G-12 Waypoint (WP). A predetermined geographical position  used for route/instrument approach definition, progress  reports, published VFR routes, visual reporting points or  points for transitioning and/or circumnavigating controlled  and/or special use airspace, that is defined relative  to a VORTAC station or in terms of latitude/longitude  coordinates.  Wide Area Augmentation System (WAAS). A method of  navigation based on GPS. Ground correction stations transmit  position corrections that enhance system accuracy and add  vertical navigation (VNAV) features. 