Tuesday, February 13, 2007

FIAR Grifo Radar


The FIAR Grifo Radar








Over the past 20 years airborne fire control radar have become smarter as the advent of micro processing has improved the speed and capacity of the system to search for, track, and identify targets. At the same time, the physical size of the hardware has shrunk. Thus, it is possible for in-service fighter aircraft to be given a state of the art radar system which, in turn, allows the use of new generations of air to air missiles.
Although FIAR (Fabbrica Italiana Apparecchiatture Radoielettriche) was formed in milan during 1941, as a manufacturer of electronic equipment for both the commercial and military markets, the company's involvement with radar only began in the early 1960s when it commenced production of the NASARR F15AM II radar , under license from Autotecnics, for the FIAT build lockheed F-104G. the F-15AM II is a multi mode radar , optimized for both air to air (target interception) and air to ground ( navigation and bombing) roles. FIAR currently has a staff of 700 and forms the airborne radar sector section of the systems and avionics equipment division within Alenia Difesa. it is the only part of Gruppo finmeccanica to be quoted on the stock exchange.
The FIAR Grifo radar from Italy, The FIAR family of Grifo radar has achieved similar success. four distinct versions of this radar have been adopted: the Grifo-M, and Grifo-7 for the Mirage III/V and F-7, respectively, in service with the Pakistan air force, the Grifo-F for Singapore's F-5E upgrade (redesigned as F-5S), and the Grifo-L for the Czech republic's aero vodochody L-159. Although previously a smaller part of Italian industry, FIAR is now the lead element of GF-Sistemi Avionici, a finmeccanica company.
Development of the Grifo pulse- doppler, multi-mode radar began in late 1980s, and following a comprehensive series of flight testing on a company owned T-39 Saberliner test bed, is considered complete. The four versions share a common architecture and much common hardware and according to the company, offer feature normally associated highly expensive and complex aircraft.
FIAR entered the market in 1991 with the Grifo, a radar developed with private venture funding
to upgrade Singapore's F-5Es. it is testament to FIAR's expertise that it won the competition in the face of stiff competition from British, Israeli, and American companies. Grifo is a pulse Doppler multi mode, multi roll radar operating in the X band (I/J band), featuring a planer antenna. with a performance claimed to be better than the APG-66 radar fitted to the F-16AB. it has five air to air search modes, with the capability of tracking up to eight targets, four air combat modes and nine air to surface modes. the last are refined by ground mapping and enhanced Doppler beam sharpening mapping. its range 39 nm, the system weight between 80-85kg (176-187 pound) ( depending on the antenna), and requires a 2KVA power supply. it is cooled by compressed air and the energy dissipation is less than 1.5 KW, with 500W transmitter power. the Grifo offers low, medium and high pulse repetition frequencies (PRFs), uses digital pulse compression and has low peak power.
Extensive use is made of built in test equipment (BITE) for maintenance simplicity and the mean time
before failure (MTBF) is between 200 and 250 hours: a major improvement on older system. For air to air use, it has range-while- search (normal), range-while-search (adaptive), spot velocity search, single target track, dual target track, situation awareness, track-while scan, air combat, boresight acquisition, HUD acquisition, vertical acquisition and slew modes, In air to surface operation, the Grifo can function in real beam map, Doppler beam sharpening , sea low, sea high, ground moving target indicator, ground/sea moving target track, air to ground ranging, freeze, expand and beacon modes, Further modes include raid assessment, terrain avoidance, precision velocity update, beacon landing (similar to ILS) and IFF.
Grifo can be integrated with semi-active or active radar guided missiles such as AMRAAM and MICA. and its can be use four type of AAM, During the system's development program some 250 flying hours were accrued in tracor's North American T-39D S aberliner airborne test bed. in addition, more than 300 flight trails were conducted with a system mounted in an F-5E.
Deliveries to Singapore of its order for around 50 Grifo-F system, a version optimized for the F-5E, began in the second half of the 1990s. In 1993 FIAR signed a second prestigious deal, being selected for the modernization program for 95 Pakistani F-7P/MP fighters,The first Grifo radar was due to be shipped to the air force's Chaklala site in july 1994 to fitted into MirageIII's. This was a much more demanding requirement because of the smaller space available and lack of a cooling system. To this end simplified version was developed, the Grifo-7, which weight only 55kg (120 LB) and has 450W power with 850W energy dissipation. The modes available are search, single target track and air combat (super search, bore sight and vertical) modes for air to air operations, and air to ground ranging for ground attack.
Two years later, Pakistan again turned to FIAR, this time in support of a modernization program for its ex-Australian MirageIII Os. The aircraft , being reworked by the Pakistan Aeronautical Complex, needed to be fitted with new avionics, including radar, global position system (GPS), inertial navigation system (INS), FLIR, upgraded electronic counter measures (ECM), and ' hands on throttle and stick ' (HOTAS) controls, The radar selected was the Grifo-M ( performance as the Grifo model), optimized for the MirageIII airframe, and Pakistan purchased 35 systems. FIAR's latest contract was signed in 1997 with Aero Vodochody of the Czech Republic. This was for 77 Grifo-L radar systems to equip the new L-159 multi role combat aircraft. FIAR is constantly working on research and development programs that will improve and develop the capabilities of the entire Grifo family. Continual upgrades of both software and hardware components, enable the systems to remain state of the art.
The Grifo incorporate full range air to air and air to ground modes. the performance demonstrated during the Saberliner tests against fighter targets included detection and lock-on ranges, look-down capability, and air to ground ranging. The company told that these tests "far exceeded the design objectives" of the radar but declined to be specific literature notes that the radar is able to detect and track multiple targets ( up to eight) at all aspects and at all altitudes.
The system weight depending on the aircraft platform, "less then 80 kg". Integration of a modern radar into new avionics architecture is never as simple as it appears and it is understood that the Grifo-F for Singapore's F-5S experienced problems during integration, though their exact nature has not been revealed. that said, FIAR issued a statement during the 1996 Farnborough International air show noting that flight trail of the Grifo-7 in a Pakistani F-7 in airplay 1996, were declared "completely satisfactory' by the Pakistan Air Force and ministry of defense. Several sorties were flown ahead of the rainy seasons in order to test the full operating of the radar in the country's challenging hot weather conditions. further trails are being conducted to verify other parameters.
At present, the Grifo's claimed lower cost and the higher performance are its main selling points. FIAR states it has "signed order for about 200 Grifo radars' with options on a further 100. other candidate aircraft for the Grifo are seen as being the A-4 Skyhawk, Mig-21, SUPER-7 and others. The Super Skyranger is new low cost, multimode radar designed as a replacement for Skyranger radar. Super Skyranger radar also proposed as retrofit for other "small nosed' fighters.
The company claims that super skyranger offers full look down/shoot down capability, using a planner array antenna scanning + 30 digree, depending on the aircraft installation. it can provide target range, range rate, and line of sight data (such as head- steer data for a slewable short-range air to air missile) to the aircraft avionics systems. it does this using an ARINC-429 serial link (with a 1553b option) and possesses what are described as " excellent ECCM features.

A modern fighter range can have a dozen or more radar modes, each optimized for a specific task. No standard terminology exists for all modes. In preparing the data table we have listed
only the most important nav\attack modes for each set. The most common are as follows:

AIR TO AIR
LOOK-DOWN ; The most common mode used in air combat, this provides clutter free indication of low flying targets.
LOOK-UP ; If the target is flying at a similar or higher altitude to the fighter, look-up mode will
provide a longer detection range.
Single-target track ; In simpler radars, once a target of interest has been detected, the set can then be locked onto it, allowing an attack to begin. The radar antenna will remain pointed at the
target, so other targets can only be observed by returning to search mode.
Track-While-Scan (TWS) ; Given enough data processing power, a radar can maintain a track on several targets while continuing to scan the forward sector. This mode allows several targets to be engaged simultaneously using fire and forget missiles, and gives enemy pilots no way of knowing that their aircraft have been single out for attack. Since the radar is still scanning , it may take up to ten seconds for the radar beam to re-scan each target, so the data processor will take some time to establish a new track, or respond to a sudden change in target course. this delay can reduced by using data -adaptive scanning. Also know as track priority. this replaces the conventional sector scan used in search mode with a series of smaller scan each directed at one of the targets of interest. Using this technique, tracks can be updated every few seconds.
Range-While-Search(RWS) ; By interleaving high and medium PRF( Pulse Repetition Frequency) waveforms. a radar operating in this mode can sue the high PRF's for long range target detection, and the medium to obtain range information.
Velocity Search ; This uses high PRF's to carry out a long range search. this gives the longest possible range against head on targets, but provides velocity and azimuth data only.
Raid assessment ; (sometimes referred to as "situation awareness") In normal operating modes, a formation of several closely grouped aircraft may appear as a single target when seen at long range. Raid assessment mode uses signal processing to resolve the formation into its individual aircraft.
Air Combat ; (often referred to as "Dogfight mode") This is a generic term for modes used at short range when the aircraft and its target are maneuvering in air combat. The scan pattern can either be fixed, or moved to anticipate target maneuvers. the most common are HUD, bore sight,
and vertical search.
HUD ; (sometimes referred to as "supersearch") This radar automatically scans the HUD field of
view, and will automatically lock on to the closest target.
Boresight ; The radar beam is pointed directly ahead of the aircraft, and the pilot maneuvers the aircraft to place the beam onto the aircraft to be tracked. lock on is commanded manually.
Vertical search ; This is particularly useful when both aircraft are maneuvering in the vertical plane, and involves setting the radar to scan vertically rather than horizontally.
Air to air ranging ; Measures the range to an air target.

AIR TO GROUND

Air to ground ranging ; Used to measure the slant range to a designated point on the ground during gun or continuously computed point (CCIP) attack.
Real beam ground mapping ; (often referred to simply as 'ground mapping') By sweeping the beam from side by side, the radar creates a radar image of the terrain ahead. this can be used to locate and attack ground targets, or to update the aircraft's navigation system.
Sea search ; This mode is optimized for the task of detecting and tracking ship targets. Unlike the land, the sea surface is itself moving, increasing the problems which the radar will have in discriminating between the target and its surroundings.
Freeze ; The radar scans to build up an image, which is then electronically stored and presented on the display, allowing the radar transmitter to be turned off . By computing the aircraft's movements, the radar allows the pilot to use the Frozen image for some length of time, before the transmitter is re-energised to take another radar 'snapshot'.
Expanded-beam ; This allows the pilot to select a small area of ground mapped terrain, then magnify its image.
Doppler beam sharpening ; By processing the doppler shift in the returned echo, the radar creates a high definition view of a small part of the ground mapped terrain. althoug this gives a higher resolution than Expanded beam mode, it can only be used for targets which are 15* or more the nose of the aircraft.
Terrain avoidance ; Detects high ground ahead of the aircraft, enabling the pilot to fly around it . Terrain following ; Flies the aircraft at a pre selected height along the planned route .
MTI (Moving Target Indication) ; By processing the Doppler shift in the echoed from moving targets on the ground . the radar can separate these from the ground clutter. Quality of MTI data reduces at high aircraft speeds.

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