A fierce competition is now underway for supplying up to 450 active phased-array radars (AESA) for the Indian Air Force’s (IAF) future combat aircraft acquisitions, with the principal contenders hailing from the US (Northrop Grumman and Raytheon), Europe (EADS Defence Electronics, THALES and SELEX Galileo), Scandinavia (Ericsson Microwave), Israel (Israel Aerospace Industries), and Russia (Phazotron JSC and Tikhomirov NIIP).
Unlike a conventional mechanically steered-array (MSA) radar, the antenna array of T/R modules is fixed, with no moving parts. The radar can steer its agile beams electronically — at nearly the speed of light — and redirect them instantaneously from one target to another. In MSA radars, a circular or elliptical antenna plate in the nose of the aircraft is moved rapidly using a gimbal system with three or four drive motors to scan an area of airspace or on the ground, a single flashlight-like beam at a time. AESA radars on the other hand can track significantly more targets and can operate in multiple modes simultaneously, such as air-to-air search (in low-, medium-, and high-PRFs) and digital ground mapping. The AESA also automatically establishes tracking files for each detected target (more than 24), thereby reducing pilot workload. With interleaved air-to-air and air-to-surface cockpit displays, the aircrew will thus be able to maintain situational awareness while executing air-to-surface missions. AESA radars also offer better air-to-ground resolution (three times higher) than MSA radars, particularly using their synthetic aperture radar (SAR) mode.
The RBE-2 along with the OSF infra-red search-and-track system is being proposed for installation on board 90 of the IAF’s 230 Su-30MKIs on order.
The Caesar’s tracking range is well beyond 200km against combat aircraft-sized targets, with a range of more than 300km against large targets like transports or aerial refueling tankers. The Caesar’s antenna, using a liquid cooling system, comprises 1,500 Gallium-Arsenide T/R modules.
ISRAEL:The X-band EL/M-2052’s array comprises ‘bricks’ of 24 T/R modules, making it easy to assemble the AESA in different configurations to match the size and shape of an existing fighter nose, up to 1,290 modules. Smaller, lower-module-count versions can be air-cooled, reducing weight and making integration simpler.
Tikhomirov NIIP, on the other hand, is busy developing its X-band AESA radar for fitment on to both the Su-35BM and the Fifth Generation Fighter Aircraft that will be co-developed by Russia’s United Aircraft Corp and India’s state-owned Hindustan Aeronautics Ltd (HAL). Thus far, three prototype AESAs have been built and are now undergoing laboratory tests, with the first functional unit due to enter the flight-test phase in 2010, and the series-produced radars entering service by 2015. The AESA’s front-end antenna array will also be offered for integration with the existing NO-11M ‘Bars’ PESA radars by 2014.
Yet another AESA variant being designed by Tikhomirov NIIP is called the ‘smart skin’ in which the T/R modules can be located anywhere on board the aircraft to generate the relevant radiation fields required for almost 360-degree airspace surveillance coverage.