The present invention provides a system and method for tracking an interrogator relay unit disposed on a shopping cart within a store. The method comprises emitting an RF interrogation signal using the IRU; receiving, at the IRU, location data from an RFID tag in response to the RF interrogation signal; transmitting the location data, an identification information of the IRU, and timestamp data to a remote server using the IRU; and generating a behavior report using the transmitted location data, the identification information, and the timestamp data.