Patent ID: 8195201

Claim:
A radio positioning system comprising: a plurality of base stations; and a radio terminal, wherein each of the base stations includes a reference signal generating portion which generates a reference signal for positioning, a transmission portion which transmits the reference signal, a reception portion which receives a signal from its outside, a positioning portion which calculates a position relative to the radio terminal or base station as a signal sender based on the received signal, and a reference signal return portion which receives a reference signal transmitted from another base station and returns the reference signal to the another base station; wherein the radio terminal includes a terminal reception portion which receives the reference signal, and a terminal transmission portion which returns the received reference signal; and wherein a reference signal transmitted by a first base station of the base stations is received and returned by the reference signal return portion in a second base station, the returned reference signal is received by the reception portion in the first base station, and the positioning portion in the first base station measures relative coordinates to the second base station based on the received reference signal.