The System: 2 SOPS Takes Over Second IIF

September 1, 2011  - By
Image: GPS World

The U.S. Air Force 50th Space Wing’s 2nd Space Operations Squadron took command and control of the second GPS Block IIF satellite on August 19. SVN-63 (PRN 01) was set healthy on August 23.

The total of 12 next-generation GPS IIF satellites built by Boeing will provide improved accuracy through advanced atomic clocks, a longer design life than legacy GPS satellites, and a new signal, L5, that will benefit civil aviation and safety-of-life applications.

The Space and Missile Systems Center’s GPS Directorate at Los Angeles Air Force Base remained in control of the satellite during a 30-day on-orbit check-out period before hand off.

The constellation is more robust and capable than at any other time in its history, the GPS Wing said. Members of 2 SOPS operate the largest Department of Defense satellite constellation via the Master Control Station and a worldwide network of monitoring stations and ground antennas.

Recalls IIA to Duty. For only the second time in a quarter century, Air Force officials plan to transition a decommissioned GPS satellite back to active status. 2 SOPS staff noticed in late May that the clock on the GPS IIA SVN-30 was starting to malfunction. 2 SOPS engineers and counterparts at Boeing and Aerospace Corp. developed a plan to bring SVN-35 back in to service to replace the ailing bird. The 18-year-old satellite was decommissioned from active service in 2009 to make room for the eventual deployment of the latest GPS Block IIR vehicle; however, its navigational signal continued to function properly.

“We keep on-orbit spares for exactly this purpose,” said Lt. Col. Jennifer Grant, 2 SOPS commander. “The robustness of our current constellation and the recent completion of the Expandable 24 architecture provide us with the flexibility to perform replacements like this with minimal impact to global users.”

OCX Hits Bump: Does Not Pass Preliminary Design Review

The next-generation GPS Ground Control system (OCX) under the direction of prime contractor Raytheon did not pass the recently concluded initial Preliminary Design Review (PDR).

Not passing this critical PDR inspection so early in the OCX process and in the current fiscal environment (Congress has already trimmed the modernization budget and shifted elements to the right) constitutes a blow to the GPS modernization effort. It adds to the worry concerning the OCX-GPSIIIA gap having to do with the ability to launch the Lockheed-produced GPS IIIA space vehicles (SVs) and payloads that are scheduled to be ready for launch a full 14–16 months before the OCX ground system was originally scheduled to be able to control the launch.

That timeline undoubtedly stretches to the right with this development.

The PDR is a formal inspection by the government acquisition agency — the Air Force’s GPS Directorate in this case — of the high-level architectural design of the OCX automated systems and the associated C2 software. The PDR, critical for any military project but especially so for the new GPS Ground C2 system, is conducted to achieve confidence that the design satisfies the functional and nonfunctional requirements and conforms with the overall enterprise architecture. Overall project status, proposed technical solutions, evolving software products, and all associated documentation are reviewed at a high level during the PDR to determine completeness and consistency with contractual standards. The PDR also serves to raise and resolve any technical and/or project-related issues, and to identify and mitigate project, technical, security, and/or business risks affecting continued detailed design and subsequent development, testing, implementation, and operations and maintenance activities.

Typically during a PDR the government has several choices concerning the outcome. It can:

  • Approve
  • Approve conditionally
  • Withhold approval
  • Disapprove or fail the program.

In this case, the government chose to withhold approval and not approve conditionally or formally fail until all PDR action items are reviewed.

LightSquared Interference

For the first time in several months, there is little in the way of concrete news to report on this topic — as of press date August 24. The Federal Communications Commission weighs its options and scrutinizes the further data that it has requested: the number and lifespan of GPS receivers that will be interfered with, and the number of terrestrial base stations LightSquared plans to deploy. Here are highlights from the “LightSquared Watch” webinar on August 18:

GPS is arguably the most efficient use of spectrum the world has ever seen; almost a billion people benefit from the GPS signal that is available today. This use represents a massive installed base and source of innovative advantage for the United States. Most importantly, it represents a high degree of trust and confidence in the United States and its stewardship of GPS.
— Scott Pace

Misinformation is rampant, and the pressure for action before analysis characterized the early stages of this process. History was reinterpreted, and the facts twisted to fit desired reality. We have heard lawyers’ assertions versus engineers’ judgements — with only the latter supported by verifiable data.
— Jules McNeff

Launches Round the World

China launched a fourth inclined geosynchronous orbit (IGSO) satellite in the Beidou/Compass navigation system on July 26. Its orbit is currently centered on an East longitude of about 93 degrees, some distance away from the other three IGSO satellites. Plans call for completion of a 14-satellite constellation by 2012.

A single GLONASS-M satellite was set to be launched on August 26. Five further GLONASS launches are planned this year: a triple and a single GLONASS-M launch in October, and the second GLONASS-K1 satellite in December.

The first two Galileo In Orbit Validation satellites are set to be launched from French Guiana on October 20, with two more following them into orbit by mid-2012.

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About the Author: Alan Cameron

Alan Cameron is the former editor-at-large of GPS World magazine.