AUTONOMOUS ULTRASONIC INDOOR TRACKING SYSTEM

• US 20090190441A1
• Filed: 01/28/2009
• Published: 07/30/2009
• Est. Priority Date: 01/29/2008
• Status: Abandoned Application

• Current Assignee: NEC Company Limited
• Original Assignee: NEC Company Limited
• Inventors: Wang, Yongcai, ZHAO, Junhui
• Application Number:
  US12/361,246
• Publication Number:
  US 20090190441A1
• Time in Patent Office: Days
• US Class Current: 367/128
• CPC Class Codes: G01S 15/74 Systems using reradiation of acoustic waves, e.g. IFF, i.e. identification of friend or foe
• CPC Class Codes: G01S 15/876 Combination of several spaced transmitters or receivers of known location for determining the position of a transponder or a reflector G01S15/872 takes precedence
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location

Abstract

The present invention provides a Positioning on One Device (POD) for locating and tracking objects and an autonomous ultrasound indoor track system (AUITS) and method for locating objects by using the POD. The AUITS can comprise: a tag device installed on a mobile object, which includes radio frequency (RF) and ultrasound transmitters for transmitting RF and ultrasound signals; and a POD for receiving the RF and ultrasound signals transmitted from the tag device to locate the mobile object. The POD can comprise: a plurality of leaf modules, each of the leaf modules including a positioning signal receiver for receiving the positioning signals (e.g. ultrasound signal) transmitted from the tag device, wherein there is a known structural topology relationship between the plurality of leaf modules. Then, the positioning signal detection times from respective positioning signal receivers and the structural topology relationship of the POD can be used for calculation of the position of the object. Compared with the prior arts, the POD and the AUITS system of the present invention presents several advantages, such as high accuracy, easy deployment, calibration free, low cost, in-device coordination, and flexibility.

Claims

1. A positioning device for locating objects, comprising:

a plurality of leaf modules, each of the leaf modules including a positioning signal receiver for receiving positioning signals transmitted from the object, wherein there is a known structural topology relationship between the plurality of leaf modules; and

a computing module for computing the position of the object according to positioning signal detection times from respective positioning signal receivers and the structural topology relationship.

2. The positioning device according to claim 1, further comprising a head module, which comprises:

a synchronization signal receiver for receiving synchronization signal; and

a synchronization unit for performing synchronization with the object.

3. The positioning device according to claim 2, wherein the head module further comprises a positioning signal receiver for receiving the positioning signals.

4. The positioning device according to claim 2, wherein the plurality of leaf modules is arranged around the head module, and when the positioning device is used, the plurality of leaf modules is in a spread state, when the positioning device is not used, the plurality of leaf modules is in a compact state.

5. The positioning device according to claim 2, wherein the synchronization signal includes an ID code specific to the object, and the positioning device obtains the ID code by receiving the synchronization signal.

6. The positioning device according to claim 1, wherein the positioning signal includes an ID code specific to the object, and the positioning device obtains the ID code by receiving the positioning signal.

7. A method for locating objects using a positioning device, the positioning device comprises a plurality of leaf modules, each of the leaf modules includes a positioning signal receiver for receiving positioning signals transmitted from the object, wherein there is a known structural topology relationship between the plurality of leaf modules, the method comprising:

starting the positioning signal receivers and recording the start time T_0,i of the positioning signal receivers, wherein i is an index for the ith positioning signal receiver;

receiving the positioning signals from the object by each of the positioning signal receivers and recording its positioning signal detection time Δ

_t,i; and

calculating the position of the object based on the recorded positioning signal detection times and the structural topology relationship of the positioning device.

8. The method according to claim 7, further comprising:

receiving a synchronization signal from the object; and

synchronizing the positioning device with the object according to the synchronization signal.

9. The method according to claim 8, wherein at the object, a predetermined back-off time is inserted between the transmission of the synchronization signal and the positioning signals.

10. The method according to claim 8, wherein the synchronization signal includes an ID code specific to the object, the method further comprises:

obtaining the ID code from the synchronization signal.

11. The method according to claim 7, wherein the positioning signal includes an ID code specific to the object, the method further comprises:

obtaining the ID code from the positioning signal.

12. An autonomous ultrasound track system for locating objects, comprising:

a tag device installed on a object, which includes a positioning signal transmitter for transmitting positioning signals; and

a positioning device for locating the position of the object, wherein the positioning device comprises;

a plurality of leaf modules, each of the leaf modules including a positioning signal receiver for receiving the positioning signals transmitted from the object, wherein there is a known structural topology relationship between the plurality of leaf modules; and

a position computing module for computing the position of the object according to positioning signal detection times from respective positioning signal receivers of the positioning device and the structural topology relationship.

13. The system according to claim 12, wherein the tag device further includes a synchronization signal transmitter for transmitting synchronization signal.

14. The system according to claim 12, wherein the position computing module is integrated into one of the leaf modules of the positioning device.

15. The system according to claim 12, further comprising a server, and the position computing module is integrated into the server.

16. An ultrasound signature method, comprising:

obtaining an ID code specific to an object;

encoding the ID code into a sequence of ultrasound pulses to be transmitted; and

transmitting the encoded sequence of ultrasound pulses.

17. The ultrasound signature method according to claim 16, wherein the step of encoding comprises at least one of:

varying the transmission time of each of the ultrasound pulses in the ultrasound pulses sequence according to the ID code, and

performing amplitude modulation, frequency modulation or phase modulation operation on the sequence of ultrasound pulses according to the ID code.

18. A tag device, comprising:

a synchronization signal transmitter for transmitting synchronization signals; and

a positioning signal transmitter for transmitting positioning signals,

wherein a predetermined period of time is inserted between the transmission of the synchronization signals and the positioning signals.

19. The tag device according to claim 18, wherein the synchronization signal includes an ID code specific to the object.

20. The tag device according to claim 18, wherein the positioning signal includes an ID code specific to the object.