COLORADO SPRINGS, Colo. — The U.S. Air Force’s revised upgrade strategy for its next-generation GPS 3 satellite navigation constellation could see anti-jam capabilities added to the system beginning with the ninth satellite, a senior service official said.

But Doug Loverro, executive director of Air Force Space and Missile Systems Center in Los Angeles, cautioned that no final decisions have been made on the GPS 3 upgrades, which are awaiting approval from the Office of the Secretary of Defense.

The office recently completed an analysis of alternatives on GPS 3 upgrades following the Air Force decision to do away with its block upgrade strategy for the program. That plan, abandoned last year, called for GPS 3 prime contractor Lockheed Martin Space Systems to build up to 32 GPS 3 satellites in three successive blocks with corresponding capability improvements.

Air Force Maj. Gen. John Hyten, director of space programs for the office of the assistant secretary of the Air Force for acquisition, said during an interview here at the 28th National Space Symposium that a final report on the analysis of alternatives is nearing completion. That report will inform decisions on which block upgrades to be introduced on GPS 3 and when.

The Air Force intends to stabilize the GPS 3 production line before introducing upgrades to the system, Hyten said.

Loverro said the decision to not to upgrade GPS 3 according to a block schedule will remove constraints and allow for adding on the technology when the threat calls for doing so. In addition, the complexity of position, navigation and timing technology has evolved since the Air Force awarded the GPS 3 prime contract in 2008.

In an interview here, Loverro said no decision has been made on the most advanced GPS 3 anti-jam capabilities, which originally were supposed to be included on the final block of satellites.

Lockheed Martin Space Systems of Denver is under contract to build the first four GPS 3 satellites, with the first slated to launch in 2014. The original contract included the first two satellites plus five options, each for two additional satellites.

The company has recently experienced cost growth on GPS 3 that has cost the company $70 million in award fees on the program, according to Air Force spokeswoman Vicki Stein.

Lockheed Martin’s estimated cost to build the first two GPS 3 satellites has risen from $1.41 billion to $1.5 billion, while Air Force estimates have grown from $1.57 billion to $1.62 billion, Stein said via email.

Lockheed Martin officials have attributed the GPS 3 cost growth to a back-to-basics program development approach that calls for rigorous component testing. Some of Lockheed Martin’s GPS 3 subcontractors have balked at the new testing standards and this has made the components more difficult to obtain, said Keoki Jackson, Lockheed Martin’s GPS 3 program director.

Lockheed Martin recently won a contract modification to begin work on the second and third satellites in the GPS 3 series.