# US 8,994,799 B2 · Method and system for determining the position of a device in a light based positioning system using locally stored maps > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,994,799 B2 - Document ID: US8994799B2 - Status: Granted - Kind: B2 - Application number: 13/446,506 - Filed: 2012-04-13 - Published: 2013-01-31 - Granted: 2015-03-31 - Earliest claimed: 2011-07-26 - Assignees: Bytelight, Inc. - Applicants: Aaron Ganick; Daniel Ryan - Inventors: Aaron Ganick; Daniel Ryan - Web page: https://patentgrep.com/patent/US8994799B2 ## CPC - G01C 21/206: {specially adapted for indoor navigation} - 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) ## Abstract In one aspect, the present disclosure relates to a method for determining a position of a device using a light based positioning system. In some embodiments, the method includes providing a map of positions of a plurality of light sources in a location; receiving an identification code from one or more of the plurality of light sources, wherein the identification code identifies the light source; matching the identification code to a light source on the map; and determining the position of the device by setting the position of the device to the position of the light source on the map. In some embodiments, the method includes receiving identification codes from a plurality of light sources; matching the identification codes to a plurality of light sources on the map; and determining the position of the device based on the location of the plurality of light sources on the map. ## Claims ### Claim 1 A method for determining a position of a mobile device using a light-based positioning system, the method comprising: determining an approximate location of the mobile device using geo-location information not derived from visible light received at the mobile device; downloading at the mobile device, from a remote server, a map data structure of positions of a plurality of asynchronous light sources at a location corresponding to the approximate location of the mobile device; receiving at the mobile device an identifier broadcast from one of the asynchronous light sources of the plurality of asynchronous light sources, wherein (i) the identifier identifies the asynchronous light source, and (ii) the identifier corresponds to a pattern of distortions within an image acquired by the mobile device, the pattern of distortions being related to a modulation frequency of modulated light emitted by the asynchronous light source identified by the identifier; matching the identifier to the asynchronous light source stored by the map data structure; and determining the position of the mobile device by setting the position of the mobile device to the position of the asynchronous light source stored by the map data structure. ### Claim 2 (depends on 1) The method of claim 1, comprising: receiving one or more additional identifiers each broadcast from others of the asynchronous light sources; matching each of the one or more additional identifiers to one of the asynchronous light sources stored by the map data structure; and determining the position of the mobile device based on (i) the position of the asynchronous light source stored by the map data structure and (ii) the positions of the others of asynchronous light sources stored by the map data structure. ### Claim 3 (depends on 1) The method of claim 1, wherein the map data structure comprises a floor plan. ### Claim 4 (depends on 1) The method of claim 1, wherein the map data structure comprises at least one of computer aided drafting files, user provided computerization, or hand drawn images. ### Claim 5 (depends on 1) The method of claim 1, wherein the asynchronous light source comprises a light emitting diode (LED). ### Claim 6 (depends on 1) The method of claim 1, wherein the asynchronous light source comprises a fluorescent light source. ### Claim 7 (depends on 1) The method of claim 1, wherein the location comprises an indoor location. ### Claim 8 (depends on 1) The method of claim 1, wherein the position of the mobile device is determined without access to a network connection. ### Claim 9 (depends on 1) The method of claim 1, wherein the geo-location information comprises at least one of GPS, GSM, WiFi, user input, accelerometer, gyroscope, digital compass, barometer, Bluetooth, or cellular tower identification information. ### Claim 10 (depends on 1) The method of claim 1, wherein the map data structure is downloaded at the mobile device via the Internet. ### Claim 11 (depends on 1) The method of claim 1, wherein each asynchronous light source emits modulated light at a different frequency of modulation. ### Claim 12 (depends on 1) The method of claim 1, wherein each asynchronous light source is a single-color light source. ### Claim 13 (depends on 12) The method of claim 12, wherein each asynchronous light source comprises one or more phosphor-converted light-emitting diodes that all emit light of approximately the same color. ### Claim 14 (depends on 1) The method of claim 1, wherein the mobile device acquires different portions of the image at different times, thereby forming the pattern of distortions on the image. ### Claim 15 A mobile device for determining position using a light-based positioning system, the mobile device comprising: an approximate location determination module configured to determine an approximate location of the mobile device using geo-location information not derived from visible light received at the mobile device; a network interface for receiving, from a remote server, when the mobile device is at a location remote from the remote server, a map data structure of positions of a plurality of asynchronous light sources at a location corresponding to the approximately location of the mobile device; an image sensor for receiving an identifier broadcast from one of the asynchronous light sources of the plurality of asynchronous light sources, wherein (i) the identifier identifies the asynchronous light source, and (ii) the identifier corresponds to a pattern of distortions within an image acquired by the image sensor, the pattern of distortions being related to a modulation frequency of modulated light emitted by an asynchronous light source; and a position determination module configured to match the identifier to the asynchronous light source stored by the map data structure and determine the position of the mobile device by setting the position of the mobile device to the position of the asynchronous light source stored by the map data structure. ### Claim 16 (depends on 15) The mobile device of claim 15, wherein the position determination module is configured to receive identifiers from a plurality of asynchronous light sources, match the identifiers to the plurality of asynchronous light sources stored by the map data structure, and determine the position of the mobile device based on the positions of the plurality of asynchronous light sources stored by the map data structure. ### Claim 17 (depends on 15) The mobile device of claim 15, wherein the map data structure comprises a floor plan. ### Claim 18 (depends on 15) The mobile device of claim 15, wherein the map data structure comprises at least one of computer aided drafting files, user provided computerization, or hand drawn images. ### Claim 19 (depends on 15) The mobile device of claim 15, wherein the asynchronous light source comprises a light emitting diode (LED). ### Claim 20 (depends on 15) The mobile device of claim 15, wherein the asynchronous light source comprises a fluorescent light source. ### Claim 21 (depends on 15) The mobile device of claim 15, wherein the location comprises an indoor location. ### Claim 22 (depends on 15) The mobile device of claim 15, wherein the position of the mobile device is determined without access to a network connection. ### Claim 23 (depends on 15) The mobile device of claim 15, wherein the geo-location information comprises at least one of GPS, GSM, WiFi, user input, accelerometer, gyroscope, digital compass, barometer, Bluetooth, or cellular tower identification information. ### Claim 24 (depends on 15) The mobile device of claim 15, wherein the network interface is configured for receiving the map data structure via the Internet. ### Claim 25 (depends on 15) The mobile device of claim 15, wherein the pattern of distortions within the image results from different portions of the image being acquired by the image sensor at different times.