The US Air Force’s (USAF) Global Positioning System Directorate has successfully completed the third of five planned launch and early orbit exercises of its next-generation Global Positioning System III (GPS III) satellite and operational control system (OCX).
Carried out in collaboration with Lockheed Martin and Raytheon using new OCX’s Iteration 1.4 and GPS III launch and checkout capability (LCC), the exercise confirmed that the software addresses mission requirements and is on track to support the launch of the first GPS III satellite.
As well as demonstrating space-ground communications, first acquisition and transfer orbit sequences, the three-day exercise also displayed the software’s orbit-raising manoeuvre planning and execution, as well as basic anomaly detection and resolution capabilities.
The exercise expands on two earlier exercises, with a longer mission timeline, and introduction of simulated vehicle and ground anomalies for validation of the combined response capabilities of the control segment, satellite and operations crew.
Lockheed Martin Navigation Systems mission area vice president Keoki Jackson said: "Exercise 3 demonstrated that the cross-organisational operations team is on track to support successful GPS III launch and on-orbit checkout missions from our Newtown facility."
Raytheon Intelligence, Information and Services business vice-president and GPS OCX programme manager Matt Gilligan said: "The system responded as designed, and met all of the launch exercise success criteria and successfully demonstrated our anomaly response."
In addition, the industry team and customer jointly executed mission planning activities, including orbit determination and the generation of upload command files.
Two more readiness exercises alongside six 24/7 launch rehearsals are planned to be carried out before the launch of the first GPS III satellite in 2015.
Scheduled for early 2014, Exercise 4 will use Iteration 1.5 software that includes the LCC capability and all critical information assurance features required to support first GPS III launch.
Under production by Lockheed, GPS III is a family of next-generation satellites designed to replace USAF’s existing GPS constellation, which provides location and time information in all weather conditions.
Image: An artist’s impression of the GPS III satellite in orbit. Photo: © 2013 Lockheed Martin Corporation.