One of the most widespread radio systems (RTK) in the world, used as part of airborne 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 such a complex that was adopted by the Swedish Air Force and a number of other countries of the world.
"ARGUS" ON THE BASE OF "ERIAI"
The S-100B "Argus" (Argus) AWACS Aviation Complex consisting of a Saab 340B and FSR-890 type RTK 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 ground (ship) command posts and fire weapons. The complex is compatible with the unified air defense system of NATO countries, and secure data exchange is provided via Link-E, L16 and L11 channels.
The aircraft is capable of solving the problem of detecting and selecting (classifying and generating target designation data) of both air 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 specially 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 corresponding commands transmitted from ground command posts, although in the future the possibility of appropriate modification of this aviation complex is being considered (for this, an aircraft needs will install the appropriate hardware). Therefore, by and large, the S-100B "Argus" cannot be considered a full-fledged AWACS aircraft, but rather can be attributed to the subclass of AWACS aircraft. But we, in order to avoid confusion, will apply the term AWACS to all considered complexes.
The history of "Argus" creation dates back to 1982, when preliminary work began in Sweden on the creation of the first aircraft of this class for the national Air Force, the distinctive features of which were to be: the relatively small size of the carrier aircraft and the entire complex as a whole; the ability to operate without restrictions from unprepared or damaged runways (airfields) in the allowable volume; low cost of the life cycle of the entire complex in comparison with foreign counterparts.
After “shaking down” all problematic issues, the Department of Logistics of the Ministry of Defense of Sweden in 1985 signed a contract with Ericsson Microwave Systems (today it is Saab Electronic Defense Systems) for the development of the FSR-890 Eriay radio complex.
At the same time, as already indicated, the radio engineering complex was originally planned to be created 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 carrier aircraft 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 of installing a rotating radome radome with the required characteristics and a number of other factors on the aircraft selected as a carrier.
In 1985, a full-size model of such an AFAR was mounted on a twin-engine turboprop aircraft Fairchild Aerospace Metro III (Fairchild Swearingen Metroliner), which was created at one time as an airliner for local airlines and in 1984-1987 supplied by the Swedish Air Force under the designation TP88 in the amount of two cars for VIP -transportations. A little later, in 1987, a "live" radar station was installed on the plane for carrying out the corresponding complex of flight tests. In the latter case, the aircraft TR88C / SA-227AC (serial number AC-421B, reg. No. 88003, board No. 883), delivered to the Swedish military in 1987, was selected for testing.
The first flight of the aircraft with a full-fledged radar installed on it took place in January 1991. In general, the tests were successful, but the command of the Swedish Air Force insisted that the aircraft not of a foreign, in this case, of an American, but of a national design, be used as a platform for the radar. The Saab 340B twin-engine turboprop passenger airliner was chosen as a candidate for the carriers of the radio technical complex, the main design differences of which in the modified version were the dorsal fairing of the main radar antenna and two ventral ridges installed to ensure acceptable track stability of the aircraft.
The modified Saab 340В made its first flight in January 1994, and on June 1 of the same year, flight tests of the aircraft began with the new RTK radar installed on it. After resolving all technical and bureaucratic issues, the Swedish Ministry of Defense signed a contract with the development company for the supply of six AWACS aviation systems based on the Saab 340V airframe. In the Swedish military department, they received the designation S-100B "Argus".
BATCH PRODUCTION AND EXPORT
In peacetime, most of the Swedish aircraft of the Argus family solve the tasks of military transport aviation and are equipped with a radio-technical complex only during a threatened period. Photo by Luke Willems
The production of new RTKs was started back in 1993, the first aircraft took off, as already indicated, in 1994, and in 1996 the first two aircraft with RTK "Eriay" were handed over to the customer. By May 2000, a squadron was formed from the six AWACS aircraft with the Eriay complex that entered the Swedish Air Force, which was deployed at the Uppsala Air Force Base. Subsequently, two S-100B Argus aircraft were leased to the Greek Air Force - for the period until 2003, until they received the EMV-145 type AWACS and Eriay systems ordered by them.
In July 2006, the company "Saab" received a contract from the Swedish Ministry of Defense for the modernization of two S-100B aircraft in the "multipurpose reconnaissance" version. The upgraded aircraft received the designation S-100D "Argus" (company designation - Saab 340B AEW-300) and are equipped with the ASC-890 "Eriay" radio complex. And in November 2007, Thailand expressed its readiness to purchase two S-100B Argus aircraft from the Swedish Air Force. The corresponding contract was signed between the Thai Air Force and the Office of the Ministry of Defense of the Swedish Ministry of Defense in 2008. The delivery of two AWACS aircraft and another Saab 340 aircraft in a transport and training version was envisaged under a larger contract worth $ 1.1 billion, which also included the supply of 12 JAS-39 Gripen fighters and various equipment. As part of the first stage, the Thai Air Force received one AWACS and one Saab 340 transport and training aircraft, as well as four Gripen D fighters and a Gripen S fighter. As part of the second stage, the customer received the second AWACS aircraft from Sweden in December 2012.
Currently, the Swedish Air Force is armed with four Argus-type AWACS aircraft, but in peacetime only two of them - S-100D aircraft - are equipped with Eriay-type RTKs and are used for their intended purpose as AWACS aircraft. The other two vehicles are used in peacetime as military transport, and the "Eriay" complex should be equipped only during a threatened period (wartime). The conversion is said to take no more than 24 hours.
Two more aircrafts with RTK type "Eriay" based on the airframe of the Saab 340 aircraft, after several years of negotiations, were ordered to the UAE Air Force. The Swedish company released a press release on this contract on November 17, 2009. It, in particular, indicated that the cost of the contract is 1.5 billion Swedish kronor, and its subject is the delivery of two AWACS aircraft based on the Saab 340 airframe with an upgraded version of the Eriay RTK, the delivery of a set of ground equipment to the customer and the implementation of after-sales technical support and provision, as well as assistance in training the customer's specialists on the operation of these aircraft and their on-board equipment.
In addition, four AWACS aircraft with an Eriay-type RTK, but based on a Saab 2000 aircraft, were acquired by the Pakistani Air Force. A number of sources also claim that another Saab 2000 is being used by the Pakistani military as a training aircraft - to train pilots, operators and technical personnel.
A contract for the supply of four Saab 2000 Eriay AWACS aircraft was signed between Pakistan and Sweden in June 2006. Moreover, initially Islamabad planned to purchase as many as 14 aircraft of the Saab 2000 family, of which seven in the version of the Saab 2000 Eriay AWACS aircraft, and the remaining seven in the passenger modification for the state-owned airline PIA (Pakistan International Airlines). However, then the order was reduced.
AWACS aircraft were carried out for the Pakistani customer by re-equipping the serial "used" Saab 2000 airliners. The Pakistani contract was executed jointly by Saab (two-thirds of the work) and Erickson Microwave Systems (one-third of the total work). At the same time, the radio technical complex was finalized in accordance with the requirements of the Pakistani Air Force, and the number of automated workstations was increased to seven. Pakistani Saab 2000 aircraft can also be used as part of a distributed AWACS network to transmit real-time data directly to the ground command and control network.
The delivery of the first aircraft was completed at the end of 2009, the ceremony of handing over the aircraft to the customer took place on December 8. The second Saab 2000 was handed over to the Pakistani Air Force by Swedish aircraft manufacturers and electronics on April 24, 2010, and the customer received the remaining two cars by the end of 2010.
The value of the Pakistani contract was not officially disclosed by Swedish contractors, but a number of foreign media reported that the "Pakistani" contract was estimated at 4.5 billion Swedish kronor, or about $ 667.2 million at the then exchange rate, including the cost of supplying ground equipment for ground stations for receiving and processing information, simulators and aircraft maintenance for 30 years of operation.
Malaysia has shown interest in purchasing AWACS aircraft based on the Saab 340 airframe, but the contract has not yet been signed. Moreover, one of the conditions put forward by the Malaysian customer is 100% technology transfer.
FAMILY "ERIAI"
The FSR-890 "Eriay" radio-technical complex was developed by the Swedish company "Erickson" on the basis of the multifunctional pulse-Doppler radar station PS-890 "Eriay", which operates in the S-band (wavelength - 10 cm, frequency - 3.2 GHz). This radar has a flat two-way active phased antenna array 9.75 m long and 0.78 m wide with electronically controlled beam pattern. The beam is controlled by an automatic system. Moreover, due to the fact that this system sets its own direction of radiation for each pulse, a higher range, speed and accuracy of detecting air and ground / surface targets are provided.
The antenna array is located on the carrier aircraft in a radio-transparent canister-shaped fairing, which has the shape of a rectangular beam and is mounted on pylons located above along the aircraft fuselage. AFAR has 192 solid-state transceiver modules, cooled by the air flow entering through the air intake in the front of the antenna radome. In this case, the transceiver modules can be used not only as elements of the radar, but are also capable of solving the 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 ensured, among other things, by the low level of its side lobes, which does not exceed -50 dB.
According to the data set forth in the work of V. S. Verba "Airborne radar surveillance and guidance systems: state and development trends", published by the "Radiotekhnika" publishing house in 2008, the PS-890 radar "uses shape-adapted signals with frequency and phase shift keying with pulse compression and a variable operating frequency. To eliminate the ambiguity of measuring the distance to the object and to improve the accuracy of determining the coordinates and speed of the target, low and medium pulse repetition rates are used”(manipulation or, as it is also called, digital modulation is modulation with a discrete signal).
The radar of the airborne radio engineering complex under consideration provides a high-precision view of the surrounding space in azimuth in two sectors with a width of -75 degrees. / +75 deg., Perpendicular to the longitudinal axis of its antenna (outside these sectors, the view of the airspace and the detection of air targets is also provided, but with deteriorated characteristics and without the possibility of target tracking), and in the elevation angle the space is scanned in the -9 deg sector. / +9 deg. The width of the directional pattern of the antenna is in azimuth, according to various sources, 0.7 degrees. or 1 degree, and in elevation - 9 degrees.
The maximum instrumental range of radar detection of air targets when flying at an altitude of 6000 m, according to foreign open press, is 450 km, providing, among other things, their over-the-horizon detection. During the demonstration flights, conducted at one time by the developer for a wide range of specialists, the radio-technical complex provided the detection of low-altitude air targets at ranges of 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 provide maximum radiation power by scanning the radar space only from one side (side). The detection range of surface targets is limited, according to the specialists of the developer company, only by the distance to the horizon - about 350 km. When patrolling at high altitude, the AWACS equipped with the Eriay RTK is capable of controlling an area over an area of more than 500,000 square meters. km, while searching for and tracking air targets at altitudes up to 20 km.
The PS-890 radar station, which is part of the RTK FSR-890, has three operating modes:
- basic (normal) airspace overview;
- an expanded view of the airspace, in which, due to the narrowing of the scanning sector and an increase in the scanning time, the detection range of air targets is also increased for targets with an RCS of about 2 sq. m is about 300 km;
- overview of ground / surface space.
The FSR-890 radio complex, in addition to the main asset - the radar station - also includes other subsystems.
The Pakistani military ordered an aviation complex based on the Eriay system deployed on a Saab 2000 aircraft. Photo from www.defence.pk
Subsystem of state recognition "friend or foe" type Mk 12. Includes an interrogator, two antennas located at the ends of the main antenna radome and forming a narrow azimuthal and fan-shaped radiation pattern in the goniometric planes, and a master oscillator. The subsystem, along with determining the nationality of targets, carries out their individual identification with the determination of the side or other registration number of the aircraft, helicopter or ship, and also determines the location of the target and allows you to obtain some other data (the working area in azimuth is similar to the radar view sectors, the detection range is not less than 300 km, the accuracy of determining the coordinates of the tracked objects - 1, 0 - 1, 5 degrees). The subsystem operating modes - 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 reconnaissance station (RRTR) allows, at a distance of up to 400 km, to detect, classify and determine the location of air, ground and surface (ship) -based radio emission sources that have an operating frequency range within 0.5-18 GHz, but with the possibility of it extensions up to 40 GHz.
The antenna system of the RRTR station receives in the horizontal plane - omnidirectional, and in the vertical plane - in the sectors
-35 hail. / +35 deg. (operating frequency range 0.5-2 GHz) and -20 degrees. / +15 deg. (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 the continuous one is 100 kHz. According to the information presented in the above-mentioned work "Aviation complexes of radar patrol and guidance", the direction of arrival of the pulse signal is determined with an accuracy of no worse than 2 ±, and the continuous one is no worse than 5 ±.
The data received by the RRTR station are compared with those signal samples that are stored in a database of more than 2000 storage units and with information coming from the radar station, as a result of which the range and probability of recognizing the class and type of objects being detected is increased. It should be especially noted that all information received by the RRTP station is stored in a memory device and, as necessary and possible, is transmitted to ground (ship) points for receiving and processing information in close to real time.
Communication and data exchange complex. It includes four VHF radio stations, satellite communications equipment operating in the Ku band, as well as two backup microwave radio stations. VHF radio stations are designed to provide telephone communication and exchange data with airborne objects using signals with amplitude and frequency modulation (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 received intelligence with ground and naval points for receiving and processing information at a distance of up to 300 km, as well as to provide telephone communication with the aforementioned consumers through two duplex channels … Moreover, the probability of interception of information by an adversary is allegedly reduced due to the use of a broadband signal with a spectrum width of about 1 MHz in these stations. As for the satellite communication station, this equipment is used to transmit data to the information reception and processing points located at a great distance from the AWACS aircraft, and to ensure the operation of two duplex telephone communication channels.
The navigation system of the S-100B "Argus" aircraft includes an inertial navigation system, equipment of the satellite navigation system NAVSTAR and other necessary navigation equipment, which together allow the crew to solve with high efficiency the tasks of determining the spatial position (not worse than 10 m) and aircraft speed (not worse 0, 6 m / s) in order to maximally pinpoint the coordinates of targets detected by the FSR-890 airborne radio complex, as well as stabilize the position of the radar antenna of the complex.
Airborne defense complex Saab HES-21. The complex provides circular coverage in azimuth and includes systems built on the basis of interferometric antennas and high-precision digital receivers for warning about the approach of missiles and about radar and laser irradiation of the aircraft, as well as an electronic warfare (EW) station with automatic weapons for shooting dipole reflectors and heat traps …
Management and control subsystem. This subsystem is built on the principle of open architecture, which allows you to quickly modernize it and increase its capabilities.
ORGANIZATION OF OPERATION OF THE COMPLEX
The specialized systems installed on board the S-100B Argus aircraft are controlled by a group of specialist operators. According to foreign open sources, there are four such operators on Swedish AWACS aircraft.
The operators of the Eriay complex have at their disposal two universal and completely interchangeable automated workstations, united into an onboard local network and having color indicators of high resolution, on which an electronic map of the area is displayed with the received intelligence displayed against its background (search results and tracking air, ground and surface targets) and various auxiliary information: the location of their own and enemy air bases; permitted and prohibited zones / corridors for flights; the coverage area of its radar; location and various necessary information about the sources of radio emission detected by the means of the on-board RRTR station; data on the aircraft located in the detection zone of the on-board radio engineering complex, indicating their nationality, current coordinates, flight speed and direction, target RCS value, etc.
Operators can exercise control over the collection of intelligence information and carry out partial processing of it, if necessary, adjust or rebuild specialized equipment and eliminate various malfunctions and emergency situations that arise in the course of a combat mission. In addition, in the materials posted on the website of the developer company, it is indicated that the radio-technical complex can be controlled remotely - in automatic mode, in which information about the air (ground, surface) situation is transmitted by radio directly to the ground control point. However, the specialists of the developer company do not exclude the possibility that, at the request of customers, in the future, the aircraft will be equipped with additional automated workstations for operators, whose tasks will include the 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 AWACS aircraft itself) with ground or ship control points (information consumers).
In conclusion of this chapter, we note that an important feature of the Eriay radio-technical complex is the modular principle of its construction, which allows its modernization, revision at the request of the customer and increasing its capabilities. In particular, the website of the developer company states that “the complex is being modernized for each new customer. Despite the fact that it has a similar appearance, inside it is already completely different. As a result of applying this policy, each customer receives the most modern technologies. " It should also be noted such an important feature of the complex as its compactness and relatively small weight, which allows the installation of RTK type "Eriay" 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.
