Process and configuration for detecting a transponder with reference to a particular cell of two adjacent overlapped cells

• US 6,424,838 B1
• Filed: 05/28/1999
• Issued: 07/23/2002
• Est. Priority Date: 06/02/1998
• Status: Expired due to Fees

• Current Assignee: Anatoli Stobbe, Merk, Holger
• Original Assignee: Anatoli Stobbe, Merk, Holger
• Inventors: Merk, Holger, Stobbe, Anatoli
• Primary Examiner(s): Le, Thanh Cong
• Assistant Examiner(s): LE, LANA N
• Application Number:
  US09/322,710
• Time in Patent Office: 1,152 Days
• Field of Search: 455/422, 455/73, 455/456, 455/67.1, 455/67.6, 455/457, 455/427, 455/428, 455/430, 342/44, 342/442, 342/42, 340/825.49, 340/825.37, 340/573.4
• US Class Current: 455/456.1
• CPC Class Codes: G01S 13/878 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S13/874 takes precedence
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 7/0008 General problems related to the reading of electronic memory record carriers, independent of its reading method, e.g. power transfer
• CPC Class Codes: G06K 7/10079 the collision being resolved in the spatial domain, e.g. temporary shields for blindfolding the interrogator in specific directions

Abstract

A process and configuration used therein for detecting a transponder in a detection region, structured into two adjacent overlapped cells, provide for detecting the transponder with reference to a particular one cell of the two cells. The detecting process includes the steps of: providing in each of the cells a field with a detectable field characteristic; acquiring the field characteristic of a first of the cells using a sensing unit of the transponder; cyclically transmitting a response signal from a transmitting unit of the transponder containing the acquired field characteristics; receiving the response signal by a receiver which contains response signal information regarding the acquired field characteristic, namely that of the field of the first cell, that of the field of the adjacent cell or an unknown field characteristic; evaluating the response signal with respect to the information of the acquired field characteristic contained in the receiver; comparing the acquired field characteristic with the field characteristics provided in the cells; determining the possible position(s) of the transponder on the basis of the results of the performed comparison; and verifying a position determination, wherein, after detection of a transponder in the first cell, the field characteristic of the adjacent cell is adjusted such that it differs from that of the first cell.

Claims

1. A process for detecting a transponder in a detection region structured into at least two adjacent overlapped cells in which the transponder is detectable with reference to a particular one of the cells, said detecting process comprising the steps of:

(a) providing in each of the at least two adjacent overlapped cells a field with a detectable field characteristic;

(b) acquiring the field characteristic of a first of the cells using a sensing unit of the transponder;

(c) cyclically transmitting a response signal from a transmitting unit of the transponder containing the acquired field characteristics;

(d) receiving the response signal by a receiver which contains response signal information regarding the acquired field characteristic;

(e) evaluating the response signal with respect to the information of the acquired field characteristic contained in the receiver;

(f) comparing the acquired field characteristic with field characteristics provided in the cells;

(g) determining the possible position(s) of the transponder on the basis of the results of the performed comparison; and

(h) verifying a position determination wherein after the detection of a transponder in the first cell the field characteristic of the adjacent cell is adjusted such that it differs from that of the first cell.

2. The process of claim 1 wherein the verification of a position determination of a transponder is carried out by comparing the information of the currently received response signal with that of the previously received response signal, and a position determination is considered to correspond to the actual one if at least two successive response signals contain the same field characteristic information.

3. The process of claim 1 wherein the verification of a position determination of a transponder takes place through the predetermined changing of the field characteristic in the first cell and reception of a corresponding response signal.

4. The process of claim 1 wherein the fields of the at least two adjacent overlapped cells are formed by low-frequency electromagnetic radiation of same frequency and synchronous in all cells, with the fields being differently adjustable for the differentiation of the cells with respect to their phase position such that upon the transponder entering fields, differing with respect to their phase position, such fields can be detected through their different phase positions.

5. The process of claim 4 wherein the phase position in a field contained in a cell is changed by 180°

in order to bring about a differentiation against another cell.

6. The process of claim 1 wherein each of the at least two cells are divided into at least two subcells in which in a first detection step in each instance same-phase fields are generated and in a further step the fields located in the subcells are adjusted to differ with respect to the field characteristics to be detected and that the field characteristics in these subcells toggle between the two operating modes.

7. The process of claim 1 wherein the response signal of the transponder is transmitted on an HF channel.

8. The process of claim 1 wherein time-coded pulses are used as the response signals of the transponder and one response signal comprises one or several pulses of identical or different lengths.

9. The process of claim 1 wherein a plurality of transponders are used and to each transponder of the plurality a time slot is assigned within a given time unit, to which time slot the cyclical transmission of the response signal of a given one of the transponders is coupled and within which the response of the given one transponder is received.

10. A configuration for detecting a transponder in a detection region structured into at least two adjacent overlapped cells in which the transponder is detectable with reference to a particular one of the cells, said detecting configuration comprising:

(a) a plurality of stationary field-generating devices each associated with a respective one of the at least two adjacent overlapped cells and for generating a field with detectable field characteristics changing at predetermined time intervals, said devices being operable with identical field characteristics as well as with differing field characteristics;

(b) a transponder having a sensing unit operable for acquiring detectable field characteristics or changes thereof and a transmitting unit operable for transmitting response signals containing the acquired field characteristics in response to the operation of said sensing unit;

(c) a receiver for receiving the response signals transmitted by said transmitting unit; and

(d) a control and memory device connected to said field-generating devices for driving said field-generating devices and connected to said receiver for evaluating the response signals received by said receiver.

11. The configuration of claim 10 wherein the fields located within the cells and provided by the field-generating devices are transmitted at low frequency, the same frequency and synchronously.

12. The configuration of claim 11 wherein the field-generating devices can be impressed with different phases.

13. The configuration of claim 12 wherein the sensing unit of the transponder is operable for detecting changes of field characteristics which manifest as different phase positions.

14. The configuration of claim 13 wherein the phase positions of the fields contained in the cells are offset by 180°

with respect to one another.

15. The configuration of claim 10 wherein each of the cells of the detection region is divided into at least overlapping subcells with a separate field-generating device associated with each subcell such that the fields located within the respective subcells can be adjusted so as to differ from each other with respect to the field characteristics to be detected.

16. The configuration of claim 10 wherein the transmitting unit of the transponder and the receiver connected to the control and memory device operate in the high-frequency range.

17. The configuration of claim 10 wherein the cells of the detection region are divided into multiple overlapping subcells with separate field-generating devices associated with the respective subcells and having antennas adapted to radiate in different directions and which multiple subcells are operated in rotation with respect to their field characteristic.

18. The configuration of claim 17 wherein the adjacent cells are operated in phase shift with respect to one another.

19. The configuration of claim 10 wherein the transponder is a security tag for safeguarding goods in an exit region of a building in order to determine whether the goods is still within the building or already outside of the building.

20. The configuration of claim 19 wherein the detection region is disposed with the first cell in an interior of the building and with the adjacent cell, regionally overlapped with the first cell, outside of the building and the overlap region of the two cells covering a door area of the building.