To provide an access control system of a construction site, allowing reduction of operation cost.
When it becomes possible to receive transmission information of an ID tag 16 not having been received by a receiver 13 till then, it is decided whether or not an ID number included in the transmission information is an ID number of the ID tag 16 decided that entrance to an excavation construction area 1 has been completed. When deciding that the read ID number is not the ID number of the ID tag 16 decided that the entrance to the excavation construction area 1 has been completed, it is decided that the ID tag 16 imparted with the read ID number belongs to an entrance-scheduled vehicle, and one is added to the number of the entrance-scheduled vehicles to the evacuation construction area 1. Thereafter, when two infrared sensors 11 simultaneously detect a detection object, one is subtracted from the number of the entrance-scheduled vehicles to the evacuation construction area 1. By thus calculating the number of the entrance-scheduled vehicles, it is decided that it is entrance of a regular vehicle 15 when the calculated number of the entrance-scheduled vehicles is zero or above.
COPYRIGHT: (C)2009,JPO&INPIT
Katsutoshi Sahara
Hiroshi Ogura
Makoto Hasegawa
Hitachi Construction Machinery Co., Ltd.
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