The transition to M-code begins

BAE Systems has produced more than one and a half million military GPS receivers. The company is transitioning receiver designs to use the modernized military code (M-code) signal for added resiliency in RF-challenged environments. We asked Luke Bishop, director and product line engineering lead for the company’s Navigation & Sensor Systems, a few questions.

BAE Systems’ MPE-M provides the benefit of M-Code operation in a challenged RF environment. Image: BAE Systems

Why transition to M-code?

There are three key reasons for users to transition to M-code as supported by Military GPS User Equipment (MGUE). First, MGUE provide U.S. forces and our allies with enhanced PNT capabilities while improving resistance to threats, such as accidental and intentional jamming. Compared to the current P(Y)-code signal specs, M-code signals are stronger. Second, MGUE provides improved resistance to spoofing. Third, MGUE is field programmable, enabling updates to accommodate future enhancements to the GPS enterprise, such as regional military protection (RMP).

Which user equipment is transitioning to M-code?

Successful MGUE Inc 1 prototype development is being leveraged into a full portfolio of weapons, ground and aviation/maritime M-code GPS receivers. Our first production M-code receiver, MPE-M, achieved production deliveries in CY2021, with more than 1,000 delivered. Additional M-code GPS form factors are under development.

We are also underway with the Foreign Military Sales (FMS) M-code program with MPE-M.

How is the transition to M-code proceeding?

As indicated by the January 2021 GAO report (GAO-21-145), M-code-capable user equipment is in the initial stages of Department of Defense (DOD) fielding for select weapon systems. Also noted by the GAO report, the DOD has conducted bulk purchases of the Increment 1 ASICs [application-specific integrated circuits] to ensure that “sufficient supplies of [them] are on hand for future integration into M-code card …based on estimated need through 2028.” We are at the beginning of M-code (MGUE). Time and the market will tell what ultimately happens.

Which of your receivers operate with an anti-jam (AJ) antenna?

BAE Systems’ receivers support both stand-alone AJ and integrated AJ. Receivers with integrated AJ include the NavFire-M, NavStorm-M and SABR-M receivers supporting high-dynamic weapons applications. Receivers directly supporting external AJ via a digital beamforming interface include the MPE-M and AMR. Our external AJ DIGAR offering provides exceptional performance for many stakeholders.

Do you use advanced signal simulation equipment?

We integrate Spirent Federal and other signal simulators in both our test and development environments, where modeled RF signals are coordinated with other sensor measurements and host vehicle messages for high-fidelity hardware-in-the-loop test cases. Our engineers create hundreds of test cases and scripted test procedures to exercise our products under all required conditions. These simulations allow us to run thousands of trials to qualify and validate performance of our products in extreme scenarios.

BAE Systems’ hardware-in-the-loop simulation environments build upon Spirent Federal signal generators to test products under extreme dynamic and threat environments. (Photo: Spirent Federal)