Military Review

All-seeing eye of Stockholm


One of the most widespread radio engineering complexes (RTK) in the world, used as part of aviation early warning and control systems (AWACS) is the Erieye system, developed by the Swedish company Saab Electronic Defense Systems. Distinctive features of the RTK are the use in its composition of a pulse-Doppler radar station (radar) based on an active phased antenna array (AFAR) and the presence of a whole family of sub-options that differ in the type of aircraft carrier. It was this complex that was adopted by the Swedish Air Force and several other countries of the world.


The S-100B “Argus” (Argus) airborne complex consisting of Saab 340B aircraft and FSR-890 RTKs was developed by order of the Royal Swedish Air Force and is primarily intended for detecting and tracking air targets and transmitting data about them to land (ship) command posts and fire weapons of destruction. The complex is compatible with NATO's unified air defense support system, and secure data exchange is provided via Link-E, L16 and L11.

The aircraft is capable of solving the problem of detecting and selecting (classifying and generating target indication data) both airborne and ground (surface) mobile targets, and the characteristics of the radar used allow the complex to detect and track targets with a speed of 14 – 2000 km / h.

It should be particularly noted that this aviation complex is not intended for direct control and guidance of tactical aviation forces, but is used only as a repeater of the relevant commands transmitted from ground command posts, although in the future the possibility of appropriate modification of this aviation complex is considered (for this purpose, will install the appropriate hardware). Therefore, by and large, the S-100B “Argus” cannot be considered a full-fledged DRLOI aircraft, but rather can be assigned to a subclass of DRLO aircraft. But we, in order to avoid confusion, will apply the term AEW and to all the considered complexes.

History The creation of the Argus dates back to 1982, when preliminary work began in Sweden to create the first aircraft of this class for the national Air Force, the distinctive features of which were: the relatively small size of the aircraft carrier and the entire complex as a whole; ability to be operated without restrictions from unprepared or in the allowable amount of damaged runways (airfields); low compared with foreign analogues cost of the life cycle of the entire complex.

After “settling” all the problematic issues, the Logistics Department of the Swedish Defense Ministry in 1985 entered into a contract with Ericsson Microveive Systems (today it is Saab Electronic Defense Systems) for the development of Eriay radio engineering complex FSR-890.

In this case, as already indicated, the radio engineering complex was originally planned to be built on the basis of a radar with an active phased antenna array. The choice of this type of antenna, as well as its placement in a fixed rectangular fairing at the top of the aircraft carrier fuselage, was at that time a rather unusual and bold decision on the part of the developer and was implemented in practice, according to foreign experts, for the first time in the history of world military aviation . This decision was dictated by the impossibility to install a rotating radome radome with the required characteristics and a number of other factors on the aircraft selected as a carrier.

In 1985, the full-size mock-up of such an AFAR was mounted on the Fairchild Aerospace Metro III twin-engine turboprop aircraft (Fairchild Swearingen Metroliner), which was created at the time as an airliner for local airlines and in 1984 – 1987 years delivered by the Swedish Air Force TX-XXX in the 88 – 1987 years used by the Swedish Air Force for local airlines. -carriage A little later, in the 88 year, the aircraft already had a “live” radar stationed to conduct the corresponding flight test complex. In the latter case, the aircraft TP227C / SA-421AC (serial number AC-88003B, registration number 883, board. No. 1987), delivered by the Swedish military in XNUMX, was selected for testing.

The first flight with a full radar installed on it took place in January 1991 years. In general, the tests were successful, but the command of the Swedish Air Force insisted that the aircraft used for the radar station was not foreign, in this case American, but nationally developed. As a candidate for the carriers of the radio-technical complex, the twin-engine turboprop passenger airliner Saab 340В was chosen, the main design differences of which in the modified version were the front radar antenna and two under-fuselage crests, which were installed to ensure acceptable stability of the aircraft.

The first flight of the modified Saab 340B made 1994 of the year in January, and the 1 of June of the same year began flight tests of the aircraft already installed on the radar of the new RTK. After resolving all the technical and bureaucratic issues, the Swedish Ministry of Defense signed a contract with the development company for the supply of six AEW systems at the base of the Saab 340В glider. they were designated S-100B «Argus» In the Swedish military.


In peacetime, most of the Swedish aircraft of the Argus family accomplish the tasks of military transport aviation and are equipped with a radio-technical complex only during a threatened period. Photo of Luke Willems

The production of new RTKs was started back in 1993, the first aircraft took off, as already mentioned, in 1994, and in 1996, the first two aircraft from the Eriay RTK were handed over to the customer. By May 2000, a squadron was deployed from the six DRLOI airplanes with the Eriai complex, which was deployed at the Uppsala air base. Subsequently, two S-100B “Argus” aircraft were leased to the Greek Air Force - for the period up to 2003, until they received the EMER-145-type airborne aircraft ordered by them with the Eriay complex.

In July 2006, the Saab company received a contract from the Swedish Ministry of Defense to upgrade two S-100B aircraft to the “multipurpose intelligence” version. The upgraded aircraft received the designation S-100D "Argus" (brand designation - Saab 340B AEW-300) and equipped with radio engineering complex ASC-890 "Eriay". And in November 2007, Thailand expressed its readiness to acquire two S-100B Argus planes from the combat strength of the Swedish Air Force. The relevant contract was signed between the Thai Air Force and the MTO Directorate of the MoD of Sweden in 2008. The delivery of two DRLOI aircraft and another Saab 340 aircraft in the transport and training version was provided for as part of a larger contract worth $ 1,1 billion, which also included the delivery of Gripen JAS-12 fighter jets and various equipment. In the framework of the first stage, the Thai Air Force received one DAROI aircraft and one Saab 39 transport and training aircraft, as well as four Gripen D fighters and four Gripen S fighters. In the framework of the second stage, the customer in December 340 of the year received from Sweden a second AEW plane.

Currently, the Swedish Air Force has four Argus-class airplanes, but in peacetime only two of them - S-100D airplanes - are equipped with Eriai-type air defense missiles and are used in their intended form as airborne aeronautical airplanes. In peacetime, the other two vehicles are used as military transport vehicles, and the Eriai complex should be equipped only in a threatened period (wartime). It is alleged that the conversion requires no more than 24 hours.

Two more airplanes with Eriai-type RTK based on the airframe of the Saab 340 aircraft after negotiations that had been going on for several years, were ordered by the UAE Air Force. The Swedish company issued a press release on this 17 contract on November 2009 of the year. It indicated, in particular, that the contract value is 1,5 billion Swedish kronor, and its subject is the delivery of two DRLOi airplanes based on the Saab 340 glider with a modernized version of the Eriai RTK, the delivery of ground equipment to the customer and the implementation of after-sales technical support and providing, as well as assistance in training the customer’s specialists in the operation of these aircraft and their on-board equipment.

In addition, four DRLOI airplanes with the Eriai-type RTC, but based on the Saab 2000 aircraft, acquired the Pakistan Air Force. A number of sources also claim that another Saab 2000 aircraft is used by the Pakistani military as training aircraft for training pilots, operators and technical personnel.

The contract for the supply of four airplanes of the Airborne Forces Saab 2000 Eriay was signed between Pakistan and Sweden in June of the 2006 year. Moreover, Islamabad initially planned to purchase the Saab 14 family of 2000, of which seven were in the Eriay Saab 2000 aircraft version, and the other seven in passenger modification for the state-owned airline PIA (Pakistan International Airlines). However, then the order was reduced.

DRLOU aircraft were made for a Pakistani customer by retrofitting Saab 2000 serial aero liners. The Pakistani contract was executed jointly by Saab (two thirds of the scope of work) and Erickson Microwave Systems (one third of the total scope of work). At the same time, the radio-technical complex was modified in accordance with the requirements of the Pakistan Air Force, and the number of automated workplaces was increased to seven. Pakistani Saab 2000 aircraft can also be used as an integral part of a distributed AWACN network for transmitting real-time data directly to a ground command and control network.

The first car was delivered at the end of 2009, the solemn ceremony of handing over the aircraft to the customer took place on December 8. The Swedish aircraft manufacturers and electronic engineers handed over the second Saab 2000 to the Pakistan Air Force 24 on April 2010, and the customer received the remaining two cars before the end of the 2010 of the year.

The cost of the Pakistani contract was not publicly announced by Swedish contractors, but some foreign media reported that the “Pakistani” contract is estimated at 4,5 billion Swedish kronor or about 667,2 million dollars at the then rate, including the cost of supplying ground equipment for ground receiving points and information processing, simulators and aircraft maintenance during 30 years of operation.

Malaysia has shown interest in acquiring DRLOI aircraft based on the Saab 340 glider, but the contract has not yet been signed. And one of the conditions put forward by the Malaysian customer is 100-percent technology transfer.


The radio engineering complex FSR-890 “Eriay” was developed by the Swedish company “Erikson” based on the PS-890 “Eriay” multi-functional pulse Doppler radar station, which operates in the S-band (wavelength - 10 cm, frequency - 3,2 GHz). This radar has a flat two-way active phased antenna array with a length of 9,75 m and a width of 0,78 m with electronically controlled beam pattern. The beam is controlled by an automatic system. Moreover, due to the fact that this system sets its own radiation direction for each pulse, a higher range, speed and accuracy of detection of air and ground / surface targets are provided.

The antenna array is located on the carrier aircraft in a radio transparent foam-shaped fairing, having the form of a beam of rectangular cross section and mounted on pylons located on the top along the aircraft fuselage. AFAR has 192 solid-state transceiver module cooled by air flow through the air intake in front of the antenna radome. In this case, transceiver modules can be used not only as radar elements, but also capable of solving problems of receiving / transmitting information and setting active electromagnetic interference. According to foreign sources, the antenna has a high degree of noise immunity, which is provided, among other things, by the low level of its side lobes, which does not exceed -50 dB.

According to the data set out in the work of VS The willows of the “Aviation complexes of the radar watch and guidance: state and development trends”, published by the publishing house “Radiotekhnika” in 2008, in the PS-890 radar “adapted signals with frequency and phase manipulation with pulse compression and varying operating frequency are used. To eliminate the ambiguity of measuring the distance to the object and improve the accuracy of determining the coordinates and speed of the target, low and medium pulse repetition frequencies are used ”(manipulation or, as it is also called, digital modulation is a modulation by a discrete signal).

The radar of the considered airborne radio-technical complex provides a high-precision overview of the surrounding space in azimuth in two sectors -75 degrees deg. / + 75 deg. Perpendicular to the longitudinal axis of its antenna (outside these sectors a review of the airspace and the detection of air targets is also provided, but with degraded performance and without the possibility of tracking the targets), and the elevation angle is observed in the -9 grad. / + 9 degrees The width of the antenna pattern is in azimuth, according to various sources, 0,7 degrees. or 1 degrees, and 9 degrees are around the elevation.

The maximum instrumental range of detection of radar air targets when flying at an altitude of 6000 m, according to the foreign open press, is 450 km, including their over-the-horizon detection. During demonstration flights conducted by a developer for a wide range of specialists, the radio engineering complex provided detection of low-altitude air targets at distances up to 400 km, and ground and surface targets - up to 300 km. In addition, to increase the target detection range, it is possible to ensure maximum radiation power by scanning the space radar on one side only (sides). The range of detection of surface targets is limited, according to the specialists of the developer, only to the distance to the horizon - about 350 km. When patrolling at high altitude, the DRLOI aircraft equipped with the Eriai RTK is capable of controlling space over an area of ​​more than 500 000 square. at the same time searching and tracking air targets at altitudes up to 20 km.

The RTK FSR-890 radar of the PS-890 type has three modes of operation:

- basic (normal) airspace review;

- an expanded overview of the airspace, in which, due to the narrowing of the scanning sector and an increase in scanning time, the detection range of airborne targets is also increased for EPR targets around 2 sq. m is about 300 km;

- overview of ground / surface space.

The composition of the radio complex FSR-890, in addition to the main means - the radar station - also includes other subsystems.

All-seeing eye of Stockholm

Pakistani military ordered an aviation complex based on the Eriai system, stationed on a Saab 2000 aircraft. Photo from

The subsystem of state recognition of “one’s own — alien” type Mk 12. It includes the interrogator, two antennas placed at the ends of the main antenna radome and forming a narrow radiation pattern in the azimuthal and fan radiation pattern in the angular planes, and the master oscillator. Along with determining the nationality of the targets, the subsystem identifies them individually with the identification of the on-board or other registration number of the aircraft, helicopter or ship, and also determines the location of the target and allows you to get some other data (the working zone is in azimuth - similar to the radar review sectors, the detection range is not less than 300 km, the accuracy of determining the coordinates of the objects followed - 1,0 - 1,5 degrees.). The operating modes of the subsystem - 1, 2, 3 / A, C, 4 and S, are based on the “NATO” standard STANAG 4193. According to foreign specialized sources, the effective detection range of a fighter-type target is 300 – 470 km, and the detection range of surface targets is up to 320 km.

The Radio and Electronic Intelligence Station (RRTR) allows, at a distance of up to 400 km, to detect, classify and locate sources of radio emission from airborne, ground-based and surface (ship-based) bases with an operating frequency range within 0,5 – 18 GHz, but with the possibility of its extension to 40 GHz.

Antenna system of the station РРТР performs reception in the horizontal plane - omnidirectionally, and in the vertical - in the sectors

-35 degrees / + 35 degrees (operating frequency range 0,5-2 GHz) and -20 degrees. / + 15 degrees (2-18 GHz), while the accuracy of determining the carrier frequency of the pulse signal is 8 MHz or 1 MHz with high accuracy, and continuous - 100 kHz. According to the information given in the above-mentioned work “Aviation Complexes of the Radar Watch and Guidance”, the direction of arrival of the pulse signal is determined with an accuracy not worse than 2 ±, and continuous is not worse than 5 ±.

The data received by the PPTP station are compared with those samples of signals stored in a database with more than 2000 storage units and with information from the radar station, resulting in increased range and recognition probability of the class and type of objects detected. It should be particularly noted that all information received by the PPTP station is stored in a memory device and, as necessary and possible, is transmitted to ground (ship) information receiving and processing points in near real time scale.

Complex communication and data exchange. Includes four VHF radio stations, satellite communications equipment operating in the Ku band, as well as two backup radio stations of the microwave range. VHF radio stations are designed to provide telephone communication and exchange data with air objects using amplitude and frequency modulated signals (AM and FM signals) with programmable frequency tuning. The data transfer rate is 4,8 kbps. Microwave radio stations, in turn, are used to carry out high-speed - 64 kbit / s - exchange of the obtained intelligence data with ground and ship data reception and processing points at a distance of up to 300 km, as well as to provide telephone communication with designated consumers through two duplex channels . Moreover, the probability of interception of information by the adversary is allegedly reduced due to the use of a broadband signal in these stations with a spectrum width of about 1 MHz. As for the satellite communications station, this equipment is used to transmit data to the information receiving and processing points located at a large distance from the AWACS aircraft, and to ensure the operation of two duplex channels of telephone communication.

The S-100B Argus navigation system includes an inertial navigation system, satellite navigation system NAVSTAR equipment and other necessary navigation equipment, which together allow the crew to solve the problems of determining spatial location (not worse than 10 m) and aircraft speed (not worse 0,6 m / s) in order to pinpoint the coordinates detected using the on-board radio equipment FSR-890 as accurately as possible and to stabilize the position of the radar antenna com Lex.

Saab HES-21 airborne defense complex. The complex provides a circular azimuth coverage and includes interferometric antennas and high-precision digital receiving devices with warning systems for missile approach and for radar and laser irradiation of an aircraft, as well as electronic warfare station (EW) with automatic ejection of dipole reflectors and heat traps .

Management and control subsystem. This subsystem is built on the principle of open architecture, which allows it to quickly upgrade and increase its capabilities.


Specialized systems installed onboard the S-100B Argus are managed by a group of specialist operators. According to foreign open sources, there are four such operators on Swedish AEW aircraft.

The operators of the Eriai complex have two universal and fully interchangeable automated workplaces, combined into an onboard local area network and incorporating color indicators of high resolution, to which an electronic map of the area is displayed with the obtained reconnaissance data against its background (search results and maintenance of air, ground and surface targets) and various supporting information: the location of their own and enemy military air bases; permitted and prohibited zones / flight corridors; zone of the radar; location and various necessary information about the sources of radio emission detected by means of onboard station РРТР; data on aircraft located in the detection zone of the onboard radio-technical complex with indication of their nationality, current coordinates, speed and direction of flight, ESR size of the target, etc.

Operators can control the collection of intelligence information and carry out partial processing, if necessary, tune or rebuild specialized equipment and eliminate various malfunctions and abnormal situations arising in the course of a combat mission. In addition, the materials posted on the website of the developer indicate that the radio complex can be controlled remotely - in automatic mode, in which information about the air (ground, surface) environment is transmitted over the radio link immediately to the ground control station. However, the specialists of the development company do not exclude the fact that, at the request of customers, in the future, the aircraft will be equipped with additional automated workstations for operators whose tasks will include guidance of tactical fighters.

Another important element of the system is the Eriey Ground Interface Segment (EGIS) - a set of specialized software and hardware that ensures reliable integration of the air component of the complex (that is, the DRLOI aircraft itself) with ground or ship control points (information consumers).

In conclusion of this chapter, we note that an important feature of the radio engineering complex "Eriay" is the modular principle of its construction, which allows for its modernization, refinement at the request of the customer and increasing its capabilities. In particular, the site of the company-developer stated that “the complex is being upgraded for each new customer. Despite the fact that it has a similar appearance, inside it is already - completely different. As a result of the application of such a policy, each customer receives the most advanced technology. ” It is also worth noting such an important feature of the complex as its compactness and relatively small mass, which makes it possible to install Eriai-type RTKs on various military and civil aircraft, including jet and turboprop regional airliners. Currently, the Eriay complexes in various modifications are operated on such aircraft as the Saab 340, Saab 2000 and Embraer-145.
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  1. corporal
    corporal 14 February 2016 07: 33
    provides a high-precision azimuthal overview of the surrounding space in two sectors with a width of -75 degrees. / +75 deg., Perpendicular to the longitudinal axis of its antenna ...., and in terms of elevation, a review of the space is carried out in the sector -9 deg. / +9 deg.
    Are these good characteristics, or so-so (the third grade is not marriage)? Compared to the circular antenna type E-3 Sentry.
    Specialists, enlighten.
    1. mirag2
      mirag2 14 February 2016 13: 38
      The Swedes create units with original technical solutions, such as their reckless tank.
      1. kotvov
        kotvov 14 February 2016 20: 33
        and, like their tank reckless. ,,
        In general, it makes me feel that not only the tanks are crazy about the Swedes. It seems to be off topic, but they are going to apply shiriat rules in court proceedings. I don’t know if these miracle weapons will help them, but at this pace there is an opportunity to accept Islam until the end of the decade.
    2. goose
      goose 16 February 2016 12: 14
      These are quite common characteristics for an antenna of this type. For Russia, there is a lack of such low-cost aircraft for the radar coverage of our vast airspace, especially in the Far East and northern Siberia.
  2. rubin6286
    rubin6286 14 February 2016 10: 36
    This DRLOiU complex does not have any outstanding characteristics. Similar complexes are in service with a number of countries, including the USA, England, France, Russia, China. The cost of the complex turned out to be acceptable for a number of countries, in particular Pakistan.
  3. fa2998
    fa2998 14 February 2016 11: 08
    Quote: Corporal
    or so-so (third grade is not marriage)?

    This is a good "budget" device, and there is a phased antenna. The fact that there is no all-round view - so the plane can maneuver, fly in a "snake" - the entire horizon is covered. And usually a threat from one direction is expected - 150 degrees (on each side) - enough ! From the pros, the best aerodynamics, the absence of drives for the antenna. The Swedes went further, this system is quickly mounted (including the internal equipment), aircraft can be used as transport. hi
    1. goose
      goose 16 February 2016 12: 15
      Given the sufficient detection range at low altitudes, there is no great need for maneuvers, only a regular positional maneuver.
  4. Lucy
    Lucy 14 February 2016 21: 32
    Quote: rubin6286
    This DRLOiU complex does not have any outstanding characteristics. Similar complexes are in service with a number of countries, including the USA, England, France, Russia, China. The cost of the complex turned out to be acceptable for a number of countries, in particular Pakistan.

    Enlighten about the Russian complex, not even in service!
    1. rubin6286
      rubin6286 15 February 2016 11: 19
      In the USSR: complexes "Igla", "Igla-1M, complete with RTR" Rhombus "system.
      1. Lucy
        Lucy 15 February 2016 22: 27
        What are we comparing! RTR equipment (“Square”, “Rhombus”, “Needle, Saber, Bayonet”,) with IL, MiG, Su. And this is the base, in addition to RTR and DRLOiU! Flying removable radar, with the issuance of the command center on the CP on the CC. By weight An-26.
  5. iouris
    iouris 15 February 2016 20: 24
    This eye is the eye of Washington. Sweden is a privileged member of the closed financial, economic and military-political bloc led by the United States.
  6. Takashi
    Takashi 16 February 2016 16: 57
    Interestingly, are there methods to pay off this station - entering or not entering a radius of 350-400 km?
  7. Scharnhorst
    Scharnhorst 20 February 2016 20: 26
    Physical laws are mandatory for all radars without exception. Any radar can be "extinguished", the question is different: can you cheat?