The PAC-3 (Patriot Advanced Capability) is another upgrade of the Patriot air defense missile system. Upgrades will add more range and accuracy needed to intercept advanced DPRK ballistic missiles. A source said around 100 billion yen or 900 million US dollars in funding would be requested in the next defense budget proposal for the year starting April 2017.
The Radar of the PAC-3 has increased detection and tracking ranges. It also has improved discrimination abilities. The radar can discriminate whether or not the aircraft is manned, or which of multiple re-entering ballistic objects are carrying ordnance. Also the software of the PAC-3 ensures that ballistic missiles with chemical warheads or with early release submunitions are destroyed at a certain altitude.
The Patriot PAC-3 is a part of three-layer missile defense network. The first line of defense comes from AEGIS missiles, designed to knock-out ballistic missiles in space. If that fails, ballistic missiles are intercepted by THAAD anti-ballistic missile system, just as they re-enter the atmosphere. The final layer of defense is the Patriot PAC-3 missile.