To securely prove that ground survey data are securely measured in the survey place at the survey time.
The method includes: a step I wherein a communication terminal 1 acquires positioning information from a GPS satellite 2; a step II wherein an authentication ID of the communication terminal and the positioning information are transmitted to a data authentication station 6 to make a request to issue a certification code 17 with time information, and the communication terminal receives the certification code issued by the data authentication station; a step III wherein ground survey data 18 are acquired and data information 13 generated by embedding and encoding the issued certification code in the ground survey data is transmitted to the data authentication station to be saved as the original in a server; a step IV wherein a user 8 downloads the data information to a user-side personal computer 81 together with the certification code and uses the data information; and a step V wherein a person 9 to be certified transmits information generated by integrating the certification code and data information to be certified to the data authentication station to decide whether the transmitted information is altered on the data authentication station side by comparing the sent information with the original.
MAE TOSHIMORI
Yasuo Fukuda
Yasuyuki Sakata