Zebra Technologies Corporation
Methods and apparatus for reference regeneration in real time location systems

Abstract:

Methods and apparatus for reference regeneration in real time location systems are disclosed. An example disclosed method includes obtaining reference phase offsets from a plurality of radio frequency identification (RFID) receivers; transmitting a first synchronization signal via a wireline link to obtain differential wireline coarse sync measurements; determining a residual offset table based at least in part on the differential wireline coarse sync measurements and the reference phase offsets; transmitting a second synchronization signal via the wireline link to obtain revised differential wireline coarse sync measurements; generating revised reference phase offsets by combining the revised differential wireline coarse sync offsets with the residual offset table; and determining a physical location of a RFID tag based at least in part on i) the revised reference phase offsets and ii) RFID receiver clock measurements corresponding to a time-of-arrival of over-the-air data transmitted from the RFID tag.