Lockheed Martin’s [LMT] prototype for the Air Force’s next generation of GPS proved that it will be able to communicate with the existing GPS satellite constellation, the company said on Nov. 21. 

GPS III showed that it was “backward-compatible”–a term used to describe technology that can communicate with transmissions from older models. GPS III is currently housed on the ground at Cape Canaveral Air Force Station, Fla. Formally called the GPS III Nonflight Satellite Testbed (GNST), the prototype was able to interact with simulators mimicking the currently orbiting GPS IIR, GPS IIR-M and GPS IIF satellites. 

The tests, which finished on Oct. 17, also showed that an Air Force receiver could pick up and track signals from GNST.

“This provides early confidence in the GPS III’s design to bring advanced capabilities to our nation, while also being backward-compatible, ” said Paul Miller, Lockheed Martin’s director for GPS III development. 

The company said GPS III will “affordably replace aging GPS satellites in orbit while improving capability to meet the evolving demands of military, commercial and civilian users.” It will also provide three times more accuracy and eight times more effective anti-jamming technology.  

Authorized by Congress in 2000, GPS III is set to make its first launch in 2015. The prototype reached another milestone in August when it communicated with its operational control system (OCX) for the first time. Raytheon [RTN] is responsible for developing the OCX.