KR101591566B1 - Position tracking method and apparatus - Google Patents

Abstract

The present invention relates to a method and apparatus for tracking a position using a clustering technique.
According to an exemplary embodiment of the present invention, there is provided a method for tracking a location, comprising: maintaining a database storing a radio wave map and a clustering table including radio signal intensity information by location, wherein the clustering table includes a plurality Wherein the plurality of clusters are mapped to a coverage area corresponding to each cluster; Receiving a radio signal including identification information of a network repeater and a strength of a signal corresponding to the network repeater; Selecting a candidate region matching the received radio signal using the clustering table; And determining a final position using the propagation map in the candidate region.

Description

[0001] POSITION TRACKING METHOD AND APPARATUS [0002]

Field of the Invention [0002] The present invention relates to a method and apparatus for tracking a location, and more particularly, to a method and apparatus for tracking a location using a clustering technique.

Various wireless communication networks utilizing mobile terminals are being developed due to the rapid development of electronic and communication technologies. In the past, a wireless voice call service that provides a voice call to mobile terminal users wirelessly provides a service capable of making a call regardless of time and place, and provides a text message service to complement a voice call service.

Recently, wireless internet service has been started to provide internet communication service to subscribers of mobile communication service due to the development of wireless Internet, and many companies are developing technology for wireless Internet.

On the other hand, among various wireless Internet services using mobile terminals, location based services (LBSs) have been attracting much attention due to their wide applicability and convenience. The location-based service refers to a communication service that grasps the location of the mobile terminal and provides additional information related to the identified location. The location-based services can be classified into four types: location-based CRM, traffic information, vehicle navigation and logistics control, geographical information system (GIS) (Customer Relationship Management).

Korean Patent Laid-Open No. 10-2010-0021747 receives a location request transmitted from a terminal, identifies a service base station and a neighbor base station for the terminal, confirms at least one subway history served by the service base station, The distance to the adjacent base station is calculated and the subway history of the smallest distance value among the calculated distance values is extracted from the selected one or more subway history and the positional value of the extracted subway history is determined as the positioning result value And the like.

However, Korean Patent Laid-Open No. 10-2010-0021747 does not disclose a technique for precise positioning in a device having a limited processing capacity.

Therefore, it is necessary to study the technology for tracking the location of the mobile terminal while reducing the amount of computation in a limited processing capacity environment.

An object of the present invention is to provide a location tracking method and apparatus capable of tracking an accurate location while reducing the amount of computation using a clustering technique.

According to an aspect of the present invention, there is provided a method of controlling a radio communication system, the method comprising: maintaining a database storing a radio wave map and a clustering table, Wherein the plurality of clusters include cluster information for a plurality of clusters to be classified, wherein a coverage region corresponding to each cluster is mapped; Receiving a radio signal including identification information of a network repeater and a strength of a signal corresponding to the network repeater; Selecting a candidate region matching the received radio signal using the clustering table; And determining a final position using the propagation map in the candidate region.

According to an aspect of the present invention, there is provided a database storing a radio wave map and a clustering table including radio signal intensity information by location, wherein the clustering table includes a plurality of Wherein the plurality of clusters includes cluster information for the clusters, wherein the plurality of clusters are mapped to coverage areas corresponding to the clusters; A receiver for receiving a radio signal including identification information of a network repeater and a strength of a signal corresponding to the network repeater; A candidate region selection unit selecting a candidate region matching the received radio signal using the clustering table; A positioning unit for determining a final position in the candidate region using the propagation map; And a controller for controlling the database, the receiving unit, the candidate region selecting unit, and the position determining unit.

According to an aspect of the present invention, there is provided a method of transmitting data to a mobile terminal, the method comprising: receiving data including strength information of a radio signal from a mobile terminal; Generating a clustering table using the received data, wherein the clustering table includes cluster information for a plurality of clusters classified according to the strength of a signal for each network repeater, and the plurality of clusters includes a coverage Region is mapped; Generating a propagation map using the received data; And transmitting the clustering table and the propagation map to the mobile terminal.

The location tracking method and apparatus according to an embodiment of the present invention can perform a location tracking operation only on a candidate region selected using the clustering technique, thereby reducing the amount of calculation at the time of location tracking.

1 is a block diagram of a location tracking device in accordance with an embodiment of the present invention.
2 is a flow chart illustrating a location tracking method in accordance with an embodiment of the present invention.
3 is a diagram for explaining a cluster related to an embodiment of the present invention.
4 is a diagram for explaining a radio map related to an embodiment of the present invention.
5 is a diagram for explaining a clustering technique related to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a location tracking method and apparatus according to an embodiment of the present invention will be described with reference to the drawings.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. In this specification, the terms "comprising ", or" comprising ", etc. should not be construed as necessarily including the various elements or steps described in the specification, Or may be further comprised of additional components or steps.

1 is a block diagram of a location tracking device in accordance with an embodiment of the present invention.

The location tracking apparatus 100 may include a database 110, a receiving unit 120, a candidate region selecting unit 130, a positioning unit 140, and a control unit 150. The location tracking device 100 may be implemented in various forms. For example, the location tracking device 100 may be implemented as a server or a mobile terminal. The mobile terminal described in this specification includes a mobile phone, a smart phone, a notebook computer, a digital broadcasting terminal, a PDA (Personal Digital Assistants), a PMP (Portable Multimedia Player), a navigation device, and a tablet PC.

The database 110 may store a radio map and a clustering table. The propagation map may be a strength map of a radio signal including intensity information of a radio signal by position. That is, it can be said that the signal fingerprint information generated at the subscriber terminal and the location identification information allocated to each place are mapped. Here, the signal fingerprint information may include received signal strength indicator (RSSI) of a radio signal measured by at least one or more network repeaters of the subscriber station and information of a network repeater transmitting the corresponding radio signal.

In addition, the clustering table includes information on a plurality of clusters mapped to at least one network repeater. Examples of the network relays include an access point (AP), a base station (BS), and a signal source. The plurality of clusters may be classified according to the intensity of a radio signal. The plurality of clusters are mapped to coverage areas corresponding to the respective clusters.

The receiving unit 120 may receive a radio signal including identification information of a network repeater and strength of a signal corresponding to the network repeater. The strength of a signal corresponding to the network repeater may include a received signal strength indicator (RSSI).

The candidate region selection unit 130 may select a candidate region matching the received radio signal based on the clustering table. The candidate region may include a candidate region in which the position tracking apparatus can be located.

The positioning unit 140 can determine the final position in which the position-tracking apparatus 100 is positioned using the propagation map in the selected candidate region.

The control unit 150 may control the database 110, the receiving unit 120, the candidate region selecting unit 130, and the positioning unit 140 as a whole.

2 is a flow chart illustrating a location tracking method in accordance with an embodiment of the present invention.

The location tracking method according to an embodiment of the present invention can be classified into a location measurement step using a clustering table, a preparation step for generating a propagation map, and a location of a mobile terminal using a clustering table and a propagation map generated in the preparation step . In this case, in the position measuring step, the mobile terminal can track its position without performing communication with the server.

Hereinafter, a method of tracking the position of the mobile terminal when the position tracking apparatus 100 is a mobile terminal will be described.

First, the preparation step of generating the clustering table and the propagation map will be described.

The mobile terminal can receive the strength information of the radio signal from at least one network repeater (S210). As an example of the strength information of the radio signal, there is a received signal strength indicator (RSSI) measured by at least one network repeater.

The mobile station can generate the clustering table stored in the database 110 and the raw data for generating the propagation map based on the strength information of the received radio signal (S220). The raw data may refer to data before being processed into a clustering table and a propagation map.

When raw data is generated, a clustering table and a propagation map can be generated using the mobile terminal direct raw data, or the mobile terminal can transmit raw data to a server, and the server can generate a clustering table and a propagation map.

First, the server or the mobile terminal can perform clustering using the raw data (S230). The clustering may include generating a plurality of clusters that are classified according to signal strength for a specific network repeater.

For example, the clustering process can be performed as follows.

The clustering range can be determined by checking the distribution of the average (R _V ) of the RSSI values for each MAC (M _I ) at all survey points (P _A ). Wherein in each MAC _(I M) of the average RSSI Value (R _V) it can mean the average (R _V) of the RSSI Value for a particular network repeater.

Clustering range is the minimum value and maximum value of the cluster, and the cluster interval (C _I ) and cluster number (C _N ). The number of clusters (C _N ) can be determined based on the cluster Interval (C _I ).

All irradiation point (P _A) a specific MAC (distribution of the R _{V A} P in) R _VD of (M _I) is received from can be represented by Equation (1).

는 신호강도들의 평균값을 의미한다.Where P _T means all candidate points (P _T : Total Point)

Means the average value of the signal intensities.

는 신호강도들의 평균값을 의미한다.That is, there are a plurality of MACs at all candidate points (P _T : Total Point), and the signal variance of each MAC should be obtained for m MACs. The variance (R _VD ) of the signal means the variance value of the signal intensities (R _V ) of the respective MACs. here

Means the average value of the signal intensities.

R _VD is a range with minimum and maximum values, and C _I can be determined by calculating the value of the signal attenuation per distance. C _I is determined as a representative value, calculate the signal attenuation per distance between each received SP represented by selecting a network repeater to determine the location. Method of Least Squares can be used to view the attenuation trend of the signal. The slope of the trend line obtained by the least squares method is C _I.

In determining, based on the C _{N I} C, for example, the distribution of R _VD If the RSSI from -30 to -100 dBm is C _N of the initial values of median RSSI (R _Mi) of the cluster 7 dogs (-35, - 45, -55, -65, -75, -85, -95 dBm). C _N can be obtained using Equation (2).

However, this trend will depend on the environment. So we can set the size of the cluster differently for each environment by analyzing the signals in this preparation stage.

Based on the clustering range, initial median values of RSSI (RSSI, R _Mi ) can be set. The final median values of RSSI (RSSI, R _Mf ) are generated by performing an expectation-maximization (EM) algorithm based on the set R _Mi , and a cluster can be generated based on the generated R _Mf . R _Mi can be obtained through Equation (3).

The R _Mf of each of the clusters obtained through the EM algorithm can be expressed by Equation (4).

The clustering table can be completed by performing RMf on all candidate points.

By performing the above-described clustering process on all the survey points, the server or the mobile terminal can generate a clustering table (S240).

3 is a diagram for explaining a cluster related to an embodiment of the present invention.

As shown, there may be multiple clusters for a particular network repeater. The plurality of clusters may be distinguished based on signal strength. And the corresponding coverage areas are different for each cluster. Thus, clusters for specific network repeaters matching different locations exist differently.

Next, the server or the mobile terminal can generate a propagation map after arranging the data using the raw data (S250, S260).

4 is a diagram for explaining a radio map related to an embodiment of the present invention. 4 shows a propagation map for a specific network repeater.

As shown in the figure, intensity information of signals of each specific location is mapped to the specific network repeater in the propagation map. Therefore, it is possible to track the position matched to the wireless signal including the network repeater identification information and the intensity of the signal for the network repeater by using the propagation map.

As described above, when the clustering table and the propagation map are generated in the preparation step, the clustering table and the propagation map can be stored in the database 110 of the mobile terminal.

When the clustering table and the propagation map are stored in the database 110 of the mobile terminal, the location of the clustering table and the propagation map can be measured using the radio signal received by the mobile terminal.

First, the mobile terminal receives the radio signal including the identification information of the network repeater and the strength of the signal corresponding to the network repeater, and collects the strength information of the radio signal (S310).

Then, the mobile station can select a candidate region matching the received radio signal using the clustering table (S320).

5 is a diagram for explaining a clustering technique related to an embodiment of the present invention.

The mobile terminal can extract a cluster region for each network repeater corresponding to the received radio signal. In this case, only a predetermined number of network repeaters may be extracted based on the intensity of the radio signal. For example, the mobile terminal may extract only the top three network repeaters.

When the network repeater is extracted, the mobile terminal can extract the cluster region for the extracted network repeater.

When the extracted cluster regions are overlapped, the mobile terminal can extract an overlap region in the extracted cluster region and select a candidate region in the extracted overlap region. In this case, the candidate region may be selected in consideration of the number of overlaps. For example, a region in which all the extracted cluster regions are overlapped may be selected as the candidate region, and an area having the largest number of overlapping regions may be selected as the candidate region. In FIG. 7, the region designated as the candidate region is indicated as "Final Clustered area".

If the candidate region is selected, the mobile terminal can determine the final position of the mobile terminal using the propagation map only within the candidate region (S330). That is, the mobile terminal can perform an operation for final position determination only for a candidate region, without performing an operation for final position determination for an area not selected as a candidate region. By doing so, it is possible to reduce the amount of computation for position tracking.

The location tracking method described above can be implemented in the form of a program command that can be executed through various computer means and recorded on a computer-readable recording medium. At this time, the computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination. On the other hand, the program instructions recorded on the recording medium may be those specially designed and configured for the present invention or may be available to those skilled in the art of computer software.

The computer-readable recording medium includes a magnetic recording medium such as a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as a CD-ROM and a DVD, a magnetic disk such as a floppy disk, A magneto-optical media, and a hardware device specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like.

The recording medium may be a transmission medium such as a light or metal line, a wave guide, or the like including a carrier wave for transmitting a signal designating a program command, a data structure, and the like.

The program instructions also include machine language code, such as those generated by the compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

The above-described position tracking method and apparatus can be applied to a case where the configuration and method of the embodiments described above are not limitedly applied, but the embodiments may be modified such that all or some of the embodiments are selectively combined .

100: Positioning device
110: Database
120: Receiver
130: candidate region selection section
140:
150:

Claims (15)

A method for a location tracking device to track the location of an object terminal,
Maintaining a database in which a propagation map and a clustering table including radio signal strength information are stored for each location, the clustering table including cluster information for a plurality of clusters classified according to signal strength for each network repeater, The cluster of which is mapped to a corresponding coverage area in each cluster);
Receiving a radio signal including identification information of a network repeater and a strength of a signal corresponding to the network repeater;
Selecting a candidate region matching the received radio signal using the clustering table; And
Determining a final position using the propagation map in the candidate region
, ≪ / RTI &
Generating the clustering table prior to the step of maintaining the database,
The step of generating the clustering table
Determining a clustering range based on the cluster information (variance of a signal that is an average distribution of signal intensities for each network repeater at all survey points); And
Creating the cluster based on the clustering range
, ≪ / RTI &
Wherein the clustering range is determined by a min value and a max value of a cluster, an interval of a cluster, and the number of clusters, the number of clusters is determined by dividing the clustering range by an interval of the clusters, Calculating a signal attenuation value per distance from each of the irradiation points received by selecting a network repeater,
The step of creating the cluster
Generating an initial center value for the strength of the signal based on the determined cluster range;
Performing an EM (Expectation Maximization) algorithm on the basis of an initial center value of the strength of the generated signal to generate a final center value for the strength of the signal; And
And generating the cluster based on a final center value of the strength of the generated signal,
The candidate region selection step
Extracting a cluster region for each network repeater corresponding to the received radio signal;
Extracting an overlap region in the extracted cluster region; And
And selecting the candidate region in the overlapping region. delete 2. The method of claim 1, wherein selecting the candidate region in the overlapping region comprises:
The number of times of overlapping is taken into consideration. The method of claim 1, wherein the step of extracting a cluster region for each network repeater comprises:
Extracting a predetermined number of network relays based on the strength of the radio signal; And
And extracting a cluster region for the extracted network repeater. 2. The method of claim 1, wherein the clustering table
Wherein the number of clusters corresponding to the first network repeater and the number of clusters corresponding to the second network repeater are different from each other. 2. The method of claim 1,
Wherein the location tracking is performed at an object terminal where the location is tracked. A database in which a propagation map and a clustering table including radio signal strength information are stored for each location, the clustering table including cluster information for a plurality of clusters classified according to signal strength for each network repeater, A coverage area corresponding to the cluster is mapped);
A receiver for receiving a radio signal including identification information of a network repeater and a strength of a signal corresponding to the network repeater;
A candidate region selection unit selecting a candidate region matching the received radio signal using the clustering table;
A positioning unit for determining a final position in the candidate region using the propagation map; And
And a control unit for controlling the database, the receiving unit, the candidate region selecting unit, and the position determining unit,
The cluster
A clustering range determined based on the cluster information (distribution of a signal, which is an average distribution of signal intensities for each network repeater at all survey points), a signal strength of a signal generated based on the determined cluster range Generating an EM (Expectation Maximization) algorithm based on an initial center value for the intensity and an initial center value for the intensity of the generated signal,
Wherein the clustering range is determined by a min value and a max value of a cluster, an interval of a cluster, and the number of clusters, the number of clusters is determined by dividing the clustering range by an interval of the clusters, Calculating a signal attenuation value per distance from each of the irradiation points received by selecting a network repeater,
The candidate region selection unit
Extracts a cluster region for each network repeater corresponding to the received radio signal, extracts an overlap region in the extracted cluster region, and selects the candidate region in the overlap region. delete 8. The apparatus of claim 7, wherein the candidate region selection unit
Wherein the candidate region is selected in consideration of the number of overlaps. 8. The apparatus of claim 7, wherein the candidate region selection unit
Extracts a predetermined number of network repeaters based on the strength of the radio signal, and extracts a cluster region for the extracted network repeater. 8. The method of claim 7, wherein the clustering table
Wherein the number of clusters corresponding to the first network repeater and the number of clusters corresponding to the second network repeater are different from each other. 8. The apparatus according to claim 7, wherein the position tracking device
And an object terminal to which a position is to be traced. Receiving data including strength information of a radio signal from a mobile terminal;
Generating a clustering table using the received data (the clustering table includes cluster information for a plurality of clusters classified according to signal strength for each network repeater, and the plurality of clusters includes a coverage Area is mapped);
Generating a propagation map using the received data; And
And transmitting the clustering table and the propagation map to the mobile terminal,
The step of generating the clustering table
Determining a clustering range based on the cluster information (variance of a signal that is an average distribution of signal intensities for each network repeater at all survey points); And
Creating the cluster based on the clustering range
, ≪ / RTI &
Wherein the clustering range is determined by a min value and a max value of a cluster, an interval of a cluster, and the number of clusters, the number of clusters is determined by dividing the clustering range by an interval of the clusters, Calculating a signal attenuation value per distance from each of the irradiation points received by selecting a network repeater,
The step of creating the cluster
Generating an initial center value for the strength of the signal based on the determined cluster range;
Performing an EM (Expectation Maximization) algorithm on the basis of an initial center value of the strength of the generated signal to generate a final center value for the strength of the signal; And
And generating the cluster based on a final center value of the strength of the generated signal,
The clustering table
Wherein the number of clusters corresponding to the first network repeater and the number of clusters corresponding to the second network repeater are different from each other. delete delete

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