GPS is the gold standard for precise positioning, navigation, and timing (PNT), impacting the lives of more than six billion users worldwide. The United States economy alone depends on the free, government-provided service across 900 million GPS receivers supporting vehicle navigation systems, general aviation, financial transactions, the electrical grid, precision agriculture, surveying and construction. The GPS enterprise must remain consistent and reliable, while keeping pace with emerging technology without interruption for the end user.
Space Systems Command (SSC) at Los Angeles Air Force Base in El Segundo, California — the U.S. Space Force’s space development, acquisition, launch and logistics field command — is responsible for maintaining and modernizing the GPS enterprise. The enterprise consists of three segments: the space segment, the control segment and the user segment. Each achieved specific milestones during an exciting and productive 2022.
There are currently 37 GPS satellites on-orbit with 31 set healthy. The constellation requires 24 operational satellites for worldwide coverage and a receiver needs to receive transmissions from four of them to determine its position in three dimensions. GPS continues to operate impressively with an average 45-cm accuracy throughout the past year with the most precise day on record at 31.5 cm. The space segment of GPS modernization focuses on GPS III and GPS IIIF satellite development with significant milestones rounded out in 2022.
For GPS III, after the successful launch of Space Vehicle 5 (SV05) on June 17, 2021, it was set healthy (usable) on May 25, 2022. The significance of SV05 is its full operational capability of the improved civilian L2 (L2C) signal. L2C improves service speed for commercial users via access to two frequencies, improves accuracy when combined with legacy civil GPS signals (L1 C/A), and is less susceptible to ionospheric interference. SV05 is the 24th satellite enabled with the Military Code (M-code), providing worldwide M-code coverage. M-code is designed to give military receivers better defense against jamming, improved accuracy, a more secure and flexible cryptography architecture, and the ability to detect and reject false signals.
On Jan. 18, 2023, SV06 successfully launched into orbit aboard a SpaceX Falcon 9 Block 5 rocket from Cape Canaveral Space Force Station, Florida. The launch of SV06 marks a key step in the larger goal of modernizing the GPS constellation. Additionally, the 10th and final satellite in the GPS III fleet finalized production and has a target launch date of 2026. GPS III Space Vehicles 7–10 are in storage and available for launch.
The next generation of GPS satellites continues development. The October 2022 contract award for GPS III Follow-On (GPS IIIF) satellites will onboard additional capabilities. In addition to introducing new civil signals designed to enhance search-and-rescue efficacy and aviation safety, laser retroreflector array for precise ranging, and a fully digital navigation payload, the GPS IIIF satellites will offer a new Regional Military Protection (RMP) capability providing up to 60 times greater anti-jamming measures. A new port on the Lockheed Martin LM2100 Combat Bus supports a substantial increase in flexibility, providing rapid integration of payloads in response to emerging threats in space.
The Next Generation Operational Control System (OCX) will replace the current GPS Operational Control System (OCS), supporting the latest U.S. Department of Defense standards and practices for cybersecurity. The updated system includes a modernized and expanded monitor station network, improved anti-jam capabilities, and enhanced operational capability to control modernized military signals.
In March 2022, OCX completed its fourth and final legacy ground antenna element (LGAE) installation on Kwajalein Island in the Republic of the Marshall Islands. OCX Block 1 and 2 are undergoing Hewlett Packard (HP) Formal Qualification Test (FQT). This event will qualify much of the system’s previously certified mission software functions. The event will also demonstrate system maturity and readiness for system acceptance, operator training, and specific developmental testing milestones with both GPS space and user segments.
The next-generation control system, OCX 3F, will modify OCX Blocks 1 and 2 to use the enhanced capabilities of GPS IIIF satellites. OCX 3F received Milestone B and Acquisition Program Baseline (APB) approval from the Milestone Decision Authority (MDA) and was authorized to enter the Engineering and Manufacturing Development (EMD) phase in May. In November, the OCX 3F program deployed 3F mission software into OCX’s Near Operations Environment (NOE) for the first time after completion of the program’s first Integration Readiness Review (IRR). The IRR event ensures that the software meets integrity standards and receives approval to be integrated and tested on the NOE prior to software releases to the operational users. OCX 3F anticipates achieving operational acceptance in 2027.
User Equipment Segment
Among the arsenal of GPS user equipment, very few pieces have the technology to use the M-code signal. Maintaining a competitive advantage against the adversary requires use of these signals; the GPS Enterprise is focused on developing Modernized GPS User Equipment (MGUE) capable of accessing these signals. The MGUE program is a joint service program developing modernized M-code-capable military GPS receivers. The program is broken into two increments (Inc 1 and Inc 2). Both are designed to deliver secure PNT performance, allow navigation warfare operations, enhance anti-jam, enhance anti-spoof and anti-tamper, and enable Blue Force Electronic Attack.
As part of the multiple elements under the MGUE Inc 1 umbrella, L3Harris delivered its final Build 7 ground card to the government on Nov. 16, 2021, and completed regression testing on that kit in February 2022. The final Delta Security Certification and Approval were completed on April 13 and April 29, 2022, respectively. Development of the L3H Ground-Based GPS Receiver Applications Module (GB-GRAM-M) card, which delivers geolocation and precise positioning capabilities for space-constrained applications while providing increased security and anti-jam capabilities, is complete and available for services procurement. MGUE Inc 1 completed qualification testing for the aviation and maritime cards on Sept. 9, 2022, with updated software builds. This build allows the program to progress to 98% of the requirements verified and enables B-2 Bombers and Guided Missile Destroyers (DDG) to continue progress toward operational testing. Completion of this commitment means significant progress toward operational testing for stakeholders and warfighters.
MGUE Inc 2 held Preliminary Design Reviews for the Miniature Serial Interface (MSI) in summer 2022, bringing the project another step closer to finalizing the EMD phase. Once all closure and action items are completed for the reviews, the government will consider each event complete. Critical Design Review (CDR) is scheduled for this summer and will validate the system design and the ability to meet system performance requirements. MGUE Inc 2 continues to execute the second competitive objective under Phase I for the Joint Modernized Handheld component; the effort is moving closer to completion of the handheld prototype and will ultimately make for a more seamless transition to operations.
The SSC’s mandate is paramount to maintaining our modern way of life. The space professionals dedicated to developing GPS technology are committed to delivering advanced capabilities to the warfighter, the civil sector, and the world. An interconnected world is ready for us. We’re on our way.
SSC is the U.S. Space Force field command responsible for acquiring and delivering the capabilities needed by warfighters to protect our nation’s strategic advantage in and from space. It manages an $11B budget for the U.S. Department of Defense and works in partnership with joint forces, industry, government agencies, academic and allied organizations to outpace emerging threats.
For analogous updates on the other three GNSS constellations, please see:
- Directions 2023: Galileo Offers New Services
- Directions 2023: BDS Development Continues Apace
- Directions 2023: GLONASS Renews Its Constellation