# US 2013/0157685 A1 · Method and apparatus for increasing accuracy of wi-fi based real-time location system (rtls) devices > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157685 A1 - Document ID: US20130157685A1 - Status: Published application - Kind: A1 - Application number: 13/330,175 - Filed: 2011-12-19 - Published: 2013-06-20 - Earliest claimed: 2011-12-19 - Assignees: Adobe Systems Incorporated - Inventors: Stacy Young - Web page: https://patentgrep.com/patent/US20130157685A1 ## CPC - G01S 5/021: {Calibration, monitoring or correction (G01S5/0252 takes precedence)} - G01S 5/02521: {using a radio-map} - H04W 64/00: Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management - 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 method and system for increasing accuracy of Wi-Fi based Real-Time Location System (RTLS) devices is disclosed. The method comprising determining whether a mobile device is in a dampening state and determining a Wi-Fi dampening factor if the mobile device is in the dampening state. The dampening factor is applied to a plurality of Wi-Fi signal strength readings to correct inaccurate readings caused by the dampened state. The system comprises a sensor module for determining whether a mobile device is in a dampening state, and a dampening factor calculator for determining a dampening factor, when the mobile device is in the dampening state. ## Claims ### Claim 1 A method of increasing accuracy of Wi-Fi based Real-Time Location system (RTLS) devices comprising: determining whether a mobile device is in a dampening state; determining a Wi-Fi dampening factor; and applying the dampening factor to a plurality of Wi-Fi signal strength readings. ### Claim 2 (depends on 1) The method of claim 1, wherein determining whether a mobile device is in a dampening state comprises: determining whether the mobile device is near a surface; and determining what surface the mobile device is near. ### Claim 3 (depends on 1) The method of claim 1 wherein determining a dampening factor comprises: retrieving a previous location of a mobile device; determining whether the location time-to-live (TTL) has expired; calculating the dampening factor when the TTL has not expired; and retrieving a previously determined dampening factor when the TTL has expired. ### Claim 4 (depends on 3) The method of claim 3, wherein calculating a dampening factor comprises: retrieving a previous Wi-Fi endpoint signal strength matrix; measuring a plurality of current Wi-Fi endpoint signal strengths; calculating a dampening factor based on the previous Wi-Fi signal strength readings from the Wi-Fi signal strength matrix and the current Wi-Fi signal strength readings; and recording the dampening factor. ### Claim 5 (depends on 3) The method of claim 3, wherein retrieving a dampening factor comprises: determining whether a previous dampening factor has been calculated for the mobile device; retrieving the previous dampening factor when one exists; and retrieving a default dampening factor when a previous dampening factor does not exist. ### Claim 6 (depends on 2) The method of claim 2, wherein determining whether a mobile device is near a surface comprises reading a proximity sensor on the mobile device. ### Claim 7 (depends on 2) The method of claim 2, wherein determining what surface the mobile device is near comprises determining whether the surface is a person holding the mobile device or whether the mobile device is lying on the surface. ### Claim 8 (depends on 7) The method of claim 7, wherein determining whether the surface is a person comprises determining whether a voice call is in progress. ### Claim 9 (depends on 7) The method of claim 7, wherein determining whether the device is lying on a surface comprises accessing the gyroscope and accelerometer readings of the mobile device to determine the movement and orientation of the mobile device. ### Claim 10 (depends on 3) The method of claim 3, wherein determining whether the location TTL has expired comprises determining whether the previous location was recorded within a predefined time interval. ### Claim 11 (depends on 5) The method of claim 5, wherein the default dampening factor is based on a pre-configured value. ### Claim 12 A system for increasing accuracy of Wi-Fi based Real-Time Location system (RTLS) devices comprising: a sensor module for determining whether a mobile device is in a dampening state; a dampening factor calculator for determining a dampening factor, when the Wi-Fi radio in the mobile device is in the dampening state; and applying the dampening factor to a plurality of Wi-Fi signal strength readings. ### Claim 13 (depends on 12) The system of claim 12, wherein the sensor module comprises a gyroscope, an accelerometer and a proximity sensor. ### Claim 14 (depends on 12) The system of claim 12 further comprising a default dampening factor for storing pre-defined dampening factor value as per the policy. ### Claim 15 (depends on 12) The system of claim 12 further comprising a Wi-Fi end point signal matrix for storing previous Wi-Fi end point signal and current Wi-Fi end point signal. ### Claim 16 (depends on 12) The system of claim 12, wherein the Wi-Fi radio is a transceiver of the mobile device. ### Claim 17 A non-transient computer readable medium for storing computer instructions that, when executed by at least one processor cause the at least one processor to perform a method of increasing accuracy of Wi-Fi based Real-Time Location system (RTLS) devices comprising: determining whether a mobile device is in a dampening state; determining a Wi-Fi dampening factor; and applying the dampening factor to a plurality of Wi-Fi signal strength readings. ### Claim 18 (depends on 17) The computer readable medium of claim 17, wherein determining whether a mobile device is in a dampening state comprises: determining whether the mobile device is near a surface; determining what surface the mobile device is near; and applying the dampening factor to a plurality of Wi-Fi signal strength readings. ### Claim 19 (depends on 17) The computer readable medium of claim 17, wherein retrieving a previous location of a mobile device; determining whether the location time-to-live (TTL) has expired; calculating the dampening factor when the TTL has not expired; and retrieving a previously determined dampening factor when the TTL has expired.