Reconstructed sky positions of S62 for an example value of d = 2500 AU of the plane on which the trajectory of this star lies (see Fig. 5). The dashed gray line represents the unlensed sky position of S62, while solid colored lines correspond to different values of γ. The inset plots displays as a function of time the astrometric deviation in µas between the cases with γ ≠ 1 and the general relativistic case with γ = 1. Depending on the value of γ, this deviation can surpass the sensitivity threshold for GRAVITY, implying the ability to potentially constrain this PPN parameter using only astrometric observations.