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Posted on 02/13/2008 9:42:11 PM PST by sukhoi-30mki

Low-Cost and Effective AEW Systems Find Buyers

Feb 13, 2008

Bill Sweetman/Defense Technology International

Airborne early warning and control (AEWC) has a reputation for being tricky and expensive. Boeing's 737 AEW aircraft for Australia, Turkey and South Korea -- one of the biggest U.S. export-only defense programs -- has run behind schedule and cost Boeing more than $1 billion in charges. The U.S. Air Force AWACS fleet -- described in 2006 as "falling apart" -- is finally budgeted for much-needed upgrades.

Two systems now on the global market, however, are a step forward in affordability, and are making sales in countries that can't afford a 737, let alone an AWACS. The Saab 2000 EriEye and IAI-Elta Conformal AEW (CAEW) system are competing for sales with the Northrop Grumman E-2D Advanced Hawkeye.

AEWC has always been a valuable asset in air combat, providing long-distance warning against low-flying targets and making fighters more effective. It is also useful in low-intensity conflicts -- suicide attackers, drug smugglers or immigrant runners. Major international government meetings and even public events might be protected by AEWC: South Africa, for example, has approached Sweden about coverage for the 2010 World Cup matches.

Some AEWC radars are being adapted to provide sea and ground surveillance, because they offer more range against small targets than the simpler radars carried by maritime patrol aircraft. The Royal Navy's SKASaC (Sea King Airborne Surveillance and Control) force is being heavily tasked to support coastal operations in the Middle East.

Saab's EriEye radar dates to the 1980s, when Ericsson (its radar unit is now Saab Microwave) created the first airborne active, electronically scanned array (AESA) radar for Sweden's domestic air defense.

The first system could not operate outside the Swedish network; but two S 100D AEW aircraft, based on the Saab 340 regional transport, are being modernized to the ASC 890 standard with radar improvements (including a wider field of view), international-standard identification-friend-or-foe (IFF) Mk. XII equipment, a Link 16 data link and Have Quick II secure radio, and three operator consoles. Once the aircraft are operational in 2009, Sweden plans to take part in USAF's Red Flag Alaska, Canada's international Maple Flag exercises and other operations.

The EriEye radar is operational with Brazil, Mexico and Greece, on the Embraer EMB-145AEW platform. According to Saab, Brazil's aircraft tracked 4,600 illegal flights in 2006. Embraer offers the system for export.

Saab is offering an AEWC system that comprises the EriEye radar and a supporting suite of sensors on board a Saab 2000 turboprop platform. It has been selected by Pakistan and Thailand and is being considered by Malaysia. The choice of a turboprop rather than a jet is "a customer perception," says Sten Soderstrom, vice president of marketing at Saab Surveillance Systems, but it is no slower than a jet and may have better endurance and hot-and-high performance.

The EriEye 2000 also carries a forward-looking infrared system, IFF, a Saab electronic surveillance measures system and a self-defense system.

Saab is providing a "third-generation" version of the radar, says Soderstrom. "We have six customers and none has exactly the same radar." In particular, its sea surveillance capability is better. Saab says that at 25,000 ft., it can track jet skis to the horizon. Altitude resolution is also improved. Four aircraft can sustain two patrol stations around the clock for 30 days.

Islamic nations such as Pakistan and Malaysia are a clear shot for Saab; elsewhere, there's competition from Israel's new Conformal Airborne Early Warning (CAEW) system, based on a Gulfstream G550 airframe (see p. 39).

The Israeli air force was flying some operational missions last year with the CAEW, and formal initial operational capability is due in the first quarter of 2008 -- 16 months after the first modified G550 was delivered to Israel for installation of the IAI-Elta radar. The system has been sold to Singapore.

Avishai Itzhakian, general manager for IAI-Elta's AEW division, says there were "several key elements" in this rapid deployment. CAEW is IAI-Elta's third AEW system since the mid-1990s. There is also a "real integrated product team" for all elements of the system, all developed within Elta. IAI-Elta completed a high-fidelity developmental simulator in 2006, and this was used to train military operators in parallel with the flight test program.

The CAEW system is based on four AESAs providing 360-deg. coverage. Large L-band AESAs are located on the fuselage sides. RF cables run through the window apertures, avoiding the need to recertify the pressure cabin. Nose and tail antennas operate in S-band: Higher frequency means more power to gain equivalent range, but makes it possible to get the same resolution within a smaller aperture.

The radar is automated and software-driven. Compared with IAI-Elta's 1995 system, the CAEW delivers the same power in 2.5 times less installed weight, has a 200-fold increase in general-purpose processing and a 3,000-fold increase in signal-processing speed. It is described as "4D" radar: every track includes the target's three-dimensional position and Doppler information. The idea "is to track a fighter in a dogfight, over land clutter," says Itzhakian.

The CAEW is believed to be the first radar to use a technology known as "track before detect" (TBD). Discussed since the 1970s, TBD improves the ability of a radar to detect small targets. To eliminate false alarms, conventional radars have to set a clutter and noise threshold below which radar returns are ignored. In TBD, those returns are assembled into the equivalent of a God's-eye picture and scanned for patterns that resemble target tracks.

CAEW uses TBD to improve detection of small targets and reduce false alarms, without a large antenna or high power levels. The technique is also valuable in helping an AESA detect and track stealthy targets. Once TBD has indicated the location of a possible target, the AESA focuses more power on that area.

CAEW has other important features. With high-speed data links -- including line-of-sight and beyond-line-of-sight options -- delivering 100-megabit/sec. data rates, a CAEW operator on the ground can use the system as effectively as an operator in the aircraft.

Another unique feature is that CAEW is not a stand-alone system. Israel is creating a total airborne surveillance (TAS) system known as Nachson (Pioneer), which will combine CAEW with signals intelligence, and overland and maritime surveillance aircraft, based on the same G550 platform.

Itzhakian explains that Israel can't afford a single platform to do all these missions. The high-speed data links tie the systems into a network, building a common air, sea and land operational picture.

The next step in the TAS plan is to remove all the crews from the aircraft. Itzhakian -- speaking at an IQPC Defense conference -- said the unmanned system was "not so far away" and noted that an earlier speaker had talked about Boeing's proposal of an unmanned G550 for the U.S. Navy's BAMS requirement. "You can figure this out for yourself," he said.

Israel's new Conformal Airborne Early Warning (CAEW) system,

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