# US 2021/0243564 A1 · Real time tracking systems in three dimensions in multi-story structures and related methods and computer program products > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2021/0243564 A1 - Document ID: US20210243564A1 - Status: Published application - Kind: A1 - Application number: 17/161,122 - Filed: 2021-01-28 - Published: 2021-08-05 - Earliest claimed: 2020-01-30 - Assignees: Wiser Systems, Inc. - Applicants: Wiser Systems, Inc. - Inventors: Seth Edward-Austin Hollar; Ryan Michael Tedrick - Web page: https://patentgrep.com/patent/US20210243564A1 ## CPC - G01S 5/0278: {involving statistical or probabilistic considerations (G01S5/0252, G01S5/0294 take precedence)} - H04W 4/029: Location-based management or tracking services - G01S 5/14: Determining absolute distances from a plurality of spaced points of known location - H04W 4/021: Services related to particular areas, e.g. point of interest [POI] services, venue services or geofences - H04W 4/33: for indoor environments, e.g. buildings - G01S 5/08: Position of single direction-finder fixed by determining direction of a plurality of spaced sources of known location - G01S: RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract A real time location system (RTLS) is provided for determining three-dimensional locations of nodes in an environment. The RTLS system includes at least one node associated with an asset in the environment. The at least one node has an unknown location. The system further includes at least one tracking device that communicates with the at least one node to obtain location data associated with the unknown location of the at least one node. A location module receives the location data associated with the unknown location of the at least one node and determines a real-time three-dimensional current location of the at least one node based on the location data. The real-time three-dimensional current location having x, y and z coordinates and the z coordinate indicates a height of the at least one node in the environment. ## Claims ### Claim 1 A real time location system (RTLS) for determining three-dimensional locations of nodes in an environment, the RTLS system comprising: at least one node associated with an asset in the environment, the at least one node having an unknown location; at least one tracking device that communicates with the at least one node to obtain location data associated with the unknown location of the at least one node; and a location module that receives the location data associated with the unknown location of the at least one node and determines a real-time three-dimensional current location of the at least one node based on the location data, the real-time three-dimensional current location having x, y and z coordinates and the z coordinate indicates a height of the at least one node in the environment. ### Claim 2 (depends on 1) The RTLS system of claim 1, wherein the location module further: receives a plurality of heights (z) in the environment; and calculates x and y coordinates for each of the plurality of heights (z) to provide x, y and z coordinates for each of the plurality of heights (z). ### Claim 3 (depends on 2) The RTLS system of claim 2, wherein the location module further: calculates a confidence factor for each x, y and z coordinate; and selects a height for the at least one node based on the calculated confidence factors, wherein the height with a greatest confidence factor is selected. ### Claim 4 (depends on 2) The RTLS system of claim 2, wherein the location module further: calculates an error factor for x, y and z coordinate; and selects a height for the at least one node based on the calculated error factors, wherein the height with a smallest error factor is selected. ### Claim 5 (depends on 4) The RTLS system of claim 4, wherein the location module further calculates the error factor for each x, y, z coordinate using a difference between measured distances and presumed distances related to the at least one node. ### Claim 6 (depends on 1) The RTLS system of claim 1, wherein the location module further: assumes a starting height (z) of the at least one node; calculates x and y coordinates of the at least one node based on the assumed starting height (z); calculate an error factor based on the assumed height (z); selects a next height (z) using a gradient descent method; and repeating calculating x and y coordinates, calculating the error factor and selecting a next height (z) until a final height of the at least one node is determined. ### Claim 7 (depends on 1) The RTLS system of claim 1, wherein the location module further: creates a list of heights (z) for the at least one node; and performs a binary search of the list of heights (z). ### Claim 8 (depends on 7) The RTLS system of claim 7, wherein the location module further: selects two heights (z) from the list of heights (z), one of the two height (z) being a low height and one of the two heights being a high height; determines a middle height between the low and high heights; calculates x and y coordinates for each of the low, medium and high heights; calculates an error factors for each of the calculated x and y coordinates; selects a new pair of low and high heights based on where the calculates error factors fall between the low and middle heights or between the middle and high heights; and repeating determining, calculating x and y coordinates, calculating an error factor and selecting a new pair of low and high heights until a final height of the at least one node is determined. ### Claim 9 (depends on 1) The RTLS system of claim 1, wherein the location data comprises angle of arrival data, time of flight measurement data, arrival timestamp data and/or departure timestamp data. ### Claim 10 (depends on 1) The RTLS system of claim 1, wherein the environment is a multi-story building. ### Claim 11 (depends on 10) The RTLS system of claim 10: wherein the at least one tracking device comprises at least one tracking device on each floor of the multi-story building; and wherein the at least one tracking device on each floor operates independently of the at least one tracking device on all other floors. ### Claim 12 A method for determining three-dimensional locations of nodes in an environment using a real time location system (RTLS), the RTLS system including at least one node associated with an asset in the environment, the at least one node having an unknown location; at least one tracking device that communicates with the at least one node to obtain location data associated with the unknown location of the at least one node; and a location module, the method comprising: receiving the location data associated with the unknown location of the at least one node at the location module; and determining a real-time three-dimensional current location of the at least one node based on the location data, the real-time three-dimensional current location having x, y and z coordinates and the z coordinate indicates a height of the at least one node in the environment. ### Claim 13 (depends on 12) The method of claim 12, further comprising: receiving a plurality of heights (z) in the environment; and calculating x and y coordinates for each of the plurality of heights (z) to provide x, y and z coordinates for each of the plurality of heights (z). ### Claim 14 (depends on 13) The method of claim 13, further comprising: calculating a confidence factor for each x, y and z coordinate; and selecting a height for the at least one node based on the calculated confidence factors, wherein the height with a greatest confidence factor is selected. ### Claim 15 (depends on 13) The method of claim 13, further comprising: calculating an error factor for x, y and z coordinate; and selecting a height for the at least one node based on the calculated error factors, wherein the height with a smallest error factor is selected. ### Claim 16 (depends on 15) The method of claim 15, further comprising calculating the error factor for each x, y, z coordinate using a difference between measured distances and presumed distances related to the at least one node. ### Claim 17 (depends on 12) The method of claim 12, further comprising: assuming a starting height (z) of the at least one node; calculating x and y coordinates of the at least one node based on the assumed starting height (z); calculating an error factor based on the assumed height (z); selecting a next height (z) using a gradient descent method; and repeating calculating x and y coordinates, calculating the error factor and selecting a next height (z) until a final height of the at least one node is determined. ### Claim 18 (depends on 1) The method of claim 1, further comprising: creating a list of heights (z) for the at least one node; and selecting two heights (z) from the list of heights (z), one of the two heights (z) being a low height and one of the two heights being a high height; determining a middle height between the low and high heights; calculating x and y coordinates for each of the low, medium and high heights; calculating an error factors for each of the calculated x and y coordinates; selecting a new pair of low and high heights based on where the calculates error factors fall between the low and middle heights or between the middle and high heights; and repeating determining, calculating x and y coordinates, calculating an error factor and selecting a new pair of low and high heights until a final height of the at least one node is determined. ### Claim 19 (depends on 12) The method of claim 12, wherein the location data comprises angle of arrival data, time of flight measurement data, arrival timestamp data and/or departure timestamp data. ### Claim 20 A computer program product for determining three-dimensional locations of nodes in an environment using a real time location system (RTLS), the RTLS system including at least one node associated with an asset in the environment, the at least one node having an unknown location; at least one tracking device that communicates with the at least one node to obtain location data associated with the unknown location of the at least one node; and a location module, the computer program product comprising: a non-transitory computer readable storage medium having computer readable program code embodied in the medium, the computer readable program code comprising: computer readable program code that receives the location data associated with the unknown location of the at least one node at the location module; and computer readable program code that determines a real-time three-dimensional current location of the at least one node based on the location data, the real-time three-dimensional current location having x, y and z coordinates and the z coordinate indicates a height of the at least one node in the environment.