Systems and Methods for Detecting Patterns in Spatio-Temporal Data Collected Using an RFID System
Systems and methods are described that collect spatio-temporal data using an RFID system that is capable of locating the spatial position of a sensor, which is typically unaware of its location. Such systems and methods can be contrasted with conventional RFID systems in that they are able to determine the location of sensors in space as opposed to with respect to read zones related to the underlying RFID reader infrastructure. One embodiment includes an RFID system having a plurality of read zones and configured to obtain the spatio-temporal state of sensors within a sensor cloud, where the spatio-temporal state of each sensor includes sensor information, a time stamp, and a spatial location specified independently of the read zones of the RFID system, a spatio-temporal database configured to store spatio-temporal state of a plurality of sensors over time, and an application server configured to trigger events based upon the detection of at least one condition by applying at least one filter to the data within the spatio-temporal database.
1 . A method for monitoring sensors using an RFID system having a plurality of read zones, comprising:
obtaining a state of a plurality of sensors using an RFID system, wherein the state of each sensor comprises sensor information, a time stamp, and a spatial location that is a representation of a single unique position in space in which the sensor is located, which is specified independently of the read zones of the RFID system, wherein obtaining the state comprises:
determining, using the RFID system, the spatial location of a sensor independent of the read zones of the RFID system based on a set of properties of signals received from the sensor when the sensor is illuminated, wherein the set of properties comprises at least one of a phase and a direction of arrival of the signals; and
storing the state of the plurality of sensors within a database, wherein the stored state of at least one sensor comprises a first spatial location within a particular read zone with a first time stamp and a different, second spatial location within the particular read zone with a different, second time stamp;
determining whether the stored state of the plurality of sensors satisfies at least one spatial condition based on the first and second spatial locations of the at least one sensor within the particular read zone; and
triggering at least one event based upon determining that the stored state satisfies the at least one spatial condition.