System and method for tracking position of moving object

1. A system for tracking the position of a moving object, the system comprising:

WSNs (wireless sensor networks) composed of a plurality of sensor nodes, each generating connection release information representing that a connection between the corresponding WSN and a moving object having a moving node serving as a sensor node attached thereto has released if having perceived the departure of the moving object; base stations managing the plurality of WSNs and collecting position information on the plurality of sensor nodes;

a node information database storing the position information on the plurality of sensor nodes collected by the plurality of base stations;

middleware checking the current position information on the moving object stored in the node information database if receiving the connection release information through any of the plurality of base stations, and deleting the current position information on the moving object stored in the node information database if the checked current position of the moving object is in a WSN having perceived the departure of the moving object; and

a moving-object tracking application provided with the position information on the moving object by the middleware to track the position of the moving object.

2. The system of claim 1 , wherein if a WSN having perceived the moving object generates connection generation information representing that the moving object has been connected to the corresponding WSN, the middleware receives the connection generation information through a base station corresponding to the WSN and updates the current position information on the moving object stored in the node information database with position information on the moving object included in the connection generation information.

3. The system of claim 2 , wherein if the checked current position of the moving object is in another WSN other than the WSN having perceived the departure of the moving object, the middleware maintains the position information on the moving object stored in the node information database.

4. The system of claim 3 , wherein the plurality of WSNs consist of a plurality of sensor nodes including a plurality of moving nodes and a plurality of stationary nodes, the plurality of moving nodes are manufactured in a portable form and are attached to property or persons that come in and out of a building, and the plurality of stationary nodes are installed on walls or ceilings at every floor.

5. The system of claim 4 , wherein in a WSN, a stationary node transmits or receives an RSSI (received signal strength indication) to or from a moving node attached to the moving object and provides basic position information for calculating the position of the moving object to a base station.

6. A method of tracking the position of a moving object, the method comprising: if a moving object having a moving node being a sensor node attached thereto has left a WSN, generating connection release information representing that the connection between the moving node and the WSN has been released;

searching for current position information on the moving object stored in a node information database that stores position information on a plurality of moving nodes and a plurality of stationary nodes, and determining whether the searched current position of the moving object is in the WSN; and

if the checked current position of the moving object is in the WSN, deleting the position information on the moving node attached to the moving object stored in the node information database.

7. The method of claim 6 , wherein in the searching of the current position information, if the checked current position of the moving object is in another WSN other than the WSN, the position information on the moving object stored in the node information database is maintained.

8. The method of claim 7 , wherein in the generating of the connection release information, the departure of the moving object is perceived through a stationary node serving as a reference point required to calculate the position of the moving node that is manufactured in a portable form and is attached to a movable object such as property or persons that come in and out of a building.

9. The method of claim 8 , wherein in the generating of the connection release information, the stationary node transmits or receives an RSSI (received signal strength indication) to or from the moving node attached to the moving object to perceive the departure of the moving node attached to the moving object.

10. A method of tracking the position of a moving object, the method comprising:

if a moving object having a moving node being a sensor node attached thereto has left a first WSN and entered a second WSN, sensing departure of the moving node from the first WSN and generating connection release information representing that the connection between the moving node and the first WSN has been released, and generating connection generation information representing that the moving object has been connected to the second WSN;

searching for current position information on the moving object stored in a node information database, determining whether the searched current position of the moving object is in the first WSN, and if the checked current position of the moving object is in the WSN, deleting the position information on the moving node attached to the moving object stored in the node information database; and

updating the searched current position information of the moving object in the node information database with position information included in the connection generation information.

11. The method of claim 10 , wherein in the generating of the connection generation information, the entrance of the moving object is perceived through a stationary node serving as a reference point required to calculate the position of the moving node that is manufactured in a portable form and is attached to a movable object such as property or persons that come in and out of a building.

12. The method of claim 11 , wherein, in the generating of the connection generation information, the stationary node transmits or receives an RSSI (received signal strength indication) to or from the moving node attached to the moving object to perceive the entrance of the moving node attached to the moving object.

13. The method of claim 10 , wherein the first WSN is a WSN of a first floor of a building, and the second WSN is a WSN of a second floor of a building.