# US 2013/0157683 A1 · Indoor localization using commercial frequency-modulated signals > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0157683 A1 - Document ID: US20130157683A1 - Status: Published application - Kind: A1 - Application number: 13/328,613 - Filed: 2011-12-16 - Published: 2013-06-20 - Earliest claimed: 2011-12-16 - Assignees: Microsoft Corporation - Inventors: Dimitrios Lymberopoulos; Jie Liu; Nissanka Arachchige Bodhi Priyantha; Yin Chen - Web page: https://patentgrep.com/patent/US20130157683A1 ## CPC - H04W 64/00: Locating users or terminals {or network equipment} for network management purposes, e.g. mobility management - G01C 21/206: {specially adapted for indoor navigation} - G01S 5/02521: {using a radio-map} - H04W 4/33: for indoor environments, e.g. buildings - H04W 4/60: Subscription-based services using application servers or record carriers, e.g. SIM application toolkits - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - 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 ## Abstract A commercial frequency-modulated (FM) radio signal indoor localization system and method for finding a location of a mobile embedded device (such as a smartphone) within a building. Indoor localization is performed by receiving commercial FM radio signals on the device, analyzing the signals using signal quality metrics, and generating signal quality vectors for each signal and signal quality metric used for the signal. The signal quality metric can be any physical signal quality indicator. The signal quality vectors are added to obtain a current location fingerprint. The current location fingerprint is compared to fingerprints stored in a fingerprint database. The location associated with the stored fingerprint that is the closest match to the current fingerprint location is designated as the current location in the building of the mobile embedded device. Locally generated radio signals can be used in conjunction with the commercial FM radio signals to improve localization accuracy. ## Claims ### Claim 1 A computer system comprising: one or more processing units; and one or more computer storage media storing computer-executable instructions which, when executed by the one or more processing units, cause the one or more processing units to: receive a commercial frequency-modulated radio signal on the computer system; analyze a signal-to-noise ratio of the commercial frequency-modulated radio signal to obtain a signal quality vector comprising the signal-to-noise ratio of the commercial frequency-modulated radio signal; add the signal quality vector comprising the signal-to-noise ratio of the commercial frequency-modulated radio signal to a current location fingerprint; and compare the current location fingerprint to a fingerprint database to obtain a current location of the computer system. ### Claim 2 (depends on 1) The computer system of claim 1, wherein the current location is an indoor location within a structure. ### Claim 3 (depends on 1) The computer system of claim 1, wherein the computer-executable instructions cause the one or more processing units to: analyze a received signal strength of the commercial frequency-modulated radio signal to obtain another signal quality vector comprising the received signal strength of the commercial frequency-modulated radio signal; and add the another signal quality vector to the current location fingerprint prior to comparing the current location fingerprint to the fingerprint database. ### Claim 4 (depends on 1) The computer system of claim 1, wherein the computer-executable instructions cause the one or more processing units to: prior to comparing the current location fingerprint to the fingerprint database, analyze another signal-to-noise ratio of another commercial frequency-modulated radio signal and add the another signal-to-noise ratio to the signal quality vector. ### Claim 5 (depends on 1) The computer system of claim 1, wherein the computer-executable instructions cause the one or more processing units to: analyze a multipath indicator of the commercial frequency-modulated radio signal to obtain another signal quality vector comprising the multipath indicator of the commercial frequency-modulated radio signal; and add the another signal quality vector to the current location fingerprint prior to comparing the current location fingerprint to the fingerprint database. ### Claim 6 (depends on 1) The computer system of claim 1, wherein the computer-executable instructions cause the one or more processing units to: find a matching fingerprint in the fingerprint database that is a closest match with the current location fingerprint. ### Claim 7 (depends on 6) The computer system of claim 6, wherein the computer-executable instructions cause the one or more processing units to: designate a corresponding location represented by the matching fingerprint as the current location. ### Claim 8 (depends on 1) The computer system of claim 1, wherein the computer-executable instructions cause the one or more processing units to: update the fingerprint database with the current location fingerprint. ### Claim 9 A method implemented by at least one computer processing unit for performing localization of a mobile device within an indoor structure, the method comprising: receiving a plurality of radio signals within the indoor structure, at least some of the plurality of radio signals including a plurality of commercial frequency-modulated radio signals; generating a signal quality vector comprising signal-to-noise ratios of the plurality of commercial frequency-modulated radio signals; adding the signal quality vector to a current location fingerprint of the mobile device; and comparing the current location fingerprint to a fingerprint database to find a current location of the mobile device within the indoor structure. ### Claim 10 (depends on 9) The method of claim 9, further comprising: analyzing received signal strengths of the plurality of commercial frequency-modulated radio signals; generating another signal quality vector comprising the received signal strengths of the plurality of commercial frequency-modulated radio signals; and prior to the comparing, adding the another signal quality vector to the current location fingerprint. ### Claim 11 (depends on 9) The method of claim 9, further comprising: analyzing frequency offset indicator indicators of the plurality of commercial frequency-modulated radio signals; generating another signal quality vector comprising the frequency offset indicators of the plurality of commercial frequency-modulated radio signals; and prior to the comparing, adding the another signal quality vector to the current location fingerprint. ### Claim 12 (depends on 9) The method of claim 9, further comprising finding a matching fingerprint in the fingerprint database that matches the current location fingerprint. ### Claim 13 (depends on 12) The method of claim 12, further comprising designating a particular location corresponding to the matching fingerprint in the fingerprint database as the current location of the mobile device within the indoor structure. ### Claim 14 (depends on 13) The method of claim 13, further comprising updating the fingerprint database with the current location fingerprint such that the current location is associated with the current location fingerprint in the fingerprint database. ### Claim 15 (depends on 9) The method of claim 9, further comprising populating the fingerprint database by recording signal quality metrics at various locations within the indoor structure and associating the signal quality metrics with the various locations as corresponding fingerprints of the various locations. ### Claim 16 A mobile device, comprising: one or more processing units; and one or more computer storage media storing computer-executable instructions which, when executed by the one or more processing units, cause the one or more processing units to: receive a commercial frequency-modulated radio signal on the mobile device; receive a locally-generated radio signal on the mobile device; analyze the commercial frequency-modulated radio signal and the locally-generated radio signal using signal quality metrics, the signal quality metrics including an individual signal quality metric representing a signal-to-noise ratio of the commercial frequency-modulated radio signal; generate signal quality vectors from the signal quality metrics, an individual signal quality vector including the signal-to-noise ratio of the commercial frequency-modulated radio signal; add the signal quality vectors to a current location fingerprint of the mobile device; and find a current location of the mobile device within a building using the current location fingerprint. ### Claim 17 (depends on 16) The mobile device of claim 16, wherein the computer-executable instructions cause the one or more processing units to: analyze another commercial FM radio signal to determine another signal-to-noise ratio of another commercial frequency-modulated radio signal; and add the another signal-to-noise ratio to the individual signal quality vector and the current location fingerprint to find the current location of the mobile device. ### Claim 18 (depends on 17) The mobile device of claim 17, wherein the locally-generated radio signal comprises a WiFi® radio signal, a Bluetooth® radio signal, or another frequency-modulated radio signal. ### Claim 19 (depends on 18) The mobile device of claim 18, wherein the computer-executable instructions cause the one or more processing units to: compare the current location fingerprint to a fingerprint database to find a matching fingerprint that matches with the current location fingerprint; and designate a corresponding location associated with the matching fingerprint as the current location of the mobile device within the building. ### Claim 20 (depends on 19) The mobile device of claim 19, wherein, of all fingerprints in the fingerprint database, the matching fingerprint most closely matches the current location fingerprint.