Misplaced Pages

#203796

61-518: On September 6, 1976, Soviet Air Forces pilot Viktor Belenko successfully defected to the West, flying his MiG-25 'Foxbat' to Hakodate , Japan. During this incident, Japan Self-Defense Force radar lost track of the aircraft when Belenko flew his MiG-25 at a low altitude, prompting the Japan Air Self-Defense Force (JASDF) to consider procurement of airborne early warning aircraft. In 1976,

122-474: A coherent oscillator with very little noise. Phase noise reduces sub-clutter visibility performance by producing apparent motion on stationary objects. Cavity magnetron and crossed-field amplifier are not appropriate because noise introduced by these devices interfere with detection performance. The only amplification devices suitable for pulse-Doppler are klystron , traveling wave tube , and solid state devices. Pulse-Doppler signal processing introduces

183-746: A US air base in South Korea; the MiG is in the permanent collection of the National Museum of the U.S. Air Force , displayed in its original owner markings. Later, Soviet Captain Aleksandr Zuyev flew his MiG-29 to Trabzon , Turkey, on 20 May 1989. That MiG-29 was promptly returned to the Soviets. The MiG-25's arrival in Japan was a windfall for Western military planners. The Japanese government had originally allowed

244-567: A budget of JPY 113.9 billion to procure two E-767s in fiscal year 1993 and JPY108.1 billion for two more E-767s in FY 1994. This large budget compared to approximately JPY8.6 billion for the E-2C and an estimated JPY29.6 billion for the E-3A was politically rationalized as a means to help ease the tension over Japan's large trade surplus against the U.S. In addition, Japanese aerospace companies are responsible for 15% of

305-822: A consultant for several years thereafter. Belenko had brought with him the pilot's manual for the MiG-25 since he expected to assist US pilots in evaluating and testing the aircraft. Belenko was not the only pilot to have defected from the Soviet Union in this way or even the first to defect from a Soviet-bloc country. He might have been aware of the US government's policy of awarding large cash prizes to defecting pilots of communist countries. In March and May 1953, two Polish Air Force pilots Lieutenant Franciszek Jarecki and Lieutenant Zdzisław Jaźwiński flew MiG-15s to Denmark. Later in 1953, North Korean pilot No Kum Sok flew his MiG-15 to

366-466: A new high-reliability multi-processor and rewrites the software to facilitate future maintenance and enhancements. The RSIP kit, built principally by Northrop Grumman Electronic Systems under a subcontract to Boeing, consists of a new radar computer, a radar control maintenance panel as well as software upgrades to the radar and mission system programs. The first E-767 made the first flight on October 4, 1994 at Paine Field , Washington . First flight with

427-408: A phenomenon called scalloping. The name is associated with a series of holes that are scooped-out of the detection performance. Scalloping for pulse-Doppler radar involves blind velocities created by the clutter rejection filter. Every volume of space must be scanned using 3 or more different PRF. A two PRF detection scheme will have detection gaps with a pattern of discrete ranges, each of which has

488-418: A son from his first marriage, never divorced his first wife, and never provided child support to her after his defection, but Belenko denied this. The journalists also claimed that his Soviet wife appealed for his return after his defection. Belenko co-wrote a 1980 autobiography, MiG Pilot: The Final Escape of Lieutenant Belenko with Reader's Digest writer John Barron , which confirmed that he had

549-404: A vulnerability region in pulse-amplitude time-domain radar . Non-Doppler radar systems cannot be pointed directly at the ground due to excessive false alarms, which overwhelm computers and operators. Sensitivity must be reduced near clutter to avoid overload. This vulnerability begins in the low-elevation region several beam widths above the horizon, and extends downward. This also exists throughout

610-616: A wife and son in the USSR, although Belenko had previously told his son that this was Soviet propaganda. Belenko almost never appeared in interviews during his life in the United States . He feared for his life until the day he died. However, in a brief and informal bar interview in 2000, he said that he was happy in the United States, remarking, "[Americans] have tolerance regarding other people's opinion. In certain cultures, if you do not accept

671-455: Is 5 km to 50 km. Range and velocity cannot be measured directly using medium PRF, and ambiguity resolution is required to identify true range and speed. Doppler signals are generally above 1 kHz, which is audible, so audio signals from medium-PRF systems can be used for passive target classification. Radar systems require angular measurement. Transponders are not normally associated with pulse-Doppler radar, so sidelobe suppression

SECTION 10

#1732845644204

732-617: Is a Pulse-Doppler radar that can determine the velocity of a tracked target. This surveillance system includes a flexible, multi-mode radar, which enables AWACS to separate maritime and airborne targets from ground and sea clutter returns that limit other modern radar systems. Its radar has a 360-degree view, and at operating altitudes it can detect targets more than 320 kilometers (200 miles) away. AWACS mission equipment can separate, manage and display these targets individually on situational displays. AN/APY-2's antenna and Identification Friend or Foe (IFF) Mk XII system's antenna are housed in

793-572: Is aimed above the horizon to avoid an excessive false alarm rate, which renders systems vulnerable. Aircraft and some missiles exploit this weakness using a technique called flying below the radar to avoid detection ( nap-of-the-earth ). This flying technique is ineffective against pulse-Doppler radar. Pulse-Doppler provides an advantage when attempting to detect missiles and low observability aircraft flying near terrain, sea surface, and weather. Audible Doppler and target size support passive vehicle type classification when identification friend or foe

854-579: Is also known as clutter rejection. Rejection velocity is usually set just above the prevailing wind speed (10 to 100 mph or 20 to 160 km/h). The velocity threshold is much lower for weather radar . | Doppler frequency × C 2 × transmit frequency | > velocity threshold . {\displaystyle \left\vert {\frac {{\text{Doppler frequency}}\times C}{2\times {\text{transmit frequency}}}}\right\vert >{\text{velocity threshold}}.} In airborne pulse-Doppler radar,

915-594: Is likely to be transacted, and because the USSR, with its political standing in Tokyo so low, can ill-afford setbacks in Soviet–Japanese economic cooperation." Belenko started a new life in the United States. In 1980, the US Congress enacted S. 2961, authorizing citizenship for him, which was signed into law by President Jimmy Carter on 14 October 1980, as Private Law 96-62. Eager to avoid attention, and reprisal from

976-410: Is low (above horizon with clear skies). The antenna type is an important consideration for multi-mode radar because undesirable phase shift introduced by the radar antenna can degrade performance measurements for sub-clutter visibility. The signal processing enhancement of pulse-Doppler allows small high-speed objects to be detected in close proximity to large slow moving reflectors. To achieve this,

1037-410: Is not available from a transponder signal . Medium pulse repetition frequency (PRF) reflected microwave signals fall between 1,500 and 15,000 cycle per second, which is audible. This means a helicopter sounds like a helicopter, a jet sounds like a jet, and propeller aircraft sound like propellers. Aircraft with no moving parts produce a tone. The actual size of the target can be calculated using

1098-472: Is required for practical operation. Tracking radar systems use angle error to improve accuracy by producing measurements perpendicular to the radar antenna beam. Angular measurements are averaged over a span of time and combined with radial movement to develop information suitable to predict target position for a short time into the future. The two angle error techniques used with tracking radar are monopulse and conical scan . Pulse-Doppler radar requires

1159-463: Is survived by two sons and four grandchildren. However, journalists learned about his death only at the end of November. One of his sons told the newspaper that his father had died after a short illness. There was no memorial service. Pulse-Doppler radar A pulse-Doppler radar is a radar system that determines the range to a target using pulse-timing techniques, and uses the Doppler effect of

1220-535: Is the angle offset between the antenna position and the aircraft flight trajectory. Surface reflections appear in almost all radar. Ground clutter generally appears in a circular region within a radius of about 25 miles (40 km) near ground-based radar. This distance extends much further in airborne and space radar. Clutter results from radio energy being reflected from the earth surface, buildings, and vegetation. Clutter includes weather in radar intended to detect and report aircraft and spacecraft. Clutter creates

1281-487: Is the phase shift induced by range motion. Rejection speed is selectable on pulse-Doppler aircraft-detection systems so nothing below that speed will be detected. A one degree antenna beam illuminates millions of square feet of terrain at 10 miles (16 km) range, and this produces thousands of detections at or below the horizon if Doppler is not used. Pulse-Doppler radar uses the following signal processing criteria to exclude unwanted signals from slow-moving objects. This

SECTION 20

#1732845644204

1342-648: The U.S. Air Force was about to deploy the E-3 Sentry airborne warning and control system aircraft, which was considered to be the prime candidate for the airborne early warning mission by JASDF. However, the Japan Defense Agency (JDA, now Ministry of Defense ) realized that the E-3 would not be readily available due to USAF needs and instead opted to procure the American E-2 Hawkeye AWACS aircraft. The E-2C

1403-524: The frequency ambiguity resolution process. The range resolution is the minimal range separation between two objects traveling at the same speed before the radar can detect two discrete reflections: range resolution = C PRF × ( number of samples between transmit pulses ) . {\displaystyle {\text{range resolution}}={\frac {C}{{\text{PRF}}\times ({\text{number of samples between transmit pulses}})}}.} In addition to this sampling limit,

1464-410: The 1960s. Earlier radars had used pulse-timing in order to determine range and the angle of the antenna (or similar means) to determine the bearing. However, this only worked when the radar antenna was not pointed down; in that case the reflection off the ground overwhelmed any returns from other objects. As the ground moves at the same speed but opposite direction of the aircraft, Doppler techniques allow

1525-518: The E-767 is essentially the same as the later E-3 models, using Northrop Grumman 's (formerly Westinghouse Electronic Systems) AN/APY-2 Passive electronically scanned array radar system. This system is a three-dimensional radar that measures azimuth, range, and elevation simultaneously, and has superior surveillance capability over water compared to the AN/APY-1 system on the earlier E-3 models. The AN/APY-2

1586-586: The Soviet Union, he took the surname Schmidt and moved around often, mostly living in small towns across the Midwest. He worked as a consultant to aerospace companies and government agencies, and married a music teacher from North Dakota , Coral Garaas. They had two sons before divorcing. The Soviet Union repeatedly spread false stories about Belenko being killed in a car accident, returning to Russia , being arrested and executed, or otherwise brought to justice. Russian journalists claimed that Belenko allegedly also had

1647-598: The Soviets finally submitted to the Japanese terms on 22 October 1976. The aircraft was moved from Hyakuri to the port of Hitachi on 11 November 1976 on a convoy of trailers. It left in 30 crates aboard the Soviet cargo ship Taigonos on 15 November 1976 and arrived about three days later in Vladivostok . A team of Soviet technicians had been allowed to view subassemblies at Hitachi, and upon finding 20 missing parts, one being film of

1708-507: The U.S. government under Foreign Military Sales rules. The base airframe for E-767 is that of a 767-200ER, Boeing designation 767-27C. (The "7C" designation is the Boeing customer code for the JASDF). The 767 airframe offers about 50 percent more floor space and nearly twice the volume of the 707 on which the E-3 is based. The mission electronics equipment are installed in forward cabin to balance

1769-558: The United States Air Force, and later for the Lockheed YF-12 . The US's first pulse-Doppler radar, the system had look-down/shoot-down capability and could track one target at a time. It became possible to use pulse-Doppler radar on aircraft after digital computers were incorporated in the design. Pulse-Doppler provided look-down/shoot-down capability to support air-to-air missile systems in most modern military aircraft by

1830-407: The United States to examine the plane and to conduct ground tests of the radar and engines only; however, it subsequently allowed the US to dismantle the plane to examine it extensively. The plane was moved by a US Air Force C-5 Galaxy cargo aircraft from Hakodate to Hyakuri Air Base on 25 September, and by then, experts had determined that the plane was an interceptor, not a fighter-bomber, which

1891-418: The aft fuselage contains an antenna for JTIDS ( Joint Tactical Information Distribution System ). The E-767 is powered by two General Electric CF6-80C2B6FA high bypass turbofan engines, generating 273.6 kN (61,500 pounds) thrust each. The original 90 kW electrical generators (one in each engine) were replaced with 150 kW generators to provide power to the radar and other equipment. The electronics system on

Boeing E-767 - Misplaced Pages Continue

1952-434: The airframe production for the 767, meaning some of the money would indirectly return to Japan. The procurement of E-767 by Japanese government was split into two stages. The first stage was the procurement of an unmodified 767 aircraft by the Japanese government through a trading company, Itochu Corporation. In the second stage, the aircraft were modified to carry AWACS equipment by US and Japanese contractors supervised by

2013-458: The audible signal. Ambiguity processing is required when target range is above the red line in the graphic, which increases scan time. Scan time is a critical factor for some systems because vehicles moving at or above the speed of sound can travel one mile (1.6 km) every few seconds, like the Exocet , Harpoon , Kitchen , and air-to-air missiles . The maximum time to scan the entire volume of

2074-403: The center is mounted above the aft fuselage on two struts. The rotodome rotates at about six rpm during operations and at 0.25 rpm to lubricate the rotation mechanisms even when the radar is not used. There are numerous blade antennae for UHF and VHF communication along the centerline of the fuselage on the top and bottom. There is a rod antenna at each wing tip for HF communication. A fairing in

2135-924: The duration of the transmitted pulse could mean that returns from two targets will be received simultaneously from different parts of the pulse. The velocity resolution is the minimal radial velocity difference between two objects traveling at the same range before the radar can detect two discrete reflections: velocity resolution = C × PRF 2 × transmit frequency × filter size in transmit pulses . {\displaystyle {\text{velocity resolution}}={\frac {C\times {\text{PRF}}}{2\times {\text{transmit frequency}}\times {\text{filter size in transmit pulses}}}}.} Pulse-Doppler radar has special requirements that must be satisfied to achieve acceptable performance. Pulse-Doppler typically uses medium pulse repetition frequency (PRF) from about 3 kHz to 30 kHz. The range between transmit pulses

2196-457: The flight to Hakodate, the Soviets attempted to charge Japan US $ 10 million. Neither the Japanese nor the Soviet bill is known to have been paid. A senior diplomat described the Soviet position as "sulky about the whole affair." The CIA concluded at the time that "both countries seem anxious to put the problem behind them" and speculated that the Soviets were reluctant to cancel a series of upcoming diplomatic visits because "some useful business

2257-423: The ground return to be filtered out, revealing aircraft and vehicles. This gives pulse-Doppler radars " look-down/shoot-down " capability. A secondary advantage in military radar is to reduce the transmitted power while achieving acceptable performance for improved safety of stealthy radar. Pulse-Doppler techniques also find widespread use in meteorological radars , allowing the radar to determine wind speed from

2318-402: The mainstream, you would be booted out or might disappear. Here we have people—you know, who hug trees, and people who want to cut them down—and they live side by side!" In this interview he also claimed that he visited Moscow but did not provide any evidence of his trip. Viktor Belenko died in a nursing home in the small town of Rosebud, Illinois on September 24, 2023, at the age of 76. He

2379-448: The mid 1970s. Pulse-Doppler systems measure the range to objects by measuring the elapsed time between sending a pulse of radio energy and receiving a reflection of the object. Radio waves travel at the speed of light , so the distance to the object is the elapsed time multiplied by the speed of light, divided by two – there and back. Pulse-Doppler radar is based on the Doppler effect , where movement in range produces frequency shift on

2440-477: The phase of each transmitted pulse for comparison to returned echoes. Early examples of military systems includes the AN/SPG-51 B developed during the 1950s specifically for the purpose of operating in hurricane conditions with no performance degradation. The Hughes AN/ASG-18 Fire Control System was a prototype airborne radar/combination system for the planned North American XF-108 Rapier interceptor aircraft for

2501-499: The radar to separate the reflections from multiple objects located in the same volume of space by separating the objects using a spread spectrum to segregate different signals: v = target speed = λ Δ Θ 4 π Δ t , {\displaystyle v={\text{target speed}}={\frac {\lambda \Delta \Theta }{4\pi \Delta t}},} where Δ Θ {\displaystyle \Delta \Theta }

Boeing E-767 - Misplaced Pages Continue

2562-502: The return signals from at least 3 different PRFs can be processed out to the maximum anticipated detection range. This is known as dwell time . Antenna motion for pulse-Doppler must be as slow as radar using MTI . Search radar that include pulse-Doppler are usually dual mode because best overall performance is achieved when pulse-Doppler is used for areas with high false alarm rates (horizon or below and weather), while conventional radar will scan faster in free-space where false alarm rate

2623-957: The returned signal has a phase difference, or phase shift , from pulse to pulse. This causes the reflector to produce Doppler modulation on the reflected signal. Pulse-Doppler radars exploit this phenomenon to improve performance. The amplitude of the successively returning pulse from the same scanned volume is I = I 0 sin ⁡ ( 4 π ( x 0 + v Δ t ) λ ) = I 0 sin ⁡ ( Θ 0 + Δ Θ ) , {\displaystyle I=I_{0}\sin \left({\frac {4\pi (x_{0}+v\Delta t)}{\lambda }}\right)=I_{0}\sin(\Theta _{0}+\Delta \Theta ),} where So Δ Θ = 4 π v Δ t λ . {\displaystyle \Delta \Theta ={\frac {4\pi v\Delta t}{\lambda }}.} This allows

2684-588: The returned signal to determine the target object's velocity. It combines the features of pulse radars and continuous-wave radars , which were formerly separate due to the complexity of the electronics . The first operational pulse-Doppler radar was in the CIM-10 Bomarc , an American long range supersonic missile powered by ramjet engines, and which was armed with a W40 nuclear weapon to destroy entire formations of attacking enemy aircraft. Pulse-Doppler systems were first widely used on fighter aircraft starting in

2745-535: The rotodome back to back. The information acquired by the radar system is processed by IBM's CC-2E central computer conformed to E-3 Block 30/35 Modification and can be displayed on the 14 displays on board. Other major subsystems in the E-767 are identification, tactical data link, and navigation. In November 2006, Boeing was awarded a $ 108 million contract to deliver Radar System Improvement Program (RSIP) kits to Japan's fleet of four E-767 Airborne Warning and Control System (AWACS) aircraft. The Foreign Military Sale

2806-722: The rotodome installed occurred on August 9, 1996 and it was delivered to JASDF on March 11, 1998 along with the second E-767. Aircraft No. 3 and No. 4 were delivered on January 5, 1999. On May 10, 2000, all four E-767s were put into service with Airborne Early Warning Group (AEWG) 601st Squadron at JASDF Hamamatsu Air Base . (The airbase's runways needed to be reinforced to accommodate the E-767.) Data from 767 AWACS B767-200 General characteristics Performance Avionics Related development Aircraft of comparable role, configuration, and era Viktor Belenko Viktor Ivanovich Belenko ( Russian : Виктор Иванович Беленко ; February 15, 1947 – September 24, 2023)

2867-435: The signal reflected from the target. Doppler frequency = 2 × transmit frequency × radial velocity C . {\displaystyle {\text{Doppler frequency}}={\frac {2\times {\text{transmit frequency}}\times {\text{radial velocity}}}{C}}.} Radial velocity is essential for pulse-Doppler radar operation. As the reflector moves between each transmit pulse,

2928-477: The sky must be on the order of a dozen seconds or less for systems operating in that environment. Pulse-Doppler radar by itself can be too slow to cover the entire volume of space above the horizon unless fan beam is used. This approach is used with the AN/SPS 49(V)5 Very Long Range Air Surveillance Radar, which sacrifices elevation measurement to gain speed. Pulse-Doppler antenna motion must be slow enough so that all

2989-445: The transmitter must be coherent and should produce low phase noise during the detection interval, and the receiver must have large instantaneous dynamic range . Pulse-Doppler signal processing also includes ambiguity resolution to identify true range and velocity. The received signals from multiple PRF are compared to determine true range using the range ambiguity resolution process. The received signals are also compared using

3050-530: The velocity of any precipitation in the air. Pulse-Doppler radar is also the basis of synthetic aperture radar used in radar astronomy , remote sensing and mapping. In air traffic control , they are used for discriminating aircraft from clutter. Besides the above conventional surveillance applications, pulse-Doppler radar has been successfully applied in healthcare, such as fall risk assessment and fall detection, for nursing or clinical purposes. The earliest radar systems failed to operate as expected. The reason

3111-598: The velocity threshold is offset by the speed of the aircraft relative to the ground. | Doppler frequency × C 2 × transmit frequency − ground speed × cos ⁡ Θ | > velocity threshold , {\displaystyle \left\vert {\frac {{\text{Doppler frequency}}\times C}{2\times {\text{transmit frequency}}}}-{\text{ground speed}}\times \cos \Theta \right\vert >{\text{velocity threshold}},} where Θ {\displaystyle \Theta }

SECTION 50

#1732845644204

3172-508: The volume of moving air associated with weather phenomenon. Pulse-Doppler radar corrects this as follows. Clutter rejection capability of about 60 dB is needed for look-down/shoot-down capability, and pulse-Doppler is the only strategy that can satisfy this requirement. This eliminates vulnerabilities associated with the low-elevation and below-horizon environment. Pulse compression and moving target indicator (MTI) provide up to 25 dB sub-clutter visibility. An MTI antenna beam

3233-408: The weight with the rotodome mounted above the aft fuselage. The aft cabin contains the crew's rest area, galley, and lavatory. The E-767's exterior is usually painted gray. The 767's windows were omitted in order to protect the crew and equipment from the intense radio frequency transmissions from its radar equipment. A rotodome about 30 feet (9.14 m) in diameter and six feet (1.83 m) thick at

3294-562: Was a Russian-born American aerospace engineer and Soviet pilot who defected in 1976 to the West while flying his MiG-25 "Foxbat" jet interceptor and landed in Hakodate , Japan. George H. W. Bush , the Director of Central Intelligence at the time, called the opportunity to examine the plane up close an "intelligence bonanza" for the West. Belenko later became a U.S. aerospace engineer . Belenko

3355-564: Was a welcome reassurance for Japanese defense planners. On 2 October 1976, the Japanese Government announced that it would ship the aircraft in crates from the port of Hitachi and billed the Soviets US$ 40,000 for crating services and airfield damage at Hakodate. The Soviets responded with a request to return the plane via their own Antonov An-22 aircraft after a rigorous inspection of the crates. The Japanese government refused, and

3416-510: Was adapted for use with weather radar in the 1950s after declassification of some World War II systems. Pulse-Doppler radar was developed during World War II to overcome limitations by increasing pulse repetition frequency . This required the development of the klystron , the traveling wave tube , and solid state devices. Early pulse-dopplers were incompatible with other high power microwave amplification devices that are not coherent , but more sophisticated techniques were developed that record

3477-560: Was born in Nalchik , Russian SFSR , in a Russian family (his passport states his ethnicity as Russian). Lieutenant Belenko was a pilot with the 513th Fighter Regiment, 11th Air Army , Soviet Air Defence Forces based in Chuguyevka , Primorsky Krai . On 6 September 1976, he successfully defected to the West by flying his MiG-25 jet fighter to Hakodate Airport in Hokkaido , Japan. This

3538-595: Was contracted through the Electronic Systems Center at Hanscom Air Force Base , Massachusetts . The sale also includes spare and repair parts, support equipment and technical documentation. Installation of the kits was completed December 2012, in Seattle, Washington. RSIP increases the AWACS aircraft's radar sensitivity, allowing it to detect and track smaller targets. It also improves the radar's existing computer with

3599-697: Was put into service with the Airborne Early Warning Group (AEWG) at JASDF Misawa Air Base in January 1987. In 1991, the JDA requested funds to upgrade the airborne early warning system by procuring the E-3. Production of the Boeing 707 -based E-3 airframe had ended in 1991, however, and the plan was shelved. The following year, Boeing proposed a 767-based AWACS, and the JDA agreed to procure two E-767 in fiscal year 1993 and two more in fiscal year 1994. JDA requested

3660-551: Was the first time that Western military intelligence were able to get a close look at the aircraft and its specifications, and many secrets and surprises were revealed. His defection caused significant damage to the Soviet Air Force . Belenko was granted asylum by U.S. President Gerald Ford , and a trust fund was set up for him, which granted him a very comfortable living in later years. The US government debriefed him for five months after his defection and employed him as

3721-543: Was traced to Doppler effects that degrade performance of systems not designed to account for moving objects. Fast-moving objects cause a phase-shift on the transmit pulse that can produce signal cancellation. Doppler has maximum detrimental effect on moving target indicator systems, which must use reverse phase shift for Doppler compensation in the detector. Doppler weather effects (precipitation) were also found to degrade conventional radar and moving target indicator radar, which can mask aircraft reflections. This phenomenon

SECTION 60

#1732845644204
#203796