The NASA-JAXA Global Precipitation Measurement mission (GPM) is an international satellite mission designed to leverage a constellation of both active and passive microwave satellite remote sensing, its overarching objective to unify and advance global precipitation measurements made from space. The GPM “Core Observatory” satellite will launch in July, 2013 carrying dual-frequency (Ka/Ku bands) precipitation radar (DPR) and the GPM multi-frequency (10-183 GHz) Microwave Imager (GMI). Central to the suite of well calibrated active and passive remote sensing employed by GPM is the need for properly formulated and physically-consistent precipitation retrieval algorithms. Moreover, these algorithms must function with a fidelity that enables accurate precipitation measurements to be made over a large fraction of the globe and hence, precipitation regimes. Assessing the retrieval fidelity requires an independent reference, in this case ground validation (GV). As such, during the pre-launch period of GPM, we coordinated with our partners at NASA GSFC to develop and implement ground-based and airborne GV infrastructure, including development of the GPM Disdrometer and Radar Observations of Precipitation Facility (DROP). Collectively the DROP and airborne infrastructure provide a means to test, refine and characterize errors in parameters and physical assumptions used in the retrieval algorithms; i.e., creating a better coupling between the measurement, retrieval techniques, and the actual physical characteristics of the precipitation being observed (e.g., type and phase, 3-D structure, size distributions, contents etc.). This presentation will discuss aspects of GPM Ground Validation approaches and in particular focus on the local, national, and international operations of the GPM DROP Facility at NSSTC.