GPS III Follow-On (GPS IIIF)

The GPS III Follow-On (GPS IIIF) program, managed by the United States Space Force and funded under Program Element (PE) 1203269SF, is a critical component of the Department of Defense's (DoD) efforts to sustain and modernize the Global Positioning System (GPS) for both military and civilian users. The primary goal of this program is to develop, test, and deliver advanced GPS III Follow-On satellites (SVs 11-12 and beyond), which will provide enhanced Positioning, Navigation, and Timing (PNT) capabilities, improved resilience, and new mission payloads to meet evolving national security and international obligations.

GPS IIIF Satellite Development is the largest line item within this budget element, focusing on the research, development, test, and evaluation (RDT&E) of the next generation of GPS satellites. These satellites are designed to maintain backward compatibility with previous generations while introducing significant enhancements such as advanced PNT technology, dual-band telemetry, tracking and control, and the integration of hosted payloads.

Notable new capabilities include the Regional Military Protection (RMP) feature, which allows for high-power regional Military Code (M-Code) signals, and the integration of Search and Rescue (SAR/GPS) payloads and Laser Retro-reflector Arrays (LRA) for improved accuracy and international cooperation.

The GPS IIIF program also supports risk reduction and technology maturation through the development of simulators, as well as systems engineering activities. These efforts are intended to ensure the successful delivery and operational readiness of the new satellites, including on-orbit checkout and anomaly resolution. The program further invests in advanced capabilities such as optical crosslinks for satellite-to-satellite communication, on-orbit reprogramming, and enhanced command and control using a Modular Open System Approach.

GPS Enterprise Integration (EI) is another key component funded within PE 1203269SF. The EI project is responsible for the technical baseline, integration, and synchronization of all GPS segments: space, control, and user equipment. The objective is to ensure that new capabilities, such as those provided by GPS IIIF satellites and the Next Generation Operational Control System (OCX), are effectively integrated and interoperable with legacy systems and ongoing modernization efforts.

EI activities include requirements management, interface validation, system-level testing, and enterprise-wide risk reduction. The Enterprise Integration function also provides critical support for the fielding and operational testing of Military GPS User Equipment (MGUE) and the transition to new control systems. It manages technical baseline documents, conducts modeling and simulation for future technology assessments, and supports spectrum protection efforts at international forums.

This ensures that GPS signals remain reliable and secure for military, civil, and international users, and that the system meets statutory and treaty obligations. Additionally, GPS EI supports cybersecurity, system safety, and program protection activities across the PNT enterprise. This includes the development and execution of cyber survivability test plans, system accreditation, and the integration of new technologies to enhance resilience against emerging threats. The EI team coordinates with multiple stakeholders, including other federal agencies and international partners, to maintain the integrity and global interoperability of the GPS system.