Farnborough Air Show

Selex Galileo Leads Europe’s E-Scan Drive

 - July 8, 2012, 2:10 AM

With facilities in Italy and the UK, Selex Galileo lies at the heart of radar developments in Europe. Not only is the company heavily involved in two of Europe’s three new-generation fighter programs, but it is also making important strides in the field of surveillance radars for patrol aircraft, helicopters and UAVs. Active electronically scanned antenna (AESA), or e-scan, technology is at the center of this capability.

Selex Galileo continues to derive good business from the mechanically scanned radar market. The Grifo radar has proved very popular for fighter upgrades and has been supplied to Pakistan for F-7 and Mirage modernizations, as well as for a number of F-5 upgrade programs. The radar is being evaluated as a potential upgrade for the U.S. Navy’s F-5 adversary fleet. The Gabbiano surveillance radar family has also achieved success, having been selected for a variety of platforms such as the Elbit Hermes 450 and Embraer KC-390. However, it is e-scan technology that is driving the future of Selex Galileo’s radars, both for fire control and search radars.

E-scan for Fire Control

Selex Galileo is involved in fire control technology as the lead partner in the Euroradar consortium that is developing the Captor-E AESA radar for the Typhoon fighter, and through its own Vixen range of e-scan radars. The Vixen 500E has been selected to replace APG-66 radars in the U.S. Customs and Border Protection fleet of Cessna Citation interceptors. It is currently undergoing operational test and evaluation.

Planned for service with Tranche 3A aircraft, the Captor-E radar has yet to receive production funding, but development is in full swing. “We are cracking on as industry with the full-scale development,” reported Bob Mason, Selex Galileo’s senior v-p marketing and sales for radar and advanced targeting. “Hardware is now coming together and we will deliver the radar in the second quarter of next year.”

Partner nations are yet to decide on the way forward for Captor-E beyond the current development activity. “We’re still in discussion with the nations as to what they are going to do,” said Mason, “but I believe things are starting to narrow down. Those that have got money will join the program at some stage. The program hasn’t stopped. It hasn’t been delayed by the prevarication of the nations. The aim is to get it flying [in a Typhoon] next year, and it will.”

In the meantime, Selex Galileo is also involved in a UK-only technology demonstration program known as Bright Adder. No details have been publicly released about this e-scan radar, but it could provide an option for the RAF’s Typhoons. Bright Adder is understood to offer advanced features that are of particular interest to the RAF, such as an electronic attack function.

As well as its involvement in the Typhoon program, Selex Galileo is providing the ES-05 Raven e-scan radar for the Saab Gripen E/F, which has been selected by Sweden and Switzerland. Raven was evolved from the company’s Vixen 1000E, and a development radar with a fixed antenna was earlier flown in the Gripen Demo in support of Saab’s bid for the Indian MMRCA fighter requirement.

Raven has been developed considerably in the meantime. It is in a production-ready configuration that is at least “two generations” beyond the fixed antenna radar, according to Selex Galileo. The first radar set has undergone final roof-testing at the company’s Crewe Toll facility in Edinburgh and is now fitted in the Gripen NG demonstrator. Flight trials will get under way immediately after the show.

Both Captor-E and Raven employ mechanical repositioners to alter the antenna’s field of regard. A fixed e-scan antenna has a look angle of roughly 60-degree off-boresight, but the repositioner allows the radar to scan across the entire forward hemisphere, and even beyond the 90-degree “3-9 line.” This offers significant tactical benefits, including the ability to undertake 90-degree “f-pole” maneuvers during beyond-visual-range missile engagements.

Captor-E and Raven employ different methods of antenna repositioning, however. The Captor radar’s antenna is mounted on two angled swashplates that rotate in combination or opposition to reposition the antenna. This arrangement avoids any rotation of the antenna, so the polarity of the embedded IFF (identification friend or foe) antennas is maintained.

Advanced IFF

By contrast, the Raven employs an angled antenna mounted on what is, in effect, a rotating drum. This offers significant advantages, but has also required the solving of some technological hurdles. One of them is the development of a sophisticated 360-degree joint, derived from the oil industry that allows the passage of radio frequency signal, power and coolant through it as the drum mounting rotates.

Because the antenna rotates, it cannot mount IFF aerials, as they would change polarity with the rotation. To overcome this issue Selex Galileo has devised the SIT426 active e-scan Mode 5/S IFF system, which it claims is the most advanced in the world. It is the first IFF to use conformal e-scan arrays, three of which are mounted around the fixed portion of the nose behind the rotating antenna.

This arrangement poses its own issues, such as the requirement to sensor-fuse data from the radar and IFF to ensure accurate alignment between the two. In the Captor-E the radar and IFF share the same antenna, so do not require data fusion. In the Gripen installation, however, the fact that the IFF is separate allows it to work in close conjunction with other sensors, such as infrared search-and-track and electronic support measures.

The biggest advantage of the system is its field of regard, which easily matches that of the radar. The side-facing arrays allow aircraft to be interrogated from a parallel track, which is of particular use in a cross-border air defense scenario and is something of which more traditional IFF installations are incapable.

Advanced E-scan for Surveillance

Selex Galileo has achieved notable success with its e-scan surveillance radars. The Seaspray is fitted to the U.S. Coast Guard’s HC-130 Hercules, and been selected for King Air 350ER multi-role enforcement aircraft. In the UK it is installed in the Lynx Wildcat. On April 4 a Seaspray 7500E radar made its first flight installed in a General Atomics Predator B as part of an SPCD (sovereign payload capability demonstration), later undertaking a successful display of its capabilities to an international audience.

Selex Galileo has a number of e-scan developments under way, including installing a Sespray 5000 into the low-cost Tecnam patrol aircraft being offered by Indra. A Seaspray is also fitted to the “Caledonian Vixen” Cessna Caravan II aircraft on show here, which the company uses as a demonstrator. The company revealed it is now working on a new-generation Seaspray with a small conformal flat-panel array that could appear around 2015/16.

PicoSAR is another Selex Galileo product that has attracted a lot of attention. This is a compact X-band SAR/GMTI radar that is ideal for light aircraft, helicopter and UAV applications.