Ну вот вам развлекаловка - почитайте чем ЛокМартин занимается для улучшения помехоустойчивости уже сейчас с блок 2, и что идет конкурс на блок 3.
Representing the second successful GPS IIR-M mission in just two months, the satellite launched today joins four IIR-M satellites and 12 other operational Block IIR satellites within the current 30-spacecraft constellation.
Each IIR-M satellite includes a modernized antenna panel that provides increased signal power to receivers on the ground, two new military signals for improved accuracy, enhanced encryption and anti-jamming capabilities for the military, and a second civil signal that will provide users with an open access signal on a different frequency.
The Global Positioning System enables properly equipped users to determine precise time and velocity and worldwide latitude, longitude and altitude to within a few meters. Air Force Space Command's 2nd Space Operations Squadron (2 SOPS) at Schriever Air Force Base, Colo., manages and operates the GPS constellation for both civil and military users.
Lockheed Martin is also leading a team which includes ITT and General Dynamics in the competition to build the U.S. Air Force’s next-generation Global Positioning System, GPS Block III. The next-generation program will improve position, navigation, and timing services for the warfighter and civil users worldwide and provide advanced anti-jam capabilities yielding improved system security, accuracy and reliability.