Patent ID: 7868815

Claim:
A wireless distance measurement system having a base station apparatus and a wireless communication terminal apparatus, the base station apparatus comprising: a transmitting section that generates a pulse based on a clock and transmits the generated pulse; a receiving section that receives the transmitted pulse via the wireless communication terminal apparatus; a phase shifting section that shifts a phase of the clock by a specific amount with a regular period; an analog to digital conversion section that converts the received pulse to a digital signal at a plurality of phases using the phase shifted clock; a correlation calculation section that performs correlation calculation between the pulse converted to the digital signal and the pulse as transmitted from the transmitting section, and forms a delay profile by adding correlation values between same phases; a detection section that detects an incoming wave from a desired wireless communication terminal apparatus based on peaks of pulses in the delay profile; and a distance calculation section that calculates a distance to the wireless communication terminal apparatus using an elapsed time after the detected incoming wave is transmitted from the transmitting section until the detected incoming wave is received in the receiving section; and the wireless communication terminal apparatus comprising: a division section that receives the pulse transmitted from the base station apparatus and divides a received signal and a transmission signal; and a first amplification section that amplifies and reradiates the received pulse to the base station apparatus again.