POSITION DETECTING SYSTEM, RESPONDER AND INTERROGATOR, WIRELESS COMMUNICATION SYSTEM, POSITION DETECTING METHOD, POSITION DETECTING PROGRAM, AND INFORMATION RECORDING MEDIUM

• US 20070018792A1
• Filed: 09/18/2006
• Published: 01/25/2007
• Est. Priority Date: 03/17/2004
• Status: Active Grant

• Current Assignee: Brother Kogyo Kabushiki Kaisha
• Original Assignee: Brother Kogyo Kabushiki Kaisha
• Inventors: Ohashi, Tsuyoshi, Nagai, Takuya, Taki, Kazunari
• Granted Patent: US 8,284,027 B2
• Time in Patent Office: Days
• US Class Current: 340/10.100
• CPC Class Codes: G01S 13/0209 Systems with very large relative bandwidth, i.e. larger than 10 %, e.g. baseband, pulse, carrier-free, ultrawideband
• CPC Class Codes: G01S 13/751 wherein the responder or reflector radiates a coded signal
• 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: H04B 1/7163 using impulse radio

Abstract

There is provided a radio communication system capable of distinguishing objects from one another while taking advantage of the low power consumption and distance measurement ability of the radio communication of the UWB method. A radio tag TGn includes: a characteristic impedance unit (3) for generating a response signal by using a pulse signal received from a broad-band antenna (1); a transmission path (2) having a predetermined length, transmitting the pulse signal received by the broad-band antenna (1) from the broad-band antenna (1) to the characteristic impedance unit (3), and transmitting the generated response signal from the characteristic impedance unit (3) to the broad-band antenna (1); and the broad-band antenna (1) for receiving the pulse signal and transmitting the response signal. The aforementioned pulse wave is transmitted to the radio tag TGn by the UWB method. The response signal from the radio tag TGn is received and the radio tag TGn is identified from the reception waveform.

Claims

1. A responder comprising:

a generating means that generates a response signal, using a pulse signal that is received through a wideband antenna;

a transmitting means that transmits the pulse signal received through the wideband antenna from the wideband antenna to the generating means and also transmits the response signal from the generating means to the wideband antenna, the transmitting means having a predetermined length; and

the wideband antenna that receives the pulse signal and transmits the response signal.

2. The responder according to claim 1, wherein the transmitting means located between the wideband antenna and the generating means has such a length as to transmit the response signal through the wideband antenna in a different transmission manner from any transmission manner of other responders, the other responders each having the same structure as the responder.

3. The responder according to claim 1, wherein the transmitting means has characteristic impedance that is constant at a predetermined value at a predetermined length.

4. The responder according to claim 1, wherein the length of the transmitting means is equal to or greater than a half a value obtained by multiplying a velocity at which the received pulse signal and the response signal are transmitted in the transmitting means by a time equivalent to a pulse width of the received pulse signal.

5. The responder according to claim 1, wherein the generating means includes a reflection control unit that controls a pulse reflection coefficient for the received pulse signal.

6. The responder according to claim 1, wherein the generating means includes a length control unit that controls an effective length of the transmitting means, based on a signal state in which the response signal is to be.

7. The responder according to claim 6, where in the length control unit controls the length to be equivalent to a value obtained by multiplying the velocity at which the pulse signal and the response signal are transmitted in the transmitting means by a period of time equivalent to the pulse width of the pulse signal, and then adding N/4 (N being 0 or a natural number) of the multiplication result to a half the multiplication result.

8. The responder according to claim 1, further comprising:

a plurality of the generating means; and

a plurality of the transmitting means that transmits the pulse signal received by the wideband antenna to each of the generating means from the wideband antenna, and also transmits the response signal from each of the generating means to the wideband antenna,

the transmitting means having different lengths from one another.

9. The responder according to claim 8, further comprising:

a common transmitting means that functions as at least a part of each of the transmitting means.

10. The responder according to claim 1, wherein the generating means includes a resonating means that can resonate at a plurality of resonant frequencies.

11. A responder comprising:

a plurality of element responders each being the responder according to claim 1, wherein at least one of the length of the transmitting means and the load impedance of the transmitting means and the generating means seen from the wideband antenna is different in each one of the element responders from another.

12. The responder according to claim 1, further comprising:

a reception antenna that receives radio waves; and

a power supply means that converts the received radio waves into electric power, and supplies the electric power to the generating means.

13. The responder according to claim 12, wherein the radio waves are continuous waves.

14. The responder according to claim 12, wherein:

the reception antenna is a narrow-band antenna that is in tune with a predetermined tuning frequency; and

the radio waves are continuous waves having the tuning frequency.

15. The responder according to claim 12, wherein the wideband antenna also serves as the reception antenna.

16. An interrogator that transmits the pulse signal to the responder according to claim 1 and receives the response signal from the responder,

the interrogator comprising:

a pulse generating means that generates the pulse signal;

a wideband antenna that transmits the pulse signal to the responder, and receives the response signal from the responder in response to the pulse signal; and

an identifying means that identifies the responder by comparing the received response signal with a template signal that is generated in advance.

17. The interrogator according to claim 16, wherein:

the pulse generating means comprises a first modulated clock signal generating means that generates a first modulated clock signal by performing a first modulating operation on a clock signal, the pulse generating means using the first modulated clock signal to generate and output the pulse signal to the wideband antenna; and

the identifying means comprises a second modulated clock signal generating means that generates a second modulated clock signal by performing a second modulating operation on the clock signal, the second modulating operation being different from the first modulating operation, the identifying means using the second modulated clock signal to generate the template signal and to obtain correlations between the response signal and the template signal.

18. The interrogator according to claim 17, wherein the first modulating operation and the second modulating operation are to delay the cock signal based on a pseudo random code.

19. The interrogator according to claim 16, further comprising:

a reflected wave detecting means that detects a reflected wave that is reflected by the wideband antenna of the responder in response to the received pulse signal;

a response wave detecting means that detects a response wave contained in the response signal; and

a response wave interval detecting means that detects a response wave interval that is a period elapsing between the time of receiving the reflected wave and the time of receiving the response wave,

the identifying means identifying the responder, based on the detected response wave interval.

20. The interrogator according to claim 16, further comprising:

a transmission/reception interval detecting unit that detects a transmission/reception interval that is a period elapsing between the time of receiving a reflected wave reflected by the wideband antenna of the responder in response to the received pulse signal and the time of transmitting the pulse signal; and

a distance recognizing means that recognizes the distance between the interrogator and the responder that transmits the reflected wave, based on the detected transmission/reception interval.

21. The interrogator according to any of claim 16, further comprising:

a determining means that determines the polarity of the response signal.

22. An interrogator that transmits the pulse signal to the responder according to claim 10 and receives the response signal from the responder,

the interrogator comprising:

a generating means that generates the pulse signal;

a wideband antenna that transmits the pulse signal to the responder, and receives the response signal from the responder in response to the pulse signal;

an analyzing unit that performs frequency analysis by sampling the received response signal; and

an identifying means that identifies each of the responder, based on a result of the frequency analysis.

23. The interrogator according to claim 22, further comprising:

a super imposing unit that super imposes the received response signal with a template signal that is generated in advance, so as to generate a superimposed signal,

the analyzing unit performing frequency analysis by sampling the superimposed signal.

24. The interrogator according to claim 23, wherein the template signal is generated based on a clock signal that is generated in advance.

25. The interrogator according to claim 16, further comprising:

a radio wave transmitting means that transmits the radio waves to a responder comprising a generating means that generates a response signal, using a pulse signal that is received through a wideband antenna, a transmitting means that transmits the pulse signal received through the wideband antenna from the wideband antenna to the generating means and also transmits the response signal from the generating means to the wideband antenna, the transmitting means having a predetermined length, and wherein the wideband antenna that receives the pulse signal and transmits the response signal, a reception antenna that receives radio waves, and a power supply means that converts the received radio waves into electric power, and supplies the electric power to the generating means.

26. A wireless communication system comprising:

one or a plurality of the responders according to claim 1;

a plurality of the interrogators, wherein each interrogator comprises a pulse generating means that generates the pulse signal, a wideband antenna that transmits the pulse signal to the responder and receives the response signal from the responder in response to the pulse signal, and an identifying means that identifies the responder by comparing the received response signal with a template signal that is generated in advance; and

a determining means that determines the position of each of the responders, based on the distance between each of the responders and each of the interrogators, the distance being detected by each of the interrogators.

27. A position detecting system that includes a plurality of interrogators each transmitting a pulse signal as an interrogating wave, and a responder that receives the pulse signal and returns a response signal based on the received pulse signal,

the position detecting system comprising:

a first distance detecting means that receives the pulse signal transmitted by each of the interrogators and detects the distance between each two of the interrogators;

a second distance detecting means that detects the distance between each of the interrogators and the responder, based on the pulse signal and the response signal; and

a device position detecting unit that detects the position of each of the interrogators and the responder in the position detecting system, based on each of the detected distances.

28. The position detecting system according to claim 27, further comprising:

a plurality of the responders;

a responder identifying means that identifies each of the responders, based on the response signal; and

a distance information transmitting means that transmits distance information to each of the interrogators, the distance information indicating each of the detected distances.

29. The position detecting system according to claim 28, further including a fixed responder that can be fixed beforehand in a position in the position detecting system,

the position detecting system further comprising:

a third distance detecting means that detects the distance between the fixed responder and each of the interrogators,

the device position detecting unit detecting the absolute position of each of the interrogators and each of the responders in the position detecting system, based on each of the detected distances.

30. The position detecting system according to claim 27, further comprising:

a receiving unit that receives a return signal that is returned from a moving body located in the position detecting system in response to the transmitted pulse signal;

a determining means that determines whether the moving body is the responder, based on the received return signal; and

a reporting unit that reports that the moving body is determined not to be the responder by the determining means.

31. The position detecting system according to claim 28, wherein the distance information transmitting means transmits the distance information in the form of pulse waves to each of the interrogators.

32. The position detecting system according to claim 27, further comprising:

an interrogator number detecting unit that detects the number of interrogators located in the position detecting system.

33. The responder that is in the position detecting system according to claim 27, comprising:

a wideband antenna that receives the transmitted pulse signal and transmits the response signal;

a generating means that modulates the received pulse signal to generate the response signal; and

a transmitting means that transmits the received pulse signal to the generating means through the wideband antenna, and also transmits the response signal from the generating means to the wideband antenna.

34. A position detecting method that is utilized in a position detecting system that includes a plurality of interrogators each transmitting a pulse signal as an interrogating wave, and a responder that receives the pulse signal and returns a response signal based on the received pulse signal,

the position detecting method comprising:

a first distance detecting step of detecting the distance between each two of the interrogators after receiving the pulse signal transmitted by each of the interrogators;

a second distance detecting step of detecting the distance between each of the interrogators and the responder, based on the pulse signal and the response signal; and

a device position detecting step of detecting the position of each of the interrogators and the responder in the position detecting system, based on each of the detected distances.

35. The position detecting method according to claim 34, wherein the position detecting system includes a plurality of the responders,

the position detecting method further comprising the Step S of:

identifying each of the responders, based on the response signal; and

transmitting distance information to each of the interrogators, the distance information indicating each of the detected distances.

36. A position detecting program that is executed in a position detecting system that includes a plurality of interrogators each transmitting a pulse signal as an interrogating wave, and a responder that receives the pulse signal and returns a response signal based on the received pulse signal,

the position detecting program causes a computer in the position detecting system to function as:

a first distance detecting means that detects the distance between each two of the interrogators after receiving the pulse signal transmitted by each of the interrogators;

a second distance detecting means that detects the distance between each of the interrogators and the responder, based on the pulse signal and the response signal; and

a device position detecting unit that detects the position of each of the interrogators and the responder in the position detecting system, based on each of the detected distances.

37. An information recording medium on which the position detecting program according to claim 36 is recorded in such a manner that the computer can read the position detecting program.