Editing MIM-104 Patriot (section)

==Introduction==
Prior to the Patriot, Raytheon was involved in a number of surface to air missile programs, including FABMDS (Field Army Ballistic Missile Defense System), AADS-70 (Army Air-Defense System – 1970) and SAM-D (Surface-to-Air Missile – Development).<ref>{{cite book|last=Delaney|first=William P.|title=Perspectives on Defense Systems Analysis|url=https://books.google.com/books?id=S7K2CAAAQBAJ&pg=PA64|year=2015|publisher=MIT Press|isbn=978-0-262-02935-3|page=64}}</ref> 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 (Mobile Interceptor Missile 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.<ref name=":0" /> Patriot was used initially as an anti-aircraft system. In 1988, it received an upgrade providing limited capability against [[tactical ballistic missile]]s (TBM), designated PAC-1 (Patriot Advanced Capability 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.<ref>{{cite news|url=https://missilethreat.csis.org/system/patriot/|title=CSIS Missile Threat Defense Project: Patriot|author=CSIS|access-date=October 3, 2024}}</ref> The Army plans to upgrade the Patriot system as part of the [[Integrated Air and Missile Defense]] system which will be designed to tie into a broader air defense architecture using an Integrated Battle Command System (IBCS).<ref name="DefNews4924" />

===Patriot equipment===
[[File:Soldiers from the 31st Air Defense Artillery Brigade at work.jpg|thumb|left|Soldiers from the 31st Air Defense Artillery Brigade conducting reload from a Guided Missile Transporter (GMT)]]
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 [[#Patriot battalion|battery]]-sized element can be installed in less than an hour. All components, consisting of the fire control section (radar set, engagement control station, antenna mast group, electric power plant) and launchers, are truck- or trailer-mounted. The radar set and launchers (with missiles) are mounted on M860 semi-trailers, which are towed by [[Oshkosh Corporation|Oshkosh]] M983 [[Heavy Expanded Mobility Tactical Truck|HEMTTs]].

[[File:Operator in de ICC (Information Coordination Central center) van een Nederlandse Patriot-batterij bij Brakstadt in Noorwegen (2009 D040309-C1204).jpg|thumb|right|An operator in the Information Coordination Central (ICC) monitors the actions of the battery via his display]]
Missile reloading is accomplished using a [[Heavy Expanded Mobility Tactical Truck|M985 HEMTT]] truck with a Hiab crane on the back. This crane is larger than the standard Grove cranes found on regular [[Heavy Expanded Mobility Tactical Truck|M977 HEMTT]] and M985 HEMTT cargo body trucks. The crane truck, known as a Guided Missile Transporter (GMT), 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 (LRPT).{{citation needed|date=December 2022}}

The heart of the Patriot battery is the fire control section, consisting of the AN/MPQ-53 or −65/65A Radar Set (RS), the AN/MSQ-104 or −132 Engagement Control Station (ECS), the OE-349 Antenna Mast Group (AMG), and the EPP-III Electric Power Plant (EPP). The system's missiles are transported on and launched from either the M901 Launching Station (LS), 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 (ICC), a command station designed to coordinate the launches of a battalion and uplink Patriot to the [[Joint Tactical Information Distribution System|JTIDS]] or [[Multifunctional Information Distribution System|MIDS]] network.{{citation needed|date=December 2022}}

====AN/MPQ-53, -65 and -65A Radar Set====
The AN/MPQ-53/65 Radar Set is a [[passive electronically scanned array]] radar equipped with [[Identification friend or foe|IFF]], electronic counter-countermeasure (ECCM), and [[track-via-missile]] (TVM) 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]] (TWT), 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" (SLC), 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.

[[File:JASDF Patriot RS(RadarSet) tsuiki 20121028 113836.jpg|thumb|A detailed view of an AN/MPQ-53 Radar Set]]
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 missile]]s. The power and agility of Patriot's radar is also highly resistant to countermeasures, including [[electronic countermeasures|ECM]], radar jamming, and use of [[radar warning receiver|RWR]] equipment. Patriot is capable of quickly changing frequencies to resist jamming. However, the radar can suffer from "blind spots."<ref name="DefNews4924" />

[[File:Raytheons GaN-based AESA Radar Prototype.jpg|thumb|An AN/MPQ-65A AESA radar set]]
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]] (AESA) radar that has greater range and sharper discrimination.<ref>{{cite web |url=http://breakingdefense.com/2015/08/army-missile-defense-must-step-up-its-game-heidi-shyu/ |first=Sydney J. Jr. |last=Freedberg |title=Army Missile Defense Must Step Up Its Game: Heidi Shyu |website=Breaking Defense.com |date=August 12, 2015 |access-date=January 5, 2018 |archive-url=https://web.archive.org/web/20180106120132/https://breakingdefense.com/2015/08/army-missile-defense-must-step-up-its-game-heidi-shyu/ |archive-date=January 6, 2018 |url-status=live }}</ref><ref>{{cite web |url=https://www.youtube.com/watch?v=ix4kse6ZRBo |title=Patriot GaN-Based AESA |author=Raytheon Technologies |date=March 10, 2016 |website=YouTube |access-date=April 4, 2023 |archive-url=https://web.archive.org/web/20161103044720/https://www.youtube.com/watch?v=ix4kse6ZRBo|archive-date=November 3, 2016 |url-status=live}}</ref> The main [[gallium nitride]] (GaN)-based AESA array measures {{convert|9|x|13|ft|m|abbr=on}}, 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.<ref>{{cite news|author=<!--not stated--> |title=New Raytheon radar showcases reliability, 360-degree capability |url=https://www.prnewswire.com/news-releases/new-raytheon-radar-showcases-reliability-360-degree-capability-300462177.html |agency=PRNewswire|work=Raytheon Company| date=May 23, 2017|access-date=2023-04-05}}</ref><ref>{{cite news|author=<!--not stated--> |title=Future drones, planes, missiles no match for new Raytheon radar|url=https://www.prnewswire.com/news-releases/future-drones-planes-missiles-no-match-for-new-raytheon-radar-300213373.html|agency=PRNewswire|work=Raytheon Company| date=February 2, 2016|access-date=2023-04-04}}</ref> The GaN AESA radar also has up to 50 percent less maintenance costs.<ref>{{Cite press release |title=AESA radar with 360-degrees coverage moves toward production readiness |url=https://www.prnewswire.com/news-releases/aesa-radar-with-360-degrees-coverage-moves-toward-production-readiness-300158463.html |language=en |last= |first= |access-date=2024-08-29 |website=PR Newswire}}</ref> 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.<ref name="armytimes15march16"/>

In October 2017, the Army announced Raytheon's Lower-Tier Air and Missile Defense System (LTAMDS) 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.<ref name="DefNews4924" /> 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 {{US$|383}}{{nbsp}}million contract to build the first six radars to enter service in 2022.<ref>[https://breakingdefense.com/2019/10/ltamds-raytheon-to-build-linchpin-of-army-air-missile-defense/ LTAMDS: Raytheon To Build Linchpin Of Army Air & Missile Defense]. ''Breaking Defense''. October 17, 2019.</ref>

====AN/MSQ-104 and -132 Engagement Control Station====
[[File:JASDF MIM-104 Patriot PAC-3 Engagement Control Station(Mitsubishi Fuso Super Great) at Nara Base 20150606-01.JPG|thumb|An AN/MSQ-132 ECS vehicle of a Japanese Patriot unit]]
[[File:Communicatiesysteem-van-de-patriot.jpg|thumb|Operator stations (pre-PDB 7)]]
The AN/MSQ-104 or AN/MSQ-132 Engagement Control Station (ECS) is the nerve center of the Patriot firing battery, costing approximately {{US$|6}}{{nbsp}}million per unit.<ref>{{cite web |title=Harpoon database encyclopedia |url=http://www.harpoondatabases.com/encyclopedia/entry1493.aspx |access-date=October 5, 2012 |url-status=dead |archive-url=https://web.archive.org/web/20140730051438/http://www.harpoondatabases.com/encyclopedia/entry1493.aspx |archive-date=July 30, 2014 }} (a database for the computer game [[Harpoon (series)|Harpoon]])</ref>{{Unreliable source?|date=September 2014}} The ECS consists of a shelter mounted on the bed of an [[M939 Truck#Models|M927 5-Ton Cargo Truck]] or on the bed of a [[Light Medium Tactical Vehicle]] (LMTV) cargo truck. The main subcomponents of the ECS are the Weapons Control Computer (WCC), the Data Link Terminal (DLT), the [[Ultra high frequency|UHF]] communications array, the Routing Logic Radio Interface Unit (RLRIU), and the two-person stations that serve as the system's human machine interface. The ECS is air conditioned, pressurized (to resist chemical/biological attack), and shielded against [[electromagnetic pulse]] (EMP) 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 {{frequency|6|MHz}}. 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 (known as PADIL, Patriot Data Information Link) that allows the ICC to centralize control of its subordinate firing batteries.

The RLRIU functions as the primary [[Router (computing)|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 (MS1 and MS3). These are the stations where Patriot operators interface with the system. The manstations consist of a monochrome (green and black) 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 [[Personal computer|PC]] [[Mouse (computing)|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 {{convert|30|in|abbr=on}} touchscreen LCDs and a standard keyboard/mouse at both stations.{{citation needed|date=December 2022}}

====OE-349 Antenna Mast Group====
[[File:JASDF Patriot AMG(AntennaMastGroup) ashiya 20161009 100600.jpg|thumb|upright|OE-349/MRC Antenna Mast Group]]
The OE-349 Antenna Mast Group (AMG) is mounted on an M927 5-Ton Cargo Truck. It includes four 4&nbsp;kW antennas in two pairs on remotely controlled masts. Emplacement of the AMG can have no greater than a 0.5-degree roll and a 10-degree crossroll. The antennas can be controlled in azimuth, and the masts can be elevated up to {{convert|100|ft|11|in|m|sp=us}} above ground level. Mounted at the base of each pair of antennas are two high-power amplifiers associated with the antennas and the radios in the co-located shelter.

It is through these antennas that the ECS and ICC send their respective UHF "shots" to create the PADIL network. The polarity of each shot can be changed by adjusting the "feedhorn" to a vertical or horizontal position. This enables a greater chance of communication shots reaching their intended target when terrain obstacles may otherwise obscure the signal.

====EPP-III Electric Power Plant====
[[File:JASDF MIM-104 Patriot PAC-2 Electric Power Plant(Nissan Diesel Big Thumb, 49-0182) left rear view at Kasuga Air Base November 25, 2017.jpg|thumb|left|EPP-III Electric Power Plant vehicle of JSDF]]
The EPP-III Diesel-Electric Power Plant (EPP) is the power source for the ECS and Radar. The EPP consists of two 150&nbsp;kilowatt diesel engines with 400&nbsp;hertz, 3-phase generators that are interconnected through the power distribution unit. The generators are mounted on a trailer or modified [[Heavy Expanded Mobility Tactical Truck|M977 HEMTT]]. Each EPP has two {{convert|100|USgal|L|adj=on}} fuel tanks and a fuel distribution assembly with grounding equipment. Each diesel engine can operate for more than eight hours with a full fuel tank. The EPP delivers its power to the Radar and ECS through cables stored in reels alongside the generators. It powers the AMG via a cable routed through the ECS.

====M901/902/903 Launching Station====
[[File:Ken H. MIM-104 Patriot(PAC-2 & PAC-3) (5092719479).jpg|thumb|upright|M901 (PAC-2) and M902 (PAC-3) Launching Stations]]
The M90x Launching Stations are remotely operated, self-contained units. The ECS controls operation of the launchers through each launcher's DLT, via fiber optic or VHF (SINCGARS) data link.

Integral levelling equipment permits emplacement on slopes of up to 10 degrees. Each launcher is trainable in azimuth and elevates to a fixed, elevated launch position. Precise aiming of the launcher before launch is not necessary; thus, no extra lags are introduced into system reaction time. Each launcher is capable of providing detailed diagnostics to the ECS via the data link.

The launching station contains four major equipment subsystems: the launcher generator set, the launcher electronics module (LEM), the launcher mechanics assembly (LMA), and the launcher interconnection group (LIG). The generator set consists of a 15&nbsp;kW, 400&nbsp;Hz generator that powers the launcher. The LEM is used for the real-time implementation of launcher operations requested via data link from the ECS. The LMA physically erects and rotates the launcher's platform and its missiles. The LIG connects the missiles themselves to the launcher via the Launcher Missile Round Distributor (LMRD).

====Patriot guided missile====
{{Infobox weapon
| name               = Patriot missile
| image              = Patriot missile launch b.jpg
| image_size         = 300
| caption            = Four Patriot PAC-2 or sixteen Patriot PAC-3 missiles can be fired from the highly mobile [[transporter erector launcher|TEL]]
| origin             = United States
| type               = [[Surface-to-air missile]]
<!-- Type selection -->| is_ranged          = 
| is_bladed          = 
| is_explosive       = 
| is_artillery       = 
| is_vehicle         = 
| is_missile         = yes
| is_UK              = yes
<!-- Service history -->| service            = 
| used_by            = <!-- Production history -->
| designer           = Raytheon
| design_date        = 
| manufacturer       = 
| unit_cost          = US$1 to 6 million<ref name="US Army Budget FY2011">{{cite web |url=http://asafm.army.mil/Documents/OfficeDocuments/Budget/BudgetMaterials/FY11//pbhl.pdf |title=US Army Budget FY2011 |date=February 2010 |website=[[Assistant Secretary of the Army (Financial Management and Comptroller)|Office of the ASA(FM&C)]] |access-date=April 6, 2010 |archive-url=https://web.archive.org/web/20170211060216/http://asafm.army.mil/Documents/OfficeDocuments/Budget/BudgetMaterials/FY11//pbhl.pdf |archive-date=February 11, 2017}}</ref>
| production_date    = 
| number             = over 10,000<ref name="Janes">{{cite web |url=http://www8.janes.com/Search/documentView.do?docId=/content1/janesdata/yb/jlad/jlad0244.htm |title=MIM-104 Patriot |date=August 12, 2008 |publisher=[[Jane's Information Group]] |access-date=August 26, 2008}} {{dead link|date=January 2018}}</ref>
| variants           = Standard, ASOJ/SOJC, PAC-2, PAC-2 GEM, GEM/C, GEM/T (or GEM+), PAC-3, PAC-3 MSE, PAAC-4 (SkyCeptor)
<!-- General specifications -->| spec_label         = See {{section link||Variants}}
| weight             = 
| length             = 
| part_length        = 
| width              = 
| height             = 
| diameter           = 
| crew               = <!-- Explosive specifications -->
| filling            = 
| filling_weight     = 
| detonation         = 
| yield              = <!-- Missile specifications -->
| armour             = 
| primary_armament   = 
| secondary_armament = 
| engine             = 
| engine_power       = 
| pw_ratio           = 
| transmission       = 
| payload_capacity   = 
| suspension         = 
| clearance          = 
| wingspan           = 
| propellant         = 
| fuel_capacity      = 
| vehicle_range      = 
| ceiling            = 
| altitude           = 
| boost              = 
| speed              = 
| steering           = 
| accuracy           = 
| launch_platform    = Mobile trainable round semi-trailer
| transport          = 
}}

The first fielded variant was the MIM-104A "Standard". It was optimized solely for engagements against aircraft and had very limited capability against ballistic missiles. It had a range of {{convert|70|km|mi|abbr=on}}, and a speed in excess of Mach 2. The MIM-104B "anti-standoff jammer" (ASOJ) is a missile designed to seek out and destroy [[Electronic countermeasures|ECM]] emitters.

The MIM-104C PAC-2 missile was the first Patriot missile that was optimized for ballistic missile engagements. The GEM series of missiles (MIM-104D/E) are further refinements of the PAC-2 missile. The PAC-3 missile is a new interceptor, featuring a Ka band active radar seeker, employing "hit-to-kill" interception, in contrast to previous interceptors' method of exploding in the vicinity of the target, destroying it with shrapnel, and several other enhancements which dramatically increase its lethality against ballistic missiles. The specific information for these different kinds of missiles are discussed in the "[[#Variants|Variants]]" section.

The first seven of these are in the larger PAC-2 configuration of a single missile per canister, of which four can be placed on a launcher. PAC-3 missile canisters contain four missiles, so that sixteen rounds can be placed on a launcher. The missile canister serves as both the shipping and storage container and the launch tube. Patriot missiles are referred to as "certified rounds" as they leave the factory, and additional maintenance is not necessary on the missile prior to it being launched.

The PAC-2 missile is {{convert|5.8|m|ftin}} long, weighs about {{convert|900|kg|lb}}, and is propelled by a solid-fueled rocket motor.

====Patriot missile design====
The PAC-2 family of missiles all have a fairly standard design, the only differences between the variants being certain internal components. They consist of (from front to rear) the [[radome]], guidance section, warhead section, propulsion section, and control actuator section.

The radome is made of slip cast fused silica approximately {{convert|16.5|mm}} thick, with a nickel alloy tip, and a composite base attachment ring bonded to the slip cast fused silica and protected by a molded silicone rubber ring. The radome provides an aerodynamic shape for the missile and [[microwave]] window and thermal protection for the [[Radio frequency|RF]] seeker and electronic components.

The Patriot guidance section consists primarily of the modular digital airborne guidance system (MDAGS). The MDAGS consists of a modular midcourse package that performs all of the required guidance functions from launch through midcourse and a terminal guidance section. The TVM seeker is mounted on the guidance section, extending into the radome.
The seeker consists of an antenna mounted on an inertial platform, antenna control electronics, a receiver, and a transmitter. The Modular Midcourse Package (MMP), which is located in the forward portion of the warhead section, consists of the navigational electronics and a missile-borne computer that computes the guidance and autopilot algorithms and provides steering commands according to a resident computer program.

The warhead section, just aft of the guidance section, contains the [[proximity fuze]]d warhead, safety-and-arming device, fuzing circuits and antennas, link antenna switching circuits, auxiliary electronics, inertial sensor assembly, and signal data converter.

The propulsion section consists of the [[rocket]] motor, external heat shield, and two external conduits. The rocket motor includes the case, nozzle assembly, propellant, liner and insulation, pyrogen igniter, and propulsion arming and firing unit. The casing of the motor is an integral structural element of the missile airframe. It contains a conventional, casebonded solid rocket propellant.

The Control Actuator Section (CAS) is at the aft end of the missile. It receives commands from the missile autopilot and positions the fins. The missile fins steer and stabilize the missile in flight. A fin [[Servomechanism|servo]] system positions the fins. The fin servo system consists of [[hydraulic]] actuators and valves and an electrohydraulic power supply. The electrohydraulic power consists of a battery, motor pump, oil reservoir, gas pressure bottle, and accumulator.