Distance measuring method

1. A computer-implemented method for measuring distance based on packets transmitted and received between a first node and a second node, comprising:

obtaining first timing for transmitting a first packet from the first node;

obtaining second timing for receiving the first packet in the second node;

obtaining third timing for transmitting a second packet corresponding to the first packet from the second node;

obtaining fourth timing for receiving the second packet in the first node;

obtaining fifth timing for transmitting a third packet from the second node;

obtaining sixth timing for receiving the third packet in the first node;

estimating a clock frequency offset based on the obtained timings;

measuring a first distance based on the clock frequency offset and timings for transmitting and receiving the first packet and the second packet;

measuring a second distance based on the clock frequency offset and timings for transmitting and receiving the first packet and the third packet; and

measuring by a micro-processor a distance between the first node and the second node based on the first distance and the second distance.

2. The computer implemented method of claim 1 , wherein each of the nodes generates a packet by including at least one of IDs of at least one of receivers, information on a response order of the receivers, information on timing for transmitting a packet from the receivers, information on timing for receiving previously received a packet, and timing for transmitting the transmitted packet.

3. The computer implemented method of claim 2 , wherein each of the packets is transmitted at any time or is transmitted at a specific time included in the packet.

4. The computer implemented method of claim 1 , further comprising when receiving the first packet, the second packet, and the third packet, a corresponding node counts them in synchronization with a clock at portions of an end of a preamble, a start or end of a specific marker, or a start or end of a header, or stores them at a corresponding position.

5. The computer implemented method of claim 1 , wherein the fifth timing is any one of timing corresponding to a defined interval between nodes from the third timing and fourth timing of the second packet, timing corresponding to a time interval included in the first packet or the second packet, and timing included in the third packet itself.

6. The computer implemented method of claim 1 , wherein the estimating the clock frequency offset includes dividing a difference value between the sixth timing and the fourth timing by a difference value between the fifth timing and the third timing, and measuring a difference between the divided resulting value and a predetermined value.

7. The computer implemented method of claim 1 , wherein the measuring the first distance includes measuring the first distance based on a difference value between the fourth timing and the first timing, a difference value between the third timing and the second timing, and the clock frequency offset.

8. The computer implemented method of claim 1 , wherein the measuring the second distance includes measuring the second distance based on a difference value between the sixth timing and the first timing, a difference value between the fifth timing and the second timing, and the clock frequency offset.

9. The computer implemented method of claim 1 , further comprising:

measuring distances between the first node and a plurality of reference nodes, respectively, when the first node is configured of a measuring node measuring a position and the second node is configured of the plurality of reference nodes that are capable of previously calculating a position; and

measuring the position of the measuring node based on the measured distances.

10. A computer-implemented method for measuring distance based on packets transmitted and received between a first node and a second node, comprising:

obtaining first timing for transmitting a first packet from the first node;

obtaining second timing for receiving the first packet in the second node;

obtaining third timing for transmitting a second packet corresponding to the first packet from the second node;

obtaining fourth timing for receiving the second packet in the first node;

obtaining fifth timing for transmitting a third packet from the first node;

obtaining sixth timing for receiving the third packet in the second node;

estimating a clock frequency offset based on the obtained timings;

measuring a first distance based on the clock frequency offset and timings for transmitting and receiving the first packet and the second packet;

measuring a second distance based on the clock frequency offset and timings for transmitting and receiving the second packet and the third packet; and

measuring by a micro-processor a distance between the first node and the second node based on the first distance and the second distance.

11. The computer implemented method of claim 10 , wherein the measuring the first distance includes measuring the first distance based on a difference value between the fourth timing and the first timing, a difference value between the third timing and the second timing, and the clock frequency offset.

12. The computer implemented method of claim 10 , wherein the measuring the second distance includes measuring the second distance based on a difference value between the third timing and the sixth timing, a difference value between the fourth timing and the first timing, and the clock frequency offset.

13. A computer-implemented method for measuring distance based on packets transmitted and received between a first node and a second node, comprising:

obtaining first timing for transmitting a first packet from the first node;

obtaining second timing for receiving the first packet in the second node;

obtaining third timing for transmitting a second packet corresponding to the first packet from the second node;

obtaining fourth timing for receiving the second packet in the second node;

obtaining fifth timing for transmitting a third packet from the second node;

obtaining sixth timing for receiving the third packet in the first node;

estimating a clock frequency offset based on the obtained timings;

measuring a first distance based on the clock frequency offset and timings for transmitting and receiving the first packet and the third packet;

measuring a second distance based on the clock frequency offset and timings for transmitting and receiving the second packet and the third packet; and

measuring by a micro-processor a distance between the first node and the second node based on the first distance and the second distance.

14. The computer implemented method of claim 13 , wherein the estimating the clock frequency offset includes dividing a difference value between the third timing and the first timing by a difference value between the fourth timing and the second timing, and measuring a difference between the divided resulting value and a specific value.

15. The computer implemented method of claim 13 , wherein the measuring the first distance includes measuring the first distance based on a difference value between the sixth timing and the first timing, a difference value between the fifth timing and the second timing, and the clock frequency offset.

16. The computer implemented method of claim 13 , wherein the measuring the second distance includes measuring the second distance based on a difference value between the sixth timing and the third timing, a difference value between the fifth timing and the fourth timing, and the clock frequency offset.