Supporters of LORAN say the nation's increasing reliance on GPS has ironically increased the importance of maintaining LORAN as a backup.

CNN: Navigation system, aid to farmers among budget cuts

Just one year ago, the Bush administration announced it would keep the ground-based LORAN system operational to serve as a backup for the satellite-based global positioning systems, which are becoming ubiquitous in cars, planes and ships.

CNN: Navigation system, aid to farmers among budget cuts

However, to do the same to the Loran system, you'd need a 40ft tower -- and around 25kW of juice to power it.

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Having LORAN in reserve makes the GPS satellite system a less attractive target for terrorists, they say.

CNN: Navigation system, aid to farmers among budget cuts

The basics behind Loran and GPS are largely the same, with devices measuring the time it takes for a signal to travel between a transmitter and your receiver.

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