See also
Further information may be found in Konopacky et al. 2014 “Gemini Planet Imager Observational Calibrations V: Astrometry and Distortion”
This page still to be written.
For now, information on astrometric performance of GPI can be found at http://www.gemini.edu/sciops/instruments/gpi/instrument-performance?q=node/12165 and in the above reference.
Quinn Konopacky, Jerome Maire, Sandrine Thomas