POSITIONING SYSTEM USING ULTRASONIC WAVES AND METHOD FOR OPERATING THE SAME

• US 20090016165A1
• Filed: 07/11/2008
• Published: 01/15/2009
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: KT Corporation
• Original Assignee: KT Corporation
• Inventors: LEE, Dong Hwal
• Granted Patent: US 7,764,574 B2
• Time in Patent Office: Days
• US Class Current: 367/127
• 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 for operating a mobile device positioning system, the method comprising:

providing a mobile device positioning system comprises a plurality of ultrasonic signal transmitters;

generating a synchronization signal for synchronizing the plurality of ultrasonic signal transmitters;

transmitting an ultrasonic signal from each of the plurality of ultrasonic signal transmitters after the synchronization signal in a predetermined order of the plurality of ultrasonic signal transmitters; and

receiving, by the mobile device, each transmitted ultrasonic signal so as to compute a distance between the mobile device and each of the plurality of ultrasonic signal transmitters.

2. The method of claim 1, further comprising:

assigning an identifier to each of the plurality of ultrasonic signal transmitters, wherein the predetermined order is saved in terms of an order of the identifiers.

3. The method of claim 1, further comprising determining the mobile device'"'"'s position using the distance between the mobile device and each of the plurality of ultrasonic signal transmitters.

4. The method of claim 3, wherein each of the plurality of ultrasonic signal transmitters transmits its ultrasonic signal in a predetermined time after its receipt of the synchronization signal, wherein the predetermined time for each of the plurality of ultrasonic signal transmitters is determined according to the predetermined order of the plurality of ultrasonic signal transmitters for transmitting the ultrasonic signals.

5. The method of claim 3, wherein determining the mobile device'"'"'s position comprises:

computing a time period between transmission and receipt of the ultrasonic signal from each of the plurality of ultrasonic signal transmitters using a time delay from the synchronization signal to the transmission of the ultrasonic signal;

computing a distance using the time period and a speed of the ultrasonic signal; and

computing the position of the mobile device using the distance between the mobile device and each of the plurality of ultrasonic signal transmitters.

6. The method of claim 5, wherein each of the plurality of ultrasonic signal transmitters transmits its ultrasonic signal in a predetermined time after its receipt of the synchronization signal, wherein the predetermined time for each of the plurality of ultrasonic signal transmitters is determined according to the predetermined order of the plurality of ultrasonic signal transmitters for transmitting the ultrasonic signals.

7. The method of claim 1, wherein each of the plurality of ultrasonic signal transmitters transmits its ultrasonic signal in a predetermined time after its receipt of the synchronization signal, wherein the predetermined time for each of the plurality of ultrasonic signal transmitters is determined according to the predetermined order of the plurality of ultrasonic signal transmitters for transmitting the ultrasonic signals.

8. A method for operating a mobile device positioning system, wherein a positioning system comprises a plurality of ultrasonic signal transmitters, the method comprising:

assigning an identification number to each of the plurality of ultrasonic signal transmitters; and

transmitting an ultrasonic signal from each of the plurality of ultrasonic signal transmitters in a predetermined order of the plurality of ultrasonic signal transmitters for transmitting the ultrasonic signals, wherein each of the plurality of ultrasonic signal transmitters transmits the ultrasonic signal with a time delay after a synchronization signal, wherein the delay time for each of the plurality of ultrasonic signal transmitters is predetermined according to the predetermined order.

9. The method of claim 8, further comprising:

computing a distance between the mobile device and each of the plurality of ultrasonic signal transmitters; and

determining the mobile device'"'"'s position using the distance between the mobile device and each of the plurality of ultrasonic signal transmitters.

10. The method of claim 9, wherein each of the plurality of ultrasonic signal transmitters is configured to transmit its ultrasonic signal in the delay time after its receipt of the synchronization signal.

11. The method of claim 9, wherein determining the mobile device'"'"'s position comprises:

computing a time period between transmission of each ultrasonic signal and the mobile device'"'"'s receipt of the ultrasonic signal based on the predetermined delay time of each of the plurality of ultrasonic signal transmitters;

computing a distance using the time period and a speed of the ultrasonic signal; and

computing the position of the mobile device using the distance between the mobile device and each of the plurality of ultrasonic signal transmitters.

12. The method of claim 11, wherein each of the plurality of ultrasonic signal transmitters is configured to transmit its ultrasonic signal in the delay time after its receipt of the synchronization signal.

13. 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 based on the synchronization signal;

receiving, by the mobile device, a first ultrasonic signal transmitted from a first source located at a first source location at a first transmission time, which is after a first predetermined interval from the first source'"'"'s receipt of the synchronization signal, wherein the first ultrasonic signal does not comprises information indicative the first transmission time; and

computing a first distance between the mobile device and the first source location using the first predetermined interval and further using a first transmission time difference between receipt of the first ultrasonic signal and receipt of the synchronization signal by the mobile device;

receiving, by the mobile device, a second ultrasonic signal transmitted from a second source located at a second source location at a second transmission time, which is after a second predetermined interval from the second source'"'"'s receipt of the synchronization signal, wherein the second ultrasonic signal does not comprises information indicative the second transmission time; and

computing a second distance between the mobile device and the second source location using the second predetermined interval and further using second transmission time difference between receipt of the second ultrasonic signal and receipt of the synchronization signal by the mobile device; and

determining the mobile device'"'"'s position using the first distance and the second distance.

14. The method of claim 13, further comprising:

receiving, by the mobile device, a third ultrasonic signal transmitted from a second source located at a third source location at a third transmission time, which is after a third predetermined interval from the third source'"'"'s receipt of the synchronization signal, wherein the third ultrasonic signal does not comprises information indicative the third transmission time; and

computing a third distance between the mobile device and the third source location using the third predetermined interval and further using a third time difference between receipt of the third ultrasonic signal and receipt of the synchronization signal by the mobile device,

wherein determining further uses the third distance.

15. The method of claim 13, wherein the first predetermined interval is different from the second predetermined interval.

16. The method of claim 13, further comprising receiving, by the mobile device, the information of the first predetermined interval.

17. The method of claim 16, wherein the information of the first predetermined interval is pre-stored in the mobile device.

18. The method of claim 13, further comprising receiving, by the mobile device, the information of the first source location.

19. The method of claim 18, wherein the information of the first source location is pre-stored in the mobile device.

20. The method of claim 13, wherein computing the first distance further uses the transmission speed of the ultrasonic signal.