While GPS is an indispensable tool for synchronizing military networks and navigating military vehicles, it is vulnerable to jamming and spoofing.

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Mission critical applications require protection from jamming or spoofing (transmission of fake data that looks legitimate). In 1998 the United States Joint Chiefs of Staff selected SAASM (Selective Availability Anti- Spoofing Module) as the security architecture to eliminate the risks of jamming and spoofing.

As required under the 2003 Joint Chiefs of Staff Instruction: Master Positioning, Navigation, and Timing Plan (CJCSI 6130.01C), all newly fielded US Department of Defense GPS systems will need to use SAASM-compliant Precise Positioning System (PPS) devices as of October 2006. Enclosure E specifies SAASM for all new GPS deployments. Procurement of non-SAASM GPS user equipment is disallowed unless wavered.


M-Code is part of the GPS modernization effort to further improve anti-jamming and secure access to military GPS signals. US Public Law 111-383 requires purchasing M-Code compatible GPS user equipment after FY17. Orolia will be supporting the transition to M-Code in its GPS clock systems.

Current Products

Orolia offers synchronization to secure SAASM GPS in its SecureSync, TSync and VersaSync platforms. Use of the SAASM versions of these products is restricted to authorized users and is available through Foreign Military Sales (FMS). Contact us for more information.

Orolia’s SecureSync offers a choice of 2 SAASM receivers; a 24-channel Miniature Ruggedized Unit (MRU) and a 12-channel Ground-Based GPS Receiver Application Module (GB-GRAM). When loaded with the crypto-keys, they receive the L1 and L2 GPS frequencies, decrypt the P(Y) code, and precisely synchronize time for the most mission-critical applications. If the keys are not present, are deleted, or have expired, these units operate the same as commercial GPS receivers by receiving and synchronizing to the C/A L1 signal (also known as standard positioning service [SPS] instead of PPS).

Products for SAASM GPS

About David Sohn

David Sohn is a Solution Architect at Orolia, designing and developing solutions leveraging the organization’s precision timing solution portfolio, including their flagship SecureSync and VersaSync products, and contributing to its entire portfolio of resilient PNT solutions. He has more than 10 years of experience designing, developing, and managing precision timing solutions and holds a BS in computer engineering from The Pennsylvania State University.

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