4:30 PM - 4:45 PM
[SGD01-10] Evaluation of precise gravimetric geoid model using GNSS/leveling data
in Kushiro/Nemuro area
Keywords:Airborne gravity survey, Geoid, Gravity, Gravimetric geoid model
We have been conducting a nationwide airborne gravity survey over Japan since 2019 to develop a new precise gravimetric geoid model of Japan. The newly developed gravimetric geoid model will be used as a reference for the new height system of Japan. We plan to complete the airborne gravity surveys by the first half of 2023 and finalize the modeling of the geoid by March 2025. We aim to develop the gravimetric geoid model with an accuracy of approximately 3 cm. In our previous study, we demonstrated that our experimental gravimetric geoid model had an accuracy better than 3cm in the Tohoku region, where the significant crustal deformation was occurring, by using the newly obtained GNSS/leveling data (Ichimura et al., Geodetic Society of Japan 2022).
In this study, we evaluate the accuracy of the gravimetric geoid model in the Kushiro/Nemuro area, where the undulation of the geoid is large, by conducting GNSS/leveling surveys.
Here we use the geoid slope validation method for the evaluation, which is the same method used in our previous study. This method compares the RMS differences of relative geoid heights at any two points (geoid slopes) between the GNSS/leveling data and the gravimetric geoid model. We can estimate the accuracy of the gravimetric geoid model from the RMS differences according to the error propagation law. This method has the advantage of ignoring the systematic error between GNSS/leveling data and the gravimetric geoid model. Figure (a) shows the geographical map of the GNSS/leveling points. The maximum elevation difference in this area is about 150 m and the maximum geoid height difference is about 4 m. The GNSS surveys were conducted from August 4 to 31, 2022. The leveling survey was conducted from June 8 to July 28, 2022.
As a result of evaluation, we confirmed that our experimental gravimetric geoid model had an accuracy of approximately 2.8 cm in the Kushiro/Nemuro area, demonstrating the target accuracy of 3 cm was achieved there.
In this study, we evaluate the accuracy of the gravimetric geoid model in the Kushiro/Nemuro area, where the undulation of the geoid is large, by conducting GNSS/leveling surveys.
Here we use the geoid slope validation method for the evaluation, which is the same method used in our previous study. This method compares the RMS differences of relative geoid heights at any two points (geoid slopes) between the GNSS/leveling data and the gravimetric geoid model. We can estimate the accuracy of the gravimetric geoid model from the RMS differences according to the error propagation law. This method has the advantage of ignoring the systematic error between GNSS/leveling data and the gravimetric geoid model. Figure (a) shows the geographical map of the GNSS/leveling points. The maximum elevation difference in this area is about 150 m and the maximum geoid height difference is about 4 m. The GNSS surveys were conducted from August 4 to 31, 2022. The leveling survey was conducted from June 8 to July 28, 2022.
As a result of evaluation, we confirmed that our experimental gravimetric geoid model had an accuracy of approximately 2.8 cm in the Kushiro/Nemuro area, demonstrating the target accuracy of 3 cm was achieved there.