MIM-104 Patriot
The MIM-104 Patriot is a mobile interceptor missile surface-to-air missile system, the primary such system used by the United States Army and several allied states. It is manufactured by the U.S. defense contractor Raytheon and derives its name from the radar component of the weapon system. The AN/MPQ-53 at the heart of the system is known as the "Phased Array Tracking Radar to Intercept on Target", which is a backronym for "Patriot". In 1984, the Patriot system began to replace the Nike Hercules system as the U.S. Army's primary high to medium air defense system and the MIM-23 Hawk system as the U.S. Army's medium tactical air defense system. In addition to defending against aircraft, Patriot is the U.S. Army's primary terminal-phase anti-ballistic missile system., the system is expected to stay fielded until at least 2040.
Patriot uses an advanced aerial interceptor missile and high-performance radar systems. Patriot was developed at Redstone Arsenal in Huntsville, Alabama, which had previously developed the Safeguard ABM system and its component Spartan and hypersonic Sprint missiles. The symbol for Patriot is a drawing of a Revolutionary War–era minuteman.
The MIM-104 Patriot has been widely exported. Patriot was one of the first tactical systems in the U.S. Department of Defense to employ lethal autonomy in combat. The system saw poor performance in the 1991 Gulf War, without any confirmed interceptions of Iraqi Scud missiles, but made successful intercepts in the 2003 Iraq War. It has also been used by Saudi and Emirati forces in the Yemen conflict against Houthi missiles. In August 2014 batteries first downed UAVs when Israeli Air Defense Command engaged two Hamas drones during Operation Protective Edge. In September 2014, Patriot first shot down a crewed aircraft, when an Israeli [|battery] intercepted a Syrian Air Force Sukhoi Su-24. Since 2023, Patriot systems have been used by Ukraine in the Russo-Ukrainian war, downing Russian Su-34 and Su-35 fighters, Mi-8 helicopters, and Kinzhal ballistic missiles.
Introduction
Prior to the Patriot, Raytheon was involved in a number of surface to air missile programs, including FABMDS, AADS-70 and SAM-D. In 1975, the SAM-D missile successfully engaged a drone at the White Sands Missile Range. In 1976, it was renamed the PATRIOT Air Defense Missile System. The MIM-104 Patriot combined several new technologies, including the MPQ-53 passive electronically scanned array radar and track-via-missile guidance.Full-scale development of the system began in 1976 and it was deployed in 1984. Patriot was used initially as an anti-aircraft system. In 1988, it received an upgrade providing limited capability against tactical ballistic missiles, designated PAC-1. The most recent upgrade by manufacturer Lockheed Martin, designated PAC-3, is a nearly total system redesign of the interceptor missiles, this time designed from the outset with the capability to engage and destroy tactical ballistic missiles. The Army plans to upgrade the Patriot system as part of the Integrated Air and Missile Defense system designed to tie into a broader air defense architecture using an Integrated Battle Command System.
Patriot equipment
The Patriot system has four major operational functions: communications, command and control, radar surveillance, and missile guidance. The four functions combine to provide a coordinated, secure, integrated, mobile air defense system.The Patriot system is modular and highly mobile. A battery-sized element can be installed in less than an hour. All components, consisting of the fire control section and launchers, are truck- or trailer-mounted. The radar set and launchers are mounted on M860 semi-trailers, which are towed by Oshkosh M983 HEMTTs.
Missile reloading is accomplished using a M985 HEMTT truck with a Hiab crane on the back. This crane is larger than the standard Grove cranes found on regular M977 HEMTT and M985 HEMTT cargo body trucks. The crane truck, known as a Guided Missile Transporter, removes spent missile canisters from the launcher and replaces them with fresh missiles. Because the crane nearly doubles the height of the HEMTT when not stowed, crews informally refer to it as the "scorpion tail". A standard M977 HEMTT with a regular-sized crane is sometimes referred to as the Large Repair Parts Transporter.
The heart of the Patriot battery is the fire control section, consisting of the AN/MPQ-53 or −65/65A Radar Set, the AN/MSQ-104 or −132 Engagement Control Station, the OE-349 Antenna Mast Group, and the EPP-III Electric Power Plant. The system's missiles are transported on and launched from either the M901 Launching Station, which can carry up to four PAC-2 missiles; the M902 LS, with sixteen PAC-3 missiles; or the M903 LS, which can be configured to carry PAC-2, PAC-3, and MSE/SkyCeptor missiles in various combinations. A Patriot battalion is also equipped with the Information Coordination Central, a command station designed to coordinate the launches of a battalion and uplink Patriot to the JTIDS or MIDS network.
AN/MPQ-53, -65 and -65A Radar Set
The AN/MPQ-53/65 Radar Set is a passive electronically scanned array radar equipped with IFF, electronic counter-countermeasure, and track-via-missile guidance subsystems.The AN/MPQ-53 Radar Set supports PAC-2 units, while the AN/MPQ-65 Radar Set supports PAC-2 and PAC-3 units. The main difference between these two radars is the addition of a second travelling-wave tube, which gives the −65 radar increased search, detection, and tracking capability. The radar antenna array consists of over 5,000 elements that "deflect" the radar beam many times per second.
The radar antenna array contains an IFF interrogator subsystem, a TVM array, and at least one "sidelobe canceller", which is a small array designed to decrease interference that might affect the radar. Patriot's radar is somewhat unusual in that it is a "detection-to-kill" system, meaning that a single unit performs all search, identification, track, and engagement functions. Most other SAM systems, by contrast, require several different radars to perform all functions necessary to detect and engage targets.
The beam created by the Patriot's flat phased array radar is comparatively narrow and highly agile compared to that of a moving dish. This characteristic gives the radar the ability to detect small, fast targets like ballistic missiles, or low radar cross-section targets such as stealth aircraft or cruise missiles. The power and agility of Patriot's radar is also highly resistant to countermeasures, including ECM, radar jamming, and use of RWR equipment. Patriot is capable of quickly changing frequencies to resist jamming. However, the radar can suffer from "blind spots".
The Army is planning upgrades to the Patriot system's radar components, including a new digital processor that replaces the one used since the system's introduction. In 2017, the Patriot got a new AN/MPQ-65A active electronically scanned array radar that has greater range and sharper discrimination. The main gallium nitride -based AESA array measures, is a bolt-on replacement for the current antenna, and is oriented toward the primary threat; two new rear panel arrays are a quarter the size of the main array and let the system look behind and to the sides, providing 360-degree coverage. The GaN AESA radar also has up to 50 percent less maintenance costs. Instead of shining a single transmitter through many lenses, the GaN array uses many smaller transmitters, each with its own control, increasing flexibility and allowing it to work even if some transmitters do not.
In October 2017, the Army announced Raytheon's Lower-Tier Air and Missile Defense System radar had been selected as the Patriot system's new radar. Unlike the previous radar which could only watch one part of the sky at a time primarily to detect ballistic missiles, the LTAMDS has 360-degree coverage to detect low flying and maneuvering drones and cruise missiles. The design has one large main array flanked by two smaller arrays, with the main panel still focused on high-altitude threats and the side panels, which are half the size with twice the power of the previous radar set, able to detect slower threats from considerable distance. Raytheon was awarded a million contract to build the first six radars to enter service in 2022.
AN/MSQ-104 and -132 Engagement Control Station
The AN/MSQ-104 or AN/MSQ-132 Engagement Control Station is the nerve center of the Patriot firing battery, costing approximately million per unit. The ECS consists of a shelter mounted on the bed of an M927 5-Ton Cargo Truck or on the bed of a Light Medium Tactical Vehicle cargo truck. The main subcomponents of the ECS are the Weapons Control Computer, the Data Link Terminal, the UHF communications array, the Routing Logic Radio Interface Unit, and the two-person stations that serve as the system's human machine interface. The ECS is air conditioned, pressurized, and shielded against electromagnetic pulse or other such electromagnetic interference. The ECS also contains several SINCGARS radios to facilitate voice communications.The WCC is the main computer within the Patriot system. This computer controls the operator interface, calculates missile intercept algorithms, and provides limited fault diagnostics. It was designed as a 24-bit parallel militarized computer with fixed- and floating-point capability, organized in a multiprocessor configuration that operates at a maximum clock rate of. Compared to modern personal computers, this represents very limited processing power, so the computer has been upgraded several times during Patriot's service life. The latest variant fielded in 2013 has performance improved by several orders of magnitude.
The DLT connects the ECS to Patriot's Launching Stations. It uses either a SINCGARS radio or fiber optic cables to transmit encrypted data between the ECS and the launchers. Through the DLT, the system operators can remotely emplace, slew or stow launchers, perform diagnostics on launchers or missiles, and fire missiles.
The UHF communications array consists of three UHF radio "stacks" and their associated patching and encrypting equipment. These radios are connected to the antennas of the OE-349 Antenna Mast Group, which are used to create UHF "shots" between sister Patriot batteries and their associated ICC. This creates a secure, real-time data network that allows the ICC to centralize control of its subordinate firing batteries.
The RLRIU functions as the primary router for all data coming into the ECS. The RLRIU gives a firing battery an address on the battalion data network, and sends/receives data from across the battalion. It also "translates" data coming from the WCC to the DLT, facilitating communication with the launchers.
Patriot's crew stations are referred to as Manstation 1 and 3. These are the stations where Patriot operators interface with the system. The manstations consist of a monochrome screen surrounded by various Switch Indicators. Each manstation also has a traditional QWERTY keyboard and isometric stick, a tiny joystick that functions much like a PC mouse. It is through these switch indicators and the Patriot user interface software that the system is operated. With newer upgrades, the operator's monochrome screen and physical switches have been replaced with two touchscreen LCDs and a standard keyboard/mouse at both stations.