Surface threats from air defenses is a tough problem because emerging threats right now can see aircraft hundreds of miles away. Today digital SAMS (surface-to-air-missile-systems) can change frequencies and they are very agile in how they operate.
Emerging and future Integrated Air Defense Systems use faster computer processors, are better networked to one-another and detect on a wider range of frequencies. These attributes, coupled with an ability to detect aircraft at further distances, make air defenses increasingly able to at times detect even stealth aircraft, in some instances, with surveillance radar.
The Russian S-500 Prometey is expected to become operational in 2017. It will likely form the upper tier of Russia’s layered integrated air defense system.
The S-500 is expected to able to detect and simultaneously attack up to ten ballistic missile warheads flying at speeds of twenty-three thousand feet per second. It is also reportedly being designed to use hit-to-kill interceptors—a design with similarities to Lockheed Martin's Terminal High Altitude Area Defense (THAAD).
Like all modern Russian air defense systems, the S-500 is expected to be highly mobile and will use a network of radars for targeting over vast distances. The missile system is expected to use the 91N6A(M) battle management radar, a modified 96L6-TsP acquisition radar, as well as the new 76T6 multimode engagement and 77T6 ABM engagement radars
SOURCES - Scout, National Interest, MissileThreat