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.