Positioning system using ultrasonic waves and method for operating the same

• US 20070070812A1
• Filed: 09/08/2006
• Published: 03/29/2007
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: KT Corporation
• Original Assignee: KT Corporation
• Inventors: Lee, Doug Hwal
• Granted Patent: US 7,406,000 B2
• Time in Patent Office: Days
• US Class Current: 367/128
• CPC Class Codes: G01S 11/16 using difference in transit time between electrical and acoustic signals
• CPC Class Codes: G01S 5/30 Determining absolute distances from a plurality of spaced points of known location

Abstract

Provided are a positioning system using ultrasonic waves and a method for controlling the positioning system. The method for controlling a positioning system installs a plurality of ultrasonic satellites generating ultrasonic signals to position a mobile. The method sequentially gives satellite identification numbers to the plurality of ultrasonic satellites, generates a synchronization signal and providing it to the plurality of ultrasonic satellites, and allows the mobile to receive ultrasonic signals, which are generated by the plurality of ultrasonic satellites in the order of the satellite identification numbers when the ultrasonic satellites receive the synchronization signal, to measure distances between the mobile and the ultrasonic satellites. The positioning system using ultrasonic waves includes ultrasonic satellites generating ultrasonic signals, a mobile that receives the ultrasonic signals from the ultrasonic satellites to recognize its current position, a reference time broadcasting device for providing a synchronization signal to ultrasonic satellites currently operating among the ultrasonic satellites and the mobile, and a server for providing the coordinates of the ultrasonic satellites to the mobile.

Claims

1. A method of determining a position of a mobile device, the method comprising:

receiving, by a mobile device, a synchronization signal;

synchronizing the mobile device using the synchronization signal;

receiving, by the mobile device at a receipt time, an ultrasonic signal transmitted from a source located at a source location at a transmission time; and

determining the mobile device'"'"'s position using information of the source location and a time difference between the receipt time and the transmission time of the ultrasonic signal.

2. The method of claim 1, further comprising receiving information indicative of the transmission time.

3. The method of claim 2, wherein the information comprises a time difference between transmission of the synchronization signal and the transmission time of the ultrasonic signal.

4. The method of claim 1, further comprising receiving, by the mobile device, the information of the source location.

5. The method of claim 1, wherein the information of the source location is prestored in the mobile device.

6. The method of claim 1, further comprising:

receiving, by the mobile device at an additional receipt time, an additional ultrasonic signal transmitted from an additional source located at an additional source location at an additional transmission time; and

wherein determining the mobile device'"'"'s position further uses information of the additional source location and a time difference between the additional receipt time and the additional transmission time.

7. The method of claim 6, wherein determining comprises computing a distance between the additional source location and the mobile device.

8. The method of claim 6, wherein the method repeats the act of receiving a further additional ultrasonic signal, and wherein determining further uses information relating to the further additional ultrasonic signal.

9. The method of claim 6, wherein each of the transmission time and the additional transmission time has a predetermined time interval from transmission of the synchronization signal from a source thereof.

10. The method of claim 9, wherein determining further uses information of each predetermined time interval.

11. The method of claim 1, wherein determining comprises computing a distance between the source location and the mobile device.

12. The method of claim 1, further comprising receiving, by the mobile device, a transmission speed of the ultrasonic signal.

13. The method of claim 12, wherein determining further uses the transmission speed of the ultrasonic signal.

14. A system of determining a position of a mobile device, comprising:

a synchronizer configured to transmit a synchronization signal;

a plurality of ultrasonic signal transmitters, each of which is configured to transmit an ultrasonic signal at a predetermined time; and

a mobile device configured to receive the synchronization signal and ultrasonic signals from at least part of the plurality of ultrasonic signal transmitters, wherein the mobile device is configured to determine the mobile device'"'"'s position using information available thereto.

15. The system of claim 14, wherein the information comprises location information of the at least part of the plurality of ultrasonic signal transmitters and information of a period during which the ultrasonic signal travels from each of the at least part of the plurality of ultrasonic signal transmitters to the mobile device.

16. The system of claim 14, wherein the mobile device is configured to receive information indicative of the predetermined time for each of the at least part of the plurality of ultrasonic signal transmitters to the mobile device.

17. The system of claim 16, wherein the information indicative of the predetermined time comprises a time difference between transmission of the synchronization signal and the predetermined time for each of the at least part of the plurality of ultrasonic signal transmitters to the mobile device.

18. The system of claim 14, wherein the mobile device is configured to receive location information of the at least part of the plurality of ultrasonic signal transmitters.

19. The system of claim 14, wherein location information of the at least part of the plurality of ultrasonic signal transmitters is pre-stored in the mobile device.

20. The system of claim 14, wherein the predetermined time of each ultrasonic signal transmitter has a time interval from transmission of the synchronization signal from a source thereof.

21. The system of claim 14, wherein the predetermined time of each ultrasonic signal transmitter is different from that of another.

22. A method of operating the system of claim 14, the method comprising,

transmitting a synchronization signal from the synchronizer;

synchronizing at least part of the plurality of ultrasonic signal transmitters and the mobile device using the synchronization signal;

transmitting an ultrasonic signal from each of the at least part of the plurality of ultrasonic signal transmitters at a predetermined time thereof; and

determining the mobile device'"'"'s position using location information of the at least part of the plurality of ultrasonic signal transmitters and information of a period during which the ultrasonic signal travels from each of the at least part of the plurality of ultrasonic signal transmitters to the mobile device.