An In-depth Look At The Raytheon’s MIM-104 Patriot Missile Defense System

Raytheon’s Global Patriot Solutions is a missile defense system consisting of radars, command-and-control technology and multiple types of interceptors, all working together to detect, identify and defeat tactical ballistic missiles, cruise missiles, drones, advanced aircraft and other threats. Patriot is the foundation of integrated air and missile defense for 17 nations.

Source Raytheon.

Patriot System

The Patriot missile system uses its ground-based radar to find, identify and track the targets. An incoming missile is detected by the phased array radar when the Patriot’s radar locks onto it. It is even possible for the Patriot missile system to operate in a completely automatic mode with no human intervention at all. An incoming missile flying at Mach 5 is traveling approximately one mile every second. There just isn’t a lot of time to react and respond once the missile is detected, making automatic detection and launching an important feature.

The Patriot missiles are launched from Patriot missile batteries based on the ground. A typical battery has five components:

  • The missiles canisters (MIM-104)
  • The missile launcher, which holds, transports, aims and launches the missiles (M-901).
  • A radar antenna (MPQ-53 or MPQ-65) to detect incoming missiles.
  • An equipment truck known as the Engagement Control Station (ECS) houses computers and consoles to control the battery. (MSQ-104)
  • A power plant truck equipped with two 150-kilowatt generators that provide power for the radar antenna and the ECS.
  • The missiles are fired from the M901 Launching station mounted on the back of the M983 Heavy Expanded Mobility Truck. A Patriot missile battery can have up to 16 launchers.

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The Patriot Missile

A Patriot missile is a single-stage solid rocket that currently comes in two forms. There is the older PAC-2 missile, which is larger and not as effective as the newer PAC-3 missile deployed since 2002.

Courtesy: Raytheon

The PAC-2 missile

The main difference between the PAC-2 and the PAC-3 is that the PAC-3 has a radar transmitter and guidance computer onboard the missile casing and uses hit-to-kill technology, directly hitting the targeted missile with a small warhead.

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The PAC-2s, on the other hand, explode near the target to either knock it off its course or explode it.

  • is 17 feet long (5.2 meters)
  • is 16 inches (41 centimeters) in diameter
  • has fins that extend out another 16 inches (41 centimeters)
  • weighs almost 2,000 pounds (900 kilograms)
  • carries a 200-pound (90-kilogram) fragmentation bomb with a proximity fuse
  • flies at Mach 5 and is supersonic within a second after launch
  • They have a maximum speed of Mach 5, a maximum range of 9 to 28 miles, depending on the target, and a maximum altitude of 6 to 9 miles.

The idea is for the PAC-2 to fly straight toward the incoming missile and then explode at the point of nearest approach. The explosion will either destroy the incoming missile with the fragments from the fragmentation bomb, or knock the incoming missile off course so it misses the target.

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The PAC-3 missile is the same length as the PAC-2 but weighs only a third as much at 686 pounds (312 kilograms). It is only 10 inches (25 centimeters) in diameter. The smaller size means that 16 PAC-3 missiles can fit on a launcher. The fragmentation warhead weighs only 160 pounds (73 kilograms) in the PAC-3.

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The idea behind a PAC-3 is for the missile to actually hit the incoming target and explode so that the incoming missile is completely destroyed. This feature makes it more effective against chemical and biological warheads because they are destroyed well away from the target. A PAC-3 missiles currently cost $2 to $3 million each.

Typically two missiles are fired at a target, but four would have to be fired at a broken-up Scud to insure that at least two attacked the warhead section. The fire unit’s radars generally detected Scuds at about 70 miles, and the unit engaged at 10-20 miles. Alerts were often provided by satellites (DSPs) originally launched to detect Soviet missiles, and the time from alert to engagement was typically 6-7 minutes. The time from engagement to the destruction of the missile was typically 15-18 seconds; the Patriots and the Scud closed at 2,000 to 4,000 ft/sec.”

Desert Victory: The War for Kuwait” by Norman Friedman, Naval Institute Press, 1991

GEM-T Missile

The Guidance Enhanced Missile, or GEM-T, is one of the highly successful Raytheon Patriot missile variants available to both U.S. forces and international customers.

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The GEM-T missile provides improved ability to defeat tactical ballistic missiles, also known as TBMs, aircraft or cruise missiles in complement to the PAC-3 missile.

A modernized, digital fuze eliminates obsolescence and introduces significant performance improvements against TBM targets. This design increases sensitivity for improved performance against high-speed TBM targets. The low-noise front end of the GEM-T has increased seeker sensitivity for better acquisition and tracking. The new low-noise oscillator has a modified down-link, which provides a higher signal-to-interference ratio, improving acquisition and tracking of small airborne threats and cruise missiles in clutter.

The Configuration-3 ground equipment, PAC-3 and GEM-T series of missiles were proven in combat during Operation Iraqi Freedom. 

The PAC-2, PAC-3 and GEM-T can be fired from the same patriot missile batteries with no modification to the MIM Patriot batteries.

Upgrade Program

In 1995, 1996 and 2000, the Patriot underwent three stages of major upgrades known as the PAC-3 configuration to increase its anti-ballistic missile capability. The Patriot got multiple system and software improvements, a new radar and a new missile almost fully designed to engage ballistic targets, the PAC-3.

According to a 2005 report by Office of the US Under Secretary of Defense For Acquisition, Technology, and Logistics, Patriot PAC-3, GEM, and GEM+ missiles demonstrated a high success rate engaging 9 hostile ballistic missiles. The report described 8 of them as successful. The ninth engagement was declared as a “probable success”.


The AN/MPQ-53 phased-array radar carries out search, target detection, track and identification, missile tracking and guidance and electronic counter-countermeasure (ECCM) functions. The radar is mounted on a trailer and is automatically controlled by the digital weapons control computer in the engagement control station, via a cable link. The radar system has a range of up to 100km, the capacity to track up to 100 targets and can provide missile guidance data for up to nine missiles.

A target engagement can be carried out in manual, semi-automatic or automatic mode. When the decision has been made to engage the target, the engagement control station selects the launch station or stations and pre-launch data is transmitted to the selected missile. After launch, the Patriot missile is acquired by the radar.

Each Patriot missile battery has one high-power radar antenna that plays a variety of roles. The antenna can:

  • scan the skies for incoming targets
  • detect a potential target
  • determine the trajectory, speed and heading of the incoming target
  • provide information to identify the target. Ideally, the radar provides enough information to determine whether the target is a friend or a foe.
  • track Patriot missiles once they are launched to help aim them at the target
  • illuminate the target, which is important to the Track-via-Missile guidance system used by the PAC-2 missiles
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The traditional image of a radar antenna is the rotating, parabolic antenna seen on top of airport control towers and aircraft carriers. The Patriot system instead uses a phased array antenna. This antenna contains 5,000 phase-shifting elements that allow the antenna to send out multiple, narrow, precisely aimed radar beams that scan the sky. With these beams, the Patriot’s radar can track up to 100 potential targets as well as up to nine outbound Patriot missiles. The radar antenna has a 63-mile (100-kilometer) range.

The ECS van is the command center of the Patriot missile battery. The ECS contains stations for three operators, as well as the computers that control the battery. The radar antenna and all of the launchers in the battery connect to the ECS, and Patriot missiles in flight also communicate with the ECS.

Inside the van there are two radar consoles. Operators can see the status of all of the targets that the system is currently tracking. Operators can let the system run in fully automatic mode, or they can intervene to select or deselect targets. There is also a communication station that allows the battery to communicate with other batteries or with the command center for the region.

The radar antenna scans the sky looking for incoming targets. Once it finds a target, it scans it more intensely and communicates with the ECS. The goal of the scan is to determine the speed and heading of the target and also to identify it as a friend or a foe. When the operator or computer decides that it has an incoming foe, the ECS calculates an initial heading for the Patriot missile. It chooses the Patriot missile it will launch, downloads the initial guidance information to that missile and launches it.

Within three seconds the missile is traveling at Mach 5 and is headed in the general direction of the target. The radar antenna on the ground has three roles at this point:

  • It continues to track the incoming missile.
  • It acquires and tracks the outbound Patriot missile to provide the ECS with information on its heading and speed.
  • It illuminates the incoming target.

The illumination signal reflects off the target and is received by an antenna in the nose of the PAC-2 missile that is heading its way. The PAC-2 missile then relays this signal back to the ECS. The ECS uses the illumination signal information along with the radar’s information on the track of the incoming target and outbound Patriot to steer the Patriot missile. The ECS sends guidance commands to the Patriot missile to adjust its course. When the Patriot missile is at the point of closest approach to the target, its fragmentation bomb explodes.

Building PAC-4 Variant

In August 2013, Raytheon and Rafael Advanced Defense Systems began to seek funding for a fourth-generation Patriot intercepting system, called the Patriot Advanced Affordable Capability-4 (PAAC-4). The system aims to integrate the Stunner interceptor from the jointly-funded David’s Sling program with Patriot PAC-3 radars, launchers, and engagement control stations. The two-stage, multimode seeking Stunner would replace single-stage, radar-guided PAC-3 missiles produced by Lockheed Martin. Government and industry sources claim the Stunner-based PAAC-4 interceptors will offer improved operational performance at 20 percent of the $2 million unit cost of the Lockheed-built PAC-3 missiles. The companies are seeking $20 million in U.S. government funding to demonstrate cost and performance claims through a prototype PAAC-4 system. Israeli program officials have said that a previous teaming agreement between Raytheon and Rafael would allow the U.S. company to assume prime contractor status, and produce at least 60 percent of the Stunner missile in the United States. The Missile Defense Agency has said that the U.S. Army is considering use of the Stunner as a potential solution to future U.S. military requirements.

Operational History

Since January of 2015, Patriot has intercepted more than 150 ballistic missiles in combat operations around the world; more than 90 of those intercepts involved the low-cost Raytheon-made Guidance Enhanced Missile family of surface-to-air missiles.

Those engagements were possible because Patriot is built on a foundation of more than 3,000 ground tests and over 1,400 flight tests.

Israel’s military said on Tuesday June 24 2018 that it fired two US-made Patriot missiles at and “intercepted” a Syrian Sukhoi fighter that entered its airspace.

The plane crashed in Syria near the country’s border zone with Israel, and the fate of the pilot is unknown, according to The New York Times. The Syrian jet is thought to be a Russian-made Su-24 or Su-22.

Patriot was deployed to Iraq a second time in 2003, this time to provide air and missile defense for the forces conducting Operation Iraqi Freedom (OIF). Patriot PAC-3, GEM, and GEM+ missiles both had a very high success rate, intercepting Al-Samoud 2 and Ababil-100 tactical ballistic missiles.


Raytheon has built more than 220 Patriot fire units and delivered them to customers in 17 nations. Many of those countries have chosen to take advantage of Patriot’s flexible architecture and upgrade their systems. 

That translates into global interoperability. Countries with Patriot can – and do – train together.  And if need be, they can operate together in combat. 

The US State Department has approved a possible foreign military sale of the Patriot air and missile defence system to Turkey for an estimated total of $3.5 billion, the Pentagon said on Tuesday.

According to the Defense Security Cooperation Agency, the department approved the sale of 80 Patriot MIM-104E Guidance Enhanced Missiles (GEM-T) missiles, 60 PAC-3 Missile Segment Enhancement (MSE) missiles and associated equipment.

“The proposed sale will increase the defensive capabilities of the Turkey military to guard against hostile aggression and shield NATO Allies who might train and operate within Turkey’s borders. Turkey should have no difficulty absorbing this system into its armed forces,” said the agency

The current operators include USA, Saudi Arabia, United Arab Emirate, Israel, Germany, Netherlands, Egypt, Japan, Kuwait, Jordan, Taiwan, Spain, South Korea, Qatar.

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