KR102157391B1 - Position recognition apparatus and method of indoor position system - Google Patents

Abstract

The present technology discloses a location recognition apparatus and method for an indoor positioning system. According to a specific example of the present invention, by applying a clamping technique that removes an RSSI value out of a threshold range among the RSSI values included in the received signal of the beacon, the measurement time and the number of times of the received signal of the beacon can be reduced, and thus the system operation It can reduce complexity and load. In addition, according to the present embodiment, as the attenuation constant applied when predicting a location between a beacon and a user is differently set for each section as the remaining RSSI value, an average error between the beacon and the user may be reduced, thereby improving the accuracy of the user location prediction.

Description

Location recognition device and method of indoor positioning system {POSITION RECOGNITION APPARATUS AND METHOD OF INDOOR POSITION SYSTEM}

The present invention relates to an apparatus and method for recognizing a location of an indoor positioning system, and more particularly, to reduce an average error of a received signal strength indication (RSSI) value of a received signal of each beacon to improve the accuracy of user location prediction of an indoor positioning system. It's about a technology that can be fundamentally improved.

Recently, there is an increasing effort and tendency to increase the convenience of consumers by providing various customized services using the user's location information indoors, and for this purpose, various studies on indoor location measurement are being conducted.

In addition, in the virtual reality (VR) industry as well as a location based service, a method of accurately calculating the location of a user is required from various aspects as the range of use of location information is expanded.

In general, since the user location estimation system was a service limited to outdoors using a GPS (Global Positioning System), it is essential to construct an indoor positioning system using a wireless transmitter capable of receiving indoors.

However, in the indoor positioning system based on the transmission signal of these wireless transmitters, if the propagation path between the transceivers is not in a free space, the problem of the accuracy of the user's location estimation due to path attenuation when the propagation path between the transceivers is obscured by an obstacle or collides with an irregular surface. Occurs.

Accordingly, the applicant intends to propose a method of improving accuracy in estimating a user location using a received signal strength indication (RSSI) value provided from each beacon.

The present invention was conceived to solve all the problems of the prior art, and an object of the present invention is to receive a beacon by applying a clamping technique that removes an RSSI value out of a predetermined threshold range among RSSI values included in a received signal of a beacon. It is intended to provide an apparatus and method for recognizing a location of an indoor positioning system that can reduce the measurement time and number of signals and thus reduce the computational complexity and load of the system.

Another object of the present invention is to reduce the average error of the distance between the beacon and the user, thereby reducing the average error of the distance between the beacon and the user by setting different attenuation constants applied when predicting the user's location using the remaining RSSI values after removing the RSSI out of the threshold range. It is to provide an apparatus and method for recognizing a location of an indoor positioning system that can improve accuracy.

The object of the present invention is not limited to the above-mentioned object, and other objects and advantages of the present invention that are not mentioned can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. In addition, it will be easily understood that the objects and advantages of the present invention can be realized by means and combinations thereof indicated in the claims.

A location recognition apparatus for an indoor positioning system according to an embodiment of the present invention for achieving the above object,

A plurality of beacons installed at predetermined locations indoors; And

Including a receiver for predicting the user location by the RSSI value for the received signal of each beacon,

The receiver

An RSSI derivation unit for receiving an RSSI (Received Signal Strength Indication) value for the received signal supplied from each beacon; A filter unit configured to remove an RSSI value out of a threshold range from among each RSSI value and output a remaining RSSI value; And a location recognition unit that predicts a user location using an RSSI value and an attenuation constant of the filter unit.

Preferably, the critical range of the filter unit is

After approximating a plurality of RSSI values by a Laplacian Gaussian operation, a normalization graph may be derived through normalization, and a threshold range may be set with a predetermined reliability among the derived normalization graphs.

Preferably the receiver

After deriving the RSSI value of the filter unit and the root mean square error (RMSE) for each distance, a linear relational expression for the derived root mean square error is derived, and at least one inflection point is a distance from the derived linear relational expression. It may further include an attenuation constant deriving unit that sets as a reference point for, determines an attenuation constant before the set reference point and an attenuation constant after the reference point, and transfers the determined attenuation constant to the position recognition unit.

A method of recognizing a location of an indoor positioning system according to another embodiment of the present invention,

An RSSI derivation step of receiving an RSSI (Received Signal Strength Indication) value for a received signal supplied from each beacon in the RSSI derivation unit and transmitting a plurality of received RSSI values to the filter unit; A filtering step of removing an RSSI value out of a threshold range from among each RSSI value and transmitting the remaining RSSI value to a location recognition unit; And a location prediction step of predicting a user location using an RSSI value of the filter unit and a set attenuation constant in the location recognition unit.

Preferably the critical range is

After approximating a plurality of RSSI values by a Laplacian Gaussian operation, a normalization graph may be derived through normalization, and a threshold range may be set with a predetermined reliability among the derived normalization graphs.

Preferably the location recognition method,

After the filtering step, an RSSI value and a root mean square error (RMSE) are derived for each distance, and then a linear relational expression for the derived root mean square error is derived, and at least one inflection point in the derived linear relational expression A step of deriving an attenuation constant of setting as a reference point for a distance, determining an attenuation constant before the set reference point and an attenuation constant after the reference point, and transferring the determined attenuation constant to the position recognition unit may be further included.

According to the present invention, by applying a clamping technique that removes the RSSI value out of the threshold range among the RSSI values included in the received signal of the beacon, it is possible to reduce the measurement time and frequency of the received signal of the beacon, thereby reducing the computational complexity and load of the system. Can be reduced. In addition, according to the present embodiment, as the attenuation constant applied when predicting the distance between the beacon and the user is different for each section as the remaining RSSI value, the average error of the distance between the beacon and the user may be reduced, thereby improving the accuracy of the user location prediction.

The following drawings appended in the present specification illustrate preferred embodiments of the present invention, and serve to further understand the technical idea of the present invention together with the detailed description of the present invention to be described later, so the present invention is described in such drawings. It is limited only to and should not be interpreted.
1 is a diagram showing the configuration of a location recognition system according to the present embodiment.
2 is a detailed configuration diagram of a receiver of the system according to this embodiment.
3 is a graph showing attenuation constants of the system of this embodiment.
4 to 5 are diagrams showing an indoor beacon layout according to the present embodiment.

Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the drawings.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described later together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in a variety of different forms, only the present embodiments are intended to complete the disclosure of the present invention, and the general knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have it, and the invention is only defined by the scope of the claims.

The terms used in the present specification will be briefly described, and the present invention will be described in detail.

The terms used in the present invention have been selected from general terms that are currently widely used while considering functions in the present invention, but this may vary depending on the intention or precedent of a technician working in the field, the emergence of new technologies, and the like. In addition, in certain cases, there are terms arbitrarily selected by the applicant, and in this case, the meaning of the terms will be described in detail in the description of the corresponding invention. Therefore, the terms used in the present invention should be defined based on the meaning of the term and the overall contents of the present invention, not a simple name of the term.

When a part of the specification is said to "include" a certain component, it means that other components may be further included rather than excluding other components unless otherwise stated. In addition, the term "unit" used in the specification refers to a hardware component such as software, FPGA, or ASIC, and "unit" performs certain roles. However, "unit" is not meant to be limited to software or hardware. The “unit” may be configured to be in an addressable storage medium or may be configured to reproduce one or more processors.

Thus, as an example, "unit" refers to components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, Includes subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, database, data structures, tables, arrays and variables. The functions provided within the components and "units" may be combined into a smaller number of components and "units" or may be further separated into additional components and "units".

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art may easily implement the present invention. In addition, in the drawings, parts not related to the description are omitted in order to clearly describe the present invention.

Hereinafter, power according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram showing the configuration of a location recognition system according to an embodiment of the present invention, and referring to FIG. 1, a location recognition system S according to an embodiment of the present invention includes a received signal strength (RSSI) of a received signal of a beacon. Indication) may be provided to predict the indoor location based on the value, and thus the system S may include a plurality of beacons 10 and receivers 20.

A plurality of beacons 10 are installed at different locations indoors, respectively, and include a received signal strength indicator (RSSI). Here, the RSSI (Received Signal Strength Indicator) transmits the strength of the radio wave from each beacon to the receiver 20 according to the distance, and the receiver 20 derives the distance between the beacon 10 and the user location based on the received RSSI value. .

In the present invention, for convenience of explanation, it may be provided as a low-power Bluetooth (BLE) beacon, and may be provided in various forms, such as a beacon using ultrasonic waves, visible light, etc., and an RF beacon of various frequency bands, but is not limited thereto.

On the other hand, low-power Bluetooth (BLE) is an ultra-low-power short-range wireless personal communication network technology, and can be manufactured with ultra-low-power and ultra-small modules, and thus Bluetooth 4.0 can be supported. The application range is less than 50m and has the advantage of providing location-based services with low power. Here, the transmission device of the low-power Bluetooth beacon performs only an advertising function of loading and transmitting data as small as 31 bytes.

On the other hand, the receiver 20 is a beacon 10 through a wireless network built in accordance with the execution of the installed app and an app for searching a wireless network built including a plurality of beacons 10 to a terminal possessed by the user. It may be provided to derive the RSSI value of the received signal provided from.

FIG. 2 is a diagram showing a detailed configuration of the receiver 20 of FIG. 1, and the receiver 20 of the present embodiment includes an RSSI receiver 210, a filter unit 230, an attenuation constant derivation unit 250, and position recognition. It may include a unit 250.

Here, the RSSI receiving unit 210 derives an RSSI value for the received signal supplied from each beacon 10 and then the derived RSSI value of each beacon 10 is transmitted to the filter unit 230.

The filter unit 230 approximates a statistical distribution of a plurality of received RSSI values with a Gaussian (G) operation value, and then normalizes it to set a threshold range with a predetermined reliability for the normalization result. For example, if the reliability of the normalization result is 90%, the RSSI value of the upper and lower 10% is determined as noise.

Accordingly, the RSSI value outside the predetermined threshold range is removed.

는 다음 식 1를 만족한다.That is, a predetermined threshold range for the RSSI value out of the threshold range

Satisfies Equation 1 below.

[Equation 1]

은 RSSI 값의 평균이고 σ는 RSSI 값의 표준편차이다.here,

Is the mean of the RSSI values and σ is the standard deviation of the RSSI values.

That is, the filter unit 230 removes an RSSI value that distorts the average value of a plurality of RSSI values by applying a clipping technique that removes an RSSI value that does not exist in the threshold range. Accordingly, the present embodiment can reduce the number of calculations and calculation time for deriving the average of the RSSI values, thereby improving reliability.

는 거리 별 RSSI 값의 평균 누적 시 신뢰도가 설정 범위 내에 존재하는 값으로 설정되며, 보통 실내 환경에서는 가중치

의 설정 범위 내에 존재하는 하나의 값으로 결정된다.Where, the weight

Is set to a value within which the reliability is within the set range when the average of RSSI values for each distance is accumulated.

It is determined as one value that exists within the set range of.

In addition, a plurality of RSSI values that have passed through the filter unit 230 are transmitted to the attenuation constant calculating unit 250.

The RSSI value for the received signal of each beacon 10 is derived from the following equation (2).

[Equation 2]

Here, n is an attenuation constant in the indoor space, and A is an RSSI value measured when the distance between each beacon 10 and an object is 1 m. Here, A is set as the average value of RSSI values received for each beacon 10 in units of 1m distance.

In addition, the attenuation constant n is determined as a representative value derived using a linear curve fitting method that minimizes the actually measured attenuation constant value and their root mean square error (RMSE) when measuring the RSSI value for each distance.

를

로 치환하여 정리하면 식 2는 다음과 식 3으로 정리된다. That is, in Equation 1

To

Equation 2 is summarized by the following equation 3.

[Equation 3]

에 대한 1차 리니어 함수로 나타내며, 선형 곡선 피팅 방식은 변수

에 대한 1차 리니어 함수의 선형 곡선으로 감쇄 상수 n이 결정된다.Here, Equation 3 is a variable

Is expressed as a linear function of

The attenuation constant n is determined by the linear curve of the linear function of

에 대한 선형 곡선으로 결정된 감쇄 상수 n에 의거 도출된다.FIG. 3 is a diagram showing the distance (d) between the beacon and the user derived based on the attenuation constant n determined by a linear curve. Referring to FIG. 3, it can be seen that an error of the attenuation constant n occurs according to the distance between the beacon and the user. have. At this time, the distance is the measured distance and variable between the beacon and the user.

It is derived based on the attenuation constant n determined by a linear curve for.

Accordingly, the attenuation constant derivation unit 250 derives a root mean square error (RMSE) for the attenuation constant n derived from the measured distance between the beacon and the user and a representative value derived from the average of a plurality of RSSI values, The distance value at which the derived root mean square error is minimized is set as a reference point, and two attenuation constants n1 and n2 are derived from two linear curves inflection at the set reference point.

For example, the root mean square error (RMSE) for each distance d of 3m, 4m, and 5m is shown in Table 1 below, and based on this, the attenuation constant n derived for the distance between the beacon 10 and the user 8m is shown in FIG. As shown in, the 3m reference point is applied differentially.

[Table 1]

In this embodiment, as shown in Figure 3, Inflection In the case of one time, two attenuation constants for distance may be derived differently, but the present invention is not limited thereto.

Example

4 is a diagram showing a state in which the beacons 10 are installed at equal intervals in a 7mx7m open space, and FIG. 5 is a diagram showing a state in which the beacons 10 are installed at equal intervals in a 6mx6m closed space. As shown in FIGS. 4 and 5, in this embodiment, an inner square separated by 1m from the beacon 10 installed at equal intervals is defined as an inner measurement area (area a), and the rest area except for the measurement area A is measured at an edge. It is set as an area b, and the transmission power of the beacon 10 used for measurement is set to 0 [dBm], and the transmission period is set to 250 [ms].

And, the attenuation constant is set as shown in Table 2.

[Table 2]

In addition, the A values in Equation 3 of the eight beacons 10 installed in the open space of FIG. 4 are measured as 64.95, 65.95, 60, 64.83, 61.89, 67.01, 66.14, and 64.54, respectively, and installed in the closed space of FIG. The values of A in Equation 3 of the eight beacons 10 are measured as 59.9, 67.38, 69.97, 64.26, 62.12, 67.3, 66.26, and 65.34, respectively.

Table 3 shows the distance error average (Suggested Method A) derived after removing noise from the RSSI values received in each of FIGS. 4 and 5 and the distance error average derived without removing noise from the received RSSI values (Existing Method A). And Table 4, and referring to Table 3, it can be seen that the proposed method is improved by 6.13% in the open space compared to the conventional method by comparing the average of the two distance errors. Referring to Table 4, the average of the two distance errors Compared to the previous method, it can be seen that the proposed method is improved by 27.56% in a closed space.

[Table 3]

[Table 4]

In addition, the distance error average (suggested method B) derived from two attenuation constants n1 and n2 centered on the reference point and the RSSI value from which noise components are removed among the plurality of RSSI values in each of FIGS. 4 and 5, and the received The distance error average (conventional method B) derived using the RSSI value and one attenuation constant n is as shown in Tables 5 and 6, and referring to Table 5, the proposed method is compared with the average of the two distance errors. It can be seen that the improvement is 36.79% in the open space compared to the existing method. Also, referring to Table 6, it can be seen that the proposed method is improved by 43.83% in a closed space compared to the existing method.

[Table 5]

[Table 6]

Accordingly, in the present embodiment, in the case of the proposed method A, which removes the RSSI value out of the threshold range among the RSSI values received from each beacon 10 in the open space and closed space modes, and then accumulates the average, the average distance error is reduced compared to the conventional method A. can confirm.

In addition, the present embodiment is a proposed method of deriving the distance (d) between the beacon 10 and the user using two attenuation constants n1 and n2 around the reference point for the remaining RSSI values after removing the RSSI value outside the threshold range. In the case of B, the improvement rate for the average error between the measured distance and the predicted distance is further increased compared to the conventional method B.

In addition, referring to Tables 3 and 4, since the noise of the RSSI value generated by the influence of the reflected wave generated at the corner in the open space is small, the average between the inner measurement area (area a) and the corner measurement area (area b) There is no difference in improvement rate for error.

However, in the case of the closed space, the noise of the RSSI value generated by the influence of the reflected wave at the corner is relatively larger than that of the open space, so that the improvement rate for the average error between the inner measurement area (area a) and the corner measurement area (area b) is high. I can.

On the other hand, referring to Tables 5 and 6, since the average error is large in 1 to 3 m in both the closed space or the open space, the attenuation constant n is set by dividing the attenuation constant from 1 to 3 m into 4 to 8 m. It can be seen that the improvement rate of the average error in the section is greatly improved.

Accordingly, in this embodiment, by applying a clamping technique that removes the RSSI value out of the threshold range among the RSSI values included in the received signal of the beacon, it is possible to reduce the measurement time and the number of times of the received signal of the beacon, thereby reducing the computational complexity and load of the system. Can be reduced. In addition, according to the present embodiment, as the attenuation constant applied when predicting a location between a beacon and a user is set differently for each section as the remaining RSSI value, an average error of the distance between the beacon and the user may be reduced, thereby improving the accuracy of the user location prediction.

According to another embodiment of the present invention, a method for recognizing a location of an indoor positioning system includes receiving an RSSI (Received Signal Strength Indication) value for a received signal supplied from each beacon in an RSSI derivation unit, and using a plurality of received RSSI values as a filter unit. A step of deriving RSSI to be delivered; A filtering step of removing an RSSI value out of a threshold range from among each RSSI value and transmitting the remaining RSSI value to a location recognition unit; And a position prediction step of predicting a user position using an RSSI value of the filter unit and a set attenuation constant in the position recognition unit, wherein the threshold range is approximated by a Laplacian Gaussian operation for a plurality of RSSI values, and then a normalization graph is derived through normalization. Then, the threshold range is set with a predetermined reliability among the derived normalization graphs, and after the filter step, the RSSI value and the root mean square error (RMSE) for each distance are derived, and then the derived root mean square error is linear. An attenuation constant that derives a relational expression, sets an inflection point as a reference point for distance from the derived linear relational expression, determines the attenuation constant before the set reference point and the attenuation constant after the reference point, and transfers the determined attenuation constant to the position recognition unit. It is provided to further include a derivation step, and each step of the user location recognition process is performed by the aforementioned RSSI derivation unit 210, filter unit 230, attenuation constant derivation unit 250, and location recognition unit 270. As a function to be used, detailed reference is omitted.

Therefore, by applying the clamping technique to remove the RSSI value out of the threshold range among the RSSI values included in the received signal of the beacon, it is possible to reduce the measurement time and frequency of the received signal of the beacon, thereby reducing the computational complexity and load of the system. have. In addition, according to the present embodiment, as the attenuation constant applied when predicting a location between a beacon and a user is differently set for each section as the remaining RSSI value, an average error between the beacon and the user may be reduced, thereby improving the accuracy of the user location prediction.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description to those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved. Therefore, the scope of the present invention is limited to the described embodiments and should not be defined, but should be defined by the claims to be described later, as well as those equivalent to the claims.

By applying a clamping technique that removes the RSSI value out of the threshold range among the RSSI values included in the received signal of the beacon, it is possible to reduce the measurement time and the number of times of the received signal of the beacon, thereby reducing the computational complexity and load of the system. In addition, in the present embodiment, as the attenuation constant applied when predicting the location between the beacon and the user is set differently for each section, as the remaining RSSI value, the indoor that can improve the accuracy of the user location prediction by reducing the average error of the distance between the beacon and the user. The accuracy and reliability of operation of the location recognition device and method of the positioning system, and furthermore, can bring a great progress in terms of performance efficiency, and the possibility of marketing or sales of a system that provides services based on the Internet of Things is sufficient. It is an invention that has industrial applicability because it can be implemented clearly in reality.

Claims (5)

A plurality of beacons installed at predetermined locations indoors; And
Including a receiver for predicting the user location by the RSSI value for the received signal of each beacon,
The receiver
An RSSI derivation unit for receiving an RSSI (Received Signal Strength Indication) value for the received signal supplied from each beacon; A filter unit configured to remove an RSSI value out of a threshold range from among each RSSI value and output a remaining RSSI value; And a location recognition unit that predicts a user location using an RSSI value and an attenuation constant of the filter unit,
After deriving the RSSI value of the filter unit and the root mean square error (RMSE) for each distance, a linear relational expression for the derived root mean square error is derived, and at least one inflection point is a distance from the derived linear relational expression. Position recognition of an indoor positioning system, characterized in that it further comprises an attenuation constant derivation unit that sets as a reference point for, determines an attenuation constant before the set reference point and an attenuation constant after the reference point, and transfers the determined attenuation constant to the position recognition unit. Device. The method of claim 1, wherein the critical range of the filter unit is
A location recognition device for an indoor positioning system, characterized in that after approximating a plurality of RSSI values by a Laplacian Gaussian operation, a normalization graph is derived through normalization, and a threshold range is set with a predetermined reliability among the derived normalization graphs. delete An RSSI derivation step of receiving an RSSI (Received Signal Strength Indication) value for a received signal supplied from each beacon in the RSSI derivation unit and transmitting a plurality of received RSSI values to the filter unit;
A filtering step of removing an RSSI value out of a threshold range from among each RSSI value and transmitting the remaining RSSI value to a location recognition unit; And
Including a position prediction step of predicting a user position using the RSSI value of the filter unit and a set attenuation constant in the position recognition unit,
After the filtering step, an RSSI value and a root mean square error (RMSE) are derived for each distance, and then a linear relational expression for the derived root mean square error is derived, and at least one inflection point in the derived linear relational expression Set as a reference point for the distance, determine an attenuation constant before the set reference point and an attenuation constant after the reference point, and transfer the determined attenuation constant to the location recognition unit, further comprising: Location recognition method. delete

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