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87-862: The MGM-5 Corporal missile was a nuclear-armed tactical surface-to-surface missile. It was the first guided weapon authorized by the United States to carry a nuclear warhead . A guided tactical ballistic missile , the Corporal could deliver either a nuclear fission , high-explosive, fragmentation or chemical warhead up to a range of 75 nautical miles (139 km). It was developed by the United States Army in partnership with Caltech's pioneering Jet Propulsion Laboratory , and initially produced by Douglas Aircraft Company . As development continued production shifted to Firestone Tire and Rubber Company (airframe) and Gilfillan Brothers Inc. (guidance). The Corporal

174-548: A smart weapon , smart munition , or smart bomb , is a guided munition intended to hit a specific target, to minimize collateral damage and increase lethality against intended targets. During the Persian Gulf War guided munitions accounted for only 9% of weapons fired, but accounted for 75% of all successful hits. Despite guided weapons generally being used on more difficult targets, they were still 35 times more likely to destroy their targets per weapon dropped. Because

261-481: A Type III Corporal was flown in 1957 it was too late for the eternally developing Corporal system. On May 23, 1957 all work on the Corporal III was ended to conserve funds for Sergeant following defense budget cuts. In 1963 the solid-fueled Sergeant missiles with self-contained inertial guidance systems which was jamming proof, and which took only an hour from occupying the site to launch of the missile, started replacing

348-469: A ballistic guided missile. As the technology to build such a weapon did not exist in the United States it had to be created. GALCIT, later transformed into the Jet Propulsion Laboratory (JPL), began incremental efforts starting with a solid-fuel rocket program called Private. It progressed to a liquid-fuel unguided sounding rocket called WAC Corporal and a much larger guided research missile,

435-484: A large range of velocity detection, but the accuracy in velocity is in the tens of knots . Antenna designs for the CW and FM-CW started out as separate transmit and receive antennas before the advent of affordable microwave designs. In the late 1960s, traffic radars began being produced which used a single antenna. This was made possible by the use of circular polarization and a multi-port waveguide section operating at X band. By

522-652: A laser designator or for another aircraft to illuminate the target. During NATO's air campaign in 1999 in Kosovo the new Italian AF AMX employed the Opher. In 1962, the US Army began research into laser guidance systems and by 1967 the USAF had conducted a competitive evaluation leading to full development of the world's first laser-guided bomb , the BOLT-117 , in 1968. All such bombs work in much

609-545: A laser designator to guide an electronically actuated bullet to a target. Another system in development uses a laser range finder to trigger an explosive small arms shell in proximity to a target. The U.S. Army plans to use such devices in the future. In 2008 the EXACTO program began under DARPA to develop a " fire and forget " smart sniper rifle system including a guided smart bullet and improved scope. The exact technologies of this smart bullet have not been released. EXACTO

696-405: A low altitude target, filtering on the radial speed is a very effective way to eliminate the ground clutter that always has a null speed. Low-flying military plane with countermeasure alert for hostile radar track acquisition can turn perpendicular to the hostile radar to nullify its Doppler frequency, which usually breaks the lock and drives the radar off by hiding against the ground return which

783-481: A medium to high PRF (on the order of 3 to 30 kHz), which allows for the detection of either high-speed targets or high-resolution velocity measurements. Normally it is one or the other; a radar designed for detecting targets from zero to Mach 2 does not have a high resolution in speed, while a radar designed for high-resolution velocity measurements does not have a wide range of speeds. Weather radars are high-resolution velocity radars, while air defense radars have

870-749: A much improved weapon system with improved reliability, ground support equipment, and especially ground guidance equipment, to provide the Army with a fully developed weapon. Only small changes to the Corporal IIb missile would be required. In 1956 all research and development work on the Corporal II had been completed. A study at Redstone Arsenal noted that the MGM-29 Sergeant missile system would become available for service in 1963 and that Corporal III equipment should only be procured for additional Corporal units. Though

957-402: A number of aircraft of the era, and were combined with the main search radars of fighter designs by the 1960s. Doppler navigation was in common commercial aviation use in the 1960s until it was largely superseded by inertial navigation systems . The equipment consisted of a transmitter/receiver unit, a processing unit and a gyro stabilised antenna platform. The antenna generated four beams and

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1044-415: A pre-assigned assembly point. From there the battalion would move to a launch site—usually somewhere in a remote forest—set up the missile on its launcher and go through a detailed checkout of the various systems. This was not a trivial operation as these electronic systems were largely vacuum tubes . A mock firing would be performed and the entire battalion would be gone as soon as possible in order to not be

1131-464: A source and an observer is what gives rise to the Doppler effect. The formula for radar Doppler shift is the same as that for reflection of light by a moving mirror. There is no need to invoke Albert Einstein 's theory of special relativity , because all observations are made in the same frame of reference. The result derived with c as the speed of light and v as the target radial velocity gives

1218-477: A successful strike in any given weather conditions than any other type of precision-guided munition. Responding to after-action reports from pilots who employed laser or satellite guided weapons, Boeing developed a Laser JDAM (LJDAM) to provide both types of guidance in a single kit. Based on the existing Joint Direct Attack Munition configurations, a laser guidance package is added to a GPS/INS-guided weapon to increase its overall accuracy. Raytheon has developed

1305-674: A system was the Green Satin radar used in the English Electric Canberra . This system sent a pulsed signal at a very low repetition rate so it could use a single antenna to transmit and receive. An oscillator held the reference frequency for comparison to the received signal. In practice, the initial "fix" was taken using a radio navigation system, normally Gee , and the Green Satin then provided accurate long-distance navigation beyond Gee's 350-mile range. Similar systems were used in

1392-508: A target of counter-battery fire. For what was the first nuclear armed missile the Corporal I was significantly unreliable and inaccurate. The continuing development of the Corporal weapon system led rapidly to the development of the Corporal II. This was initiated while the Corporal I was still under development. Though Corporal I was deemed operable many shortcomings in both the missile and ground equipment tactical usability had become obvious during development. Engineer-User trials had shown that

1479-596: A velocity output as the received signal from the target is compared in frequency with the original signal. Early Doppler radars included CW, but these quickly led to the development of frequency modulated continuous wave ( FMCW ) radar, which sweeps the transmitter frequency to encode and determine range. With the advent of digital techniques, Pulse-Doppler radars (PD) became light enough for aircraft use, and Doppler processors for coherent pulse radars became more common. That provides Look-down/shoot-down capability. The advantage of combining Doppler processing with pulse radars

1566-421: Is an air-dropped guided bomb containing metal penetrator rods of various sizes. It was designed to attack targets where an explosive effect may be undesirable, such as fuel storage tanks or chemical weapon stockpiles in civilian areas. The Germans were first to introduce PGMs in combat, with KG 100 deploying the 3,100 lb (1,400 kg) MCLOS -guidance Fritz X armored glide bomb , guided by

1653-420: Is higher (compared to the emitted frequency) during the approach, it is identical at the instant of passing by, and it is lower during the recession. This variation of frequency also depends on the direction the wave source is moving with respect to the observer; it is maximum when the source is moving directly toward or away from the observer and diminishes with increasing angle between the direction of motion and

1740-410: Is less, as the distance between the two changes more slowly. From the point of view of the pitcher, the frequency remains constant (whether he's throwing balls or transmitting microwaves). Since with electromagnetic radiation like microwaves or with sound, frequency is inversely proportional to wavelength, the wavelength of the waves is also affected. Thus, the relative difference in velocity between

1827-470: Is much larger. Doppler radar tends to be lightweight because it eliminates heavy pulse hardware. The associated filtering removes stationary reflections while integrating signals over a longer time span, which improves range performance while reducing power. The military applied these advantages during the 1940s. Continuous-broadcast, or FM, radar was developed during World War II for United States Navy aircraft, to support night combat operation. Most used

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1914-415: Is required. That extra weight imposed unacceptable kinematic performance limitations that restricted aircraft use to night operation, heavy weather, and heavy jamming environments until the 1970s. Digital fast Fourier transform (FFT) filtering became practical when modern microprocessors became available during the 1970s. This was immediately connected to coherent pulsed radars, where velocity information

2001-432: Is to provide accurate velocity information. This velocity is called range-rate . It describes the rate that a target moves toward or away from the radar. A target with no range-rate reflects a frequency near the transmitter frequency and cannot be detected. The classic zero doppler target is one which is on a heading that is tangential to the radar antenna beam. Basically, any target that is heading 90 degrees in relation to

2088-559: The Kehl-Straßburg radio guidance system , to successfully attack the Italian battleship Roma in 1943, and the similarly Kehl-Straßburg MCLOS-guided Henschel Hs 293 rocket-boosted glide bomb (also in use since 1943, but only against lightly armored or unarmored ship targets). The closest Allied equivalents, both unpowered designs, were the 1,000 lb (450 kg) VB-1 AZON (from "AZimuth ONly" control), used in both Europe and

2175-695: The AAW-144 Data Link Pod, on US Navy F/A-18 Hornets . In World War II, the U.S. National Defense Research Committee developed the VB-6 Felix, which used infrared to home on ships. While it entered production in 1945, it was never employed operationally. The first successful electro optical guided munition was the AGM-62 Walleye during the Vietnam war. It was a family of large glide bombs which could automatically track targets using contrast differences in

2262-649: The CBI theater , and the US Navy 's Bat , primarily used in the Pacific Theater of World War II — the Navy's Bat was more advanced than either German PGM ordnance design or the USAAF's VB-1 AZON, in that it had its own on board, autonomous radar seeker system to direct it to a target. In addition, the U.S. tested the rocket-propelled Gargoyle , which never entered service. Japanese PGMs—with

2349-518: The Corporal E . In late 1949 the Army desired to accelerate the Corporal program to create a military weapon by turning the Corporal E into a crash program and cancel the intended additional research variants. The resultant Corporal ballistic missile was developed by JPL and first flew in its weapon version at White Sands Missile Range , New Mexico, on August 7, 1952. The Corporal crash program involved utilizing as much existing equipment as it could including

2436-502: The Iraq War included a single 2,000-pound (910 kg) JDAM and two 1,000-pound (450 kg) LGBs. With LJDAM, and the new GBU-39 Small Diameter Bomb (SDB), these same aircraft can carry more bombs if necessary, and have the option of satellite or laser guidance for each weapon release. A cannon-launched guided projectile (CLGP), is fired from artillery , ship's cannon , or armored vehicles . Several agencies and organizations sponsored

2523-485: The NEXRAD network being deployed at the end of the 1980s. Doppler radars were used as a navigation aid for aircraft and spacecraft. By directly measuring the movement of the ground with the radar, and then comparing this to the airspeed returned from the aircraft instruments, the wind speed could be accurately determined for the first time. This value was then used for highly accurate dead reckoning . One early example of such

2610-511: The UHF spectrum and had a transmit Yagi antenna on the port wing and a receiver Yagi antenna on the starboard wing. This enabled bombers to fly an optimum speed when approaching ship targets, and let escort fighter aircraft train guns on enemy aircraft during night operation. These strategies were adapted to semi-active radar homing . In 1951, Carl A. Wiley invented synthetic-aperture radar , which, though distinct from mainstream Doppler radar,

2697-435: The 1990s. The Raytheon Maverick is the most common electro optical guided missile. As a heavy anti-tank missile it has among its various marks guidance systems such as electro-optical (AGM-65A), imaging infrared (AGM-65D), and laser homing (AGM-65E). The first two, by guiding themselves based on the visual or IR scene of the target, are fire-and-forget in that the pilot can release the weapon and it will guide itself to

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2784-718: The British Royal Artillery Guided Weapons Range on the Scottish island of South Uist in the Outer Hebrides was used. Missiles were fired toward designated target coordinates in the Atlantic Ocean. Radar on Hirta (the main island of the St Kilda archipelago of Scotland) identified missile landing points. Frequently, Soviet spy ship 'fishing trawlers ' would intrude into the target area. The UK adoption of

2871-567: The CLGP programs. The United States Navy sponsored the Deadeye program, a laser-guided shell for its 5 in (127 mm) guns and a program to mate a Paveway guidance system to an 8 in (203 mm) shell for the 8"/55 caliber Mark 71 gun in the 1970s ( Photo ). Other Navy efforts include the BTERM , ERGM , and LRLAP shells. Precision-guided small arms prototypes have been developed which use

2958-705: The Corporal IIb in Europe. By June 1964 the Corporal system was history in American service. In June 1966 the last Corporal unit, the 27th Guided Weapons Regiment Royal Artillery , retired its Corporals. The first three Corporal battalions were activated in March 1952 with an Engineer-User launch program beginning in January 1953. In the same year the Corporal II system was sold to the United Kingdom. The extremely ambitious original goal of

3045-419: The Corporal consisted of a complex system of internal and ground guidance. During the initial launch phase, inertial guidance kept the missile in a vertical position and pre-set guidance steered it during its launch. The ground guidance system was a modified World War II SCR-584 radar which tracked the missile's position, as well as its slant range. This information was sent to an analog computer which calculated

3132-579: The Corporal program was to have 16 battalions of missiles deployed by July 1954. Two batteries of Corporal I had been organized and equipped by July 1954. The 259th Corporal Battalion deployed to Europe in February 1955. It was followed by other units and by 1960 there were six battalions in Germany, two in Italy and four in the United States. Live-fire training for Germany-based US forces took place at Fort Bliss but later

3219-665: The Corporal resulted in the islet of Rockall being incorporated into the United Kingdom in 1955, the last addition to the UK, to prevent its use by Soviet observers: the UK Minister of Defence Harold Macmillan was concerned that, were they to do so, the Soviets might discover how to jam Corporal guidance and tracking radio signals. A version of the Corporal was made as a die-cast toy by manufacturers such as Corgi and Dinky . The Corgi Corporal, marketed to children as "the rocket you can launch",

3306-522: The Corporal system was of concern from the beginning of the weapon program. Electronic anticountermeasures were addressed over the length of the program and would have been greatly improved in Corporal III. Though a variety of warheads from high explosive and fragmentation to chemical had been developed the warhead which the missile was equipped was the W-7 (Mk.7). A Corporal battalion was composed of 250 men requiring 35 vehicles to deploy and took nine hours to set up

3393-435: The Doppler effect. Radars may be: Doppler allows the use of narrow band receiver filters that reduce or eliminate signals from slow moving and stationary objects. This effectively eliminates false signals produced by trees, clouds, insects, birds, wind, and other environmental influences but various inexpensive hand held Doppler radar devices not using this may produce erroneous measurements. CW Doppler radar only provides

3480-496: The Doppler function for weather radar has a long history in many countries. In June 1958, American researchers David Holmes and Robert Smith were able to detect the rotation of a tornado using the mobile continuous-wave radar (photo to the right). Norman's laboratory, which later became the National Severe Storms Laboratory (NSSL), modified this radar to make it a pulsed Doppler radar allowing more easily to know

3567-450: The Doppler offset being measured is caused by the relative motion between the ground station and the fast-moving satellite. The combination of Doppler offset and reception time can be used to generate a locus of locations that would have the measured offset at that intersects the Earth's surface at that moment: by combining this with other loci from measurements at other times, the true location of

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3654-458: The Enhanced Paveway family, which adds GPS/INS guidance to their Paveway family of laser-guidance packages. These "hybrid" laser and GPS guided weapons permit the carriage of fewer weapons types, while retaining mission flexibility, because these weapons can be employed equally against moving and fixed targets, or targets of opportunity. For instance, a typical weapons load on an F-16 flying in

3741-631: The German Mistel (Mistletoe) " parasite aircraft " was no more effective, guided by the human pilot flying the single-engined fighter mounted above the unmanned, explosive-laden twin-engined "flying bomb" below it, released in the Mistel's attack dive from the fighter. The U.S. programs restarted in the Korean War . In the 1960s, the electro-optical bomb (or camera bomb ) was reintroduced. They were equipped with television cameras and flare sights, by which

3828-486: The PRF of the radar. This is not a problem for weather radars. Velocity information for aircraft cannot be extracted directly from low-PRF radar because sampling restricts measurements to about 75 miles per hour. Specialized radars quickly were developed when digital techniques became lightweight and more affordable. Pulse-Doppler radars combine all the benefits of long range and high velocity capability. Pulse-Doppler radars use

3915-522: The RFNA and improve performance, the propellants were changed to IRFNA (inhibited red fuming nitric acid), 14%   NO 2 , 2.5%   H 2 O , 0.6%   HF and 82.9%   HNO 3 oxidizer, with 46.5%   aniline, 46.5%   furfuryl alcohol and 7%   hydrazine as fuel. this required elaborate and time-consuming preparation immediately before launch, making its tactical responsiveness questionable. Guidance for

4002-623: The US Army whose names correspond to the progression in Army enlisted ranks, starting with Private before ultimately leading to the MGM-29 Sergeant. The U.S. Army Ordnance California Institute Technology ( ORDCIT ) program that eventually produced the Corporal ballistic missile began in June 1944 with a contract to the Guggenheim Aeronautical Laboratories California Institute of Technology (GALCIT) to develop

4089-531: The WW II SCR-584 radar. Corporal used a pressure-fed liquid-fueled rocket motor burning red fuming nitric acid (RFNA) and aniline ; the exact mixture of fuel and oxidizer changed over the Corporal service period. From round 11 of the test program it became RFNA as oxidizer and a fuel consisting of 80%   aniline with 20%   furfuryl alcohol . As the Corporal was a crash program and constantly under development after 1958 to reduce decomposition of

4176-479: The accuracy and reliability of the missile system. When compared to other early missiles the final production Corporal II was reasonably accurate. Still the aggregate accuracy of all Type IIs with a CEP (Circular Error Probable) of 350 meters which was still short of the desired 300 meters. The role of JPL was greatly reduced in 1955–56. The deficiencies of the Corporal II led to the design and development of Corporal III. The objectives of Corporal III were to produce

4263-427: The air was degraded. The problem of poor visibility does not affect satellite-guided weapons such as Joint Direct Attack Munition (JDAM) and Joint Stand-Off Weapon (JSOW), which make use of the United States' GPS system for guidance. This weapon can be employed in all weather conditions, without any need for ground support. Because it is possible to jam GPS, the guidance package reverts to inertial navigation in

4350-431: The antenna beam cannot be detected by its velocity (only by its conventional reflectivity ). Ultra-wideband waveforms have been investigated by the U.S. Army Research Laboratory (ARL) as a potential approach to Doppler processing due to its low average power, high resolution, and object-penetrating ability. While investigating the feasibility of whether UWB radar technology can incorporate Doppler processing to estimate

4437-550: The bomb would be steered until the flare superimposed the target. The camera bombs transmitted a "bomb's eye view" of the target back to a controlling aircraft. An operator in this aircraft then transmitted control signals to steerable fins fitted to the bomb. Such weapons were used increasingly by the USAF in the last few years of the Vietnam War because the political climate was increasingly intolerant of civilian casualties, and because it

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4524-401: The catcher catches balls more frequently because the balls are less spaced out (the frequency increases). The inverse is true if the pitcher is moving away from the catcher. The catcher catches balls less frequently because of the pitcher's backward motion (the frequency decreases). If the pitcher moves at an angle, but at the same speed, the frequency variation at which the receiver catches balls

4611-431: The damage effects of explosive weapons decrease with distance due to an inverse cube law, even modest improvements in accuracy (hence reduction in miss distance) enable a target to be attacked with fewer or smaller bombs. Thus, even if some guided bombs miss, fewer air crews are put at risk and the harm to civilians and the amount of collateral damage may be reduced. The advent of precision-guided munitions resulted in

4698-461: The design requirements. The system was sent to Vietnam and performed well. Without the existence of targeting pods they had to be aimed using a hand held laser from the back seat of an F-4 Phantom aircraft, but still performed well. Eventually over 28,000 were dropped during the war. Laser-guided weapons did not become commonplace until the advent of the microchip . They made their practical debut in Vietnam, where on 13 May 1972 they were used in

4785-399: The direction of the waves, until when the source is moving at right angles to the observer, there is no shift. Imagine a baseball pitcher throwing one ball every second to a catcher (a frequency of 1 ball per second). Assuming the balls travel at a constant velocity and the pitcher is stationary, the catcher catches one ball every second. However, if the pitcher is jogging towards the catcher,

4872-430: The early 1990s during Operation Desert Storm when they were used by coalition forces against Iraq . Even so, most of the air-dropped ordnance used in that war was "dumb," although the percentages are biased by the large use of various (unguided) cluster bombs . Laser-guided weapons were used in large numbers during the 1999 Kosovo War , but their effectiveness was often reduced by the poor weather conditions prevalent in

4959-427: The enemy. Doppler radar The Doppler effect (or Doppler shift), named after Austrian physicist Christian Doppler who proposed it in 1842, is the difference between the observed frequency and the emitted frequency of a wave for an observer moving relative to the source of the waves. It is commonly heard when a vehicle sounding a siren approaches, passes and recedes from an observer. The received frequency

5046-481: The event of GPS signal loss. Inertial navigation is significantly less accurate; the JDAM achieves a published Circular Error Probable (CEP) of 43 ft (13 m) under GPS guidance, but typically only 98 ft (30 m) under inertial guidance (with free fall times of 100 seconds or less). The precision of these weapons is dependent both on the precision of the measurement system used for location determination and

5133-506: The exception of the anti-ship air-launched, rocket-powered, human-piloted Yokosuka MXY-7 Ohka , "Kamikaze" flying bomb did not see combat in World War II. Prior to the war, the British experimented with radio-controlled remotely guided planes laden with explosives, such as Larynx . The United States Army Air Forces used similar techniques with Operation Aphrodite , but had few successes;

5220-445: The ground station can be determined accurately. A notable example of utilizing Doppler information is in the detection and classification of small unmanned aerial vehicles . Radar systems operating at extremely high frequency offer enhanced Doppler resolution for a given coherent processing interval. This increased resolution allows access to micro-Doppler signatures (MDSs), where micro-Doppler refers to Doppler modulations caused by

5307-677: The late 1970s this changed to linear polarization and the use of ferrite circulators at both X and K bands. PD radars operate at too high a PRF to use a transmit-receive gas filled switch, and most use solid-state devices to protect the receiver low-noise amplifier when the transmitter is fired. Doppler radars are used in aviation , sounding satellites, Major League Baseball 's StatCast system , meteorology , radar guns , radiology and healthcare (fall detection and risk assessment, nursing or clinic purpose ), and bistatic radar ( surface-to-air missiles ). Partly because of its common use by television meteorologists in on-air weather reporting,

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5394-455: The missile to fire once the launch position had been reached. Corporal missile battalions in Europe were highly mobile, considering the large number of support vehicles and personnel required to support the transportation, checkout, and launch of this liquid-fueled nuclear-tipped (or conventional HE or chemical) missile. In Germany, frequent unannounced 'Alerts' were performed—necessitating assembling all personnel and moving vehicles and missiles to

5481-482: The position of the echoes and having a greater power The work was accelerated after such event in the United States as the 1974 Super Outbreak when 148 tornadoes roared through thirteen states. The reflectivity only radar of the time could only locate the precipitation structure of the thunderclouds but not the mesocyclonic rotation and divergence of winds leading to the development of tornadoes or downbursts . The NSSL Doppler became operational in 1971 and led to

5568-560: The precision in setting the coordinates of the target. The latter critically depends on intelligence information, not all of which is accurate. According to a CIA report, the accidental United States bombing of the Chinese embassy in Belgrade during Operation Allied Force by NATO aircraft was attributed to faulty target information. However, if the targeting information is accurate, satellite-guided weapons are significantly more likely to achieve

5655-548: The primary reason for mechanical and electrical causes arose because the systems of the Corporal I were too delicate. Problems detected in the E-U trials were addressed in the Corporal II. The Type II Corporal was subsequently improved in the Corporal IIa and IIb (M2A1) versions. The first Corporal II prototype was flown on October 8, 1953. The first complete Type II system was delivered in February 1955, The Type II Corporal greatly improved

5742-493: The project began as a surface to air missile seeker developed by Texas Instruments . When Texas Instruments executive Glenn E. Penisten attempted to sell the new technology to the Air Force they inquired if it could instead be used as a ground attack system to overcome problems they were having with accuracy of bombing in Vietnam. After 6 attempts the weapon improved accuracy from 148 to 10 ft (50 to 3 m) and greatly exceeded

5829-540: The renaming of older, low-technology bombs as " unguided bombs ", "dumb bombs", or "iron bombs". Recognizing the difficulty of hitting moving ships during the Spanish Civil War , the Germans were first to develop steerable munitions, using radio control or wire guidance. The U.S. tested TV -guided ( GB-4 ), semi-active radar -guided ( Bat ), and infrared -guided ( Felix ) weapons. The CBU-107 Passive Attack Weapon

5916-510: The same way, relying on the target being illuminated, or "painted," by a laser target designator on the ground or on an aircraft. They have the significant disadvantage of not being usable in poor weather where the target illumination cannot be seen, or where a target designator cannot get near the target. The laser designator sends its beam in a coded series of pulses so the bomb cannot be confused by an ordinary laser, and also so multiple designators can operate in reasonable proximity. Originally

6003-502: The second successful attack on the Thanh Hóa Bridge ("Dragon's Jaw"). This structure had previously been the target of 800 American sorties (using unguided weapons) and was partially destroyed in each of two successful attacks, the other being on 27 April 1972 using AGM-62 Walleyes . They were used, though not on a large scale, by the British forces during the 1982 Falklands War . The first large-scale use of smart weapons came in

6090-647: The shifted frequency ( f r {\displaystyle f_{r}} ) as a function of the original frequency ( f t {\displaystyle f_{t}} ) : which simplifies to The "beat frequency", (Doppler frequency) ( f d {\displaystyle f_{d}} ), is thus: Since for most practical applications of radar, v ≪ c {\displaystyle v\ll c} , so ( c − v ) → c {\displaystyle \left(c-v\right)\rightarrow c} . We can then write: There are four ways of producing

6177-534: The southern Balkans. The Lockheed-Martin Hellfire II light-weight anti-tank weapon in one mark uses the radar on the Boeing AH-64D Apache Longbow to provide fire-and-forget guidance for that weapon. Lessons learned during the first Gulf War showed the value of precision munitions, yet they also highlighted the difficulties in employing them—specifically when visibility of the ground or target from

6264-444: The specific term " Doppler Radar " has erroneously become popularly synonymous with the type of radar used in meteorology. Most modern weather radars use the pulse-Doppler technique to examine the motion of precipitation , but it is only a part of the processing of their data. So, while these radars use a highly specialized form of Doppler radar , this type of radar is much broader in its meaning and its applications. The work on

6351-486: The target without further input, which allows the delivery aircraft to manoeuvre to escape return fire. The Pakistani NESCOM H-2 MUPSOW and H-4 MUPSOW is an electro-optical (IR imaging and television guided) is a drop and forget precision-guided glide bomb. The Israeli Elbit Opher is also an IR imaging "drop and forget" guided bomb that has been reported to be considerably cheaper than laser-homing bombs and can be used by any aircraft, not requiring specialized wiring for

6438-465: The trajectory and any necessary correction to hit the target. A Doppler radar was used to accurately measure the missile's velocity, and this information was also used in the trajectory calculation. The Doppler radar was also used to send the final range correction and warhead arming command after the missile re-entered the atmosphere. Transponder beacons were used in the missile to provide a return signal for tracking at maximum range. The vulnerability of

6525-582: The velocity of a moving target when the platform is stationary, a 2013 ARL report highlighted issues related to target range migration. However, researchers have suggested that these issues can be alleviated if the correct matched filter is used. In military airborne applications, the Doppler effect has 2 main advantages. Firstly, the radar is more robust against counter-measure. Return signals from weather, terrain, and countermeasures like chaff are filtered out before detection, which reduces computer and operator loading in hostile environments. Secondly, against

6612-411: The video feed. The original concept was created by engineer Norman Kay while tinkering with televisions as a hobby. It was based on a device which could track objects on a television screen and place a "blip" on them to indicate where it was aiming. The first test of the weapon on 29 January 1963 was a success, with the weapon making a direct hit on the target. It served successfully for three decades until

6699-574: Was a mechanical device containing a steel ball rotated by a motor whose speed was controlled by the Doppler determined ground speed. The angle of this motor was controlled by the 'drift angle'. Two fixed wheels, one 'fore and aft' the other 'left to right' drove counters to output distance along track and across track difference. The aircraft's compass was integrated into the computer so that a desired track could be set between two waypoints on an over water great circle route. It may seem surprising to 21st. century readers, but it actually worked rather well and

6786-602: Was based on Doppler principles, and originally patented as "Pulsed Doppler Radar Methods and Means," #3,196,436. Modern Doppler systems are light enough for mobile ground surveillance associated with infantry and surface ships. These detect motion from vehicles and personnel for night and all weather combat operation. Modern police radar guns are a smaller, more portable version of these systems. Early Doppler radar sets relied on large analog filters to achieve acceptable performance. Analog filters, waveguide, and amplifiers pick up vibration like microphones, so bulky vibration damping

6873-469: Was designed as a tactical nuclear missile for use in the event of Cold War hostilities in Western Europe. The first U.S. Army Corporal battalion was deployed in Europe in 1955. Eight Corporal battalions were deployed in Europe and remained in the field until 1964, when the system was replaced by the solid-fueled MGM-29 Sergeant missile system. The Corporal was the second in a series of JPL rockets for

6960-402: Was developing a similar " smart bullet " weapon designed to hit targets at a distance of up to 6 mi (10 km). Pike is a precision-guided mini-missile fired from an underslung grenade launcher. Air burst grenade launchers are a type of precision-guided weapons. Such grenade launchers can preprogram their grenades using a fire-control system to explode in the air above or beside

7047-442: Was extracted. This proved useful in both weather and air traffic control radars. The velocity information provided another input to the software tracker, and improved computer tracking. Because of the low pulse repetition frequency (PRF) of most coherent pulsed radars, which maximizes the coverage in range, the amount of Doppler processing is limited. The Doppler processor can only process velocities up to ± ⁠ 1 / 2 ⁠

7134-512: Was great improvement over other 'dead reckoning' methods available at the time. It was generally backed up with position fixes from Loran , VORs , NDBs , or as a last resort sextant and chronometer. It was possible to cross the Atlantic with an error of a couple of miles when in range of a couple of VORs or NDBs. Its major shortcoming in practice was the sea state, as a calm sea gave poor radar returns and hence unreliable Doppler measurements. But this

7221-488: Was infrequent on the North Atlantic Location-based Doppler techniques were also used in the U.S. Navy's historical Transit satellite navigation system , with satellite transmitters and ground-based receivers, and are currently used in the civilian Argos system , which uses satellite receivers and ground-based transmitters. In these cases, the ground stations are either stationary or slow-moving, and

7308-555: Was possible to strike difficult targets (such as bridges) effectively with a single mission; the Thanh Hoa Bridge , for instance, was attacked repeatedly with iron bombs, to no effect, only to be dropped in one mission with PGMs. Although not as popular as the newer JDAM and JSOW weapons, or even the older laser-guided bomb systems, weapons like the AGM-62 Walleye TV guided bomb are still being used, in conjunction with

7395-462: Was rotated by a servo mechanism to align with the aircraft's track by equalising the Doppler shift from the left and right hand antennas. A synchro transmitted the platform angle to the flight deck, thus providing a measure of 'drift angle'. The ground speed was determined from the Doppler shift between the forward and aft facing beams. These were displayed on the flight deck on single instrument. Some aircraft had an additional 'Doppler Computer'. This

7482-412: Was test fired in 2014 and 2015 and results showing the bullet altered course to correct its path to its target were released. In 2012 Sandia National Laboratories announced a self-guided bullet prototype that could track a target illuminated with a laser designator . The bullet is capable of updating its position 30 times a second and hitting targets over a mile away. In mid-2016, Russia revealed it

7569-463: Was timed to coincide with the British test firing in 1959. A 1/40 scale plastic model kit of the Corporal missile with its mobile transporter was produced in the late 1950s and was reissued by Revell - Monogram in 2009. A 1/48 scale plastic model kit of the Corporal missile with its launcher was produced in 1959 by Hawk and was reissued in 1969 in a glow in the dark version. Guided weapon A precision-guided munition ( PGM ), also called

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