The RoboCup 2006 championship in Bremen ended on Sunday with Germany winning 11 of the 33 robot football categories. China came in second with nine medals, followed by Japan with six and Iran with five. Japan won the humanoid competition, with a kid-size robot from Osaka.

While all that has been going on, another group of robots is diligently patrolling Berlin's Olympic Stadium, one of 12 venues hosting the World Cup tournament currently under way in the country.

The RoboCup’s goal is to develop a team of fully autonomous humanoid robots that can play - and win - against a human World Cup champion team by 2050.

With RoboCup over, robot enthusiasts are now shifting their attention to another group of robots busy protecting the historical Berlin stadium, home to the Olympic Games in 1936 and host to a handful of matches for the 2006 World Cup tournament.

Eleven moveable robots are patrolling the stadium area every night through 9 July, when the final of the World Cup takes place in the Berlin stadium.

The robots, built and operated by Robowatch in Berlin, are part of a contract that Fifa awarded to Best Veranstaltungsdienste to provide security services at the World Cup stadia in Berlin, Frankfurt Leipzig.

"The security company wanted to ensure 150 percent security so they hired us to help out," said Robowatch spokesman Benjamin Stengl in an interview today. "We've been commissioned to provide 20 robots if necessary."

One group of robots is programmed for outdoor surveillance. With the help of GPS (global positioning system) technology, they patrol the exterior area of the Berlin stadium and fences up to 2km away from control centre, which is located within the stadium.

Another group focuses on indoor surveillance, programmed with a layout of the stadium interior, including administration rooms, underground parking spaces and storage areas.

The robots communicate with the control centre via 3G (third-generation) mobile technology. Each robot is equipped with a 3G card, which connects to a dedicated base station in the stadium. All data is encrypted.

"We could have used Wi-Fi technology but it would have required additional access points and thus higher costs," Stengl said.

In addition, all of the robots are equipped with video cameras, radar sensors, temperature gauges and infrared scanners. Camera heads on the robots can turn in all directions and can be controlled remotely by a technician in the control centre.

"If a robot registers something that has changed, such as a hole in a fence, it stops and sends an alert to the control centre," Stengl said. " The radar sensors are also able to detect human bodies through most walls."

Upon request, the outdoor robots can be equipped with technology to detect alpha, beta and gamma rays, as well as biological weapons.

The outdoor robots are 1.4m long and weigh 40kg. They move on miniature tracks similar to those on army tanks, and can reach speeds up 7kmph (kilometres per hour).

The indoor robots and slightly smaller, at 1.18m, and weigh 25kg. They roll on wheels at speeds up to about 4kmph.

The robot software system is based on the open-source Linux operation system. "We decided to use Linux for a couple of reasons," Stengl said. "One is security. Another is that we've found it easier to program our application on this platform."