Cell ID based positioning from cell intersections
First Claim
1. A method for locating a wireless device, comprising the steps of:
- obtaining measured signal strengths of two or more identifiable signals from the wireless device; and
determining location of the wireless device by comparing the measured signal strengths to reference signal strengths of the two or more identifiable signals,wherein the reference signal strengths have associated geographic contours, and wherein the determining includes;
identifying first and second reference signal strengths between which the measured signal strengths for each of the identifiable signals respectively lie, the associated geographic contours for the first and second reference signal strengths defining an annular region for each of the identifiable signals;
identifying two or more different intersecting geographic contours between the annular regions for each of the identifiable signals;
constructing a single region that encompasses both of the two different intersecting geographic contours and has a geometrical shape that is fitted to the geographic contours; and
computing the determined location using the geometrical shape of the single region.
2 Assignments
0 Petitions
Accused Products
Abstract
Systems and methods are described for determining location of wireless devices using signal strength of signals detected by the wireless devices. The strength of signals received from identifiable sources is typically compared to reference signal strength measurements collected or estimated at known locations. Information identifying the source of the signals is typically obtained from data provided in the signals. Mappers associate combinations of reference signal strengths with geometrically shaped geographical regions such that signal strength measurements can be used as indices to locate a region in which a wireless device can be found. Systems and methods are described for receiving signal strength information from known locations where the information can be used to update and improve mapping system databases.
23 Citations
25 Claims
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1. A method for locating a wireless device, comprising the steps of:
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obtaining measured signal strengths of two or more identifiable signals from the wireless device; and determining location of the wireless device by comparing the measured signal strengths to reference signal strengths of the two or more identifiable signals, wherein the reference signal strengths have associated geographic contours, and wherein the determining includes; identifying first and second reference signal strengths between which the measured signal strengths for each of the identifiable signals respectively lie, the associated geographic contours for the first and second reference signal strengths defining an annular region for each of the identifiable signals; identifying two or more different intersecting geographic contours between the annular regions for each of the identifiable signals; constructing a single region that encompasses both of the two different intersecting geographic contours and has a geometrical shape that is fitted to the geographic contours; and computing the determined location using the geometrical shape of the single region. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A system comprising:
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a database configured to maintain expected signal strengths of signals within a geographic area; a mapper for identifying regions of the geographic area wherein each region is characterized by a range of expected signal strengths for each of one or more of the signals detectable in the each region; and one or more servers for locating a wireless device in one of the identified regions based on signal strengths measured by the wireless device, wherein the expected signal strengths have associated geographic contours, and wherein the servers locate the wireless device by; identifying first and second expected signal strengths between which the measured signal strengths for each of the identifiable signals respectively lie, the associated geographic contours for the first and second expected signal strengths defining an annular region for each of the identifiable signals; identifying two or more different intersecting geographic contours between the annular regions for each of the identifiable signals; constructing a single region that encompasses both of the two different intersecting geographic contours and has a geometrical shape that is fitted to the geographic contours; and computing the determined location using the geometrical shape of the single region. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification