System and method for enabling determination of a position of a transponder

• US 8,229,472 B2
• Filed: 07/25/2006
• Issued: 07/24/2012
• Est. Priority Date: 07/25/2005
• Status: Active Grant

• Current Assignee: ELTA Systems Limited (Government of Israel)
• Original Assignee: ELTA Systems Limited (Government of Israel)
• Inventors: Fireaizen, Moshe
• Primary Examiner(s): Brandt, Christopher M
• Application Number:
  US11/989,478
• Publication Number:
  US 20100001896A1
• Time in Patent Office: 2,191 Days
• Field of Search: 455/456.1, 455/456.2, 455/456.3, 455/456.5, 455/456.6, 455/562.1, 342/42, 342/387, 342/394
• US Class Current: 455/456.4
• 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: G01S 3/48 the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured

Abstract

There is provided a method and system for positioning a transponder, the system comprising an antenna array of at least two spaced-apart antennas coupled to a common generating and switching unit. The generating and switching unit is configured for generating a periodic signal and switching the signal between said at least two antennas, constituting a positioning signal transmitted to the transponder. The system comprises a receiver for receiving a returned signal and a phase difference estimator coupled to the receiver and operable to measure phase differences between portions of the returned signal. The system further comprises a positioning utility coupled to said phase difference estimator and configured to determine the position of the transponder relative to the positioning system.

Claims

1. A system for positioning a transponder, comprising:

an antenna array of at least two spaced-apart antennas coupled to a common generating and switching unit, the common generating and switching unit being configured to generate a periodic signal (TS) and to switch the periodic signal between the at least two spaced-apart antennas, the periodic signal constituting a positioning signal transmitted to the transponder;

a receiver for receiving a returned signal (RS) from the transponder;

a phase difference estimator coupled to the receiver and operable to measure phase differences between portions of the returned signal, the portions being separated by a time delay and having a same single frequency, wherein each portion is transmitted by a different antenna of the at least two spaced-apart antennas; and

a positioning utility coupled to the phase difference estimator and configured to determine a position of the transponder relative to the positioning system based on the measurement of the phase differences.

2. A system according to claim 1 wherein the determination of the position of the transponder includes determination of a range of the transponder relative to the positioning system, based on TOA (Time of Arrival) comparison between the positioning signal transmitted by the system and the returned signal from the transponder.

3. A system according to claim 1 wherein the determination of the position of the transponder includes determination of a range of the transponder relative to the positioning system, based on information received from a source external to the system, about the range of the transponder relative to the system.

4. A system according to claim 1, wherein the at least two spaced-apart antennas are coupled to the common generating and switching unit via substantially identical feed lines.

5. A system according to claim 1, wherein the antenna array comprises four antennas spaced apart in a tetrahedron form.

6. A system according to claim 1 further configured, based on the determination of the position of the transponder, to transmit transponder position related information.

7. A system according to claim 1 wherein the antenna array includes at least three spaced-apart antennas.

8. A system according to claim 1 wherein the common generating and switching unit is operable to generate the periodic signal as including signal parts of at least a first frequency and a second frequency, and to switch the periodic signal between the at least two spaced-apart antennas such that signal parts of the first frequency are switched between the at least two spaced-apart antennas and are followed by signal parts of the second frequency, which are switched between the at least two spaced-apart antennas.

9. A system according to claim 8 wherein the first frequency is in a range of about 1 GHz or more and the second frequency differs from the first frequency by about 1 MHz.

10. A method for positioning a transponder, comprising:

generating a periodic signal and switching the periodic signal between at least two spaced-apart antennas of an antenna array of known locations coupled to a common generating and switching unit;

transmitting the periodic signal to the transponder and receiving a returned signal from the transponder;

measuring phase differences between portions of the returned signal, the portions being separated by a time delay and having a same single frequency, wherein each portion is transmitted by a different antenna of the at least two spaced-apart antennas; and

determining a position of the transponder relative to the system based on the measurement of the phase differences.

11. The method according to claim 10 further comprising:

determining a range of the transponder relative to the positioning system based on TOA (Time of Arrival) comparison between the periodic signal transmitted by the system and the returned signal from the transponder.

12. The method according to claim 10 further comprising:

receiving from an external source information about a range of the transponder relative to the positioning system, and determining the position of the transponder based on the information.

13. A method according to claim 10 further comprising:

comparing the position of the transponder with position information of the position of the transponder established using GPS (Global Positioning System) and/or INS (Inertial Navigation System) systems; and

assessing an accuracy of the position information.

14. A method according to claim 10 wherein the antenna array comprises four antennas spaced apart in a tetrahedron form.

15. A method according to claim 10 wherein the generating the periodic signal includes generating signal parts of at least a first frequency and a second frequency, and switching the periodic signal between the at least two spaced-apart antennas such that signal parts of the first frequency are switched between the at least two spaced-apart antennas and are followed by signal parts of the second frequency, which are switched between the at least two spaced-apart antennas.

16. A method according to claim 10 wherein the antenna array comprises three spaced-apart antennas.

17. A method according to claim 15, wherein the first frequency is in a range of about 1 GHz or more and the second frequency differs from the first frequency by about 1 MHz.