The PAC-3 upgrade is a significant upgrade to nearly every aspect of the system.
It took place in three stages deployed in 1995, 1996 and 2000, and units were designated Configuration 1, 2, or 3.

The system itself saw another upgrade of its WCC and its software, and the communication setup was given a complete overhaul.
Due to this upgrade, PAC-3 operators can now see, transmit, and receive tracks on the Link 16 Command and Control (C2) network using a Class 2M Terminal or MIDS LVT Radio.
This capability greatly increases the situational awareness of Patriot crews and other participants on the Link 16 network that are able to receive the Patriot local air picture.
The software can now conduct a tailored TBM search, optimizing radar resources for search in a particular sector known to have ballistic missile activity, and can also support a "keepout altitude" to ensure ballistic missiles with chemical warheads or early release submunitions (ERS) are destroyed at a certain altitude.
For Configuration 3 units, the Patriot radar was completely redesigned, adding another travelling wave tube (TWT) that increased the radar's search, detection, tracking, and discrimination abilities.
The PAC-3 radar is capable, among other things, of discriminating whether or not an aircraft is manned and which of multiple reentering ballistic objects are carrying ordnance.

The PAC-3 upgrade carried with it a new missile design, nominally known as MIM-104F and called PAC-3 by the Army.
The PAC-3 missile evolved from the Strategic Defense Initiative's ERINT missile, and so it is dedicated almost entirely to the anti-ballistic missile mission.
Due to miniaturization, a single canister can hold four PAC-3 missiles (as opposed to one PAC-2 missile per canister).
The PAC-3 missile is also more maneuverable than previous variants, due to 180 tiny pulse solid propellant rocket motors mounted in the forebody of the missile (called Attitude Control Motors, or ACMs) which serve to fine align the missile trajectory with its target to achieve hit-to-kill capability.
However, the most significant upgrade to the PAC-3 missile is the addition of a Kₐ band active radar seeker.
This allows the missile to drop its uplink to the system and acquire its target itself in the terminal phase of its intercept, which improves the reaction time of the missile against a fast-moving ballistic missile target.
The PAC-3 missile is accurate enough to select, target, and home in on the warhead portion of an inbound ballistic missile.
The active radar also gives the warhead a "hit-to-kill" (kinetic kill vehicle) capability that completely eliminates the need for a traditional proximity-fused warhead.
However, the missile still has a small explosive warhead, called Lethality Enhancer, a warhead which launches 24 low-speed tungsten fragments in radial direction to make the missile cross-section greater and enhance the kill probability.
This greatly increases the lethality against ballistic missiles of all types.

The PAC-3 upgrade has effectively quintupled the "footprint" that a Patriot unit can defend against ballistic missiles of all types, and has considerably increased the system's lethality and effectiveness against ballistic missiles.
It has also increased the scope of ballistic missiles that Patriot can engage, which now includes several intermediate range.
However, despite its increases in ballistic missile defense capabilities, the PAC-3 missile is a less capable interceptor of atmospheric aircraft and air-to-surface missiles.
It is slower, has a shorter range, and has a smaller explosive warhead compared to older Patriot missiles.

Patriot's PAC-3 interceptor is the primary interceptor for the new MEADS system, which was scheduled to enter service alongside Patriot in 2014.
On November 29, 2012, the MEADS detected, tracked, intercepted and destroyed an air-breathing target in its first-ever intercept flight test at White Sands Missile Range, New Mexico.

Lockheed Martin Missiles and Fire Control is the prime contractor on the PAC-3 Missile Segment upgrade to the Patriot ai
The PAC-3 upgrade is a significant upgrade to nearly every aspect of the system. It took place in three stages deployed in 1995, 1996 and 2000, and units were designated Configuration 1, 2, or 3.
The system itself saw another upgrade of its WCC and its software, and the communication setup was given a complete overhaul. Due to this upgrade, PAC-3 operators can now see, transmit, and receive tracks on the Link 16 Command and Control (C2) network using a Class 2M Terminal or MIDS LVT Radio. This capability greatly increases the situational awareness of Patriot crews and other participants on the Link 16 network that are able to receive the Patriot local air picture. The software can now conduct a tailored TBM search, optimizing radar resources for search in a particular sector known to have ballistic missile activity, and can also support a "keepout altitude" to ensure ballistic missiles with chemical warheads or early release submunitions (ERS) are destroyed at a certain altitude. For Configuration 3 units, the Patriot radar was completely redesigned, adding another travelling wave tube (TWT) that increased the radar's search, detection, tracking, and discrimination abilities. The PAC-3 radar is capable, among other things, of discriminating whether or not an aircraft is manned and which of multiple reentering ballistic objects are carrying ordnance.
The PAC-3 upgrade carried with it a new missile design, nominally known as MIM-104F and called PAC-3 by the Army. The PAC-3 missile evolved from the Strategic Defense Initiative's ERINT missile, and so it is dedicated almost entirely to the anti-ballistic missile mission. Due to miniaturization, a single canister can hold four PAC-3 missiles (as opposed to one PAC-2 missile per canister). The PAC-3 missile is also more maneuverable than previous variants, due to 180 tiny pulse solid propellant rocket motors mounted in the forebody of the missile (called Attitude Control Motors, or ACMs) which serve to fine align the missile trajectory with its target to achieve hit-to-kill capability. However, the most significant upgrade to the PAC-3 missile is the addition of a Kₐ band active radar seeker. This allows the missile to drop its uplink to the system and acquire its target itself in the terminal phase of its intercept, which improves the reaction time of the missile against a fast-moving ballistic missile target. The PAC-3 missile is accurate enough to select, target, and home in on the warhead portion of an inbound ballistic missile. The active radar also gives the warhead a "hit-to-kill" (kinetic kill vehicle) capability that completely eliminates the need for a traditional proximity-fused warhead. However, the missile still has a small explosive warhead, called Lethality Enhancer, a warhead which launches 24 low-speed tungsten fragments in radial direction to make the missile cross-section greater and enhance the kill probability. This greatly increases the lethality against ballistic missiles of all types.
The PAC-3 upgrade has effectively quintupled the "footprint" that a Patriot unit can defend against ballistic missiles of all types, and has considerably increased the system's lethality and effectiveness against ballistic missiles. It has also increased the scope of ballistic missiles that Patriot can engage, which now includes several intermediate range. However, despite its increases in ballistic missile defense capabilities, the PAC-3 missile is a less capable interceptor of atmospheric aircraft and air-to-surface missiles. It is slower, has a shorter range, and has a smaller explosive warhead compared to older Patriot missiles.
Patriot's PAC-3 interceptor is the primary interceptor for the new MEADS system, which was scheduled to enter service alongside Patriot in 2014. On November 29, 2012, the MEADS detected, tracked, intercepted and destroyed an air-breathing target in its first-ever intercept flight test at White Sands Missile Range, New Mexico.
Lockheed Martin Missiles and Fire Control is the prime contractor on the PAC-3 Missile Segment upgrade to the Patriot ai
MIM-104 Patriot