The calibrator plans for the PINPT observations of this work, which involve two in-beam phase calibrators and three out-of-beam calibrators of PSR J2222–0137 (shown in red). More source information can be found in Table A.1. Among the two in-beam calibrators, FIRST J222201–013236, marked by golden circle, was used in previous astrometric campaigns (Deller et al. 2013; Guo et al. 2021); FIRST J222112–012806, marked by blue diamond, is used for core-shift determinations (see Sect. 4.2.2). The adopted phase calibration strategies are described in Sect. 2.2 and summarized in Table 1.