Patent ID: 6285885
Filing Date: 2001-09-04
Classification: G01S

Abstract:
A radio communication apparatus in a mobile station which can communicate with a base station by radio, the base station having a function of repeating a received radio signal, the apparatus comprising:first means for transmitting a first radio-frequency signal containing a predetermined pseudo-noise code signal toward the base station;second means for detecting a first timing at which the first means transmits the first radio-frequency signal;third means for receiving a second radio-frequency signal after the first means transmits the first radio-frequency signal;fourth means for converting the second radio-frequency signal received by the third means into a baseband signal;a memory storing the predetermined pseudo-noise code signal;fifth means for calculating a correlation between the baseband signal generated by the fourth means and the predetermined pseudo-noise code signal stored in the memory;sixth means for detecting a second timing at which the correlation calculated by the fifth means peaks substantially, said sixth means comprising:first sub-means for differentiating the calculated correlation into a differentiation result;a second sub-means for deciding whether or not the differentiation result generated by the first sub-means becomes smaller than a predetermined reference value; andthird sub-means for using a timing at which the second sub-means decides that the differentiation result becomes smaller than the predetermined reference value as the second timing at which the calculated correlation peaks substantially;seventh means for calculating a time interval between the first timing detected by the second means and the second timing detected by the sixth means; andeighth means for calculating a distance between the mobile station and the base station on the basis of the time interval calculated by the seventh means.