Locating system for items having RFID tags

A method of locating an object within an archive containing a plurality of objects, each of the objects including an RFID tag having a unique identifier, the method comprising:

• moving an RFID reader device relative to the archive, the RFID reader device having an RFID reader adapted to detect and read the RFID tags of the objects, the RFID reader having a range for detecting and reading the RFID tags;
• determining whether there are any RFID tags within the range of the RFID reader;
• querying each RFID tag sensed by the RFID reader for the identifier associated with the RFID tag;
• determining whether the identifier for each RFID tag is an old identifier stored in a memory or a new identifier not stored in the memory, and if one or more of the identifiers is a new identifier:
• defining a linkage between each object associated with a new identifier and each other object within the range of the RFID reader device,
• saving each linkage in a data structure adapted to store a relative position of each object in the archive relative to each other object in the archive, and
• storing each new identifier in the memory,
• determining whether any object associated with an old identifier is no longer within range of the RFID reader device;
• deleting each old identifier associated with an object that is no longer within range of the RFID reader device from the memory;
• comparing the identifiers stored in the memory to the linkages stored in the data structure;
• determining that a linkage has been broken when the linkages defined by the identifiers stored in the memory is less than the linkages stored in the data structure for the identifiers stored in the memory;
• and
• determining which object of the broken linkage has been moved.