Device and method for location of an RFID transmitter

• US 9,778,340 B2
• Filed: 06/29/2012
• Issued: 10/03/2017
• Est. Priority Date: 06/29/2012
• Status: Active Grant

• Current Assignee: Blinksight
• Original Assignee: Blinksight
• Inventors: Mutz, Matthieu, Mutz, Stphane
• Primary Examiner(s): Gregory, Bernarr
• Assistant Examiner(s): Pervin, Nuzhat
• Application Number:
  US14/410,948
• Publication Number:
  US 20150323642A1
• Time in Patent Office: 1,922 Days
• Field of Search: 342417
• CPC Class Codes: G01S 3/74 Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14
• CPC Class Codes: G06K 7/10009 sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
• CPC Class Codes: H04B 7/08 at the receiving station

Abstract

A device for locating a remote RFID transmitter in an environment providing separate paths of propagation of a wirelessly transmitted ultra-wide band signal. The receiver of the device has a module for estimating the impulse response of the plurality of paths of the first channel defined by a first antenna and a module for estimating the impulse response of the plurality of paths of the second channel defined by the second antenna, a module for calculating a plurality of argument differences between each component of the impulse response and each component of the impulse response for the plurality of paths respectively. The device further comprises a module for converting the plurality of argument differences into a plurality of arrival angles of the plurality of paths, a module for determining a location of the transmitter from the plurality of arrival angles.

Claims

1. A receiver comprising:

a first estimation module;

a second estimation module;

a third extraction module;

a fourth module; and

at least one conversion module;

wherein the receiver is connected to at least one first antenna configured to receive an emitted signal, the emitted signal emitted wirelessly by an RFID transmitter in an environment involving one or more signal propagation path relative to the receiver and connected to at least one second antenna configured to receive the emitted signal,

the at least one first antenna and the at least one second antenna being connected in the receiver to respectively a first receiving part supplying a first channel signal as a function of the emitted signal and connected to a second receiving part supplying a second channel signal as a function of the emitted signal,

the at least one first antenna defining a first receiving channel for receiving of the emitted signal,

the at least one second antenna defining a second receiving channel for receiving of the emitted signal,

the at least one first antenna- and the at least one second antenna being at a distance from each other and respectively having first and second predetermined positions relative to each other such that the first receiving channel is substantially identical to the second receiving channel,

wherein the emitted signal is of the ultra-wide band type, and

the first estimation module is configured to estimate a first complex impulse response of the first receiving channel to the emitted signal as a function of the emitted signal and of the first channel signal,

the second estimation module is configured to estimate a second complex impulse response of the second receiving channel to the emitted signal as a function of the emitted signal and of the second channel signal,

the third extraction module is configured to extract from the first complex impulse response one or more first time component associated respectively with the one or more signal propagation path arriving at the at least one first antenna and to extract from the second complex impulse response one or more second time component associated respectively with the one or more of signal propagation path arriving at the at least one second antenna,

the fourth module is configured to calculate one or more argument difference between an argument of the one or more first time component of the first complex impulse response and an argument of the one or more second time component of the second complex impulse response respectively for the one or more signal propagation path, and

the at least one conversion module is configured to convert each argument difference into an angle of arrival of each signal propagation path relative to the receiver.

2. The receiver according to claim 1, further comprising a first converter configured to convert the emitted signal being a radio frequency signal received by the at least one first antenna into the first channel signal in base band sent to the first estimation module and a second converter configured to convert the emitted signal being a radio frequency signal received by the at least one second antenna into the second channel signal in base band sent to the second estimation module.

3. The receiver according to claim 2, further comprising at least one analog-to-digital converter configured to convert the first channel signal in base band into the first channel signal in digital base band sent to the first estimation module and to convert the second channel signal in base band respectively into the second channel signal in digital base band sent to the second estimation module.

4. The receiver according to claim 1, wherein the first estimation module is configured to calculate the first complex impulse response by making a correlation between the first channel signal and a signal calculated by circular permutations of a sequence contained in the emitted signal, the second estimation module is configured to calculate the second complex impulse response by making a correlation between the second channel signal and the signal calculated by circular permutations of the sequence contained in the emitted signal.

5. The receiver according to claim 4, wherein the sequence contained in the emitted signal is pre-registered in the device.

6. The receiver according to claim 4, wherein the sequence contained in the emitted signal is a sequence of pulses present in a synchronisation heading of a preamble of the emitted signal.

7. The receiver according to claim 1, wherein the conversion module is configured to calculate each angles of arrival ANGi of each signal propagation paths relative to the receiver according to the following equation:

ANGi=arccos((arg(hiA)−

arg(hiB))·

c/(ω

·

D)),

wherein;

arg(hiA)−

arg(hiB) is the argument differences between the argument arg(hiA) of each first time component of the first complex impulse response and the argument arg(hiB) of each second time component of the second complex impulse response respectively for each signal propagation paths,

ω

is the pulsation corresponding to a central emission frequency of the emitted signal,

D is a separation distance between the at least one first antenna and the at least one second antenna, and

c is the speed of light.

8. The receiver according to claim 1, wherein the at least one first antenna and the at least one second antenna are at a distance from each other by a distance equal to a wavelength of an emission frequency of the emitted signal.

9. The receiver according to claim 1, wherein the conversion module is configured to convert each argument differences into each angle of arrival in a determined two-dimensional plan.

10. The receiver according to claim 9, comprising as antennas only a single first antenna and a single second antenna.

11. The receiver according to claim 1, wherein the conversion module is configured to convert each argument differences into each angle of arrival which is three-dimensional.

12. The receiver according to claim 1, wherein the first and second estimation modules are configured to calculate the first and second complex impulse responses in the form of first and second multiplicities of samples in discrete time,

the extraction module configured to select each first time component associated respectively with each signal propagation path among the first multiplicity of samples of the first complex impulse response, and

the extraction module configured to select each second time component associated respectively with each signal propagation path among the second multiplicity of samples of the second complex impulse response.

13. The receiver according to claim 12, wherein the extraction module is configured to select the first and second time components by retaining the first and second samples which are non-zero in absolute value or greater in absolute value than a prescribed non-zero threshold.

14. The receiver according to claim 12, wherein

the first multiplicity of samples hnA= of the first complex impulse response and the second multiplicity of samples hnB= of the second complex impulse response are configured to be calculated according to the following formulas:

15. The receiver according to claim 1, wherein the receiver comprises a single local oscillator shared between the first receiving part and the second receiving part.

16. The receiver according to claim 15, wherein the physical arrangement of the first receiving channel and of the second receiving channels is done symmetrically relative to the oscillator placed on an axis of symmetry.

17. The receiver according to claim 2, wherein the receiver comprises a single local oscillator shared between the first receiving part and the second receiving part, with the physical arrangement of the first converter and of the second converter being done symmetrically relative to the oscillator placed on an axis of symmetry.

18. The receiver according to claim 1, wherein the module to determine the location of the transmitter calculates this location of the RFID transmitter as a function of pre-registered coordinates of elements of the environment reflecting the emitted signal and as a function of each angle of arrival of each signal propagation paths.

21. The receiver of claim 1, comprising at least one determination module configured to determine a location of the RFID transmitter from the one or more angle of arrival.

22. A device for locating an RFID transmitter in an environment involving one or more signal propagation path of an emitted signal, the emitted signal emitted wirelessly by an RFID transmitter, wherein the device comprises:

at least one first receiver according to the receiver in claim 1, the at least one first receiver connected to the at least one first antenna and to the at least one second antenna for calculating, as argument difference, one or more of first argument difference respectively for the one or more signal propagation path;

at least one third antenna located in a third predetermined position; and

at least one second receiver connected to the at least one first antenna and to the at least one third antenna for calculating, as argument difference, one or more second argument difference respectively for the one or more signal propagation path,

the first predetermined position of the at least one first antenna, the second predetermined position of the at least one second antenna and the third predetermined position of the at least one third antenna being non-aligned, and

the conversion module configured to convert the one or more first argument difference and the one or more second argument difference respectively into one or more angle of arrival of the one or more signal propagation path relative to the receivers.

23. The device according to claim 22, wherein the device further comprises, as receiver, at least one third receiver connected to the third antenna and to the second antenna for calculating one or more third argument difference respectively for the one or more signal propagation path,

the conversion module configured to convert the one or more first argument difference, the one or more second argument difference and the one or more third argument difference respectively into one or more angle of arrival of the one or more signal propagation path relative to the receivers.

19. A method for location of an RFID transmitter in an environment involving one or more signal propagation path for propagation of an emitted signal, the emitted signal emitted wirelessly by an RFID transmitter, by means of at least one receiver, the method comprising:

receiving the emitted signal on at least one first receiving antenna of the at least one receiver and at least one second receiving antenna of the at least one receiver, the at least one first receiving antenna defining a first receiving channel for receiving of the emitted signal, the at least one second receiving antenna defining a second receiving channel for receiving of the emitted signal, the at least one first receiving antenna and the at least one second receiving antenna being at a distance from each other and respectively having first and second predetermined positions relative to each other such that the first receiving channel is substantially identical to the second receiving channel, and the emitted signal being of the ultra-wide band type;

estimating, by a first estimation module of the at least one receiver, a first complex impulse response of the first receiving channel to the emitted signal as a function of the emitted signal and of a first channel signal supplied by a first receiving part of the at least one receiver;

estimating, by a second estimation module of the at least one receiver, a second complex impulse response of the second receiving channel to the emitted signal as a function of the emitted signal and of a second channel signal supplied by a second receiving part of the at least one receiver;

extracting, by a third extraction module of the at least one receiver, one or more first time components associated respectively with one or more signal propagation path arriving at the at least one first receiving antenna from the first complex impulse response, and one or more second time components associated respectively with the one or more signal propagation path arriving at the at least one second receiving antenna from the second complex impulse response;

calculating, by a fourth module of the at least one receiver, one or more argument differences between an argument of each first time component of the first complex impulse response and an argument of each second time component of the second complex impulse response respectively for one or more signal propagation path; and

converting, by at least one conversion module of the at least one receiver, the one or more argument differences into one or more angle of arrival of the one or more signal propagation path relative to the at least one receiver.

20. The method of claim 19, wherein a location of the RFID transmitter is determined from a plurality of angles of arrival of a plurality of signal propagation paths.