SYNTHETIC APERTURE RFID HANDHELD WITH TAG LOCATION CAPABILITY

摘要

A system for determining a bearing or location of a radio frequency identification (RFID) tag using a handheld RFID reader is described. In one embodiment, the reader is equipped with an accelerometer. A user moves the reader while the reader receives the tag's signal and determines the tag signal's phase at multiple locations. The locations of the reader antenna can be reconstructed using the accelerometer data. By using the phase determined at multiple locations in conjunction with the location of the reader antenna, the reader can determine the bearing of the tag. For an RFID reader not equipped with an accelerometer, the sign and ratio of the rate of change in the phase of a tag's signal to the distance traveled by the reader antenna can be used to determine the location of the tag relative to the reader.

主权项

1. A radio frequency identification (RFID) reader comprising:
a location or movement determination component comprising a sensor, the location or movement determination component configured to measure location or acceleration of the RFID reader; and an RFID radio comprising a first antenna that transmits a first radio frequency (RF) query; wherein a first phase and a second phase for a tag signal sent by a tag is calculated in response to the first RF query and in response to the RFID reader being moved, the first phase corresponding to the tag signal received at a first position of the first antenna, and the second phase corresponding to the tag signal received at a second position of the first antenna; wherein a trajectory or positions of the moving reader is calculated using data from the location or movement determination component; and wherein a bearing for the tag is determined using the calculated trajectory or positions and the calculated first phase and second phase for the tag.