KR102023030B1 - Magnetic field based indoor positioning method using smart device and system having the method - Google Patents

Abstract

The present invention relates to a magnetic field-based indoor positioning method and system using a smart device, and more particularly, to a smart device capable of positioning through a fingerprint method based on magnetic field information of a magnetic field sensor provided in a smart device of a user indoors. The present invention relates to a magnetic field-based indoor positioning method and system.

Description

Magnetic field based indoor positioning method using smart device and system having the method

The present invention relates to a magnetic field-based indoor positioning method and system using a smart device, and more particularly, to a smart device capable of positioning through a fingerprint method based on magnetic field information of a magnetic field sensor provided in a smart device of a user indoors. The present invention relates to a magnetic field-based indoor positioning method and system.

In order to locate a specific target, a global positioning system (GPS) of the United States is generally used. The GPS receives a signal from a satellite located outside the earth to locate a specific target.

As described above, technologies for positioning specific targets using satellites are called global positioning satellite systems. In addition to US GPS, there are GLONASS in Russia, Galileo in Europe, and BeiDou in China.

The global navigation satellite system has been widely used in military applications, aircraft, ships, etc., but recently, it is also widely used in the civil field, and is mainly used to identify a specific target in an outdoor environment.

Meanwhile, the global navigation satellite system is mainly used in an outdoor environment because when the signal is used in an indoor environment, the signal is not only attenuated by the building but also becomes an obstacle to the signal, so that the size of the signal is changed so that an incorrect signal is received. Because of the multipath fading problem that arises, its use is limited indoors.

In order to solve such a problem, infrastructure-based positioning techniques such as wireless access point (AP), Bluetooth, and RFID are used to locate a specific object indoors.

The infrastructure-based positioning techniques install a device that transmits data such as a wireless access point (AP), Bluetooth or RFID to estimate the location inside a building and estimate the location using signal information received from the device.

In addition, the method for estimating the position is a triangulation method for determining the position by measuring the angle of arrival of the received signal and in advance to store the strength of the received signal at a randomly set position in a given space and compare it with the measured value The fingerprint method of estimating the position is mainly used.

However, the infrastructure-based positioning techniques have a problem in that it is not cost-effective because equipment such as the wireless access point, Bluetooth or RFID must be installed, and the infrastructure-based positioning techniques use devices developed for transmitting data. Because of this, the positioning error is large.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to position indoors without installing a device that generates a separate signal such as a wireless access point (AP), Bluetooth, or RFID in a building. The present invention provides a magnetic field-based indoor positioning method and system using a smart device.

In order to solve the above-described object, the present invention collects three-axis magnetic field data (hereinafter referred to as 'offline data') at a plurality of positions (hereinafter referred to as 'reference positions') within a location for positioning to generate a fingerprint map. Building; Acquiring three-axis magnetic field data (hereinafter, referred to as 'online data') outputted from the smart device at a location where the smart device is located in the place; And positioning a reference location having the smallest difference between the offline data and the online data as the location of the smart device in the fingerprint map. do.

In a preferred embodiment, the fingerprint map stores location information of the reference locations.

In a preferred embodiment, the triaxial magnetic field data of the offline data is obtained with respective triaxial magnetic field data for the 0 degree, 90 degree, 180 degree and 270 degree directions at each reference position.

In a preferred embodiment, the offline data further includes the magnetic field strength calculated from the three-axis magnetic field data of the offline data, the online data further includes the magnetic field strength calculated from the three-axis magnetic field data of the online data.

In a preferred embodiment, the positioning step comprises: calculating a difference between the offline data and the online data; Obtaining a mean square root error from the calculated difference; And outputting location information of a reference location having offline data having the smallest mean square root error in the fingerprint map.

In addition, the present invention further provides a computer program stored in a recording medium for performing a magnetic field-based indoor positioning method using the smart device.

The present invention also provides a smart device in which the computer program is stored.

In addition, the present invention server; And a smart device capable of transmitting and receiving three-axis magnetic field data to and from the server, wherein the server receives the three-axis magnetic field data in real time from the smart device, calculates a difference between the online data and the offline data to locate the smart device. It further provides a magnetic field-based indoor positioning system using a smart device capable of outputting.

The present invention also provides a smart device that stores the computer program; And a server storing offline data, wherein the smart device communicates with the server to receive offline data, calculates a difference between the offline data and online data, and outputs the location of the smart device. It further provides a magnetic field-based indoor positioning system.

According to the magnetic field-based indoor positioning method and system using the smart device of the present invention, since the location can be estimated using only the magnetic field sensor provided in the smart device, the infrastructure for installing signals for location tracking is installed in the room. The advantage is that you do not need to build a.

In addition, the present invention obtains three-axis magnetic field data of the offline data in the 0 degree, 90 degree, 180 degree and 270 degree direction and compares the position with the 3-axis magnetic field data output from the smart device and the difference Positioning can minimize positioning error even when using 3-axis magnetic field data measured differently according to directions.

1 shows a system according to an embodiment of the invention,
2 is a flowchart illustrating a magnetic field-based indoor positioning method using a smart device according to an embodiment of the present invention;
3 is a diagram for describing a fingerprint map operation according to an embodiment of the present invention;
4 is a graph illustrating a performance comparison result between a magnetic field-based indoor positioning method and a conventional infrastructure-based positioning method using a smart device according to an embodiment of the present invention.

The terms used in the present invention were selected as general terms as widely used as possible, but in some cases, the terms arbitrarily selected by the applicant are included. In this case, the meanings described or used in the detailed description of the present invention are considered, rather than simply the names of the terms. The meaning should be grasped.

Hereinafter, with reference to the preferred embodiments shown in the accompanying drawings will be described in detail the technical configuration of the present invention.

However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Like numbers refer to like elements throughout the specification.

Magnetic field-based indoor positioning method using a smart device according to an embodiment of the present invention is a method for positioning the location of the smart device in the room using the magnetic field information output from the magnetic field sensor provided in the smart device.

In addition, the magnetic field-based indoor positioning method using a smart device according to an embodiment of the present invention is performed by a computer, the computer program for performing the magnetic field-based indoor positioning method using a smart device by operating the computer Stored.

In addition, the computer refers to a broad computing device including not only a general personal computer but also a smart device such as a smartphone or a tablet PC.

In addition, the computer program may be stored and provided in a separate recording medium, and the recording medium may be those specially designed and configured for the present invention or may be known and available to those skilled in the computer software field. .

For example, the recording medium may be magnetic media such as hard disks, floppy disks and magnetic tape, optical recording media such as CDs and DVDs, magnetic-optical recording media capable of both magnetic and optical recording, ROM, RAM, flash memory. Etc. may be a hardware device specifically configured to store and execute program instructions, alone or in combination.

Further, the computer program may be a computer program composed of program instructions, local data files, local data structures, etc. alone or in combination, and may be executed by a computer using an interpreter as well as machine code such as produced by a compiler. It can be a computer program written in high-level language code.

In addition, the computer program may be stored in a server capable of transmitting the computer program via a communication network.

1 is a diagram illustrating a magnetic field-based indoor positioning system using a smart device according to an embodiment of the present invention. Referring to FIG. 1, a magnetic field-based indoor positioning system 100 using a smart device of the present invention is smart. The device 110 and the smart device 110 and the server 120 is connected through a communication network.

The computer program may be stored in the smart device 110 or in the server 120.

If the computer program is stored in the smart device 110, offline data to be described below is stored in the server 120, and the smart device 110 receives the offline data from the server 120. The location of the smart device 110 may be received by the reception.

However, the offline data may be stored in the smart device 110, and in this case, the location may be determined only by the smart device 110 without requiring the server 120.

In addition, when the computer program is stored in the server 120, the server 120 may receive the 3-axis magnetic field data from the smart device 110 to position the smart device 110, positioning The result may be transmitted to the smart device 110.

Hereinafter, a method of positioning a location based on a magnetic field using a smart device according to an embodiment of the present invention will be described in detail with reference to FIG. 2.

Referring to FIG. 2, in the magnetic field-based indoor positioning method using a smart device according to an embodiment of the present invention, a fingerprint map may be largely constructed (S1000), a three-axis magnetic field data acquisition step (S2000) output from the smart device, and Positioning the location of the smart device (S3000) is made.

In the building of the fingerprint map (S1000), first, 3-axis magnetic field data is collected using a smart device at a plurality of locations (hereinafter, referred to as a reference location) of a location for positioning (S1100).

In addition, since the value of the three-axis magnetic field data varies depending on the measured direction even at the same position, the three-axis magnetic field data is acquired in four directions, 0 degrees, 90 degrees, 180 degrees, and 270 degrees, for each reference position.

Next, the magnetic field strength is obtained from the acquired three-axis magnetic field data using the following equation (S1200).

Here, M _A is magnetic field strength, m _x is x-axis magnetic field data, m _y is y-axis magnetic field data m _z is z-axis magnetic field data.

The magnetic field strength is a value that is additionally calculated to improve positioning accuracy, and the positioning may be performed using only the three-axis magnetic field data without calculating the magnetic field strength.

However, it is preferable to use the magnetic field strength to improve the positioning accuracy.

Next, a fingerprint map is generated using the three-axis magnetic field data and the magnetic field data (hereinafter, referred to as 'offline data') (S1300).

Here, the fingerprint map is an operation of generating an indoor map map divided into a predetermined size, and databaseting the previously collected fingerprint and the collected location information. In the present invention, the fingerprint means the offline data.

In addition, the fingerprint map stores location information for representing the reference locations for collecting the offline data on the indoor map map.

Accordingly, the fingerprint map may be databased as shown in Table 1 to construct the fingerprint map.

number
Reference location
direction x-axis magnetic field (m _x ) y-axis magnetic field (m _y ) z-axis magnetic field (m _z ) magnetic field
Century (M _A )

One

x1, y1
0 degrees 30 100 -10 105 90 degrees -20 140 13 142 180 degrees -20 -110 50 122 270 degrees 110 90 60 154

2

x2, y2 0 degrees -50 110 42 127 90 degrees -80 12 77 112 180 degrees 36 -123 89 156 270 degrees 41 -45 68 91 .
.
. .
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

That is, the fingerprint map may output a reference position, which is a location of offline data collected on an indoor map map divided into a predetermined size.

After constructing the fingerprint map, a step of acquiring three-axis magnetic field data output from a smart device at an arbitrary location in the place is performed (S2000).

First, three-axis magnetic field data output from the smart device is acquired (S2100).

Next, after acquiring the three-axis magnetic field data, the magnetic field strength is calculated using Equation 1 (S2200).

If the magnetic field strength is not included in the offline data, the magnetic field strength may not be calculated from the 3-axis magnetic field data output from the smart device.

Next, after acquiring the three-axis magnetic field data and the magnetic field strength (hereinafter referred to as 'online data') output from the smart device at an arbitrary position in the place, the online data and the offline data in the fingerprint map. In step S3000, the reference location having the smallest difference in data is positioned as the location of the smart device.

In step S3000, the location of the smart device is first calculated in operation S3100.

Next, the root mean square error (RMSE) is calculated from the calculated difference using the following equation (S3200).

는 상기 j번째 참조 위치에 해당하는 k번째 방향의 오프라인 데이터의 x축 자기장과 온라인 데이터의 x축 자기장 간의 차,

는 상기 j번째 참조 위치에 해당하는 k번째 방향의 오프라인 데이터의 y축 자기장과 온라인 데이터의 y축 자기장 간의 차,

는 상기 j번째 참조 위치에 해당하는 k번째 방향의 오프라인 데이터와 온라인 데이터의 z축 자기장 간의 차,

는 상기 j번째 참조 위치에 해당하는 k번째 방향의 오프라인 데이터의 자기장 세기와 온라인 데이터의 자기장 세기 간의 차, N은 측정된 방향의 총 개수를 의미한다.Here, D _j is the mean square root error between the offline data and the online data of the j th reference location,

Is the difference between the x-axis magnetic field of the offline data in the k-th direction corresponding to the j-th reference position and the x-axis magnetic field of the online data,

Is a difference between the y-axis magnetic field of the offline data in the k-th direction corresponding to the j-th reference position and the y-axis magnetic field of the online data,

Is the difference between the z-axis magnetic field of the offline data and the online data in the k-th direction corresponding to the j-th reference position,

Is a difference between the magnetic field strength of the offline data in the k-th direction corresponding to the j-th reference position and the magnetic field strength of the online data, and N denotes the total number of measured directions.

가 포함되어 계산되었으나, 상기

,

,

만으로 평균 제곱근 오차 계산이 가능하다.Meanwhile, in Equation 2, the difference between the magnetic field strength of the offline data and the magnetic field strength of the online data is calculated to obtain the mean square root error.

Was calculated to include, but

,

,

Only the root mean square error can be calculated.

를 포함하여 계산하는 것이 바람직하다.However, in order to improve the positioning accuracy

It is preferable to calculate including.

Next, the position of the reference location having the smallest mean square root error in the fingerprint map is output (S3300).

FIG. 3 is a diagram for describing an operation of a fingerprint map according to an embodiment of the present invention. Referring to FIG. 3, the fingerprint map includes a plurality of reference positions in an indoor map map s divided into a predetermined size. a ₁ , ... a _n ) exist and each reference position is measured and mapped to offline data in four directions (0 degrees, 90 degrees, 180 degrees, 270 degrees).

If the on-line data is acquired at the location (b) where the smart device is located, the fingerprint map (the reference map having the lowest mean square root error calculated between the off-line data and the on-line data in the fingerprint map s) may be used. search and print from s).

FIG. 4 shows performance comparison results between a magnetic field-based indoor positioning method using a smart device and a conventional infrastructure-based positioning method using a smart device according to an embodiment of the present invention.

Referring to FIG. 4, an experiment was conducted in an indoor corridor and a laboratory, and comparing the positioning error between the conventional infrastructure-based positioning technology and the magnetic field-based indoor positioning method using the smart device of the present invention, the infrastructure-based positioning It can be seen that simple and effective positioning is possible without greater complexity than technology.

Therefore, the magnetic field-based indoor positioning method using the smart device of the present invention has the advantage that it is possible to position the location using only the smart device without installing an infrastructure by installing a separate signal generator device for indoor positioning.

In addition, the magnetic field-based indoor positioning method using the smart device of the present invention obtains three-axis magnetic field data and magnetic field strengths in four directions when offline data acquisition and positioning the position by comparing with the offline data measured values according to the direction Even using this varying 3-axis magnetic field data, positioning errors can be minimized.

As described above, the present invention has been illustrated and described with reference to preferred embodiments, but is not limited to the above-described embodiments, and is provided to those skilled in the art without departing from the spirit of the present invention. Various changes and modifications will be possible.

100: indoor positioning system 110: smart equipment
120: server

Claims (9)

3-axis magnetic field data and magnetic field strength (hereinafter referred to as 'offline data') measured while looking in the 0, 90, 180, and 270 degree directions at multiple locations of the location for positioning (hereinafter referred to as 'reference position') Collecting and constructing a fingerprint map;
Acquiring three-axis magnetic field data and magnetic field strength (hereinafter referred to as 'online data') output from the smart device at any location within the place; And
Positioning a reference location having the smallest difference between the offline data and the online data as the location of the smart device in the fingerprint map;
Positioning step:
Calculating a difference between the offline data and the online data;
Obtaining a mean square root error from the calculated difference; And
And outputting, to the location of the smart device, a reference location having offline data having the smallest mean square root error in the fingerprint map.
The mean square root error is calculated by the following Equation 1 magnetic field-based indoor positioning method using a smart device.
[Equation 1]

D _j is the mean square root error between the offline data and the online data of the jth reference position,

Is the difference between the x-axis magnetic field of the offline data in the k-th direction corresponding to the j-th reference position and the x-axis magnetic field of the online data,

Is a difference between the y-axis magnetic field of the offline data in the k-th direction corresponding to the j-th reference position and the y-axis magnetic field of the online data,

Is the difference between the z-axis magnetic field of the offline data and the online data in the k-th direction corresponding to the j-th reference position,

Is a difference between the magnetic field strength of the offline data in the k-th direction corresponding to the j th reference position and the magnetic field strength of the online data,
N means the total number of measured directions. The method of claim 1,
Magnetic location-based indoor positioning method using a smart device, characterized in that the location information of the reference location is stored in the fingerprint map. A computer program stored in a recording medium for performing a magnetic field-based indoor positioning method using a smart device according to any one of claims 1 to 2. Smart device having the computer program of claim 3 stored. A server storing the computer program of claim 3; And
Includes; smart device capable of transmitting and receiving three-axis magnetic field data with the server,
The server receives the real-time three-axis magnetic field data from the smart device, calculates the difference between the online data and offline data and outputs the location of the smart device, characterized in that the magnetic device based indoor location using a smart device. The smart device of claim 4; And
A server storing offline data;
And the smart device communicates with the server to receive offline data, calculates a difference between the offline data and the online data, and outputs the location of the smart device. delete delete delete

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