This paper provides an overview of the next generation of the Global-Positioning System (GPS) space and ground segments as embodied in the GPS Block II follow-on (GPS IIF) program. The GPS IIF program includes the procurement of 33 satellites and the operation and support of the new GPS operational control segment. The program is using the principles of acquisition reform to develop and field a new generation of satellites, support equipment, and software. Performance improvements in GPS signal power, accuracy, and service to civilian users are described. These improvements provide a foundation and, combined with the flexibility of the GPS IIF system, they allow for upgrading the system to even greater capability. The elements of the GPS IIF system are described in significant detail.