The MIM-104 Patriot surface-to-air missile defense system serves as the backbone of the US Army's missile defense, capable of engaging hostile aircraft, ballistic cruise missiles and loitering munitions.

The MIM-104 Patriot (an acronym for Phased Array Tracking Radar to Intercept on Target) entered service in the early 1980s.

The system is built around the AN/MPQ-53, a phased-array radar system that can track, identify and engage high volumes of targets with a range exceeding 100km. It marries surveillance, tracking and engagement into a single unit to simplify operations.

Patriot systems come in fully mobile batteries that include a command center, a radar station to detect incoming threats, and launchers.

They are capable of operating nearly autonomously, requiring human interaction only for the final launch system.

The Patriot replaced the Nike Hercules as the US Army's primary high-to-medium air defense (HIMAD) system as well as the mobile medium-range surface-to-air MIM-23 Hawk missile.

The Iranian air force still manufactures and relies on a modified air-to-air version of the MIM-23 Hawk missile known as the Sedjil.

Upgrades

The Patriot system is popular among US partners and allies for its reliability and unparalleled capabilities.

Patriots are operated or being purchased by the Netherlands, Germany, Japan, Israel, Saudi Arabia, Kuwait, Taiwan, Greece, Spain, South Korea, the United Arab Emirates, Qatar, Romania, Sweden, Poland and Bahrain.

The system has seen several upgrades over the years.

The PAC-3 Missile Segment Enhancement (PAC-3 MSE), fielded in 2015, features larger, dual pulse solid rocket motors; larger fins; and upgraded actuators and thermal batteries to achieve greater speeds and maneuverability for defeating more-advanced ballistic and cruise missiles.

The PAC-3 MSE can engage targets at altitudes of up to 15km and ranges of 35km.

Each launcher can carry 12 PAC-3 MSEs.

Meanwhile, the Lower Tier Air and Missile Defense Sensor (LTAMDS) is a next generation missile defense radar expected to replace the original AN/MPQ-53 radar system.

It provides 360-degree protection against ballistic missiles, cruise missiles, manned and unmanned aircraft and hypersonics.

During a live-fire demonstration of the LTAMDS in March, the sensor tracked a cruise missile surrogate flying at high altitude and speed before relaying the data to an Integrated Battle Command System and guiding a Patriot missile to intercept the target.