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Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

Afifi A, El-Rabbany A - Sensors (Basel) (2015)

Bottom Line: In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model.As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model.Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada. akram.afifi@ryerson.ca.

ABSTRACT
This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

No MeSH data available.


Receiver clock errors of the GPS decoupled clock model.
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sensors-15-14701-f010: Receiver clock errors of the GPS decoupled clock model.

Mentions: As shown in Figure 6, the positioning results of the combined GPS/Galileo traditional PPP model have a convergence time of 15 min to reach decimeter-level precision. The ambiguity parameters results in Figure 8 shows that the un-calibrated hardware delayed that lumped to the ambiguity parameter affects the ambiguity parameters convergence. Figure 9, Figure 10 and Figure 11 show the results of the GPS decoupled clock model.


Performance Analysis of Several GPS/Galileo Precise Point Positioning Models.

Afifi A, El-Rabbany A - Sensors (Basel) (2015)

Receiver clock errors of the GPS decoupled clock model.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507674&req=5

sensors-15-14701-f010: Receiver clock errors of the GPS decoupled clock model.
Mentions: As shown in Figure 6, the positioning results of the combined GPS/Galileo traditional PPP model have a convergence time of 15 min to reach decimeter-level precision. The ambiguity parameters results in Figure 8 shows that the un-calibrated hardware delayed that lumped to the ambiguity parameter affects the ambiguity parameters convergence. Figure 9, Figure 10 and Figure 11 show the results of the GPS decoupled clock model.

Bottom Line: In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model.As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model.Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

View Article: PubMed Central - PubMed

Affiliation: Department of Civil Engineering, Ryerson University, Toronto, ON M5B 2K3, Canada. akram.afifi@ryerson.ca.

ABSTRACT
This paper examines the performance of several precise point positioning (PPP) models, which combine dual-frequency GPS/Galileo observations in the un-differenced and between-satellite single-difference (BSSD) modes. These include the traditional un-differenced model, the decoupled clock model, the semi-decoupled clock model, and the between-satellite single-difference model. We take advantage of the IGS-MGEX network products to correct for the satellite differential code biases and the orbital and satellite clock errors. Natural Resources Canada's GPSPace PPP software is modified to handle the various GPS/Galileo PPP models. A total of six data sets of GPS and Galileo observations at six IGS stations are processed to examine the performance of the various PPP models. It is shown that the traditional un-differenced GPS/Galileo PPP model, the GPS decoupled clock model, and the semi-decoupled clock GPS/Galileo PPP model improve the convergence time by about 25% in comparison with the un-differenced GPS-only model. In addition, the semi-decoupled GPS/Galileo PPP model improves the solution precision by about 25% compared to the traditional un-differenced GPS/Galileo PPP model. Moreover, the BSSD GPS/Galileo PPP model improves the solution convergence time by about 50%, in comparison with the un-differenced GPS PPP model, regardless of the type of BSSD combination used. As well, the BSSD model improves the precision of the estimated parameters by about 50% and 25% when the loose and the tight combinations are used, respectively, in comparison with the un-differenced GPS-only model. Comparable results are obtained through the tight combination when either a GPS or a Galileo satellite is selected as a reference.

No MeSH data available.