Patent ID: 9087244
Filing Date: 2015-07-21
Classification: G01S,G06K

Abstract:
1. An apparatus, comprising: a transmission antenna that transmits a command to an RFID tag; at least four reception antennas that receive a response from the RFID tag and output a reception signal; a measurement unit that measures time differences between timings at which the reception signals are output from the respective reception antennas and calculates relative coordinates of the RFID tag with respect to a position of the RFID tag position detection apparatus based on the respective measured time differences; a plurality of time-to-digital converters that is disposed in the reception antennas, respectively, includes a start input terminal and a stop input terminal into which the reception signal output from the corresponding reception antenna is input, and outputs a time necessary from a change in a level of a signal input from the start input terminal to a change in a level of a signal input from the stop input terminal, a processor that calculates each time difference based on each time output from each time-to-digital converter; and a controller that is connected to the start input terminals of the respective time-to-digital converters and supplies a set of signals to the start input terminal in such a manner that signal levels thereof simultaneously change.