A system configured to operate an exchange protocol for sending and receiving ultra-wideband frames, wherein sending and receiving the ultra-wideband frames comprises:
- sending, by a master beacon device and one or more beacon repeater devices, ultra-wideband beacon frames, wherein the ultra-wideband beacon frames are transmitted as interleaved pairs of ultra-wideband beacon frames, wherein each interleaved pair is sent either from the master beacon device or one of the one or more beacon repeater devices, wherein each interleaved pair includes a first ultra-wideband beacon frame and a second ultra-wideband beacon frame, wherein, for each interleaved pair, the first ultra-wideband beacon frame and the second ultra-wideband beacon frame are transmitted with a master time delay;
- receiving, by one or more tag devices, at least one of the interleaved pairs of ultra-wideband beacon frames;
- receiving, by the one or more beacon repeater devices, at least one of the interleaved pairs of ultra-wideband beacon frames;
- receiving, by one of a plurality of tag response receptor units, at least one of the interleaved pairs of ultra-wideband beacon frames;
- sending, by the one or more tag devices, ultra-wideband tag response frames;
- and
- receiving, by the one of the plurality of tag response receptor units, at least one of the ultra-wideband tag response frames,
- wherein the exchange protocol defines a location rate frame format comprising:
- a beacon section comprising a sequence of time slots, wherein the time slots are respectively associated to one of the first ultra-wideband beacon frame or the second ultra-wideband beacon frame of interleaved pair such that a separation in time of the time slots associated to each of the interleaved pair is given by the master time delay, and wherein, between time slots assigned to the first ultra-wideband beacon frame and the second ultra-wideband beacon frame of an opening interleaved pair comprising an initial one of the ultra-wideband beacon frames within the beacon section, an array of time slots that are respectively assigned to the first ultra-wideband beacon frames of the remaining pairs is provided, and
- a tag response section comprising a sequence of time slots that are respectively associated to one of the ultra-wideband tag response frames,
- wherein the master beacon device and optionally one or more beacon repeater devices, respectively include:
- a beacon transmission unit configured to transmit two successive ultra-wideband beacon frames at the time slots of the beacon section that are associated to one of the interleaved pairs, and
- a master clock defining a master time to ensure the separation of the two ultra-wideband beacon frames to be the master time delay or a repeater clock calibrated to the master clock, respectively;
- wherein each tag device comprises:
- a tag clock defining a tag time that is specific for a respective tag device, wherein the tag time is calibrated with respect to the master time using the master time delay,
- a reception unit configured to receive the two successive ultra-wideband beacon frames sent from the master beacon device or from one of the one or more beacon repeater devices at the time slots of the beacon section, and
- a tag response emission unit configured to transmit an ultra-wideband tag response frame at a time slot of the tag response section;
- wherein each tag response receptor units comprises:
- a receptor clock defining a respective receptor time for the respective tag response receptor unit, wherein the receptor time is calibrated with respect to the master time using the master time delay, and wherein each tag response receptor unit is configured to receive the ultra-wideband tag response frame sent from the tag device at the respective time slot of the tag response section;
- and
- wherein at least one distance determination unit includes a calculation unit configured to, for continuously performed location rate frames and for each of the tag devices:
- determine path time periods for each of the tag devices, wherein each path time period is associated to any one of the two successive ultra-wideband beacon frames, a respective ultra-wideband tag response frame, and a transmission path from the master beacon device or one of the one or more beacon repeater devices to one of the plurality of tag response receptor units,
- derive accumulated time-of-flight periods from the path time periods indicating a cumulated signal propagation time for one of the two successive ultra-wideband beacon frames and the ultra-wideband tag response frames along the transmission paths, and
- determine distance values associated to tag device positions from the accumulated time-of-flight periods and a plurality of installation position data representing optionally the distances between each of the plurality of tag response receptor units and the beacon transmission unit of the master beacon device or the one of the one or more beacon repeater device.