Increasingly, advanced asset surveillance systems use GPS to monitor the location and movement of assets. Not so well known, however, are its applications in other areas. GPS devices now form a key part of emergency vehicles' arsenals. They are also used for high-precision surveying, transportation monitoring, just-in-time stock management, farming, docking ships and they may soon be used to automatically land commercial aircraft. In the UK, more and more trains depend on a firm GPS location fix before their doors will open. But the dependability of GPS is coming under threat from both natural and man-made sources. At risk are not only sat-nav users, but also critical national infrastructure. Earlier in February, the BBC reported an imminent change in solar activity that could corrupt GPS receivers. See http://news.bbc.co.uk/1/hi/sci/tech/8494225.stm . Now, the latest threat is from jammers http://news.bbc.co.uk/1/hi/sci/tech/8533157.stm, according to experts. Small GPS jamming devices are widely available on the internet.
