Paveway
Paveway (in allusion to English to pave the way , "pave the way") is a name for a number of US precision bombs . Strictly speaking, however, it is not a complete weapon, but merely a laser guide that is mounted on existing unguided bombs in order to turn them into precision weapons at low cost. In addition to deliveries to the two main users, the US Air Force and the US Navy , the system was also exported to a large number of other countries, mainly to members of NATO .
history
Although guided bombs such as the Henschel Hs 293 or Fritz X were already used in World War II, they played no role in the post-war period due to the strategy of massive retaliation . Aircraft like the Republic F-105 were designed to carry a nuclear weapon into the target area, unplug it, and get home safe. The Vietnam War showed that the precision-guided ammunition capability gap had catastrophic consequences: 11 lost aircraft and more than 300 bombs dropped later, the Thanh Hóa Bridge was still standing.
At Texas Instruments, an engineer who came from the sonar industry , Word thought about how to improve the precision of bombs. At the end of 1964 he happened to meet the laser engineer Dave Salonimer, who was about to convince the US Army to use lasers for target illumination for artillery strikes . For demonstration purposes, an AGM-45 Shrike should now be launched from the ground and guided to the target with the help of a laser seeker. The Shrike was suboptimal for this, but cheap and easy to convert. A development contract was not received. The engineers at Texas Instruments continued to stick to the idea of directing a bomb or artillery shell to the target using a laser.
Word promoted a laser-guided bomb to Col. Joe Davis at Eglin Air Force Base . The bomb craters near Thanh Hóa Bridge had now grown to over 800, and the bridge was still standing. Davis told Word that he wanted a bomb that would be unlatched about 10,000 feet and fly the rest of the way to the target, and that the warhead should be large enough that two bombs could destroy even the toughest target. The Texas Instruments team then drew up a concept, which was ridiculed by engineers and the military. On a Friday morning in June 1965, the team reported to Colonel Davis that those responsible were listless to solve the bomb problem. He then requested an offer for twelve guided bombs with a CEP 50 of 30 feet, a fixed price of less than $ 100,000 and delivery in six months by Monday morning . After a ruined weekend, the team delivered the 18-page offer for $ 99,000 after 72 sleepless hours. The concept, referred to in retrospect by Word as "a pile of junk" that would never fly, was then reviewed by military and civil advisors in Eglin. Meanwhile, Word and his team went to the nearby beach with a six-case beer.
The technical offer convinced Colonel Joe Davis, who sent it to Wright-Patterson Air Force Base in Ohio, where the Air Force's research and development projects were supervised. After a few days it was sent to the Limited Warfare Office in Wright-Patterson. The director Jack Short finally placed a development contract for US $ 100,000 under pressure from Davis and Word Texas Instruments. The default was a CEP 50 of 30 feet, considerably better than the 100 to 1000 feet of unguided bombs, and six months to delivery.
In order to make the "pile of scrap" flyable, a tight development program had to be implemented. The control and steering unit of an AGM-45 Shrike was bolted to the stern of an M117 bomb. The main problem was the transfer of information from the viewfinder to the control unit. The data transfer rate could finally be increased to 10 pulses per second, which was the minimum for the steering. Since no one at Texas Instruments had any idea about lasers and no one had seen a laser in action, one of the two available lasers was borrowed. This was set up in Plano, Texas and illuminated the water tower so that the engineers could measure the backscatter . Due to the ignorance, no laser protection measures were taken; a Polaroid film held in front of the lens served as an activity control: if the laser burned through the film, it was definitely on. The calculations for the steering algorithm were carried out on an analog computer that was programmed with gears and gears. The idea of designing the seeker head as a shuttlecock (badminton birdie) led to its designation birdie head . Since no money was available for wind tunnel tests , a backyard swimming pool was used as a replacement. Johnson made models of bombs from WWII to test their aerodynamic properties in the pool. After about a month he had a 10-inch model of the laser bomb ready and tossed it in the pool to see if it was stable. He tested different wing shapes in order to find the smallest possible geometry so that the bomb would fit under an airplane wing. Flight tests began in late 1965. Since there was no money for telemetry , a sturdy tape recorder was simply screwed into the space of the detonator . After each drop, the Texas Instruments team had to dig the bomb out of the sand and clay of West Florida to get to the recorder. Eight out of ten drops were a success.
The Air Force began front-line testing in 1968. The bomb, now called Paveway, was adapted to the Mark 80 series. Laser target lighting containers were also purchased. An F-4 Phantom could carry up to two 2,000 pound bombs. From 1970, road junctions on the Ho Chi Minh Trail , bulldozers , all kinds of hard targets and tanks were fought with the paveway. On April 27, 1972, twelve phantoms of the 8th Tactical Fighter Wing flew a paveway attack on the Thanh Hóa Bridge, which was still standing, which destroyed half of it. In a follow-up attack on May 13, 14 Phantoms flew with a 2,000-pound paveway and aimed at the central pillar, destroying the bridge. Since the US command was not yet satisfied, 8,000 pounds of explosives in the form of AGM-62 Walleye and Mark 84 were dropped from Vought A-7 on October 6 . The central pillar was hit a second time, which tore the bridge apart. It was now considered permanently destroyed and removed from the target list.
After the start of series production, the Paveway series was continuously developed: in order to reduce the cost per bomb, the Paveway II series was developed. The kits were tested in 1974 and series production began in 1977. Development of the Paveway III series for combating heavily defended targets began in 1980; this version went into production in 1983.
When, after the start of the air offensive in the Iraq war in 1991, it was determined by the US air forces that the available BLU-109 / B bunker-breaking bombs were not suitable for the destruction of the largest Iraqi bunker systems, a weapon with significantly increased capabilities was started develop. The laser-guided bomb GBU-28 / B belongs to the Paveway III series, although the bomb is an independent development with the exception of the converted GBU-24 viewfinder.
The newest variant, Paveway IV, was developed at the request of the Royal Air Force and has a programmable detonator and insensitive explosives. As with the retrofits of the Paveway II and III series, this bomb is also equipped with a GPS and inertial navigation system so that it can hit its target without a laser.
variants
Paveway I
The first Paveway, then still called Pave Way, was dropped in April 1965. The follow-up order to Texas Instruments was for KMU-342 / B laser steering kits for the 750 lb M117 bomb. The upgraded M117s with KMU-342 / B were designated as BOLT-117 (BOLT = Bomb, Laser, Terminal Guidance) and were first dropped over Vietnam in 1968. After the initial success, the kit has been adapted to a wide variety of bombs such as: B. the 2000 lb MK-84 and 500 lb MK-82 bombs, as well as cluster bombs. While the mono warhead variants were called the Pave Way , the cluster bomb variants were called the Pave Storm . With the appearance of the Paveway II, the Pave Way was renamed Paveway I.
The kit consists of a moving seeker head, a Computer Control Group (CCG) at the stern, and a group of wings. The laser seeker is gimbaled and automatically adjusts itself to the weapon speed vector thanks to its round box wing . The laser light reflected from the target passes through the viewfinder window and an infrared filter and is then focused through an aspherical lens onto a silicon- based photoelectric sensor with four quadrants. The detector field is a little too close to the lens, in front of the focal point , so that the laser is not point-shaped. When the weapon takes the correct course, the laser illuminates all four quadrants. If the laser point is outside, the quadrants are illuminated to different degrees. Since each quadrant generates an electrical current that is proportional to the incident laser light, control commands (up / down; left / right; no commands) can be determined by the CCG after an amplifier and mixer if the current exceeds a threshold value. The steering commands are implemented electro-pneumatically: for this purpose, a gas generator is put into operation two seconds after being released , and the pressure of up to 7.5 MPa is implemented through a distributor on four solenoid valves that are activated by the CCG to close the control surfaces move. If there is no control command, the control surfaces turn into the flow. In order to avoid fluttering , the control surfaces are connected with oil dampers. The CCG has a simple two-position controller , i. H. the control surfaces are either fully deflected or not deflected at all, which leads to a suboptimal trajectory because the bomb wants to target the laser point directly. The wing group is in two parts, with a fixed tail unit at the stern and movable canards on the head, with the exception of the kit KMU-342 / B, which has movable tail fins. The kits of the GBU-2 / B, GBU-10 / B and GBU-12 / B bombs came in two different versions, with short and long wings. The long-wing version had a lower release speed, but more range.
| Warhead | Steering set | Control unit | Wing group | |
|---|---|---|---|---|
| GBU-1 / B | M117 (340 kg) | KMU-342 / B | - | - |
| GBU-2 / B | CBU-75 / B (810 kg) | KMU-421 / B | - | - |
| GBU-3 / B | CBU-74 / B | KMU-422 / B | - | - |
| GBU-5 / B | CBU-100 (Rockeye II) | KMU-420 / B | - | - |
| GBU-6 / B | CBU-79 / B (900 kg) | KMU-351 / B | - | - |
| GBU-7 / B | CBU-80 / B | KMU-351 / B | - | - |
| GBU-10 / B | Mark 84 (900 kg) | KMU-351A / B | MAU-157 / B | MXU-600 / B |
| GBU-10A / B | SME-351B / B | MAU-157A / B | MXU-600A / B 1 | |
| GBU-10B / B | SME-351C / B | MAU-157 (...) / B | MXU-600 (…) / B 1 | |
| GBU-11 / B | M118E1 (1400 kg) | SME-370B / B | MAU-157 / B | MXU-601 / B |
| GBU-11A / B | KMU-370C / B | MAU-157A / B 2 | MXU-601A / B | |
| GBU-12 / B | Mark 82 (227 kg) | KMU-388 / B | MAU-157 / B | MXU-602 / B |
| GBU-12A / B | KMU-388A / B | MAU-157A / B 2 | MXU-602A / B 1 |
1 Version with long wings
2 The rudders are kept in the neutral position by springs, improved thermal batteries, new release cables and guide wires
Paveway II
Due to the success of the Pave Way bombs in Vietnam, the first revision of the system was heralded with the Paveway II. The Computer Control Group (CCG) was simplified and made cheaper, and the fixed fins were replaced with hinged ones. As a result, the distinction between long and short wing versions was no longer necessary. At the same time, handling and storage were easier. The first Paveway II kits were tested in 1974 and series production began in 1977. The control principle is identical to that of the Paveway I, as described above. In total, more than 100,000 Paveway IIs were built, mostly by Raytheon but also by Lockheed Martin.
The CEP 50 is 6 m. Since bad weather can make lasering impossible, GPS / INS receivers were later integrated. The bombs converted in this way are called EGBU. The EGBU-10 is also referred to as GBU-50, the EGBU-12 as GBU-49, and the EGBU-16 as GBU-48. The GBU-51 / B is not derived from an EGBU, but a new version with BLU-126 / B Low Collateral Damage Bomb warhead. The GBU-58 with 250 lb warhead was introduced in 2011 and, as the GBU-59, also has GPS / INS.
| Warhead | Steering set | Control unit | Wing group | |
|---|---|---|---|---|
| GBU-10C / B | Mark 84 (900 kg) | KMU-351D / B | MAU-169 / B | MXU-651 / B |
| GBU-10D / B | SME-351E / B | MAU-169A / B | ||
| GBU-10E / B | - | MAU-169B / B, -D / B, -E / B | ||
| GBU-10F / B | - | MAU-169C / B | ||
| GBU-10G / B | BLU-109 (883 kg) | - | MAU-169 / B | |
| GBU-10H / B | - | MAU-169A / B | ||
| GBU-10J / B | - | MAU-169B / B, -D / B, -E / B | ||
| GBU-10K / B | - | MAU-169G / B | ||
| GBU-12B / B | Mark 82 (227 kg) | KMU-388B / B | MAU-169 / B | MXU-650 / B |
| GBU-12C / B | SME-388C / B | MAU-169A / B | ||
| GBU-12D / B | - | MAU-169B / B, -D / B, -E / B | ||
| GBU-12E / B | - | MAU-169C / B | ||
| GBU-12F / B | - | N / A | ||
| GBU-16 / B | Mark 83 (460 kg) | KMU-455 / B | MAU-169 / B | MXU-667 / B |
| GBU-16A / B | - | MAU-169A / B | ||
| GBU-16B / B | - | MAU-169B / B, -D / B, -E / B | ||
| GBU-16C / B | - | MAU-169C / B | ||
| GBU-17 / B | Variant with HSM (Hard Structure Munition) penetrator, was not built | |||
| GBU-48 (V) 1 / B | Mark 83 (460 kg) | - | MAU-169K / B | MXU-667 / B |
| GBU-49 (V) 1-3 / B | Mark 82 (227 kg) | - | MXU-650 / B | |
| GBU-50 / B | Mark 84 (900 kg) | - | MXU-651 / B | |
| GBU-51 / B | BLU-126 / B (227 kg) | - | - | |
| GBU-58 | Mark 81 (113 kg) | - | - | - |
| GBU-59 | - | - | - | |
Paveway III
When the Paveway II was developed in the late 1970s, there was still a capability gap in the precise bombing of targets from low flight . A Paveway I can be thrown from low altitude when it is pulled up, but the steering algorithm immediately controls the bomb back down so that no usable range is achieved. In order to be able to stand at a distance from air defense systems, a bomb was required that can be dropped from a climb and that approaches the target on a trajectory parabola . Texas Instruments received a development contract in 1980 for a Low-Level LGB (LLLGB), which was called Paveway III. Originally, four warheads were planned: HSM, Mk 82, Mk 83 and Mk 84. Of these, only the Mk-84 variant was implemented. The system has been in production since 1983, and more than 10,000 units have been manufactured since then. Since the Paveway III is much more expensive than the Paveway II, the latter is still in production.
The weapon’s GCU (Guidance Control Unit) is a microprocessor-controlled autopilot that works as a proportional controller . In this way, an optimal trajectory can be selected, which increases the range in low flight to over 18 km and in altitude drop to over 30 km. In addition, the laser seeker has been given a larger field of view and the wing group has been enlarged. As with a modern, heat-seeking air-to-air missile, the viewfinder consists of a fixed seeker head with a glass window and a gimbal-mounted CCD sensor behind it . This enables the viewfinder to track a laser point at high angular speeds and squint angles, regardless of the trajectory of the weapon. The Paveway III achieves a CEP 50 of 1 m. Since bad weather can make lasing impossible, GPS / INS receivers were integrated from the end of the 90s. Flight tests began in 1999 and operational readiness was achieved in 2000. The bombs converted in this way are called EGBU.
There are two special versions of the Paveway III: The GBU-27 was developed for the F-117 Nighthawk and uses the wing group of a Paveway II to make do with the cramped space in the weapon bay. The GBU-28 "Deep Throat" was hastily developed for use in the Second Gulf War and belongs to the Paveway III family, although the bomb is an independent development with the exception of the modified GBU-24 seeker.
| Warhead | Detonator | Control unit | Wing group | |
|---|---|---|---|---|
| GBU-21 / B | Variant with HSM (Hard Structure Munition) penetrator, was not built | |||
| GBU-22 / B | Mark 82 (227 kg) | - | WGU-12/39/43 / B | BSU-82 / B |
| GBU-23 / B | Variant with Mark 83, was not built | |||
| GBU-24 / B | Mark 84 (900 kg) | FMU-81 (…) / B, FMU-139 (…) / B | WGU-12 / B, -12A / B | BSU-84 / B |
| GBU-24A / B | BLU-109 / B (883 kg) | FMU-143 (...) / B | WGU-12B / B | |
| GBU-24B / B | BLU-109A / B (883 kg) | WGU-39 / B | ||
| GBU-24C / B | BLU-116 / B (876 kg) | FMU-157 / B | WGU-12B / B, WGU-39 / B | BSU-84 / B, -84A / B |
| GBU-24D / B | WGU-39 / B | |||
| EGBU-24E / B | BLU-109A / B (883 kg) | FMU-143E / B | WGU-39A / B | BSU-84B / B |
| GBU-24F / B | BLU-116A / B (876 kg) | FMU-159 / B | WGU-39 / B | BSU-84 / B, -84A / B |
| EGBU-24G / B | FMU-159 / B | WGU-39A / B | BSU-84B / B | |
| GBU-24 (V) 1 / B | Mark 84 (900 kg) | FMU-81 (...) / B | WGU-43 / B | BSU-84A / B |
| GBU-24 (V) 2 / B | BLU-109 (…) / B (883 kg) | FMU-143 (..) / B | ||
| GBU-24 (V) 3 / B | Mark 84 (900 kg) | FMU-81 (...) / B | WGU-43B / B | |
| GBU-24 (V) 4 / B | BLU-109 (…) / B (883 kg) | FMU-143 (...) / B | ||
| GBU-24 (V) 7 / B | Mark 84 (900 kg) | FMU-81 (...) / B | WGU-43A / B | |
| GBU-24 (V) 8 / B | BLU-109 (…) / B (883 kg) | FMU-143 (...) / B | ||
| EGBU-24 (V) 9 / B | Mark 84 (900 kg) | FMU-81 (...) / B | WGU-43G / B | |
| EGBU-24 (V) 10 / B | BLU-109 (…) / B (883 kg) | FMU-143 (...) / B | ||
| EGBU-24 (V) 12 / B | WGU-43H / B | |||
| GBU-27 / B | WGU-25 (...) / B | BSU-88 / B | ||
| EGBU-27A / B | WGU-39A / B | BSU-88A / B | ||
| EGBU-27B / B | BLU-116 / B (876 kg) | FMU-157 / B | WGU-39A / B | BSU-88 (...) / B |
| GBU-28 / B | BLU-113 / B (2270 kg) | - | WGU-36 / B | BSG-92 / B |
| GBU-28A / B | BLU-113A / B (2270 kg) | - | WGU-36A / B | |
| EGBU-28B / B | FMU-143F / B, -G / B, -H / B | WGU-36B / B | BSG-92A / B | |
| EGBU-28C / B | BLU-122 / B (2018 kg) | FMU-143F / B, -G / B, -H / B, FMU-152 / B | WGU-36D / B | BSG-92B / B |
| EGBU-28D / B | FMU-143G / B, -H / B, FMU-152A / B | WGU-36E / B | ||
| EGBU-28E / B | BLU-113 (…) / B (2270 kg) | FMU-143F / B, -G / B, -H / B | WGU-36E / B | BSG-92A / B |
| GBU-33 / B | Export name for the GBU-24 ... / B, was replaced by -24 (V) ... / B | |||
Paveway IV
The Paveway IV was designed to meet the Royal Air Force's Air Staff Target (AST) 1248 and is intended to replace the 1000 lb Paveway II there. The system went into series production in 2008. The Royal Saudi Air Force (RSAF) also wanted to procure this weapon for the Eurofighter Typhoon , but this was blocked by the USA. In mid-2013, it was suggested that the US wanted to give up its blockade. A procurement contract for the RSAF for approximately 2,400 bombs was signed in late March 2014.
The Paveway IV is a modified 500 lb Mark 82 bomb that will be equipped with a new laser kit. This includes GPS, INS and the laser finder. The GPS now has antennas on and under the bomb to reduce the impact of GPS whining . The pilot can now select the angle of the weapon in the target. The seeker head of the bomb is also equipped with a radar, which means that the Paveway IV can explode in the air above the target, upon impact or after penetrating a target, depending on the programming. The Aurora fuse required for this is produced by Thales, and only armed the weapon shortly before the target. The body of the bomb is filled with the insensitive explosive PBXN-109, which burns down in a controlled manner in the event of fragmentation or cook-off , instead of exploding. As a special feature, the weapon is equipped with a data link in order to be able to change the firing mode during flight. Furthermore, thanks to proportional navigation, the bomb can also hit moving targets if these are marked with a laser. The laser finder can also be replaced by an infrared finder and the bomb can be fitted with a Leigh Aerosystems hydrofoil kit to increase range.
| Warhead | Detonator | Control unit | Wing group | |
|---|---|---|---|---|
| PAVEWAY IV | Mark 82 (IM) | Aurora | - | - |
Web links
Individual evidence
- ^ A b c d e f Shelby G. Spiers: Paveway History , accessed December 18, 2013
- ↑ Incorrectly referred to as Paveway II in the image description, but recognizable as Paveway I on the fixed tail unit
- ↑ Smart bombs in Vietnam. In: Defense Today. September 2009, accessed December 12, 2013 .
- ↑ a b Paveway I. In: Directory of US Military Rockets and Missiles. December 12, 2013, accessed December 12, 2013 .
- ↑ a b Laser Guidance. In: Air Power Australia. Retrieved December 12, 2013 (1981/2005).
- ↑ a b c Paveway II. In: Directory of US Military Rockets and Missiles. December 12, 2013, accessed December 12, 2013 .
- ↑ Reuters: Raytheon Re-Introduces 250-Pound Paveway Precision-Guided Munition , June 18, 2011 ( Memento of December 19, 2013 in the Internet Archive )
- ↑ a b c d Paveway III. In: Directory of US Military Rockets and Missiles. December 12, 2013, accessed December 12, 2013 .
- ↑ Modern laser guided bombs. In: Defense Today. December 2009, accessed December 12, 2013 .
- ↑ Janes: Saudi Arabia becomes first Paveway IV export customer , March 25, 2014
- ↑ Thales: Aurora Fuze for PGB PWIV - NDIA Fuze Conference , May 11, 2006 ( Memento from July 19, 2013 in the Internet Archive )
- ^ Defense industry daily: My PGM for a Fuze ... But Paveway-IV is Ready Now , December 5, 2013
- ↑ Raytheon: Precision Guided Bomb (Paveway IV) IM Development , 2006 ( Memento from December 19, 2013 in the Internet Archive )
- ^ AIN online: Raytheon UK Helps The RAF's Smartest Bomb Get Smarter , July 8, 2012
- ↑ Flightglobal: Raytheon offers Paveway IV to UK , February 25, 2003