Denso Wave Corporation

Masayuki Ogawa

Kohei Enomoto

Yusuke Masuda

A tag measurement environment evaluation device includes a processor and a memory storing a program. The program is configured to, when executed by the processor, cause the processor to determine a moving tag evaluation value of each of a plurality of wireless tags based on a radio wave transmitted from each of the wireless tags and received by a tag reader configured to communicate with each of the wireless tags, and determine whether a measurement environment is suitable for a moving tag detection based on the moving tag evaluation values.

Tag measurement environment evaluation device

A configuration which can easily discriminate a moving wireless (radio) tag from a stationary wireless (radio) tag. The configuration uses an antenna to measure phases of response waves received from a wireless tag. Based on the measurements, the configuration measures changes in distance from the wireless tag to the antenna and detects travel of the wireless tag. Based on the measurements, the configuration measures changes in velocity of the wireless tag relative to the antenna. A wireless tag having a rate of changes in signs of the velocity, of not less than a predetermined value in the measured velocity changes, is detected as being a stationary tag.

Apparatus for detecting tag movements and wireless tag reader

In a configuration for detection of a movement state of a radio tag using a phase difference of a response wave from the radio tag, a phase &#x3c6;[i] and a measurement time t[i] of a response wave from a radio tag measured are sequentially stored in a memory. A difference from a previous phase and a difference from a previous measurement time with respect to each phase &#x3c6;[i] stored in the memory are calculated as a phase difference &#x394;&#x3c6;[i] and a time difference &#x394;t[i]. A phase addition value &#x3c6;sum[i] obtained by cumulatively adding a plurality of the phase differences &#x394;&#x3c6;[i] is calculated so as to correct a phase difference in which the corresponding time difference &#x394;t[i] among the calculated plurality of the phase differences &#x394;&#x3c6;[i] exceeds a time threshold tsa [i], whereby the movement state of the radio tag is detected based upon the calculated phase addition value &#x3c6;sum[i].

Device and method for detecting movement of radio tag

A tag reader includes: a phase calculation section that sequentially calculates a phase of a reception wave; a phase difference calculation section that calculates a phase difference as a difference of phases calculated at two time points; and a tag angle calculation section that calculates a tag angle between a straight line connecting an antenna and the wireless tag and a line on which the wireless tag is moving. The phase difference calculation section calculates two values of the phase difference. The tag angle calculation section calculates a first tag angle and a second tag angle. The tag reader comprises a tag distance calculation section that calculates an antenna-tag minimum distance as a minimum distance from the line to the antenna.

Growing community of inventors

Chita-gun, Japan

Masayuki Ogawa