3:30 PM - 5:00 PM
[SGD01-P09] The consistency between the GEONET routine solution and the multi-GNSS PPP solution
Keywords:GNSS, precise point positioning, PPP, GEONET
In order to upgrade the management of the positional information of Japan, the Geospatial Information Authority of Japan (GSI) has been carrying on the research aiming to construct the crustal deformation model using daily solution of the GEONET routine analysis (hereafter “the routine analysis”). Meanwhile, the precise point positioning (PPP) attract attention in the field of geodesy and surveying these days. In this presentation, I will show the result on the investigation of the consistency between the PPP solution and the routine analysis solution for the all stations of the GEONET.
The PPP solution used is ambiguity resolved solution by static analysis. In the analysis, we used the ephemeris that GSI estimated using MADOCA software developed by the Japan Aerospace Exploration Agency (JAXA). We used the three combinations of GNSS systems for PPP, that is, “GPS only”, “GPS and GLONASS”, and “GPS, GLONASS and QZSS (Quasi-Zenith Satellite System)”. The evaluation of the consistency is performed as follows: first calculating daily difference of the PPP solution from the routine analysis solution (the final solution, F5) station by station, then averaging them for the evaluation period.
It is known that in the routine analysis solution time series the offset of coordinate appears at the date when station maintenance such as change of the antenna, radome, or GNSS receiver performed. The offset is also shown in the PPP solution time series at the maintenance day, but the amount is not always same as that of the routine analysis solution. To avoid this discrepancy, we set the evaluation period for one month in August, 2021 when no station maintenance was performed.
GNSS solution is strongly affected by phase characteristic model of the GNSS antenna used in the analysis, especially for the up-down component. Therefore, we use same antenna phase characteristic model for PPP analysis as the routine analysis. For GLONASS and QZSS, the same characteristics model as GPS’s are used.
Our primitive result shows that for the east-west and north-south component the difference between the PPP and the routine analysis solutions are as small as about several millimeters with slight dependency on the latitude for all the three combinations of GNSSs. For up-down component, on the other hand, there is about one to two centimeters bias downwards clearly appeared in PPP solution with respect to the routine analysis solution for all the combinations of GNSSs. It is important that even the “GPS-only” case has the bias, which implies the bias may come from the difference of analysis method, not from the GNSS used. Also, the case of the combination “GPS, GLONASS and QZSS” seems to have slightly lager bias than the other two cases.
The PPP solution used is ambiguity resolved solution by static analysis. In the analysis, we used the ephemeris that GSI estimated using MADOCA software developed by the Japan Aerospace Exploration Agency (JAXA). We used the three combinations of GNSS systems for PPP, that is, “GPS only”, “GPS and GLONASS”, and “GPS, GLONASS and QZSS (Quasi-Zenith Satellite System)”. The evaluation of the consistency is performed as follows: first calculating daily difference of the PPP solution from the routine analysis solution (the final solution, F5) station by station, then averaging them for the evaluation period.
It is known that in the routine analysis solution time series the offset of coordinate appears at the date when station maintenance such as change of the antenna, radome, or GNSS receiver performed. The offset is also shown in the PPP solution time series at the maintenance day, but the amount is not always same as that of the routine analysis solution. To avoid this discrepancy, we set the evaluation period for one month in August, 2021 when no station maintenance was performed.
GNSS solution is strongly affected by phase characteristic model of the GNSS antenna used in the analysis, especially for the up-down component. Therefore, we use same antenna phase characteristic model for PPP analysis as the routine analysis. For GLONASS and QZSS, the same characteristics model as GPS’s are used.
Our primitive result shows that for the east-west and north-south component the difference between the PPP and the routine analysis solutions are as small as about several millimeters with slight dependency on the latitude for all the three combinations of GNSSs. For up-down component, on the other hand, there is about one to two centimeters bias downwards clearly appeared in PPP solution with respect to the routine analysis solution for all the combinations of GNSSs. It is important that even the “GPS-only” case has the bias, which implies the bias may come from the difference of analysis method, not from the GNSS used. Also, the case of the combination “GPS, GLONASS and QZSS” seems to have slightly lager bias than the other two cases.