Method for locating a backscatter-based transponder

• US 20060125605A1
• Filed: 12/13/2005
• Published: 06/15/2006
• Est. Priority Date: 12/13/2004
• Status: Abandoned Application

• Current Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Original Assignee: Atmel Germany GmbH (Microchip Technology Incorporated)
• Inventors: Friedrich, Ulrich, Fischer, Martin, Ziebertz, Dirk, Pangels, Michael, Masuch, Jens
• Application Number:
  US11/299,801
• Publication Number:
  US 20060125605A1
• Time in Patent Office: Days
• US Class Current: 340/10.410
• 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: H04Q 5/22 the subordinate centre not permitting interconnection of subscribers connected thereto

Abstract

A method and apparatus for locating a transponder is provided. A carrier signal is transmitted by a base station and a transponder transmits a locating signal that is generated through phase modulation and backscattering of the carrier signal sent by the base station when the transponder is within a transmission range of the base station, whereby the transponder is located on the basis of the locating signal.

Claims

1. A method for locating a transponder, the method comprising the steps of:

transmitting a carrier signal by a base station;

transmitting, by the transponder, a locating signal that is generated through phase modulation and backscattering of the carrier signal sent by the base station when the transponder is within a transmission range of the base station; and

locating the transponder on the basis of the locating signal.

2. The method according to claim 1, wherein the base station transmits at least one command to the transponder while the transponder transmits the locating signal.

3. The method according to claim 1, wherein the transponder is a passive transponder, and wherein the transponder transmits the location signal when an operating energy level of the carrier signal is sufficient for supplying the transponder.

4. The method according to claim 1, wherein a selection process is performed by the base station when a plurality of transponders transmit a location signal and a transponder is to be selected from the plurality of transponders.

5. The method according to claim 1, wherein the selection method is an ALOHA method, in particular a slotted ALOHA method.

6. The method according to claim 4, wherein the selection process is a deterministic process, in particular a binary process.

7. The method according to claim 1, wherein the locating signal is generated by modulation with a subcarrier of the carrier signal transmitted from the base station.

8. The method according to claim 1, wherein a memory internal to the transponder contains one or more parameters for setting the locating signal.

9. The method according to claim 8, wherein the one or more parameters are used to set a frequency and/or a duty cycle of a modulation signal with which the carrier signal is modulated.

10. The method according to claim 9, wherein the frequency and/or the duty cycle are derived from an oscillator clock internal to the transponder.

11. The method according to claim 1, wherein the transponder terminates the transmission of the locating signal when a predefinable maximum time has elapsed and/or the transponder receives a command.

12. The method according to claim 1, wherein the transponder is located by an additional base station.

13. The method according to claim 1, wherein a frequency of the carrier signal is in the UHF frequency range.

19. The method according to claim 1, wherein the transponder is a backscatter-based transponder, and wherein the carrier signal transmitted by the base station is an unmodulated carrier signal.

14. A method for locating a backscatter-based transponder, the method comprising the steps of:

transmitting a locating command via a base station to the transponder;

receiving the locating command by the transponder;

transmitting, by the transponder, a locating signal that is generated by phase modulation and backscattering of a carrier signal transmitted from the base station; and

locating the transponder on the basis of the locating signal.

15. The method according to claim 14, wherein, prior to transmitting the locating command to the transponder, the base station performs a selection process, whereby the transponder to be located is selected from a plurality of transponders.

16. The method according to claim 15, wherein the selection process is an ALOHA method or a slot-based ALOHA method.

17. The method according to claim 15, wherein the selection process is a deterministic method or a binary method.

18. The method according to claim 14, wherein the transponder stops transmitting the locating signal when a predeterminable maximum time period has expired and/or the transponder receives a command.

20. An object location system comprising:

a base station for transmitting a carrier signal; and

a transponder being attached or integrated into the object, the transponder identifying the object, the transponder transmitting a locating signal that is generated through phase modulation and backscattering of the carrier signal transmitted by the base station when the transponder is within a transmission range of the base station, the object being located on the basis of the locating signal.