Northrop Grumman matures EGI-M capability

Northrop Grumman's EGI-M undergoes flight-testing at Holloman AFB in New Mexico. (US Air Force )

Programme officials at Northrop Grumman are advancing development of the company's prototype Embedded GPS/Inertial Navigation System Modernization (EGI-M) capability, which once mature will provide military code (M-Code)-enabled GPS aerial navigation capability to the US armed forces and allies.

The EGI-M prototype, dubbed the LN-351, represents the “next evolution” of the company's fibre-optic, gyro-based internal navigation capabilities, said Ryan Arrington, vice-president for navigation and cockpit systems at Northrop Grumman, during a June 2025 interview with Janes.

The EGI-M capability development effort has become more important as US and allied air assets find themselves increasingly operating in GPS-contested or denied environments. M-Code-enabled GPS capability “is very necessary”, as adversarial GPS jamming tactics, techniques, and procedures advance and mature in effectiveness, Arrington noted.

Most GPS capabilities for assured positioning, navigation, and timing (APNT) aboard the US armed forces' weapon systems are based on selective availability anti-spoofing module (SAASM)-enabled GPS PNT. At its core, SAASM capabilities consist of an enhanced security architecture for GPS signal transmission, which is designed to encrypt and decipher signals via ‘over-the-air' rekeying of signal receivers.

M-Code, on the other hand, is a military-only GPS signal located in the L1 and L2 GPS bands that utilises a higher power signal, advanced message encryption formats, and signal modulation techniques to improve transmissions while hardening the signal against electronic warfare (EW) or signals intelligence (SIGINT) threats.

While designed for use aboard the F-22A Raptor fighter jet and E-2D Advanced Hawkeye early warning aircraft, the EGI-M prototype will also be certified to current civilian airworthiness standards set by the Federal Aviation Administration (FAA), Arrington said. This FAA certification “is a big requirement now for the DoD [Department of Defense]”, he told Janes.