GPS Anti-Jam M-Code Takes Two Steps Forward

WASHINGTON: DoD’s long-awaited M-Code secure channel for GPS signals is making slow but steady progress toward becoming a reality, with a fourth GPS III satellite slated to launch next month and final upgrades to the Air Force’s OCS ground control stations.

The highly encrypted M-Code to protect GPS signals from jamming and spoofing currently is enabled on 22 GPS satellites of various generations; 24 are needed to bring the M-Code to full operational capability.

“Right now we’ve got 22; SV-4 makes 23; and once you reach that magic number of 24, that gives you global M-Code coverage,” Chris Pettigrew, spokesperson for GPS prime contractor Lockheed Martin, told Breaking D today.

Space and Missile Systems Center (SMC) announced last night that the fourth Global Positioning System III satellite, Space Vehicle-4 (SV-4), was delivered to Cape Canaveral Air Force Station on July 14, where it will undergo pre-launch preparations. This includes integration with SpaceX’s Falcon 9 rocket, which also was used to launch GPS SV-3 on June 30.

The delivery of the fourth GPS III satellite “brings us another step closer in advancing the GPS constellation with more capable satellites,” said Col. Edward Byrne, SMC’s Medium Earth Orbit Space Systems Division chief.

According to a July 1 SMC briefing to the independent National Space-Based Positioning, Navigation, and Timing (PNT) Advisory Board, the launch of GPS III SV-4 is slated for “no earlier than” Sept. 30. SV-5 was “declared available for launch” on May 7, added the briefing slides, presented by Lt. Col. Ken McDougall, of the PNT Mission Integration office at SMC.

SMC also announced that on June 27 the Space Force took “a major step toward operational acceptance” of the M-Code, with Lockheed Martin’s completion of the M-Code Early Use (MCEU) hardware and software upgrade package for the GPS Operational Control System (OCS).

The upgrade allows the M-Code to be used not just by GPS III, but by all older GPS satellites that are M-Code capable (GPS IIR-M and GPS IIF satellites.) It also allows M-Code functioning to be monitored by ground controllers, as well as supporting testing and fielding of user equipment. The upgrades were installed at the Master Control Station at Schriever AFB , and the Alternate Master Control Stations at Vandenberg AFB — the two major facilities for command and control of the GPS constellation.

Pettigrew said the upgrades have enabled improved cybersecurity at the ground control stations.

As Breaking D readers know, OCS is Lockheed Martin’s stop-gap GPS control system built as a bridge to Raytheon’s long-troubled and much delayed Next Generation Operational Control Segment (OCX), which was originally designed specifically to handle the M-Code. The full-up OCX system currently is slated for delivery in 2021, and is expected to become operational beginning in 2022.

“MCEU will be in a trial period prior to Operational Acceptance in November 2020,” SMC’s press release said. “Once Operational Acceptance is granted, upcoming Military Ground User Equipment (MGUE) will be able to leverage the M-Code signal-in-space to provide more secure position, navigation and timing (PNT) to warfighters.”

According to McDougall’s briefing slides, operational acceptance of the upgraded MCEU is currently slated for Nov. 18.

Of course, the question of when M-Code receivers for solider, sailors and airmen on the ground will become available is another fine kettle of fish.

“Development of GPS user equipment that can utilize the M-Code signal has lagged behind the fielding of GPS M-code satellites for more than a decade, due to prolonged development challenges,” the Government Accountability Office (GAO) chided in its March 2019 report on space acquisition issues.