KR101301020B1 - A movable node position searching device and the position searching method thereof - Google Patents

Abstract

The mobile node position recognizing apparatus and the mobile node position recognizing apparatus using the same include: a reference node which periodically receives a packet from the mobile node and outputs signal strength information; And a positioning server for calculating the position of the mobile node based on the spatial information from the signal strength information received from the reference node.

Mobile node, reference node, positioning server, location estimation

Description

A mobile node position recognizing apparatus and a mobile node position recognizing method using the same

The present invention relates to a device and a method for recognizing a location of a mobile node, and more particularly, to a mobile node indoors using a propagation strength estimation algorithm using the propagation strength and spatial information measured in an indoor environment. The present invention relates to a device and a method for recognizing a location of a.

The present invention is derived from a study conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy [Task management number: 2008-S-023-02, Title: Development of NanoQplus-based sensor network simulator].

As interest in ubiquitous sensor networks and home networks grows, the location of wireless mobile nodes in the room is also becoming more important.

Location Awareness can be used for various applications such as identifying the patient's location in U-Health, applying the location of logistics in industrial environment, and context-aware service using location in home network environment.

In the case of outdoors, it is possible to recognize the location using GPS. However, indoors cannot receive satellite signals and cannot use technologies such as GPS.

Conventional indoor location recognition technology can be classified into two methods: a zone method that can be identified with connectivity and a triangulation method that uses a distance using signal strength.

The first method is to find a location by entering a communication area of a wireless terminal whose location is known in advance, but the implementation is simple, but it is impossible to determine the exact location of the location within the area. Many terminals are needed.

The second method is to find the position of a node using triangulation after finding the distance from three or more anchor nodes. In order to know the distance between nodes, radio signal strength is generally used. However, the error is large due to the complicated interior structure.

Therefore, there is a need for a new technology for improving indoor location recognition in wireless network environments such as sensor network networks and home network networks in complex indoor space environments.

An object of the present invention is to provide an apparatus and method for accurately calculating position information of a mobile node in a complex indoor space environment.

Another object of the present invention is to provide an apparatus and method for accurately calculating the position of a wireless communication device in a wireless network environment such as a network network and a home network network.

Another object of the present invention is to provide an apparatus and a method capable of providing more accurate location information by using propagation intensity prediction using spatial information.

Another object of the present invention is to provide an apparatus and a method capable of accurately calculating the position of a mobile node rather than a zone-based method.

It is also an object of the present invention to provide an apparatus and method for calculating the position of a mobile node using fewer reference nodes than a method using an ultrasonic sensor.

Another object of the present invention is to provide an apparatus and a method for calculating the position of a mobile node without additional work such as initializing and correcting the position of the mobile node.

The mobile node position recognizing apparatus of the present invention comprises: a plurality of reference nodes which periodically receive packets from the mobile node and output signal strength information; And a positioning server for calculating the position of the mobile node using the signal strength information received from the reference node, and prestored spatial information and reference node arrangement information.

In particular, the communication unit for receiving the signal strength information from the reference node; And a position estimator configured to calculate a position of the mobile node according to a position estimation algorithm based on the signal strength information, prestored spatial information, and arrangement information of the reference node.

The position estimator may calculate position information of the mobile node using a ray-tracing signal prediction algorithm.

The reference node may be configured to receive a packet from the mobile node using any one of Bluetooth, RFID, Zigbee, UWB, and wireless LAN.

In addition, the reference node and the positioning server is characterized in that for transmitting and receiving data in a wireless communication method.

The positioning server may calculate a location of the mobile node using signal strength information received from three or more reference nodes.

In addition, when the mobile node requests its own location, the positioning server transmits the location information to the reference node having the strongest signal strength among the reference nodes that receive the signal.

On the other hand, the mobile node position recognition method of the present invention, the step of receiving a packet from the mobile node at the reference node; Extracting the strength of the signal received at the reference node; Transmitting the signal strength information extracted from the reference node to a positioning server; And calculating, by the positioning server, the position of the mobile node using signal strength information received from the reference node, previously stored spatial information, and reference node arrangement information.

In particular, the positioning server, when receiving the signal strength information from three or more reference nodes, characterized in that for calculating the position of the mobile node.

In addition, when the mobile node requests its own location, the positioning server transmits the location information to the reference node having the strongest signal strength among the reference nodes that receive the signal.

The positioning server may calculate position information of the mobile node using a ray-tracing signal prediction algorithm.

The receiving of the packet from the mobile node at the reference node may include receiving the packet from the mobile node using any one of Bluetooth, RFID, Zigbee, UWB, and wireless LAN. do.

The mobile node position recognition apparatus and method according to the present invention can expect the following effects.

First, accurate location information about a mobile node in an indoor wireless environment can be calculated.

Second, it can replace technologies that can only be used in outdoor environments such as GPS.

Third, the position of the mobile node can be calculated more accurately than the zone-based method.

Fourth, the position of the mobile node can be calculated using fewer reference nodes than the method using the ultrasonic sensor.

Fifth, the position of the mobile node can be calculated without additional work such as initializing and correcting the position of the mobile node.

The present invention will now be described in detail with reference to the accompanying drawings. Hereinafter, a repeated description, a known function that may obscure the gist of the present invention, and a detailed description of the configuration will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

First, data flow for locating a mobile node in a wireless environment is described. The wireless environment described in the present invention includes a single hop multiple AP (or sync node) environment and is applicable to all wireless network protocols capable of extracting signal strength such as Bluetooth, RFID, Zigbee, UWB, and WLAN. It is possible.

1 is a view for explaining a mobile node position recognition apparatus according to a preferred embodiment of the present invention.

The mobile node position recognition apparatus of the present invention periodically receives a packet from the mobile node and outputs signal strength information, and signal strength information, prestored spatial information, and reference node received from the reference node 20. The positioning server 30 calculates the position of the mobile node 10 using the placement information. Here, a plurality of reference nodes 20 exist, and the positioning server 30 may receive signal strength information from three or more reference nodes 20 to estimate the position of the mobile node 10.

The mobile node 10 sends the packet to the reference node 20 periodically or as needed. The pre-installed reference node 20 receives the corresponding packet from the mobile node 10 and detects the signal strength of the mobile node 10. Here, the reference node 20 is a node that serves as an anchor in triangulation.

The reference node 20 transmits signal strength information of the mobile node 10 to the positioning server 30. The reference node 20 and the positioning server 30 may exchange data by wire or wirelessly.

The positioning server 30 includes a communication unit 32, a position estimating unit 34, a spatial information DB 36, and a reference node arrangement information DB 38.

The communication unit 32 receives the signal strength information transmitted from the reference node 20 and transfers it to the position estimating unit 34.

The position estimator 34 calculates the position of the mobile node 10 using a position estimation algorithm. In more detail, the position estimator 34 stores the signal strength information received from the reference node 20, the spatial information stored in the spatial information DB 36, and the reference node 20 stored in the reference node arrangement information DB 38. The position of the mobile node 10 is calculated according to the position estimation algorithm based on the arrangement information of. Here, a signal prediction algorithm such as ray tracing may be used as the location estimation algorithm. In addition to ray tracing, heuristic algorithms for extracting signal strength using spatial information can be used.

The spatial information DB 36 stores data on the indoor building (ie, spatial information), and provides the stored spatial information to the position estimating unit 34 as requested. Spatial information can be in various formats, including CAD files, data composed of 3D polygons, and the like.

The reference node arrangement information DB 38 stores the placement information of the reference node 20, and provides the stored reference node arrangement information to the position estimating unit 34 as requested. The reference node arrangement information may be two-dimensional or three-dimensional coordinates according to the space.

2 is a flowchart illustrating a process of a mobile node location recognition method according to the present invention.

Referring to FIG. 2, the mobile node periodically transmits a packet signal and the reference node receives it (S201).

According to the prior art, a reference node sometimes sends a beacon message to a mobile node. However, in this case, since the mobile node needs to receive and process a plurality of messages, the mobile node is overloaded and beacon messages are not processed at the same time.

Therefore, in the present invention, the mobile node uses a method of sending a message to the reference node. This approach can be easily applied in an environment that already has infrastructure.

Next, the reference node extracts signal strength based on the packet signal received from the mobile node. The reference node transmits signal strength information of the mobile node to the positioning server.

When the positioning server receives signal strength information from one or more reference nodes, the positioning server starts calculating the position of the mobile node according to the position estimation algorithm (S202). The number of the reference nodes described above may vary depending on the number of reference nodes installed, and as the number of reference nodes increases, more accurate position calculation is possible.

On the other hand, when the mobile node requests its own location, the positioning server transmits the location information to the reference node having the strongest signal strength among the reference nodes that receive the signal.

Since the positioning server already knows the coordinates (arrangement information) of each reference node, it first selects a position (primary region) where the mobile node may be based on the corresponding coordinates of each reference node (S203). This can be obtained with a free-space model, which is an obstacle-free environment at the position of each reference node. By primarily narrowing the range, the calculation speed can be increased.

The signal strength of each reference node is estimated using a position estimation algorithm using spatial information with respect to the primary region set in step S203 (S204).

Next, the position coordinates are determined by comparing the signal strength estimated in step S204 with the actual signal strength. That is, the position coordinates of the mobile node are determined at the position where the estimated signal strength coincides with the actual signal strength for each reference node or the error is the smallest (S205).

The spatial information may be in various formats including a CAD file, data composed of 3D polygons, and the like, and the reference node arrangement information may be two-dimensional or three-dimensional coordinates according to the corresponding space.

The location tracking by the conventional triangulation method calculates the location under the assumption that the same signal attenuation occurs in an obstacle-free environment because there is no spatial information. Therefore, there are many errors.

On the other hand, in the present invention, the signal strength according to the spatial structure is estimated using a predictable algorithm.

Therefore, the accuracy can be higher than the invention that does not use the existing spatial structure. When calculating the position based on the actual received signal strength, the position estimation algorithm estimates the position using a signal prediction algorithm such as Ray-Tracing.

In addition to ray tracing, heuristic algorithms for extracting signal strength using spatial information can be used.

The location coordinates of the current mobile node are determined by comparing the signal strength estimated using the prediction algorithm with the signal strength information transmitted through the actual reference node.

Some steps of the invention may be embodied as computer readable code on a computer readable recording medium. A computer-readable recording medium includes all kinds of recording apparatuses in which data that can be read by a computer system is stored. Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, CD-RW, magnetic tape, floppy disk, HDD, optical disk, magneto optical storage, , Transmission over the Internet). The computer readable recording medium can also be distributed over network coupled computer systems so that the computer readable code is stored and executed in a distributed fashion.

As described above, an optimal embodiment has been disclosed in the drawings and specification. Although specific terms have been employed herein, they are used for purposes of illustration only and are not intended to limit the scope of the invention as defined in the claims or the claims. Therefore, those skilled in the art will appreciate that various modifications and equivalent embodiments are possible without departing from the scope of the present invention. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

1 is an exemplary view showing an information transmission flow for position measurement.

2 is a flowchart illustrating a process of a mobile node location recognition method according to the present invention.

3 illustrates an example of RF signal strength estimation according to a reference node.

<Explanation of symbols for the main parts of the drawings>

10: mobile node 20: reference node

30: positioning server 32: communication unit

34: position estimation unit 36: spatial information DB

38: Base node placement information DB

Claims (12)

A plurality of reference nodes periodically receiving a packet from the mobile node and outputting signal strength information; And The location of the mobile node is calculated using signal strength information received from the plurality of reference nodes, and pre-stored spatial information and reference node arrangement information, and the mobile node may be located based on the coordinates of each of the plurality of reference nodes. After selecting the first primary region, the signal strength for each of the plurality of reference nodes is estimated using a position estimation algorithm using the pre-stored spatial information for the primary region, and the estimated signal strength and the plurality of primary regions are estimated. And a positioning server for comparing the signal strength information received from the two reference nodes with each other to determine a position coordinate for the mobile node. The method according to claim 1, A communication unit for receiving signal strength information from the plurality of reference nodes; And And a position estimator configured to calculate a position of the mobile node according to a position estimation algorithm based on the signal strength information, pre-stored spatial information, and arrangement information of the plurality of reference nodes. Device. The method according to claim 2, And the position estimating unit calculates position information of the mobile node using a ray-tracing signal prediction algorithm. The method according to claim 1, And the plurality of reference nodes receive a packet from the mobile node using any one of Bluetooth, RFID, Zigbee, UWB, and wireless LAN. The method according to claim 1, And the plurality of reference nodes and the mobile node transmit and receive data in a wireless communication manner. The method according to claim 1, And the positioning server calculates a position of the mobile node using signal strength information received from three or more reference nodes. The method according to claim 1, When the mobile node requests its location, the positioning server transmits location information to the reference node having the strongest signal strength among the plurality of reference nodes that have received the corresponding signal. Device. Receiving a packet from a mobile node at a plurality of reference nodes; Extracting strengths of signals received at the plurality of reference nodes; Transmitting signal strength information extracted from the plurality of reference nodes to a positioning server; And The location server calculates a location of the mobile node using signal strength information received from the plurality of reference nodes, pre-stored spatial information and reference node arrangement information, and based on the coordinates of each of the plurality of reference nodes. After selecting a primary region in which a mobile node may exist, the signal strength of each of the plurality of reference nodes is estimated using a position estimation algorithm using the pre-stored spatial information for the primary region, and the estimated signal And comparing the strength with signal strength information received from the plurality of reference nodes to determine position coordinates for the mobile node. The method of claim 8, And the positioning server calculates the position of the mobile node when receiving the signal strength information from three or more reference nodes. The method of claim 8, When the mobile node requests its location, the positioning server transmits location information to the reference node having the strongest signal strength among the plurality of reference nodes that have received the corresponding signal. Way. The method of claim 8, And the location server calculates location information of the mobile node using a ray-tracing signal prediction algorithm. The method of claim 8, Receiving a packet from a mobile node at the plurality of reference nodes, A method for recognizing a mobile node location, comprising receiving a packet from the mobile node using any one of Bluetooth, RFID, Zigbee, UWB, and wireless LAN.

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