Scientists in Germany have developed a surveillance system for coastal areas and ports using mobile telephone network signals. It is aimed at terrorists who could approach a coastline undetected in speedboats and bring explosives on land.
The system is based on what is called passive coherent location (PCL), a “passive” form of radar in that it consists of a receiver but lacks its own transmitter of pulsed electromagnetic signals to bounce off objects.
Instead, it relies on the continuous signals emitted by mobile telephone base station towers, which are reflected by objects in the vicinity and then picked up by the receiver and evaluated. This is considerably more difficult than using conventional radar.
The system was developed by the Bonn-based Fraunhofer Institute for Communication, Information Processing and Ergonomics (FKIE).
In sea trials off the German town of Eckernfoerde and island of Fehmarn, the FKIE scientists successfully tracked speedboats just a few metres in length from 4 kilometres away, said project manager Reda Zemmari.
Combined with electro-optical or infrared systems, PCL enables recognition and classification of the speedboats favoured by pirates to approach cargo ships in busy sea-lanes close to land, he added.
“The mobile phone radar can be transported on a small car trailer and therefore be deployed flexibly,” Zemmari remarked. The surveillance area must have sufficient mobile telephone coverage, however.
According to the FKIE, PCL could also help prevent airplanes and helicopters from flying into wind turbines.
Tall turbines’ blinking red lights that warn pilots at night disturb many people, so the scientists hope to equip the turbines with airplane detectors that switch the lights on only when a plane is approaching.
Zemmari emphasized that the PCL system didn’t snoop on mobile telephone users. “All we use is the transmitter’s operating signal, which doesn’t carry customers’ data packets,” he said.