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:
Mar. 15, 2016
Filed:
Nov. 21, 2005
Geoff M. Lyon, Menlo Park, CA (US);
Salil Pradhan, San Jose, CA (US);
Geoff M. Lyon, Menlo Park, CA (US);
Salil Pradhan, San Jose, CA (US);
Hewlett-Packard Development Company, L.P., Houston, TX (US);
Abstract
A method and apparatus for an RFID tag to facilitate the determination of its location while at the same time minimizing the energy drain on the tag's battery. At predetermined intervals, the tag transmits its identifier along with status information. If the status indicates that the tag is in a new location, the tag will then expend additional battery energy by participating in the determination of its location. The distance from an interrogator to the tag is determined by transmitting two signals from the interrogator that propagate at different velocities. By determining the difference in arrival times at the tag of the two signals, the distance from the interrogator to the tag can be determined.