3:45 PM - 4:00 PM
[SGD02-08] Multi-GNSS analysis of GPS, GLONASS, and Galileo satellites at GEONET sites applying the GAMIT program
Keywords:Multi-GNSS, GEONET, GAMIT program
Shimada (2020) analyzed GEONET observation data for 42 days from January to February 2019 using GPS and Galileo satellite at the 134th Meeting of the Geodetic Society of Japan, using the GAMIT program, and coordinates repeatability was discussed. Nakao et al. (2020, 2021) studied multi-GNSS analysis of GPS, GLONASS, and Galileo of GEONET observation data using the Bernese program at the 134th and 136th Meetings of the Geodetic Society. Furthermore, the Geospatial Information Authority of Japan is trying to analyze GPS and GLONASS simultaneously.
In the GAMIT program, in version 10.71 released in March 2020, the orbit calculation accuracy of the multi-GNSS satellite is improved, and the analysis accuracy of the multi-GNSS satellite is improved.
In this presentation, we report the multi-GNSS analysis results of the GEONET observation data using the GEONET observation network using GPS, GLONASS, and Galileo satellites using the GAMIT/GLOBK program version 10.71.
For the precise orbits, the GPS and GLONASS satellite used the IGS final calendar (igs and igl sp3 files, respectively), and the Galileo satellite used the CODE precision ephemerides. ITRF2014 was used as the reference coordinate system, and the IGS points in and around East Asia were used as the fiducial coordinate reference sites. As for GLONASS and Galileo satellites, not all IGS point receivers are capability to receive them, so there are fewer coordinate reference points than GPS satellites.
Table 1 shows the coordinate value reproducibility (weighted rms) in the preliminary analysis of GEONET points in the Niigata region from January 10 to 19, 2022. For the EW component of the horizontal component, the analysis using only GPS satellites gives better results than the multi-GNSS analysis, but for the N-S component, the repeatability of the analysis with the GPS and GLONASS satellite becomes better than those by the analysis of only GPS satellites. The result is that there is almost no change, or the coordinate value reproducibility is slightly low. Furthermore, it seems that the repeatability by the analysis of the vertical component the GPS satellite with the Galileo satellite has better repeatability compared eith than the analysis of only the GPS satellite.
This result indicates that the multi-GNSS analysis may be more accurate than the analysis of GPS satellites alone depending on the components. This is because the orbital inclination of the GLONASS satellite is large and the area of the hole that the satellite near the North Pole cannot cover is small, and the number of satellites larger than that of the GPS satellites alone in the analysis of the multi-GNSS satellite is related to the analysis accuracy.
However, during this period, the Niigata region was hit by heavy snowfall, and it is conceivable that there was a large vertical fluctuation due to the use of groundwater for snow melting. Therefore, it may not be appropriate to evaluate the vertical coordinate repeatability calculated by assuming that the coordinate values for 10 days should not change. Therefore, in the presentation, we will report the analysis results of all GEONET points for the observation data in the fall of 2020.
In the GAMIT program, in version 10.71 released in March 2020, the orbit calculation accuracy of the multi-GNSS satellite is improved, and the analysis accuracy of the multi-GNSS satellite is improved.
In this presentation, we report the multi-GNSS analysis results of the GEONET observation data using the GEONET observation network using GPS, GLONASS, and Galileo satellites using the GAMIT/GLOBK program version 10.71.
For the precise orbits, the GPS and GLONASS satellite used the IGS final calendar (igs and igl sp3 files, respectively), and the Galileo satellite used the CODE precision ephemerides. ITRF2014 was used as the reference coordinate system, and the IGS points in and around East Asia were used as the fiducial coordinate reference sites. As for GLONASS and Galileo satellites, not all IGS point receivers are capability to receive them, so there are fewer coordinate reference points than GPS satellites.
Table 1 shows the coordinate value reproducibility (weighted rms) in the preliminary analysis of GEONET points in the Niigata region from January 10 to 19, 2022. For the EW component of the horizontal component, the analysis using only GPS satellites gives better results than the multi-GNSS analysis, but for the N-S component, the repeatability of the analysis with the GPS and GLONASS satellite becomes better than those by the analysis of only GPS satellites. The result is that there is almost no change, or the coordinate value reproducibility is slightly low. Furthermore, it seems that the repeatability by the analysis of the vertical component the GPS satellite with the Galileo satellite has better repeatability compared eith than the analysis of only the GPS satellite.
This result indicates that the multi-GNSS analysis may be more accurate than the analysis of GPS satellites alone depending on the components. This is because the orbital inclination of the GLONASS satellite is large and the area of the hole that the satellite near the North Pole cannot cover is small, and the number of satellites larger than that of the GPS satellites alone in the analysis of the multi-GNSS satellite is related to the analysis accuracy.
However, during this period, the Niigata region was hit by heavy snowfall, and it is conceivable that there was a large vertical fluctuation due to the use of groundwater for snow melting. Therefore, it may not be appropriate to evaluate the vertical coordinate repeatability calculated by assuming that the coordinate values for 10 days should not change. Therefore, in the presentation, we will report the analysis results of all GEONET points for the observation data in the fall of 2020.