PORTABLE TERMINAL DEVICE, RADIO COMMUNICATION UNIT, RADIO AUTHENTICATION RANGE MEASURING METHOD AND RADIO AUTHENTICATION RANGE MEASUREMENT PROGRAM

摘要

PROBLEM TO BE SOLVED: To enhance the measuring precision of a distance between a portable terminal device and a radio communication unit. SOLUTION: Radio waves and sound waves transmitted from the portable terminal device 100 or a key unit 200 in the same timing are received, and a distance between the key unit 200 and the portable terminal device 100 is calculated on the basis of a difference in arrival time between reception ID 2 and ID4 received by the radio waves and reception ID1 and ID3 received by the sound waves. In addition, timing control parts 114 and 214 are provided which adjust timing for transmitting a transmission ID to be transmitted to a modulating/sound wave transmitting parts 111 and 211 and a transmission ID to be transmitted to transmitting and receiving parts/modulating and demodulating parts 113 and 213. COPYRIGHT: (C)2007,JPO&INPIT