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Credit: Lisa Perdue, Orolia

What's The Deal?

M-Code – it is here. Public Law 111-383, Section 913 requires all military GPS user equipment purchased after FY 2017 to be M-Code capable, unless a waiver is issued by the Secretary of Defense.


With Military GPS User Equipment (MGUE), or M-Code receivers, becoming available to vendors, now is the time to start getting serious about the integration and performance testing of MGUE and systems that rely on it.

Currently there are two GPS security architectures – and both are available only to authorized users. The first, Selective Availability Anti-Spoofing Module (SAASM), has been required for all newly fielded DoD GPS systems as of October 2006. It uses the GPS Precise Position Service, which is provided using encrypted signals (P(Y) Code) on two frequencies – L1 (1575.42MHz) and L2(1227.6MHz).

MGUE is the second one, utilizing the M-Code signals. As one aspect of the GPS modernization program, M-Code is also an encrypted signal provided on L1 and L2 frequencies.

What is MNSA?

M-Code includes new cryptography: Modernized Navstar Security Algorithm (MNSA), to ensure the system is secure. The key management has been designed to make the system easier to use and manage by the end users. The encrypted details are kept very restricted and are only available to qualified persons. MNSA M-Code is currently being transmitted on 19 satellites today, and MGUE is available from several providers, so let’s get started!

1   Advanced Encryption Standard

2  Simulator Data Set

3  Modernized Navstar Security Algorithm

4  Military Navigation

M-Code Testing Methods

Before today, other test methods were necessary to allow users to integrate the MGUE without access to MNSA information.

AES M-Code – Rather than using the MNSA encryption, it is possible to use a known AES encryption method for testing purposes only. This method is useful to test integration, performance and specific user scenarios in an unclassified setting.

M-Code SDS – Simulator Data Sets are signals created with MNSA for replay in authorized simulators. The simulator vendor does not need to know the MNSA methods to incorporate the SDS into their simulators. This method is useful for testing the security algorithms and is a replay of already created data, so no user inputs are specified.

MNSA M-Code – Full testing of both the performance and the security features of the MGUE are possible. The user has full control over scenario settings with the real encryption used on the M-Code signal. This method is developed by simulator manufacturers with cooperation of the SMC Production Corps. It is only available to authorized users.

Why M-Code?

M-Code offers several operational benefits over the previous P(Y) code signals.

Jamming Resistance – Using spot beams from the GPS III satellites, M-Code will be delivered to specific regions through a high gain antenna, improving the power level available to the receivers on the ground within those regions.

Blue Force Electronic Attack Compatibility – Due to the modulation type of the M-Code signal, it is possible to purposely jam the commercial GPS L1 C/A signal while continuing to receive and use the M-Code signal. M-Code can also be acquired without the use of C/A code, so there is no reliance on non-military signals.

Anti-Spoof – Not only is the M-Code signal encrypted, MGUE is also able to detect and reject false signals.

M-Code Enabled Timing & Sync Solutions

Flexible, Resilient PNT for Every Environment

•   M-Code capabilities for SecureSync® DISA approved time server
•   Versa mobile PNT platform for rugged, small SWaP-C requirements
•   Improved resistance to jamming and interference
•   Advanced security features
•   More accurate performance

Orolia offers an easy, cost-effective upgrade from SAASM to M-Code.

The Versa Platform supports M-Code for mobile military missions.

The Real-Deal for Simulation
Available Now, Shipping Today

BroadSim MNSA is a fully flexible implementation of the Modernized NavStar Security Algorithm. Any aspect of your scenario can be changed, such as time, date, location, constellation, downlink data, signal configuration, and visible satellites.

BroadSim MNSA is compatible with all of the existing capabilities that the Skydel simulation engine supports – including jamming, spoofing, and more. No additional hardware is required.

Skydel Badge@2x.png

Approved by the SMC Production Corps.

BroadSim MNSA
What Our Customers Think

" Competition among companies has long spurred the invention of newer/better products while companies often race to be the first to market a new technology. Meanwhile on the sidelines, the customers sit and wait, often ‘pre-ordering’ a product in hopes that it will eventually be delivered before we retire. With that being said... The wait for a MNSA M-Code simulator is over! Orolia Defense & Security stepped up big time and they are actively shipping MNSA M-Code for their BroadSim simulators. "

— Edgar Gomez, PNT Engineer at Centauri 

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