The current GPS constellation provides worldwide 24-hour navigation services with three-dimensional location (latitude, longitude and altitude), but the weaker signal is subject to interference by low-level radio waves, and the low signal strength from the satellites means that they can be blocked by buildings and vegetation.
Boeing is building at least 12 IIF generation satellites under contract to the U.S. Air Force. The new satellites will deliver two times greater signal accuracy, more robust civil signals that will be suitable for commercial aviation, a more secure military signal that resists jamming, a 12-year design life for long-term service, and the ability to update the satellite software system remotely for ongoing improvements to system operations.
The first GPS IIF satellite, SV-1, has been delivered to the launch site at the Cape Canaveral Air Force Station in Florida. The launch of this first second-generation satellite is tentatively scheduled for this month.
Source: ASM Magazine