In some embodiments, a radio frequency identification (RFID) reader with multiple antennas may determine the location of an RFID tag relative to the reader's antennas, by using a difference-in-time-of-arrival technique to triangulate on the RFID tag based on the difference in distances between the tag and each antenna. A given point in the signal from the RFID tag may provide a narrow point in time from which to make the calculations, while a common clock to the multiple receive paths may permit making accurate measurements of the difference in time of reception of that point at the different antennas. In some embodiments, movement of the RFID tag may be determined by calculating a series of locations over time.