Radio Frequency Identification (RFID) involves the attachment of a tiny transceiver to an object, allowing it to be tracked by a network of receivers. Its most obvious application for the accountant is in tracking warehouse inventory. However, consider extending the application to the yard storage area, where a great deal of additional inventory may be stored in trailers.
To set up a yard inventory system, attach an active RFID tag to each trailer, which emits a location signal to a set of yard receivers every few minutes. The receivers triangulate the signal from each RFID tag to determine the locations of all trailers, and store this information in a database that can be interfaced to other corporate systems. A simpler and less expensive approach is to attach passive RFID tags to each trailer, and have a transciever poll them at the yard gate as they are moved in and out of the yard. The active tag approach results in extremely accurate trailer locating within the yard, while the passive tag approach tells you that the trailer is somewhere in the yard (but not its precise location). Complete RFID solutions for continuous yard inventories are provided by WhereNet, BlueBean, and Real Time Location Systems. These solutions are intended for comprehensive yard management, where inventory management is a useful ancillary result. To reduce the cost of these systems, consider using a local RFID systems integrator who can assemble components from multiple suppliers to create the most cost-effective solution.
Given the expense of extending the RFID system into the yard, this is not a cost-effective solution for a dozen or so storage trailers, especially if their turnover level is low. However, for larger numbers of trailers or substantial churn, it may be so difficult to manually track trailers that RFID is the only practical solution.
An additional concern is how to handle changes in the inventory stored within each trailer. For example, a trailer may be moved to the loading dock, some inventory is offloaded and other items added, and then the trailer is moved back into the yard. This scenario is not difficult to handle, as long as each trailer is designated as a separate inventory location in the inventory tracking database, and if the standard inventory move procedures are used for changes to trailer contents.