# US 8,786,494 B2 · Method to modify calibration data used to locate a mobile unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,494 B2 - Document ID: US8786494B2 - Status: Granted - Kind: B2 - Application number: 13/771,542 - Filed: 2013-02-20 - Published: 2013-06-27 - Granted: 2014-07-22 - Earliest claimed: 2007-02-05 - Assignees: Andrew Corporation - Applicants: Andrew LLC - Inventors: Martin Alles; John Carlson; George Maher; Selcuk Mazlum - Web page: https://patentgrep.com/patent/US8786494B2 ## CPC - G01S 5/021: {Calibration, monitoring or correction (G01S5/0252 takes precedence)} - G01S 5/0244: {Accuracy or reliability of position solution or of measurements contributing thereto} - G01S 5/02526: {using non-dedicated equipment, e.g. user equipment or crowd-sourcing} - H04W 4/02: Services making use of location information - H04W 4/029: Location-based management or tracking services - 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 of modifying calibration data used to geo-locate a mobile station located in an indoor environment is disclosed. When a mobile station is located indoors, the signal strength of signals received and/or transmitted by the mobile station have the tendency to be lower than the strength of the signals received by a mobile station located outdoors. As a result of these lower signal strengths, geo-location efforts which rely on signal strengths may result in unsatisfactory location accuracy. Modifying pre-existing calibration data obtained outdoors may provide a way to simulate indoor calibration data characteristics. ## Claims ### Claim 1 A method for determining a location of a mobile station, comprising: providing a database of previously-gathered calibration data for a predetermined region in a wireless network; collecting observed network measurement data, the observed network measurement data collected by the mobile station and transmitted to the network or collected by the network; modifying said observed network measurement data; and comparing said modified network measurement data with said database of calibration data to thereby determine the location of the mobile station. ### Claim 2 (depends on 1) The method of claim 1 wherein said database comprises previously-gathered calibration data at one or more predetermined calibration points within said region. ### Claim 3 (depends on 2) The method of claim 2 wherein said previously-gathered calibration data at one or more predetermined calibration points is combined to form previously-gathered calibration data for one or more non-uniform grid points within said region. ### Claim 4 (depends on 1) The method of claim 1 wherein said database comprises previously-gathered calibration data for one or more non-uniform grid points within said region. ### Claim 5 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes signal strength information measured at a predetermined calibration point within said region for a signal transmitted from a known location within or in proximity to said region. ### Claim 6 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes signal strength information measured by a receiver at a known location within or in proximity to said region for a signal transmitted from a predetermined calibration point within said region. ### Claim 7 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes round trip time information for signals traveling between a predetermined calibration point within said region and a known location within or in proximity to said region. ### Claim 8 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes time difference of arrival information for a first signal traveling between a first known location and a predetermined calibration point within said region and a second signal traveling between a second known location and said calibration point. ### Claim 9 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes information identifying a serving cell of a transmitter transmitting a signal received at a predetermined calibration point within said region. ### Claim 10 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes information identifying a serving sector of a transmitter transmitting a signal received at a predetermined calibration point within said region. ### Claim 11 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes information regarding a state of said wireless network. ### Claim 12 (depends on 1) The method of claim 1 wherein said previously-gathered calibration data includes calibration data gathered at a predetermined calibration point within said region wherein said predetermined calibration point is not located within a structure. ### Claim 13 (depends on 12) The method of claim 12 wherein said observed network measurement data is collected at a mobile station located within a structure. ### Claim 14 A method for determining a location of a mobile station, comprising: providing a database of previously-gathered calibration data for a predetermined region in a wireless network, wherein said network includes a serving transmitter; collecting observed network measurement data including a first signal characteristic from said serving transmitter, the observed network measurement data collected by the mobile station and transmitted to the network or collected by the network; modifying said observed network measurement data using said first signal characteristic; and comparing said modified network measurement data with said database of calibration data to thereby determine the location of the mobile station. ### Claim 15 (depends on 14) The method of claim 14 wherein said database comprises previously-gathered calibration data for one or more non-uniform grid points within said region. ### Claim 16 (depends on 14) The method of claim 14 wherein said previously-gathered calibration data includes calibration data gathered at a predetermined calibration point within said region wherein said predetermined calibration point is not located within a structure. ### Claim 17 (depends on 16) The method of claim 16 wherein said observed network measurement data is collected at a mobile station located within a structure. ### Claim 18 (depends on 14) The method of claim 14 wherein said first signal characteristic is signal strength. ### Claim 19 (depends on 18) The method of claim 18 wherein said collecting observed network measurement data further includes collecting a second signal characteristic from a neighboring transmitter wherein said second signal characteristic is signal strength. ### Claim 20 (depends on 19) The method of claim 19 wherein the modifying of said calibration data uses a difference between said first and second signal characteristics. ### Claim 21 (depends on 14) The method of claim 14 wherein said first signal characteristic is signal strength of a control channel transmitted by said serving transmitter and received by said mobile station. ### Claim 22 (depends on 21) The method of claim 21 wherein said collecting observed network measurement data further includes collecting a second signal characteristic from a neighboring transmitter wherein said second signal characteristic is signal strength of a control channel transmitted by said neighboring transmitter and received by said mobile station. ### Claim 23 (depends on 14) The method of claim 14 wherein said observed network measurement data includes a data set comprising: [P1, . . . Pn, TA] where: P1 represents the signal strength of said serving transmitter as measured at said mobile station, Pn represents a signal strength of at a nth neighboring transmitter as measured at said mobile station, and TA represents a timing advance parameter; and wherein said modified network measurement data includes a data set comprising: [0, . . . P1-Pn-1,P1-Pn, TA] where: 0 represents a difference between P1 and P1, P1-Pn-1 represents a difference between P1 and Pn-1, and P1-Pn represents a difference between P1 and Pn. ### Claim 24 (depends on 23) The method of claim 23 wherein said first neighboring transmitter is not a member of said wireless network. ### Claim 25 A method for determining a location of a mobile station, comprising: providing a database of previously-gathered calibration data for a predetermined region in a wireless network; collecting observed network measurement data from each of a plurality of transmitters including a signal characteristic from each one of said plural transmitters, the observed network measurement data collected by the mobile station and transmitted to the network or collected by the network; determining an average value for select ones of said signal characteristics; modifying said observed network measurement data using said average value; and comparing said modified network measurement data with said database of calibration data to thereby determine the location of the mobile station. ### Claim 26 (depends on 25) The method of claim 25 wherein said database comprises previously-gathered calibration data for one or more non-uniform grid points within said region. ### Claim 27 (depends on 25) The method of claim 25 wherein said previously-gathered calibration data includes calibration data gathered at a predetermined calibration point within said region wherein said predetermined calibration point is not located within a structure. ### Claim 28 (depends on 25) The method of claim 25 wherein said observed network measurement data is collected at a mobile station located within a structure. ### Claim 29 (depends on 25) The method of claim 25 wherein said signal characteristic is signal strength. ### Claim 30 (depends on 29) The method of claim 29 wherein the modifying of said calibration data uses a difference between said average value and said signal characteristic for a first one of said plural transmitters. ### Claim 31 (depends on 25) The method of claim 25 wherein said signal characteristic is signal strength of a control channel. ### Claim 32 (depends on 25) The method of claim 25, wherein the observed network measurement data includes received signal strength of said transmitters as said mobile station. ### Claim 33 (depends on 25) The method of claim 25 wherein said observed network measurement data includes a data set comprising: [P1, P2, P3, TA] where: P1 represents the signal strength of a first one of said plural transmitters as measured at said mobile station, P2 represents a signal strength of a second one of said plural transmitters as measured at said mobile station wherein P2 >P1, P3 represents a signal strength of a third one of said plural transmitters as measured at said mobile station wherein P2 >P3, and TA represents a timing advance parameter; and wherein said modified network measurement data includes a data set comprising: [P1-PAVG, P2-PAVG, P3-PAVG,TA] where: PAVG represents an average value of P1, P2, and P3, P1-PAVG represents a difference between P1 and PAVG, P2-PAVG represents a difference between P2 and PAVG, P3-PAVG represents a difference between P3 and PAVG. ### Claim 34 (depends on 33) The method of claim 33 wherein said first transmitter is a serving transmitter for said mobile station and said second and third transmitters are neighboring transmitters. ### Claim 35 (depends on 25) The method of claim 25 wherein at least one of said plurality of transmitters is not a member of said wireless network.