AESA Radars Are A Highlight of Aero-India
By Bill Sweetman 
Active electronically scanned array (AESA) radar technology is a requirement for India’s Medium Multi-Role Combat Aircraft (MMRCA) competition, the biggest in the world. Consequently, a lot of maneuvering was apparent at the Aero India show last month, as fighter manufacturers worked to define their AESA answers and (in some cases) stall competitors.
Boeing’s F/A-18E/F Super Hornet has the simplest answer. Raytheon’s APG-79 radar is standard on the Block 2 airplane, the current variant, and Boeing has not indicated it’s considering alternatives. This allows Boeing to wave a low-risk banner, offering, essentially, the aircraft flying with the U.S. Navy and on order for Australia.
Lockheed Martin had a choice of three radars. Raytheon’s Advanced Combat Radar (RACR) and Northrop Grumman’s Scalable Active Beam Radar (SABR) fit in an F-16, but Lockheed ultimately chose Northrop Grumman’s APG-80, in service in the United Arab Emirates’ F-16E/F. Two reasons are behind this, says Northrop Grumman: The proposed F-16IN for India is similar to the E/F and can accept the APG-80, which needs more power and cooling than RACR or SABR, and is lower risk. Northrop Grumman says no APG-80 antennas have had to be repaired, in normal use, since tests started over four years ago. “The antenna will outlast the airframe,” the company says. A few modules might fail over its lifetime, but they won’t affect performance enough to make it worth unsealing the radome and replacing them.
Eurofighter holds a unique view of the AESA issue. Executives say the Selec Captor mechanically scanned array (MSA) beats any in-service AESA for the Typhoon’s mission. A clue to their thinking emerged at an Aero India seminar. Peter Gutsmiedl, senior vice president of engineering at EADS Military Air Systems, pointed out ways in which an AESA could be integrated into Typhoon, including small side arrays, an azimuth gimbal and the so-called “swashplate” radar, a canted antenna on a rotating mount. The goal is to overcome drawbacks of a fixed AESA: narrower field of view than an MSA and diminishing effective aperture and performance at the edges of that field.
Meanwhile, a spat between France and Sweden is developing. In 2007, Saab struck a deal with Thales to provide an AESA antenna for the Gripen Demo program, to be mated with the signal processor from the JAS 39C’s Saab PS-05 MSA radar. The Thales AESA replaced the passive-scan antenna of Rafale’s RBE2.
But three things happened: Thales and Dassault were given the go-ahead to develop and produce the AESA for Rafale; Dassault has taken a large shareholding in Thales; and the Gripen NG has emerged—in India and Brazil—as a competitor to Rafale. Thales will honor the Gripen Demo contract but its AESA will not be available for a production NG.
Sweden has talked about RACR, but would prefer the PS-05/A’s “back end” modules for ease of integration and to stay away from control issues associated with U.S. components. The answer may lie with Selex, which, first as Ferranti, then as GEC-Marconi and subsequently as BAE Systems, was Sweden’s partner on the original PS-05/A.
Selex, in accordance with the philosophy of John Roulston, leader of the Captor design team, has been working on simpler, lower-cost AESAs—in fact, its first production contract was not for a fighter radar but a retrofit to U.S. Coast Guard HC-130s. Its Vixen series of forward-looking radars, banned by the U.S. from South Korea’s F/A-50, also received a launch order from U.S. Customs and Border Protection, with the 500-module Vixen 500 to be integrated on Cessna Citations.
It’s not surprising, therefore, that Saab is in talks with Selex about using its AESA technology in the Gripen NG radar. The NG is not competing with the Typhoon except in India. It is also unlikely (as different as they are) that both aircraft would make an MMRCA short list.
Photo: Bill Sweetman
