECU for the one-month moderate ionospheric period. Nevertheless, for the high ionospheric period, the RMS is greater than the RMS in the moderate period. A sub-meter-level horizontal accuracy and meter-level vertical accuracy can be achieved when the RTGIM is employed in RT-SF-PPP.

Download Full-text

Regiomontan: A Regional High Precision Ionosphere Delay Model and Its Application in Precise Point Positioning

Sensors ◽

10.3390/s20102845 ◽

2020 ◽

Vol 20 (10) ◽

pp. 2845

Author(s):

Janina Boisits ◽

Marcus Glaner ◽

Robert Weber

Keyword(s):

Precise Point Positioning ◽

Ionospheric Delay ◽

Single Frequency ◽

External Information ◽

Delay Model ◽

Dual Frequency ◽

Propagation Delays ◽

Point Positioning ◽

The Difference ◽

High Level

Propagation delays of GNSS signals caused by the ionosphere can range up to several meters in zenith direction and need to be corrected. Geodetic receivers observing at two or more frequencies allow the mitigation of the ionospheric effects by forming linear combinations. However, single frequency users depend on external information. The ionosphere delay model Regiomontan developed at TU Wien is a regional ionospheric delay model providing high accuracy information with a latency of only a few hours. The model is based on dual-frequency phase observations of a regional network operated by EPOSA (Echtzeit Positionierung Austria) and partners. The corrections cover a geographical extent for receiver positions within Austria and are provided in the standardized IONEX format. The performance of Regiomontan as well as its application in Precise Point Positioning (PPP) were tested with our in-house PPP software raPPPid using the so-called uncombined model with ionospheric constraint. Various tests, e.g., analyzing the coordinate convergence behavior or the difference between estimated and modeled ionospheric delay, proving the high level of accuracy provided with Regiomontan. We conclude that Regiomontan performs at a similar level of accuracy as IGS final TEC maps, but with explicitly reduced latency.

Download Full-text