Military code, or M-code, is a more robust jam-resistant global positioning system (GPS) capability that has been under development since the late 1990s and in use by the U.S. Department of Defense (DOD) to ensure unimpeded military access to GPS signals. M-Code uses more modern and flexible encryption methods to make it resistant to spoofing.
In order to use M-code, DOD needs M-code-capable satellites in place to broadcast the signal, a ground system to control the satellites, and equipment—also known as user equipment—to receive it for military operations. As part of the program to enable M-code to be received in end user equipment, efforts have been under way to develop a low size, weight and power military GPS user equipment (MGUE) increment 2 miniature serial interface (MSI), including a next generation application specific integrated circuit (ASIC).
One of the companies awarded the contract for this is Raytheon Intelligence & Space (RI&S), who is developing one MSI card for aviation and maritime systems and another MSI card for ground-based systems. Green Hills Software said that its INTEGRITY-178 tuMP real-time operating system (RTOS) will be used in both solutions running on the Arm processor-based ASIC. RI&S selected the INTEGRITY-178 tuMP RTOS based on its use in previous programs and for its ability to simultaneously meet both safety and security requirements. Those requirements included the highest DO-178C design assurance level (DAL A) and the NSA-defined separation kernel protection profile (SKPP) for “high robustness” security.
The military GPS user equipment is the GPS receiver for the modernized GPS enterprise, and it is capable of receiving M-code from newer satellites, including GPS-III. The MGUE increment 2 (Inc 2) MSI program is developing a smaller M-code ASIC and receiver card that consumes less power while increasing functionality, security and performance. The smaller card will enable use in handheld and dismounted applications as well as mounted, maritime and aviation platforms. The Government Accountability Office estimates that approximately 700 different types of weapon systems will ultimately require M-code cards and M-code-capable receivers, including ships, aircraft, ground vehicles, munitions, and handheld devices.
Dan O’Dowd, founder and CEO of Green Hills Software, said, “Green Hills Software has a long history of working with RI&S on GPS and navigation systems, and we are pleased to be part of their MSI with next generation ASIC solution. Airborne GPS solutions require both safety and security, and the INTEGRITY-178 RTOS has an unrivalled pedigree in the combination of certified high-robustness security with certified DO-178C safety assurance.”
The INTEGRITY-178 tuMP high-assurance RTOS from Green Hills Software is designed to meet both DO-178C DAL A airborne safety requirements and the NSA-defined SKPP. Green Hills Software said it is the only commercial operating system ever certified to the SKPP, and that certification was done by the National Information Assurance Partnership to Common Criteria EAL 6+ and “high robustness.”
Beyond the separation kernel, INTEGRITY-178 tuMP provides a complete set of APIs for use by multi-level security applications within a secure partition, for example, an MLS guard, which is a fundamental requirement in a cross-domain system. It is also the first and only RTOS to be part of a cross-domain solution certification to NSA’s new “Raise the Bar” initiative. INTEGRITY-178 was the first commercial RTOS approved as complying with DO-178B Level A objectives, and INTEGRITY-178 tuMP is the only RTOS to be part of a multicore certification to DO-178C and CAST-32A multicore objectives. The RTOS directly supports a modular open systems approach, and it was the first RTOS to be certified conformant to the FACE Technical Standard, edition 3.0.
Background to MGUE Increment 1 and 2
In January 2017, DOD approved the MGUE Increment 1 program, the first of two increments, to formally begin development of M-code cards and to eventually conduct operational testing of those cards on four military service-nominated systems. DOD defined the criteria to complete the program as:
- Verifying technical requirements on all types of final M-code test cards;
- Certifying readiness for operational testing by the Air Force Program Executive Officer;
- Completing operational testing for the four lead weapon systems for, at a minimum, the first card available;
- Completing manufacturing readiness assessments for all Increment 1 card contractors.
The MGUE Increment 2 program builds on Increment 1 technology and is developing smaller M-code cards to use in equipment for which Increment 1 cards were not developed and where they do not meet required needs, such as the size and power requirements of some weapon systems. The Increment 2 program specifically addresses requirements for handheld receivers, munitions, and space-based receivers.
The Air Force issued a request for proposals for the Increment 2 card and next-generation ASIC development in December 2019, and competitively awarded contracts to Rockwell Collins, Interstate Electronics, and Raytheon in November 2020.
According to the Increment 2 program schedule, the next-generation ASIC is expected to be available in fiscal year 2024 at the earliest, at which point programs adopting the technology will still have to conduct M-code card integration and testing, as needed. The program anticipates an M-code card demonstration in the fourth quarter of fiscal year 2025. Officials said that to mitigate risk, the program set its delivery date in fiscal year 2026 to allow time—if needed—for a second ASIC development phase, which is often needed for complex ASICs. Once the card is available, integration and testing will still be needed for specific receiver applications.
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