Pseudolite

Pseudolites are ground based radio transmitters that transmit a signal of a satellite navigation system (GNSS). They are acting as a navigation satellite, but are operating from the ground (on earth). Hence the name, a compression of "pseudo satellite".

Pseudolites are intended to complement the satellite navigation systems, esp. to extend the satellite navigation technology to difficult environments like indoors, where the coverage of the satellite navigation system itself is poor.

Users need to have a slightly modified satellite navigation receiver to make use of these signals. This is because receivers are designed to capture weak signals from distant satellites. The receiver is not designed to cope with the relatively high-powered transmissions of the pseudolite.