System, tag and method of performing location tracking with ultra wideband (UWB)

A tag for performing location tracking with ultra wideband (UWB), comprising:

• a processor, a real-time clock (RTC) and a non-transitory storage device storing computer executable code,
• wherein the tag is communicatively connected to a network formed by a plurality of base stations, wherein one of the base stations is configured as a master base station and each of remaining ones of the base stations is configured as a slave base station;
• wherein the computer executable code, when executed at the processor of the tag, causes the processor of the tag to perform:
• configuring a plurality of Time Division Multiple Access (TDMA) slots within a predetermined time frame, wherein the TDMA slots sequentially includes a clock calibration packet (CCP) slot, a personal area network (PAN) identifier request slot, a PAN identifier response slot, and a plurality of TDMA tag slots;
• creating a plurality of timers for the TDMA slots, wherein each of the timers is configured to indicate time of one of the TDMA slots;
• in the CCP slot, performing perform clock synchronization among the base stations and the tag;
• in the PAN identifier request slot, sending a reservation request to the base stations, wherein the base stations are configured to assign a corresponding TDMA tag slot to the tag in response to the reservation request;
• in the PAN identifier response slot, receiving the corresponding reservation request from the base stations;
• and
• in each of the TDMA tag slots,
• sending the corresponding ranging request to the base stations within the TDMA tag slot corresponding to the tag, wherein the base stations are configured to send a corresponding ranging response to the tag with a corresponding timestamp indicating the time of the TDMA tag slot corresponding to the corresponding tag;
• receiving the corresponding ranging response with the corresponding timestamp from the base stations;
• calculating a wake-up time based on the corresponding timestamp, wherein the wake-up time is a time period prior to the time of the TDMA tag slot corresponding to the tag;
• entering a deep sleep mode, wherein the RTC remains active in the deep sleep mode;
• and
• in response to the RTC indicating the wake-up time, waking up from the deep sleep mode, performing location calculation to obtain locating information within the TDMA tag slot corresponding to the tag, and re-entering the deep sleep mode after the TDMA tag slot corresponding to the tag.

A method of performing location tracking with ultra wideband (UWB), comprising:

• providing a network formed by a plurality of base stations communicatively connected to one another and to a plurality of tags, wherein one of the base stations is configured as a master base station and each of remaining ones of the base stations is configured as a slave base station;
• configuring a plurality of Time Division Multiple Access (TDMA) slots within a predetermined time frame, wherein the TDMA slots sequentially includes a clock calibration packet (CCP) slot, a personal area network (PAN) identifier request slot, a PAN identifier response slot, and a plurality of TDMA tag slots for the tags;
• creating a plurality of timers for the TDMA slots, wherein each of the timers is configured to indicate time of one of the TDMA slots;
• in the CCP slot, performing clock synchronization among the base stations and the tags;
• in the PAN identifier request slot,
• for the master base station, listening for a reservation request from each of the slave base station and the tags;
• and
• for the slave base station, sending the reservation request to the master base station, and relaying the reservation request from the tags to the master base station;
• in the PAN identifier response slot,
• for the master base station, in response to the reservation request received from each of the slave base station and the tags, recording each of the slave base station and the tags, assigning a corresponding TDMA tag slot to each of the tags sending the reservation request, and sending a corresponding reservation response respectively to each of the slave base station and the tags;
• and
• for the slave base station, receiving the corresponding reservation response from the master base station;
• and
• in each of the TDMA tag slots, listening, by the base stations, to ranging requests from the tags, and in response to receiving a corresponding ranging request from a corresponding tag of the tags, sending a corresponding ranging response to the corresponding tag with a corresponding timestamp indicating the time of a TDMA tag slot corresponding to the corresponding tag.