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Precise Point Positioning with Partial Ambiguity Fixing.

Li P, Zhang X - Sensors (Basel) (2015)

Bottom Line: Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence.Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP.Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate.

View Article: PubMed Central - PubMed

Affiliation: School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China. lipan.whu@gmail.com.

ABSTRACT
Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate.

No MeSH data available.


Related in: MedlinePlus

Distribution of fixing rate percentages of static PPP by employing FAR and PAR, respectively.
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sensors-15-13627-f007: Distribution of fixing rate percentages of static PPP by employing FAR and PAR, respectively.

Mentions: In this section, we will compare the fixing rate of FAR and PAR using the results of the second 90 min of each 3-hour-long observations. The statistical results for static PPP are plotted in Figure 7 and those for kinematic PPP are presented in Figure 8. Compared to FAR, the average fixing rate of PAR is added by 14.7% (from 83.5% to 98.2%) in static PPP and by 15.1% (from 80.1% to 95.2%) in kinematic PPP. This can be explained by the fact that when FAR fails, a successful ambiguity resolution is still possible with PAR after removing the bad quality ambiguity. In addition, for both FAR and PAR, the fixing rate in kinematic PPP is lower than in static PPP. This is because the float ambiguity precision in kinematic PPP is lower than in static PPP.


Precise Point Positioning with Partial Ambiguity Fixing.

Li P, Zhang X - Sensors (Basel) (2015)

Distribution of fixing rate percentages of static PPP by employing FAR and PAR, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507701&req=5

sensors-15-13627-f007: Distribution of fixing rate percentages of static PPP by employing FAR and PAR, respectively.
Mentions: In this section, we will compare the fixing rate of FAR and PAR using the results of the second 90 min of each 3-hour-long observations. The statistical results for static PPP are plotted in Figure 7 and those for kinematic PPP are presented in Figure 8. Compared to FAR, the average fixing rate of PAR is added by 14.7% (from 83.5% to 98.2%) in static PPP and by 15.1% (from 80.1% to 95.2%) in kinematic PPP. This can be explained by the fact that when FAR fails, a successful ambiguity resolution is still possible with PAR after removing the bad quality ambiguity. In addition, for both FAR and PAR, the fixing rate in kinematic PPP is lower than in static PPP. This is because the float ambiguity precision in kinematic PPP is lower than in static PPP.

Bottom Line: Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence.Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP.Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate.

View Article: PubMed Central - PubMed

Affiliation: School of Geodesy and Geomatics, Wuhan University, 129 Luoyu Road, Wuhan 430079, China. lipan.whu@gmail.com.

ABSTRACT
Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate.

No MeSH data available.


Related in: MedlinePlus