Michael Bateson, managing director of Siemens Datatrak had claimed GPS-enabled tracking systems could only be accurate 75% of the time in cities, because tall buildings could block satellite signals used to calculate a vehicle's position. The firm claimed using low frequency radio waves provided an answer to the so-called Urban Canyon Effect in cities.
But Minorplanet says GPS-enabled devices are compatible with a system called 'Dead Reckoning', which corrects any errors and verifies the actual vehicle movements, keeping track of location if the vehicle is temporarily lost.
Andrew Tillman, Minorplanet operations director, said: 'GPS signals, like those received by the Minorplanet system, cover almost the entire face of the earth.'
He claimed positions based on low-frequency radio waves could be unreliable in out of the way areas. 'These systems are often lost if the vehicle exits a heavily populated area or moves into Scotland or Europe,' he said.