Patent ID: 8912949

Claim:
An ultra-sensitive system for measuring distance, comprising: plural UWB transmitter-receivers ( 1 ) periodically transmitting PN codes of M system and preliminarily disposed on known positions; a server ( 3 ) to synchronize the plural UWB transmitter-receivers ( 1 ); and an RF tag (T) attached to a moving object ( 20 ) as to receive signals (I 0 ) synchronously and periodically transmitted from the UWB transmitter-receivers ( 1 ) and reflect the signals (I 0 ) adding inherent tag recognition signal, wherein the UWB transmitter-receiver ( 1 ) is composed as to obtain the distance to the moving object ( 20 ) attached with the RF tag (T) by synchronous summation and correlative calculation of the PN codes of M system reflected by the RF tag (T).