Patent ID: 7605699
Filing Date: 2009-10-20
Classification: G01S,G01V

Abstract:
1. A system for location recognition using IC tags, wherein an interrogator makes a first communication with multiple IC tags existing in a communication area A by radio, and at the same time, one of said multiple IC tags makes a second communication with other IC tags existing in a communication area B (<A) by probe signals, the one of said multiple IC tags comprising: a first responder that responds with own information Xa to the interrogator; a transmitter that sends said probe signals to the other IC tags when own information Xa is specified by the interrogator; a receiver that receives a probe signal sent out by one IC tag of the other IC tags whose information Xb is specified by the interrogator; a storage that stores information Xb of the one IC tag of the other IC tags specified as a source IC tag by the interrogator in a memory when a reception strength of said probe signal is more than a predetermined level; and a second responder that responds with the information Xb of the source IC tag stored in the memory to the interrogator in response to a readout command, wherein relative positions of said multiple IC tags are recognized from the information Xa and the information Xb collected via the interrogator and wherein the storage stores the information Xb of the one IC tag of the other IC tags until the readout command is received, the readout command specifying the one of said multiple IC tags corresponding to information Xa.