The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 27, 2011
Filed:
May. 16, 2008
Pedro E. Coronel, Zurich, CH;
Wolfgang H. Schott, Rueschlikon, CH;
Beat Weiss, Edlibach, CH;
International Business Machines Corporation, Armonk, NY (US);
Abstract
Packets are periodically transmitted by a plurality of radio beacons deployed at known positions over a location estimation area. Monitoring is conducted for incoming packets. Upon receipt of a packet from a kone of the beacons, received signal strength, RSSI, is measured at each of the antenna outputs, the packet is decoded to obtain the unique identifier and the unique sequence number, and the received signal strength at each of the antenna outputs is spatially averaged. The measuring, decoding, and spatial averaging are repeated for additional packets from the kone of the beacons during a pre-defined time window T. The plurality of spatially averaged received signal strengths are temporally averaged over the pre-defined time window T, to obtain a spatially and temporally averaged value of received signal strength. The distance dfrom the apparatus to the kone of the beacons is approximated based on the spatially and temporally averaged value of received signal strength. The approximate distance dis designated as {circumflex over (d)}. This is repeated for the K beacons that have successfully transmitted packet(s) during the pre-defined time window, k=1 to K. The location of the object is estimated as an approximate intersection of spheres with radii {circumflex over (d)}. Each sphere is centered at the known position of the kone of the beacons.