System and method of optimizing the process of identifying items tagged with RFID tags in an enclosed shielded space

• US 9,349,030 B2
• Filed: 12/28/2013
• Issued: 05/24/2016
• Est. Priority Date: 12/29/2012
• Status: Active Grant

• Current Assignee: Meps Real-Time, Inc.
• Original Assignee: Meps Real-Time, Inc.
• Inventors: Elizondo, Paul M. II
• Primary Examiner(s): Rushing, Mark
• Application Number:
  US14/142,749
• Publication Number:
  US 20140184391A1
• Time in Patent Office: 878 Days
• US Class Current: 1/1
• CPC Class Codes: G06K 7/10356 using a plurality of antennas, e.g. configurations including means to resolve interference between the plurality of antennas
• CPC Class Codes: G06K 7/10366 the interrogation device being adapted for miscellaneous applications
• CPC Class Codes: G06Q 10/087 Inventory or stock management, e.g. order filling, procurement or balancing against orders
• CPC Class Codes: H04B 1/713 using frequency hopping

Abstract

A system and method comprises a plurality of RF antennas having beams directed to a storage space in which medical items having RFID tags are stored. Each antenna is controlled to inject energy at a different frequency in a frequency-hopping set of frequencies to activate the tags. The return signal strength is monitored and for each tag that responds, the antenna location, frequency of the injected energy, identification response, and signal strength are stored as identification data. If a tag fails to respond in new scans, the antenna at which the tag last responded receives all the frequency-hopping frequencies in an attempt to locate the tag. If new tags are found, they are compared to a list of expected new medical items.

Claims

1. A wireless automated reader system to identify medical items having an RFID tag associated with them by reading the RFID tags, the RFID tags being responsive to electromagnetic energy (“

EM energy”

) having a predetermined range of frequencies by transmitting identification signals, the medical items being stored in a storage space of an enclosure, the system comprising;

a plurality of reader antennas located at different positions, each of which has a beam directed into the storage space of the enclosure for activating RFID tags of items residing in the storage space and receiving identification signals transmitted by the activated RFID tags;

a processor having a memory;

an energy source having a plurality of different frequency-hopping frequencies each of which is within the predetermined range of frequencies to which the RFID tags respond with transmitted identification signals, the energy source being responsive to control signals to provide a set of a plurality of injection signals to selected reader antennas, the injection signals having different frequency-hopping frequencies; and

;

an antenna controller that controls the energy source to deliver the set of a plurality of injection signals to the plurality of reader antennas in a standard data scan in which the antenna controller controls the energy source to deliver an injection signal of a different frequency to each reader antenna and to cycle through the reader antennas with a different injection signal of a different frequency until all of the frequency-hopping frequencies of the set of a plurality of injection signals have been used, and to deliver the set of a plurality of injection signals in a concentrated data scan in which a particular reader antenna is selected and the antenna controller controls the energy source to deliver the plurality of injection signals using all of the frequency-hopping frequencies only to the selected antenna;

wherein the antenna controller includes an RSSI module (received signal strength indicator) that is configured to analyze received signal strength of each received response to the injected signals from the RFID tags, and the antenna controller also communicates identification signals representing the frequency, the reader antenna location, the received signal strength, and the identification response from each of the responding RFID tags;

wherein, the processor is programmed to receive the identification signals from the antenna controller and store in memory the identification signals as a data scan associated with a particular time;

wherein the processor is further programmed to compare the identification signals generated in a present data scan to identification signals previously generated and stored in a prior data scan to determine if any medical items are missing in the present data scan; and

wherein if any identification signals are found in the comparison to be missing from the present data scan, the processor is further programmed to analyze the identification data of a previous data scan to determine the reader antenna that had a higher return signal strength than another reader antenna when the missing item was last identified as being present, and to control the energy source and antenna controller to use the concentrated data scan at the identified reader antenna to determine if the missing item is in the storage space.

2. The wireless automated reader system of claim 1, further comprising a Faraday cage positioned around the storage space.

3. The wireless automated reader system of claim 1, wherein the antenna controller controls the energy source to deliver the plurality of injection signals of the set of plurality of injection signals to the plurality of reader antennas sequentially.

4. The wireless automated reader system of claim 3, wherein the antenna controller controls the energy source to deliver the plurality of injection signals of the set of plurality of injection signals to the selected reader antenna sequentially.

5. The wireless automated reader system of claim 1 further comprising:

a door located to provide access to the storage space;

a door sensor connected to the storage space and the door to provide a door-open signal when the door is opened;

wherein the processor is programmed to receive the door-open signal from the door sensor and store the door-open signal in a data base in the memory along with a time at which it was received;

wherein the processor is further programmed when an item is indicated as missing in a current data scan to search the data base of door open signals and determine if a door-open signal was received between the time of the last stored data scan and the latest data scan, where an item is missing, to determine if a door-open signal was received, and if the door-open signal was received and the concentrated data scan does not locate the missing medical item, the processor provides an item taken signal indicating that the item was taken from the storage area.

6. The wireless automated reader system of claim 5, wherein the processor is programmed to check for missing medical items from the stored standard data scan at a predetermined time of day.

7. The wireless automated reader system of claim 5, wherein the processor is programmed to check for missing medical items from the stored standard data scan immediately after the door is closed after a door-open signal is received.

8. The wireless automated reader system of claim 5, wherein the processor is programmed to notify a remote server each time a missing medical item is determined to have been taken from the storage space.

9. The wireless automated reader system of claim 5, wherein the processor is further programmed to identify any new medical items identified in the standard data scan, compare the new medical items identified in the storage space to a predetermined list of expected new medical items to be placed into the storage space.

10. The wireless automated reader system of claim 9, wherein the processor is further programmed to control the antenna controller to initiate the concentrated data scan on at least one of the reader antennas in a case where the comparison shows that not all of the expected new medical items are detected within the storage space.

11. The wireless automated reader system of claim 1, wherein the storage space is devoid of metallic portions whereby medical items placed in the storage space will not come into direct contact with any metallic portions that may detune their RFID devices.

12. The wireless automated reader system of claim 1, wherein in the concentrated data scan, the processor is programmed to monitor the received signal strength for all the injected frequencies and determines which frequencies provide higher levels of detection of the medical item than other frequencies and stores those higher levels of detection frequencies.

13. The wireless automated reader system of claim 1, wherein the processor is further programmed while in the standard data scan to determine the location of a medical item in the storage space that is responding to multiple reader antennas by comparing the received signal strength readings from the multiple antennas.

14. A method for reading wirelessly and automatically RFID tags associated with medical items to identify medical items, the RFID tags being responsive to electromagnetic energy (“

EM energy”

) having a predetermined range of frequencies by transmitting identification signals, the medical items being stored in a storage space of an enclosure, the method comprising;

directing a plurality of reader antenna beams from different positions into the storage space of the enclosure for activating RFID tags of items residing in the storage space and receiving identification signals transmitted by the activated RFID tags;

delivering a set of a plurality of injection signals to the plurality of reader antennas, each injection signal having a frequency selected from a plurality of frequency-hopping frequencies each of which is within the predetermined range of frequencies of the EM energy, the set of a plurality of injection signals being delivered in a standard data scan in which an injection signal of a different frequency is directed to the storage space by each reader antenna, and cycling through the reader antennas with a different injection signal of a different frequency until all of the frequency-hopping frequencies of the set of a plurality of injections signals have been used, and delivering the set of a plurality of injection signals in a concentrated data scan in which a particular reader antenna is selected and delivers the plurality of injection signals using all of the frequency-hopping frequencies only to the selected antenna;

monitoring received signal strength of responses of RFID tags to injection signals and communicating identification signals representing the frequency, the antenna location, the received signal strength, and the identification response from each of the responding RFID tags;

storing in a memory the received identification signals as a data scan associated with a particular time;

comparing the identification signals generated in a present data scan to identification signals previously generated and stored to determine if any medical items are missing in the present data scan; and

wherein if any identifications are found in the comparison to be missing from the present data scan, analyzing the identification data of a previous data scan to determine the reader antenna that had a higher return signal strength than another reader antenna when the missing item was last identified as being present, and using the concentrated data scan at the identified reader antenna to determine if the missing item is in the storage space.

15. The method for reading wirelessly and automatically RFID tags of claim 14 further comprising:

monitoring opening of a door located to provide access to the storage space and providing a door-open signal when the door is opened;

storing the door-open signal in a data base along with a time associated therewith;

searching the data base of door-open signals and determining if a door-open signal was received between the time of the last stored data scan and the latest data scan, where an item is missing, to determine if a door-open signal was received, and if the door-open signal was received and the concentrated data scan does not locate the missing medical item, providing an item taken signal indicating that the item was taken from the storage area.

16. The method for wirelessly automatically reading RFID tags of claim 15, further comprising checking for missing medical items from the stored standard data scan at a predetermined time of day.

17. The method for wirelessly automatically reading RFID tags of claim 15, further comprising checking for missing medical items from the stored standard data scan immediately after the door is closed after a door-open signal is received.

18. The method for wirelessly automatically reading RFID tags of claim 15, further comprising notifying a remote server each time a missing medical item is determined to have been taken from the storage space.

19. The method for wirelessly automatically reading RFID tags of claim 15, further comprising identifying any new medical items identified in the standard data scan, and comparing the new medical items identified in the storage space to a predetermined list of expected new medical items to be placed into the storage space.

20. The method for wirelessly automatically reading RFID tags of claim 19, further comprising initiating the concentrated data scan on at least one of the reader antennas in a case where the comparison shows that not all of the expected new medical items are detected within the storage space.