People rely on GPS for navigation, vehicle and freight tracking and location-based smartphone services. However, low-powered GPS signals are easily drowned out by other sources, which are increasing in number, said Professor Andrew Dempster from the University of New South Wales School of Surveying and Spatial Information Systems.
Among them are low-cost jamming units that can be used by criminals to knock out tracking systems.
"GPS signals are weak and can easily be outpunched by poorly-controlled signals from television towers, devices such as laptops and MP3 players, or even mobile satellite services," he said, according to a New South Wales statement.
Dempster spoke at a workshop on GPS vulnerability organised in Canberra by the Australian Centre for Space Engineering Research (ACSER).
"This is not only a significant hazard for military, industrial and civilian transport and communication systems, but criminals have worked out that they can jam GPS," he said.
Dempster said his research team had detected interference in GPS signals caused by a TV tower in Sydney's northern suburbs.
While they had not detected any criminal jamming activity, Dempster said overseas criminals are already using jammers.