KR102603337B1 - System for tracking location using access point and imu and method thereof - Google Patents

Abstract

The present invention relates to a location tracking system and method using AP and IMU.
According to the present invention, in the location tracking method using a location tracking system using an AP and an IMU, the user terminal acquires the distance range between the user terminal and the AP from an AP (access point) installed nearby, and Sensing data through an installed inertial measurement unit (IMU), obtaining converted data by converting the sensed data into a global coordinate system, determining whether the user is walking using the converted data, and determining whether the user is walking. If it is determined that the user is walking, estimating the user's stride length using the converted data, estimating the direction of the user using the converted data, and combining the converted data and the user's stride length into a PDR (Pedestrian Dead) step. Reckoning) technique to estimate the user's location, and if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is within the distance range between the user terminal and the AP The estimated user's location is determined as the current location.

Description

Location tracking system and method using AP and IMU {SYSTEM FOR TRACKING LOCATION USING ACCESS POINT AND IMU AND METHOD THEREOF}

The present invention relates to a location tracking system and method using an AP and IMU, and to a location tracking system and method using an AP and IMU for accurately tracking the location of an iOS-based user terminal.

The indoor location positioning method using an existing smartphone is to receive an indoor map from the smartphone through a Wi-Fi AP (Access Point) installed indoors and then use the RSS (Received Signal Strength) value provided by the Wi-Fi AP. A method of tracking the user's location was used.

However, due to a change in Wi-Fi information provision policy due to Apple's iOS 13 update in September 2019, there is a problem of not being able to receive RSS values from Wi-Fi AP.

Therefore, in the indoor environment of iPhone users, a method of calculating the user's current location through the inertial measurement unit (IMU) mounted on the smartphone was needed for user location location technology through Wi-Fi AP.

The technology behind the present invention is disclosed in Korean Patent No. 10-1600561 (announced on March 7, 2016).

The technical problem to be achieved by the present invention is to provide a location tracking system and method using AP and IMU to accurately track the location of an iOS-based user terminal.

According to an embodiment of the present invention to achieve this technical problem, in a location tracking method using a location tracking system using an AP and an IMU, the distance between the user terminal and the AP is determined through short-distance communication with an AP (access point) installed nearby. Obtaining a range, sensing data through an inertial measurement unit (IMU) installed in the user terminal, converting the sensed data into a global coordinate system to obtain converted data, using the converted data to determining whether the user is walking; if it is determined that the user is walking, estimating the user's stride length using the converted data; estimating the direction of the user using the converted data; and estimating the user's location by applying the user's stride length to a PDR (Pedestrian Dead Reckoning) technique, and the distance obtained through the coordinates of the estimated current location of the user and the AP is the user If it is within the distance range between the terminal and the AP, determining the estimated user's location as the current location.

The step of obtaining the distance range between the user terminal and the AP includes obtaining the distance range between the user terminal and the AP using the received signal strength (RSSI) of the AP, and determining the distance range between the user terminal and the AP. Accordingly, it can be divided into nearby state (immediate), near state (near), far state (far), and unidentifiable state (unknown).

If the distance obtained through the coordinates for the estimated user's current location and the coordinates between the AP is not included in the distance range between the user terminal and the AP, correcting the user's location based on the RSSI value More may be included.

In the step of correcting the user's location based on the RSSI value, if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is shorter than the distance range between the user terminal and the AP, By extending a virtual straight line connecting the user terminal and the AP, the point where it intersects the inner circle corresponding to the corresponding distance range of the AP can be determined as the user's current location.

In the step of correcting the user's location based on the RSSI value, if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is longer than the distance range between the user terminal and the AP, The point where the straight line connecting the user terminal and the AP intersects the outer circle corresponding to the corresponding distance range of the AP can be determined as the user's current location.

In the step of determining whether the user is walking, the acceleration value measured from the inertial measurement device is a threshold value ( ) or more, it can be determined that the user is walking.

In the step of estimating the user's stride length, the user's stride length can be estimated by applying the converted data to the equation below.

here, is the user's stride length, is the maximum acceleration value, is the minimum acceleration value, is the correction constant.

In the step of estimating the user's location, the user's location can be estimated using the equation below.

here, and is the initial location of the user, and is the location of the user moved to the kth time, is the stride length of the user, is the direction of the user.

The inertial measurement device may include a gyro sensor, an acceleration sensor, a geomagnetic sensor, and a compass sensor.

The user terminal may be based on the iOS operating system.

The nearby state indicates a case where the user terminal exists within a first reference distance from the AP, and the short-distance state indicates a case where the user terminal exists at a distance greater than the first reference distance but less than a second reference distance from the AP. Indicates that the remote state indicates that the user terminal exists at a distance greater than or equal to the second reference distance from the AP but less than the third reference distance, and the unidentifiable state indicates that the user terminal exists at a distance greater than or equal to the third reference distance from the AP. It can indicate a case where exists.

According to another embodiment of the present invention, in a location tracking system using an AP and an IMU, a communication unit that obtains the distance range between the user terminal and the AP through short-distance communication with an AP (access point) installed nearby, the user terminal A data sensing unit that senses data through an installed inertial measurement unit (IMU), a conversion data acquisition unit that converts the sensed data into a global coordinate system to obtain conversion data, and uses the conversion data to determine whether the user is walking. And, if it is determined that the user is walking, a position estimation unit that estimates the user's stride length and the user's direction using the converted data, and a PDR (Pedestrian Dead Reckoning) technique that estimates the converted data and the user's stride length. A location estimation unit that estimates the user's location by applying it to the location, and if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is within the distance range between the user terminal and the AP, It includes a control unit that determines the estimated user's location as the current location.

In this way, according to the present invention, without the need to install additional Wi-Fi APs used in existing indoor location determination techniques, the starting location can be determined through the minimum existing Wi-Fi AP, and the user can be detected through the IMU sensor of the smartphone. The location can be estimated.

Additionally, effective location estimation may be possible in situations where external communication is difficult, such as a disaster environment.

1 is a configuration diagram for explaining the configuration of a location tracking system according to an embodiment of the present invention.
Figure 2 is a flowchart for explaining a location tracking method according to an embodiment of the present invention.
FIG. 3 is a diagram for explaining step S210 of FIG. 2.
FIG. 4 is a diagram for explaining step S240 of FIG. 2.
Figure 5 is a diagram for explaining step S280 of Figure 2.
FIGS. 6A and 6B are diagrams for explaining step S290 of FIG. 2.
Figure 7 is a block diagram explaining a location tracking method according to an embodiment of the present invention.
Figure 8 is a diagram showing the results of tracking an indoor location using a location tracking system according to an embodiment of the present invention.
Figure 9 is a diagram showing the accuracy when only the location tracking system according to an embodiment of the present invention and the existing PDR technique are used.

Below, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. In order to clearly explain the present invention in the drawings, parts that are not related to the description are omitted, and similar parts are given similar reference numerals throughout the specification.

Throughout the specification, when a part is said to “include” a certain element, this means that it may further include other elements rather than excluding other elements, unless specifically stated to the contrary.

Then, with reference to the attached drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the present invention.

1 is a configuration diagram for explaining the configuration of a location tracking system according to an embodiment of the present invention.

As shown in Figure 1, the location tracking system 100 according to an embodiment of the present invention includes a communication unit 110, a data sensing unit 120, a conversion data acquisition unit 130, a direction estimation unit 140, and a location estimation unit. It includes 150 and a control unit 160.

First, the communication unit 110 obtains the distance range between the user terminal and the AP.

At this time, the communication unit 110 uses the received signal strength (RSSI) of the AP to obtain the distance range between the user terminal and the AP, and depending on the distance range between the user terminal and the AP, the nearby state (immediate) or the near state (near state) ), it is divided into a remote state (far) and an unidentifiable state (unknown).

In addition, the nearby state indicates a case where the user terminal exists within a first reference distance from the AP, and the near state indicates a case where the user terminal exists at a distance greater than the first reference distance but less than the second reference distance from the AP. The state indicates that the user terminal exists at a distance greater than or equal to the second reference distance from the AP but less than the third reference distance, and the unidentifiable state indicates that the user terminal exists at a distance greater than or equal to the third standard distance from the AP.

At this time, the first to third reference distances may be set to 5m, 10m, and 15m, respectively, and may vary depending on the settings of the location tracking system 100.

Additionally, received signal strength (RSSI) refers to the signal power received by a wireless receiver, and in embodiments of the present invention, it is used to measure the distance range between the AP and the user terminal.

Here, the user terminal is a portable user terminal, implemented as a device that can exchange information by connecting to a wired or wireless network, such as a laptop computer, smart pad, or smart phone, and means a terminal running on the iOS operating system.

Additionally, an AP (access point) is equipment that supports connecting a wireless device to another wired device through a network, and in an embodiment of the present invention, it refers to Wi-Fi equipment.

Next, the data sensing unit 120 senses data through an inertial measurement unit (IMU) installed in the user terminal.

Here, the inertial measurement unit (IMU) is a device for measuring the specific force, angular ratio, and sometimes magnetic field surrounding the body using an acceleration sensor, a rotation sensor, and a magnetic force sensor. In the embodiment of the present invention, it is installed in the user terminal. and senses each data.

Next, the conversion data acquisition unit 130 acquires conversion data by converting the sensed data into a global coordinate system.

Here, the global coordinate system is a coordinate system representing latitude, longitude, and height based on the Prime Meridian, and in the present invention, the sensed local coordinate system is converted to a global coordinate system and used.

Next, the direction estimation unit 140 determines whether the user is walking using the conversion data, and if it is determined that the user is walking, it estimates the user's stride length using the conversion data.

Then, the location estimation unit 150 uses the converted data to estimate the user's location by applying the user's direction and stride length to the PDR (Pedestrian Dead Reckoning) technique.

Here, the PDR technique is an algorithm that calculates the relative position from the starting point by identifying movement information such as the speed, acceleration, direction, and distance at which a person moves using a plurality of sensors. In the embodiment of the present invention, the user's location is calculated. Used to estimate .

Next, the control unit 160 determines whether the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is within the distance range between the user terminal and the AP.

At this time, if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is not within the distance range between the user terminal and the AP, the control unit 160 determines the user's location based on the RSSI value. Correct.

That is, if the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is shorter than the distance range between the user terminal and the AP, the control unit 160 creates a virtual network connecting the user terminal and the AP. By extending the straight line, the point where it intersects the inner circle corresponding to the corresponding distance range of the AP is determined as the user's current location.

Hereinafter, a location tracking method according to an embodiment of the present invention will be described using FIGS. 2 to 7.

Figure 2 is a flowchart for explaining a location tracking method according to an embodiment of the present invention.

First, the communication unit 110 obtains the distance range between the user terminal and the AP (S210).

At this time, the distance range between the user terminal and the AP refers to a nearby state, a short-distance state, a far-distance state, and an unidentifiable state.

FIG. 3 is a diagram for explaining step S210 of FIG. 2.

As shown in FIG. 3, the distance range between APs means a range with the first to third reference distances as the radius based on the AP.

At this time, the communication unit 110 sets the case where the user terminal exists within a first reference distance from the AP as a nearby state, and the case where the user terminal exists at a distance greater than the first reference distance but less than the second reference distance from the AP is considered close. Set to status.

In addition, the communication unit 110 sets the remote state when the user terminal exists at a distance greater than or equal to the second reference distance from the AP but less than the third standard distance, and when the user terminal exists at a distance greater than or equal to the third standard distance from the AP. Set to unconfirmable state.

Next, the data sensing unit 120 senses data through an inertial measurement unit (IMU) attached to the user terminal (S220).

That is, the data sensing unit 120 senses data about the acceleration, turning radius, and direction of movement of the user through an inertial measurement device.

Next, the conversion data acquisition unit 130 acquires conversion data by converting the sensed data into a global coordinate system (S230).

At this time, the converted data acquisition unit 130 applies the sensed data to a low-pass filter to preprocess the sensed data, and converts the preprocessed data into a global coordinate system to obtain converted data.

Next, the direction estimation unit 140 determines whether the user is currently walking (S240).

FIG. 4 is a diagram for explaining step S240 of FIG. 2.

That is, as shown in FIG. 4, the direction estimation unit 140 determines that the three-axis acceleration value measured from the inertial measurement device is a threshold value ( ) or more, reaches the maximum acceleration value (A_max) and then has a value smaller than the threshold value, it is determined that the user is walking.

Here, when the user is not walking, the direction estimation unit 140 continuously determines whether the user is walking.

On the other hand, when the user is walking, the direction estimation unit 140 estimates the user's stride length and direction using the conversion data (S250).

That is, the direction estimation unit 140 estimates the user's stride length by applying the converted data to Equation 1 below.

here, is the user's stride length, is the maximum acceleration value, is the minimum acceleration value, is the correction constant.

Next, the location estimation unit 150 estimates the user's location by applying the converted data and the user's stride length to the PDR technique (S260).

That is, the location estimation unit 150 estimates the user's location using Equation 2 below.

here, and is the user's initial location, and is the location of the kth moved user, is the user's stride length, is the user's direction.

Here, the user's direction ( ) is calculated using the CLHeading class provided from iOS's CoreLocation library on data measured through an inertial measurement device.

Next, the control unit 160 determines whether the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is within the distance range between the user terminal and the AP (S270).

In other words, it is determined whether the coordinates for the estimated current location of the user are located in a nearby state, a near state, a far state, or an unconfirmable state.

Next, if the obtained distance is within the distance range between the user terminal and the AP, the control unit 160 determines the estimated user's location as the current location (S280).

Figure 5 is a diagram for explaining step S280 of Figure 2.

For example, as shown in FIG. 5, when the estimated current location of the user is close to the AP, the control unit 160 determines the estimated user's location as the current location.

On the other hand, if the obtained distance is not within the distance range between the user terminal and the AP, the control unit 160 corrects the estimated user's location based on the RSSI value (S290).

FIGS. 6A and 6B are diagrams for explaining step S290 of FIG. 2.

For example, as shown in FIG. 6A, when the estimated user's current location is outside the second reference distance, the control unit 160 connects the estimated user's current location and the AP with a virtual straight line and sets the corresponding distance range. The point that intersects the outer circle corresponding to is corrected to the user's current location.

For another example, as shown in Figure 6b, when the estimated user's current location is within the first reference distance, the control unit 160 connects the estimated user's current location and the AP with a virtual straight line, and The point that intersects the inner circle corresponding to the distance range is corrected to the user's current location.

Figure 7 is a block diagram explaining a location tracking method according to an embodiment of the present invention.

That is, as shown in Figure 7, the location tracking method according to an embodiment of the present invention tracks the location of the user terminal using the Wi-Fi signal of the iOS-based user terminal and a plurality of data sensed from an inertial measurement device. .

Figure 8 is a diagram showing the results of indoor location tracking using the location tracking system according to an embodiment of the present invention, and Figure 9 is a case where only the location tracking system according to an embodiment of the present invention and the existing PDR technique are used. This is a drawing showing the accuracy of.

As shown in Figure 8, the blue line is the user's location tracked through the location tracking system according to an embodiment of the present invention, and it can be confirmed that the tracked location is corrected to the actual moved location by using the AP signal.

In addition, as shown in Figure 9, it can be seen that the location estimation results using the location tracking system according to the embodiment of the present invention reduced the error by 20% to 30% compared to when using only the existing PDR technique. .

According to this embodiment of the present invention, if the starting position is determined through the minimum existing Wi-Fi AP without the need to install additional Wi-Fi APs used in existing indoor location determination techniques, the IMU sensor of the smartphone You can estimate the user's location through .

Additionally, effective location estimation may be possible in situations where external communication is difficult, such as a disaster environment.

The present invention has been described with reference to the embodiments shown in the drawings, but these are merely illustrative, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

100: Location tracking system, 110: Department of Communications,
120: data sensing unit, 130: conversion data acquisition unit,
140: direction estimation unit, 150: position estimation unit,
160: control unit

Claims (18)

In the location tracking method using a location tracking system using AP and IMU,
Obtaining the distance range between the user terminal and the AP through short-distance communication with an AP (access point) installed nearby,
Sensing data through an inertial measurement unit (IMU) installed in the user terminal,
Obtaining converted data by converting the sensed data into a global coordinate system,
Determining whether the user is walking using the converted data,
If it is determined that the user is walking, estimating the user's stride length using the converted data;
estimating the direction of the user using the converted data,
Estimating the user's location by applying the converted data and the user's stride length to a PDR (Pedestrian Dead Reckoning) technique,
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is within the distance range between the user terminal and the AP, determining the estimated user's location as the current location, and
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is not within the distance range between the user terminal and the AP, the user's location is determined based on the received signal strength (RSSI) value. Including a correction step,
The step of correcting the user's location based on the RSSI value is,
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is shorter than the distance range between the user terminal and the AP, extend the virtual straight line connecting the user terminal and the AP , determining the point that intersects the inner circle corresponding to the corresponding distance range of the AP as the current location of the user,
If the distance obtained through the coordinates between the estimated coordinates of the user's current location and the AP is longer than the distance range between the user terminal and the AP,
A location tracking method that determines the point where a straight line connecting the user terminal and the AP intersects an outer circle corresponding to the corresponding distance range of the AP as the user's current location. According to paragraph 1,
The step of obtaining the distance range between the user terminal and the AP is,
Obtain the distance range between the user terminal and the AP using the received signal strength (RSSI) of the AP,
A location tracking method that classifies a nearby state (immediate), a near state (near), a far state (far), and an unidentifiable state (unknown) according to the distance range between the user terminal and the AP. delete delete delete According to paragraph 2,
The step of determining whether the user is walking is,
The acceleration value measured from the inertial measurement device is the threshold ( ) or more, a location tracking method that determines that the user is walking. According to clause 6,
The step of estimating the user's stride length is,
A location tracking method that estimates the user's stride length by applying the converted data to the equation below:

here, is the user's stride length, is the maximum acceleration value, is the minimum acceleration value, is the correction constant. In clause 7,
The step of estimating the user's location is,
A location tracking method that estimates the user's location using the equation below:

here, and is the initial location of the user, and is the location of the user moved to the kth time, is the stride length of the user, is the direction of the user. According to paragraph 1,
The inertial measurement device,
A location tracking method including a gyro sensor, an acceleration sensor, a geomagnetic sensor, and a compass sensor. According to paragraph 1,
The user terminal is
A location tracking method based on the iOS operating system. According to paragraph 2,
The nearby state represents a case where the user terminal exists within a first reference distance from the AP,
The short-distance state represents a case where the user terminal exists at a distance from the AP that is greater than a first reference distance but less than a second reference distance,
The remote state represents a case where the user terminal exists at a distance from the AP that is greater than or equal to a second reference distance but less than a third reference distance,
The location tracking method indicates that the unconfirmable state indicates that the user terminal exists at a distance greater than or equal to a third reference distance from the AP. In a location tracking system using AP and IMU,
A communication unit that obtains the distance range between the user terminal and the AP through short-distance communication with an AP (access point) installed nearby,
A data sensing unit that senses data through an inertial measurement unit (IMU) installed in the user terminal,
A conversion data acquisition unit that converts the sensed data into a global coordinate system and obtains conversion data,
A direction estimation unit that uses the converted data to determine whether the user is walking, and when it is determined that the user is walking, estimates the user's stride length and the user's direction using the converted data;
A location estimation unit that estimates the user's location by applying the converted data and the user's stride length to a PDR (Pedestrian Dead Reckoning) technique, and
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is within the distance range between the user terminal and the AP, it includes a control unit that determines the estimated user's location as the current location; ,
The control unit,
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is not within the distance range between the user terminal and the AP, the user's location is determined based on the received signal strength (RSSI) value. correct,
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is shorter than the distance range between the user terminal and the AP, extend the virtual straight line connecting the user terminal and the AP , determining the point that intersects the inner circle corresponding to the corresponding distance range of the AP as the current location of the user,
If the distance obtained through the coordinates of the estimated user's current location and the coordinates between the AP is longer than the distance range between the user terminal and the AP, a straight line connecting the user terminal and the AP, A location tracking system that determines the point that intersects the outer circle corresponding to the distance range as the user's current location. According to clause 12,
The Department of Communications,
The distance range between the user terminal and the AP is obtained using the received signal strength (RSSI) of the AP, and depending on the distance range between the user terminal and the AP, it is in a nearby state (immediate state), a near state (near state), or a far state. Location tracking system divided into (far) and unconfirmed (unknown) status. delete delete delete According to clause 12,
The user terminal is
A location tracking system based on the iOS operating system. According to clause 13,
The nearby state represents a case where the user terminal exists within a first reference distance from the AP,
The short-distance state represents a case where the user terminal exists at a distance from the AP that is greater than a first reference distance but less than a second reference distance,
The remote state represents a case where the user terminal exists at a distance from the AP that is greater than or equal to a second reference distance but less than a third reference distance,
The location tracking system indicates that the unconfirmable state indicates that the user terminal exists at a distance greater than or equal to a third reference distance from the AP.