The recently released House mark for the 2019 National Defense Authorization Act (NDAA) includes an additional $5M to add to the $10M appropriated in the 2018 budget, for a GPS backup technology demonstration. The draft bill says:
GPS Backup Demonstration
The committee continues to support the demonstration of backup and complementary positioning, navigation, and timing capabilities of the Global Positioning System (GPS) as required by section 1606 of the National Defense Authorization Act for Fiscal Year 2018 (Public Law 115-91). The committee encourages the Secretary of Defense, Secretary of Transportation, and Secretary of Homeland Security to continue to work together to jointly develop and implement a plan for carrying out this backup GPS capability demonstration in 2019 and 2020. Further, the committee expects the Secretaries to submit the final report next year as required by Public Law 115-91. The committee directs the Secretary of Defense to provide a briefing to the congressional defense committees by December 1, 2018, on the progress being made on this demonstration.
The allocation of $5M for the purpose is included in the funding tables published separately.