The AN/MPQ-53 and AN/MPQ-65 Radar Set

The AN/MPQ-53/65 Radar Set is a passive electronically scanned array radar equipped with 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 traveling 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 also 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. This is in contrast to most SAM systems, where several different radars are necessary 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.

 

1. How can you decipher the name “Patriot”? Is it an acronym?
2. What are the main operational functions of the Patriot system?
3. How can you justify that the Patriot system is modular and highly mobile?
4. What is considered to be the heart of the Patriot battery?
5. Show the difference between the AN/MPQ-53 and the AN/MPQ-65 radar sets. What is a “detection-to-kill” system?
6. What are specific features of AN/MPQ-53 radar?
7. How does a new active electronically scanned array radar (of a Dutch Patriot unit) differ from the An/MPQ-53 radar?

 

3. Work in groups. There have been a lot of upgrades to the Patriot system. Divide into 5 groups to look for the information about the upgrades for your group. Present your findings to the class.

· Group 1 – upgrades to the PAC-2 system.

· Group 2 – upgrades to the PAC-3 system.

· Group 3 – upgrades to the PAC-3 system made by Lockheed Martin Missiles and Fire Control.

· Group 4 – upgrades of the Raytheon and Rafael Advanced Defense system

· Group 5 – the Patriot system future upgrades

 

MIM-104B (PAC-1)

Patriot Advanced Capability (PAC-1), known today as the PAC-1 upgrade, was a software-only upgrade. The most significant aspects of this upgrade were changing the way the radar searched and the way the system defended its assets. Instead of searching low to the horizon, the top of the radar's search angle was lifted to near vertical (89 degrees) from the previous angle of 25 degrees. This was done as a counter to the steep parabolic trajectory of inbound ballistic missiles. The search beams of the radar were tightened, and while in "TBM search mode" the "flash", or the speed at which these beams were shot out, was increased significantly. While this increased the radar's detection capability against the ballistic missile threat set, it decreased the system's effectiveness against traditional atmospheric targets, as it reduced the detection range of the radar as well as the number of "flashes" at the horizon. Because of this, it was necessary to retain the search functions for traditional atmospheric threats in a separate search program, which could be easily toggled by the operator based on the expected threat. Additionally, the ballistic missile defense capability changed the way Patriot defended targets. Instead of being used as a system to defend a significant area against enemy air attack, it was now used to defend much smaller "point" targets, which needed to lie within the system's TBM "footprint". The footprint is the area on the ground that Patriot can defend against inbound ballistic missiles.

 

MIM-104C (PAC-2)

During the late 1980s, tests began to indicate that, although Patriot was certainly capable of intercepting inbound ballistic missiles, it was questionable whether or not the MIM-104A/B missile was capable of destroying them reliably. This necessitated the introduction of the PAC-2 missile and system upgrade.

For the system, the PAC-2 upgrade was similar to the PAC-1 upgrade. Radar search algorithms were further optimized, and the beam protocol while in "TBM search" was further modified. PAC-2 also saw Patriot's first major missile upgrade, with the introduction of the MIM-104C, or PAC-2 missile. This missile was optimized for ballistic missile engagements. Major changes to the PAC-2 missile were the size of the projectiles in its blast-fragmentation warhead (changed from around 2 grams to around 45 grams), and the timing of the pulse-Doppler radar fuse, which was optimized for high-speed engagements (though it retained its old algorithm for aircraft engagements if necessary). Engagement procedures were also optimized, changing the method of fire the system used to engage ballistic missiles. Instead of launching two missiles in an almost simultaneous salvo, a brief delay (between 3 and 4 seconds) was added in order to allow the second missile launched to discriminate a ballistic missile warhead in the aftermath of the explosion of the first.

MIM-104D (PAC-2/GEM)

There were many more upgrades to PAC-2 systems throughout the 1990s and into the 21st century, again mostly centering on software. However, the PAC-2 missiles were modified significantly—four separate variants became known collectively as guidance enhanced missiles (GEM).

The main upgrade to the original GEM missile was a new, faster proximity fused warhead. Tests had indicated that the fuse on the original PAC-2 missiles were detonating their warheads too late when engaging ballistic missiles with an extremely steep ingress, and as such it was necessary to shorten this fuse delay. The GEM missile was also given a new "low noise" seeker head designed to reduce interference in front of the missile's radar seeker, and a higher performance seeker designed to better detect low radar cross-section targets. The GEM was used extensively in Operation Iraqi Freedom (OIF), during which air defense was highly successful.

Just prior to OIF, it was decided to further upgrade the GEM and PAC-2 missiles. This upgrade program produced missiles known as the GEM/T and the GEM/C, the "T" designator referring to "TBM", and the "C" designator referring to cruise missiles. These missiles were both given a totally new nose section, which was designed specifically to be more effective against low altitude, low RCS targets like cruise missiles. Additionally, the GEM/T was given a new fuse which was further optimized against ballistic missiles. The GEM/C is the upgraded version of the GEM, and the GEM/T is the upgraded version of the PAC-2. The GEM+ entered service in 2002, and the US Army is currently upgrading its PAC-2 and GEM missiles to the GEM/C or GEM/T standard.

MIM-104F (PAC-3)

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 K_a 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. ^[26]

Lockheed Martin Missiles and Fire Control is the prime contractor on the PAC-3 Missile Segment upgrade to the Patriot air defense system which will make the missile more agile and extend its range by up to 50%. The PAC-3 Missile Segment upgrade consists of the PAC-3 missile, a very agile hit-to-kill interceptor, the PAC-3 missile canisters (in four packs), a fire solution computer, and an Enhanced Launcher Electronics System (ELES). The PAC-3 Missile Segment Enhancement (MSE) interceptor increases altitude and range through a more powerful dual-pulse motor for added thrust, larger fins that collapse inside current launchers, and other structural modifications for more agility.