Patent ID: 9013308
Filing Date: 2015-04-21
Classification: G01S,G06K,G08B

Abstract:
1. A method of detecting tampering of a physical article, the method comprising: receiving, at a first point in time, at least two response signals from at least one Radio Frequency (RF) tag in a set of RF tags on the physical article, wherein the at least two response signals include an RF tag code and an indication of an electrical characteristic of the at least one RF tag; forming a first response RF signature for the physical article based on the RF tag code and the indication of the electrical characteristic of the at least one RF tag; receiving a second response signal from at least one other RF tag in the set of RF tags on the physical article at a second point in time; forming a second response RF signature for the physical article based on the received second response signal; assessing a relative spacing between the at least one RF tag and the at least one other RF tag on the physical article has changed from the first point in time to the second point in time based on a comparison between the first and second response RF signatures; and determining tampering of the physical article as a result of the relative spacing assessment.