System and method for location determination using time differences

• US 20070139257A1
• Filed: 08/07/2006
• Published: 06/21/2007
• Est. Priority Date: 12/16/2005
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Lai, Yu-Sheng, Wang, Wen-Yang
• Granted Patent: US 7,538,716 B2
• Time in Patent Office: Days
• US Class Current: 342/126
• CPC Class Codes: G01S 15/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S15/46
• CPC Class Codes: G01S 15/74 Systems using reradiation of acoustic waves, e.g. IFF, i.e. identification of friend or foe

Abstract

The present invention relates to a system and a method for location determination using time differences. The method of the invention comprises the steps of: transmitting a transmission signal by using a directional transmitter rotating at an angular velocity, the transmission signal comprising a transmission identification and the transmitting time; receiving the transmission signal by using an omnidirectional transceiver, and adding a personal identification to the transmission signal to be a response signal; transmitting the response signal; receiving the response signal by using an omnidirectional receiver and recording the receiving time; and calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time. By utilizing the system and the method of the invention, the corresponding location of the omnidirectional transceiver can be calculated accurately without disposing a lot of sensors in the space, and the system of the invention need not be reconfigured for new environments. Therefore, the conventional problems of high installation cost and complicated settings can be improved.

Claims

1. A system for location determination using time differences, comprising:

a directional transmitter, rotating at an angular velocity, for transmitting a transmission signal, the transmission signal comprising a transmission identification and a transmitting time;

an omnidirectional transceiver, for receiving the transmission signal, adding a personal identification to the transmission signal to be a response signal, and transmitting the response signal; and

an omnidirectional receiver, for receiving the response signal from the omnidirectional transceiver and recording a receiving time, the directional transmitter and the omnidirectional receiver disposed in a wireless transceiver device for calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time.

2. The system for location determination according to claim 1, wherein the wireless transceiver device further comprises a driving device for driving the directional transmitter to rotate at the angular velocity.

3. The system for location determination according to claim 1, wherein the wireless transceiver device further comprises a first calculating device for producing the transmission signal for the directional transmitter and determining whether the transmission identification in the response signal is equal to the transmission identification of the wireless transceiver device, if the transmission identifications are equal, the receiving time is recorded, and then the location of the omnidirectional transceiver corresponding to the directional transmitter is calculated according to the difference between the receiving time and the transmitting time.

4. The system for location determination according to claim 3, wherein the location of the omnidirectional transceiver comprises an angle and a distance, the angle is calculated according to the angular velocity, the transmitting time and a referring time;

the distance is calculated according to the difference between the receiving time and the transmitting time.

5. The system for location determination according to claim 4, wherein the wireless transceiver device further comprises a register for saving a referring time when the directional transmitter passes by a referring direction, and transmitting the referring time to the first calculating device.

6. The system for location determination according to claim 3, wherein the wireless transceiver device further comprises a first memory device for saving the transmission identification, and transmitting the transmission identification to the first calculating device.

7. The system for location determination according to claim 3, wherein the wireless transceiver device further comprises a timer for transmitting the transmitting time to the first calculating device.

8. The system for location determination according to claim 1, wherein the omnidirectional transceiver is disposed in an electrical badge comprising a second calculating device for adding the personal identification to the transmission signal.

9. The system for location determination according to claim 8, wherein the electrical badge further comprises a second memory device for saving the personal identification, and transmitting the personal identification to the second calculating device.

10. A method for location determination using time differences, comprising the steps of:

continuously transmitting a transmission signal by using a directional transmitter rotating at an angular velocity, the transmission signal comprising a transmission identification and a transmitting time;

receiving the transmission signal by using an omnidirectional transceiver, adding a personal identification to the transmission signal to be a response signal, and transmitting the response signal;

receiving the response signal by using an omnidirectional receiver and recording a receiving time; and

calculating the location of the omnidirectional transceiver corresponding to the directional transmitter according to the difference between the receiving time and the transmitting time.

11. The method for location determination according to claim 10, wherein the step for receiving the response signal further comprises a step for determining whether the transmission identification of the response signal is equal to the transmission identification of the transmission signal.

12. The method for location determination according to claim 10, wherein the step for transmitting the transmission signal further comprises a step for saving a referring time when the directional transmitter passes by a referring direction.

13. The method for location determination according to claim 12, wherein the step for calculating the location further comprises a step for calculating an angle and a step for calculating a distance, the angle is calculated according to the angular velocity, the transmitting time and a referring time;

the distance is calculated according to the difference between the receiving time and the transmitting time.