Wherenet Corporation

David J Stryker

Donald K Belcher

Robert W Boyd

Michael Andrew Wohl

Ronald J Hash

Timothy C Harrington

A reader geometry visualization tool for a geo-location system technician's personal computer is operative to display a map of an asset management environment. The technician interactively places and manipulates a distribution of tag transmission readers and any potential impairments to RF transmissions on the map. The locations of the readers (and any impairments) are coupled as input parameters to a mathematical model of a tag-based geo-location system. The performance of the map-parameterized geo-location system model is then computed as a geometric dilution of precision (gdop) value for the intended object coverage area. The computed (gdop) performance is visually characterized on the displayed map, as by way of different colors to indicate how accurately the proposed reader geometry will enable the system to locate objects anywhere in the coverage area.

Computer workstation tool for displaying performance estimate of tagged object geo-location system for proposed geometry layout of tag transmission readers

A distributed radio geo-location and tracking system has a distributed subsystem architecture that distributes its processing workload over a plurality of information handling and processing subsystems. For maximum detection capability, each of a plurality of tag emission receivers is equipped with a circularly polarized, omnidirectional antenna, to provide hemispherical coverage. The receivers are coupled to a partitioned plurality of detection processors, that are coupled via distributed association processors to multiple location processors. Each detection processor demodulates and time stamps received energy correlated to known spreading codes of the tags, to associate received energy with only one tag. It transmits a message containing this information over a communication framework to an association processor. The computational load is equitably distributed by a flow control mechanism among available association processors, with all receptions of a single tag transmission being directed to the same association processor. An association processor organizes received messages by tag and time-of-arrival (TOA), and transmits association reports over an association communication process of the communication framework to one of plural distributed location processors. A location processor determines the geographical locations of tags using the TOA information in the association reports.

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Palo Alto, CA, United States of America

David J Stryker