APPARATUS AND METHOD FOR ESTIMATING LOCATION USING MULTI-ANTENNA RADIO RECEIVER

• Main Authors: CORONEL PEDRO E, WEISS BEAT, SCHOTT WOLFGANG H
• Format: Patent
• Language: English
• Published: 19.11.2009

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 kth one 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 kth one 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 dk from the apparatus to the kth one of the beacons is approximated based on the spatially and temporally averaged value of received signal strength. The approximate distance dk is designated as {circumflex over (d)}k. 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)}k. Each sphere is centered at the known position of the kth one of the beacons.