Abstract: A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse compression radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulse compression radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.

Abstract: A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse compression radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulse compression radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.

Abstract: A system for measuring range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated signal compression radar system. The reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The signal compression radar system transmits signals coordinated by the backscatter state of the tag and creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar signals between the radar system and the RFID tag. The radar may use signals typical of pulse compression radar systems such as chirp modulation or Orthogonal Frequency Domain Modulation (OFDM), either pulsed or semi-continuous.

Abstract: A system for measuring range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated signal compression radar system. The reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The signal compression radar system transmits signals coordinated by the backscatter state of the tag and creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar signals between the radar system and the RFID tag. The radar may use signals typical of pulse compression radar systems such as chirp modulation or Orthogonal Frequency Domain Modulation (OFDM), either pulsed or semi-continuous.

Abstract: A system for measuring the range to an RFID tag including situations containing high clutter and multi-path signals is disclosed. The system includes an RFID reader; an RFID tag; and a coordinated pulse compression radar system. In the system the RFID reader causes the tag to respond to received signals in a first backscatter state at a first time and a second backscatter state at a second time. The pulse compression radar system transmits short pulses coordinated by the backscatter state of the RFID tag and the system creates a differential signal comprised of the differences between radar signals obtained during the first and second states of the tag to obtain an uncorrupted measure of a round trip time of flight of said radar pulses between the pulse radar system and the RFID tag.