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Person location system

  • US 5,513,243 A
  • Filed: 12/27/1994
  • Issued: 04/30/1996
  • Est. Priority Date: 01/20/1992
  • Status: Expired due to Term
First Claim
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1. A person location system comprising:

  • a plurality of radio base stations, connected to a public switched telephone network, for respectively covering microcells, each of said base stations being uniquely identified by an identifier and having a memory;

    a user station located in one of said microcells and uniquely identified by a user'"'"'s address, said user station detecting field intensities of signals transmitted from surrounding radio base stations and transmitting a field intensity signal containing detected field intensities, identifiers of the surrounding base stations and said user'"'"'s address to one of the surrounding base stations;

    a radio central station for covering an area containing all of said microcells, the radio central station being connected to said public switched telephone network for receiving a polling signal containing said user'"'"'s address via the public switched telephone network and broadcasting a copy of the polling signal within said area, said radio central station serving as a transmitting station of a radio paging system for transmitting said polling signal and a radio paging signal having a message for radio pagers owned by subscribers of the radio paging system; and

    a management center connected to said public switched telephone network for transmitting said polling signal through a switched connection established by said public switched telephone network to said central station,each of said base stations receiving the field intensity signal from said user station and storing the received field intensity signal into said memory, each of the base stations being responsive to said polling signal for notifying the field intensities and the identifiers contained in the stored field intensity signal through a switched connection established by said public switched telephone network to said management center if the user'"'"'s address in said polling signal matches the user'"'"'s address in said field intensity signal,said management center determining the location of said user station based on the field intensities and the identifiers notified by the base station.

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