M-Code Comes Closer: As Soon as Latest Launched Satellite Turns On - Inside GNSS - Global Navigation Satellite Systems Engineering, Policy, and Design

M-Code Comes Closer: As Soon as Latest Launched Satellite Turns On

The U.S. Space Force brought broadcast of the modernized encrypted M-Code signal one step closer to global availability for authorized military users with the launch of the fifth GPS III satellite on June 17. In contrast to most GPS launches, the rocket blast-off was actually moved forward from its originally scheduled date in July. No reason was given for this break in protocol.

GPS III Space Vehicle-5 (SV-5), built by Lockheed Martin, brings the number of M-code broadcasting satellites in the GPS constellation to 24, critical for global access to the jam-resistant signal. This number includes earlier GPS IIR-M and GPS IIF satellites as well as five of the Third Generation. GPS III SV-5 will replace one of the early models.

The code will begin broadcasting once the satellite is operational, which should be two weeks after launch, according to Col. Edward Byrne, senior materiel leader, Medium Earth Orbit Space Systems Division at Space and Missile Systems Center (SMC).

SMC plans to orbit 10 GPS III satellites and then update to a follow-on version called GPS IIIF.

Full operational use of M-code must still await full operational capability of the updating ground control system OCX, scheduled for Q3 of 2023.

“Digital capabilities will roll in over the next year to take advantage of the GPS III capabilities,” added Byrne.”That will allow us to declare IOC [initial operational capability] for the constellation,” he said. “OCX and the user equipment piece do not come online until the third quarter of 2023; that is when we would expect to have our initial operational capability for the GPS enterprise across across all segments: space, ground and user equipment.”