Patent ID: 11968592
Assignee: PAYLESSGATE CORPORATION
Field: Digital communication (Electrical engineering)
Classification: CPC G  H | IPC H

Claim 17:
18. A position determination method which is used in a position determination system including a personal portable terminal that is to be carried by a person whose position is determined and a position determination apparatus that determines the position of the personal portable terminal to determine the position of the personal portable terminal,
the position determination method comprising:
detecting that the person who carries the personal portable terminal comes into an area within a predetermined distance from the position determination apparatus by using the personal portable terminal, and activating a personal terminal side transmitter by using a personal terminal side controller;
transmitting a position determination signal to be used for position determination to the position determination apparatus through the personal terminal side transmitter by using the personal portable terminal;
receiving the position determination signal which is transmitted by the personal terminal side transmitter through a plurality of first and second position determination side receivers that are arranged at different first and second positions which are spaced at first and second distances away from the personal portable terminal, respectively, by using the position determination apparatus, the second distance being greater than the first distance; and
determining the position of the personal portable terminal based on a difference between an intensity of the position determination signal that is received by the first position determination side receivers and an intensity of the position determination signal that is received by the second position determination side receivers by using a position determination side calculator included in the position determination apparatus,
the method further comprising
prior to the transmission of the position determination signal through the personal terminal side transmitter,
transmitting unique identification information that is stored in a personal terminal side storage device included in the personal portable terminal and a one-time password that is assigned to the unique identification information and can be used only once to the position determination side receiver by using the personal terminal side transmitter,
performing authentication of the personal portable terminal based on the identification information and the one-time password by using the position determination side calculator,
wherein the transmission of the identification information and the one-time password by the personal portable terminal to the position determination apparatus includes
obtaining information relating to an issue time when the one-time password is issued by using the personal terminal side controller from a personal terminal side clock included in the personal portable terminal, applying the information to a predetermined function that is stored in the personal terminal side storage device, and further encrypting the information which is obtained by the predetermined function with a common key that is stored in the personal terminal side storage device whereby issuing the one-time password,
wherein the authentication of the personal portable terminal based on the identification information and the one-time password by using the determination side calculator includes
obtaining a reception time by using the determination side clock when the measurement side receiver receives the identification information and the one-time password from the personal terminal side transmitter,
retrieving the common key corresponding to the identification information based on the received identification information, decrypt the one-time password by using the obtained common key, and obtain the information relating to the issue time to which the function is applied,
comparing a difference between the information relating to the issue time that is obtained at one reception time and information relating to the one reception time with a difference between the information relating to the issue time that is obtained at another reception time and information relating to the another reception time, and
authenticating the personal portable terminal if the compared difference falls within a predetermined time range, or disabling the authentication of the personal portable terminal if the compared difference falls out of the predetermined time range.