07/04/09 - tempur april 2009
Just like the fierce competition now underway for supplying M-MRCAs for the Indian Air Force (IAF), a parallel competition is proceeding ahead for supplying new-generation passive infra-red search-and-track (IRST) systems coupled with active electronically scanned array (AESA) radars for both the yet-to-be-selected M-MRCA, and
Just like the fierce competition now underway for supplying M-MRCAs for the Indian Air Force (IAF), a parallel competition is proceeding ahead for supplying new-generation passive infra-red search-and-track (IRST) systems coupled with active electronically scanned array (AESA) radars for both the yet-to-be-selected M-MRCA, and for the Tejas light combat aircraft (LCA), which is now being flight-tested. All in all, more than 460 IRST systems are expected to be ordered. Bidding to supply the IRSTs are Europes EuroFirst consortium (offering the PIRATE), a consortium of Frances THALES and Sagem Défense Sécurité offering the Optronique Secteur Frontal (OSF), Swedens Saab offering the IR-OTIS, and Russias Urals Optical & Mechanical Plant (UOMZ) offering the 13SM1 sensor.
The PIRATE, or passive infra-red airborne tracking equipment, is a second-generation imaging infra-red (IIR) system and has been developed by the EuroFirst consortium led by THALES Optronics and Selex-Galileo. PIRATE incorporates both a forward looking infra-red (FLIR) and IRST capability. The system itself utilises a highly sensitive IIR sensor mounted to the port side of the canopy. This sensor scans across wavelengths from 3 micron to 11 micron in two bands. This allows the detection of both the hot exhaust plumes of turbofans as well as surface heating caused by friction. By supercooling the sensor even small variations in temperature can be detected at long range. Although no definitive ranges have been released an upper limit of 80nm has been hinted at, but a more typical figure would be 50nm. The use of processing techniques further enhances the output, giving a near high-resolution image of targets. The actual output from the system can be directed to any of the multi-function head down AMLCDs mounted within a combat aircrafts cockpit. Additionally, the image can be overlaid on both the helmet-mounted display sight and heads-up display (HUD). The IIR sensor is stabilised within its mount so that it can maintain a target within its field-of-view (FOV). Up to 200 targets can be simultaneously tracked by the system using one of several different modes: multiple target track (MTT), single target track (STT), single target track identification (STTI), sector acquisition and slaved acquisition. In MTT mode the system will scan a designated volume space looking for potential targets. In STT mode PIRATE will provide high-precision tracking of a single designated target. An addition to this mode, STT Identification allows for visual identification of the airborne target, the resolution being superior to that provided by the Caesar AESA. When in sector acquisition mode, the PIRATE will scan a volume of space under direction of another sensor such as the Caesar. In slave acquisition the use of off-board sensors is made, with the PIRATE being commanded by data obtained from an AEW & C platform, for example. When a target is found in either of these modes PIRATE will automatically designate it and switch to STT. Once a target has been tracked and identified, PIRATE can be used to cue a within-visual-range air-to-air missile, i.e. a missile with a high off-boresight tracking capability. Additionally, the data can be used to augment that of the Caesar or off-board sensor information obtained from an integrated EW suite. This will enable the IRST-equipped aircraft to overcome severe ECM environments and still engage its targets.
Northrop Grummans AAQ-32 Internal FLIR targetting system (IFTS), coupled with the APG-80 AESA, is currently operational on board the Lockheed Martin-built Block 60/62 F-16E/F Desert Faclon M-MRCAs of the United Arab Emirates Air Force (UAEAF). The IFTS includes a navigation FLIR sensor and a targeting FLIR both mounted within a single pod. It allows the aircraft to detect and identify both ground and airborne targets, even at night or in adverse weather. The IFTS relies on the aircraft for its power and cryogenic cooling requirements. While the targetting FLIR and laser designator have been repackaged in a pod, the wide-area navigation stabilised FLIR sensor is housed above the nose. The IFTS, however, is not being offered to India for the F-16IN M-MRCA. The OSF, coupled with the THALES-developed RBE-2 AESA, is mounted in front of the cockpit and consists of two optronic modules. The starboard module has a long-wave (8-12 micron) IIR camera and is used for airborne target search and track. The range of the camera is believed to be up to 90km in ideal conditions. The portside module carries a CCD TV camera for daytime target identification. The system also includes a laser rangefinder. The OSF suite carries out search, target identification, telemetry and automatic target discrimination and tracking. By cueing the OSF with the tracks provided by the RBE-2 or by another aircraft via a secure operational data link, a pilot can easily identify an aggressor force at a range of several tens of nautical miles. For example, he can pick up three F/A-18s preparing to penetrate at 20,000 feet and three additional F/A-18s protecting the former at 40,000 feet. Saab Dynamics, on the other hand, is offering the IR-OTIS in combination with both its Ericsson-built Nora AESA and the existing PS-o5/A mechanically scanned airborne multi-mode radar. The IR-OTIS has been flight-tested since 2001, and is located just in front of the aircraft canopy, slightly offset to port and is about 20cm in diameter. The IR-OTIS FOV will be cued by a helmet-mounted display system (as will the radar). It will also have an autonomous search programme and tracking function. The information will be storable for evaluation and comparison with radar information in real-time, and also as video for later use.
Another novel IRST solution being proposed comes from Lockheed Martin, which has already been selected to supply the IRST sensor for the Boeing F/A-18E/F Block 2 Super Hornet. The podded system will provide passive detection and tracking of airborne targets at long-range. The long-wave IR sensor will be mounted in the nose of the 1,820 litre centreline fuel tank. Boeing and Lockheed Martin are co-developing a proof-of-concept demonstrator. The IRSTs sub-systems include a sensor head that houses a three-axis inertially stabilised gimbal that scans the optics and detector assembly; a COTS processor that hosts the algorithms and a high-density digital recorder, and an air-to-liquid heat exchanger (environmental control sub-system, or ECS). The US Navy plans to buy 150 such IRSTs, with the system scheduled to become operational in 2012. The IRST, when coupled with Raytheons APG-79 AESA, provides the F/A-18E/Fs mission computer with track file data on all targets while simultaneously providing IIR imagery to cockpit displays. The IRST will operate in either track-while-scan or single target track mode, with cockpit selectable hands-on-throttle-and-stick (HOTAS) controlled scan volumes in azimuth and elevation. The IRST will be mounted in the forward section of the centreline fuel tank, thereby ensuring that its FOV is maximised. UOMZs 13SM1 (OLS-UEM) IRST, originally developed for the MiG-35 and working in conjunction with the Phazotron JSC-built Zhuk-AE AESA, has a 120-degree FOV in azimuth, 55 degrees and -15 degrees FOV in elevation, has a detection range of 28km in the forward hemisphere and 70km in the rear hemisphere, and has a total weight of 60kg. UOMZ has also developed the OLS-K pod-mounted look-down IRST that combines a TV camera with an IIR sensor and laser rangefinder/designator, all of which are housed within a belly-mounted 110kg-pod. The OLS-K is thus a multi-purpose IRST sensor that is used for not only airborne target detection, but also for detection and engagement of ground-based targets out to 40km.