We present a 0.16 % precise and 0.27 % accurate determination of R _ { 0 } , the distance to the Galactic Center .
Our measurement uses the star S2 on its 16-year orbit around the massive black hole Sgr A* that we followed astrometrically and spectroscopically for 27 years .
Since 2017 , we added near-infrared interferometry with the VLTI beam combiner GRAVITY , yielding a direct measurement of the separation vector between S2 and Sgr A* with an accuracy as good as 20 \mu as in the best cases .
S2 passed the pericenter of its highly eccentric orbit in May 2018 , and we followed the passage with dense sampling throughout the year .
Together with our spectroscopy , in the best cases with an error of 7 km/s , this yields a geometric distance estimate : R _ { 0 } = 8178 \pm 13 _ { \mathrm { stat . } } \pm 22 _ { \mathrm { sys . } } pc .
This work updates our previous publication in which we reported the first detection of the gravitational redshift in the S2 data .
The redshift term is now detected with a significance level of 20 \sigma with f _ { \mathrm { redshift } } = 1.04 \pm 0.05 .