The contracts are worth $120 million. The parts will be for satellites 5 through 8.
The Air Force plans to purchase and launch as many as 32 of the next-generation spacecraft to replace an older system for military and civilian use.
"The GPS III program was laid out at the very beginning to reduce risk early and facilitate affordable satellite production over the long term," said Lt. Col. Todd Caldwell, the U.S. Air Force's GPS III program manager.
"This most recent award and our team's ability to convert the contract structure to fixed-price is a sign that we are on track to meet the affordability objectives and commitments we originally set out to achieve."
The Air Force describes its GPS III acquisition program as "back-to-basics." It emphasizes early investments in systems engineering, industry-leading parts standards, and the development of a full-size GPS III satellite prototype to significantly reduce risk, improve the predictability of production and lower overall costs.
"The Air Force's back-to-basics acquisition strategy and the progress we have already made on our GPS III prototype gives us high confidence in our ability to perform efficient and affordable fixed-price satellite production going forward," said Keoki Jackson, vice president of Lockheed Martin's Navigation Systems mission area.
"As our world becomes increasingly dependent on GPS technology, the new GPS III satellites will be a critical element of both our national and economic security and we are committed to achieving mission success for the billions of military, commercial and civilian users worldwide."