Synthetic aperture RFID handheld with tag location capability

• Main Authors: Nikitin Pavel, Rao Kvs, Leland Hunter, Brueckmann Rainer, Kelly Stephen
• Format: Patent
• Language: English
• Published: 05.12.2017
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; SELECTING; TESTING

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.