Long live the VOR! Walter DCA WASHINGTON, March 7 (Reuters) - The Transportation Department said on Thursday it would ensure that global positioning systems used in aviation and other transportation are state-of-the-art and adequately backed up. Transportation Secretary Norman Mineta said the agency would launch a plan that included back-up strategies as well as continued partnership with the Pentagon to modernize satellite navigation systems used in civil transportation. The department would also study GPS applications for aviation and other civil transportation over the long term, and obtain new technology to prevent jamming or other intentional interference. Developed by the Defense Department, GPS uses a constellation of two dozen orbiting satellites as reference points to quickly and precisely calculate positions anywhere in the world. It has many common applications and is widely used to track the position of trucks, ships and trains. The Federal Aviation Administration plans to use it to safely pack more planes into the skies and allow precision landings in bad weather. The precise time kept by the GPS system has also spawned myriad other civilian uses such as coordinating power transmissions and synchronizing telephone networks. A Transportation Department report in September concluded that air, rail, road and sea users of GPS technology should be prepare for outages and keep ground-based navigation aids on line as back-up. The study found that the relatively weak GPS signal is susceptible to unintentional disruption from atmospheric effects, buildings and radio signals. It was also vulnerable to tampering. The September report by Transportation Department's Volpe National Transportation System Center outside Boston concluded that with proper precautions there should be optimism about the potential of GPS. The report recommended development of affordable backup navigation. Those could include systems that make use of both GPS and radio positioning systems as well as other technologies.