KR102099499B1 - Method and apparatus for estimating location - Google Patents

Abstract

Disclosed is a method and apparatus for position estimation. The position estimation apparatus calculates displacement at at least three or more locations where the tag node is located, calculates a distance between the tag node and the anchor node at at least three locations, and based on the distance corresponding to each of the at least three locations and locations Estimate the position of the anchor node.

Description

METHOD AND APPARATUS FOR ESTIMATING LOCATION}

The description below relates to a technique for estimating the location of an object indoors.

Since GPS technology is difficult to apply indoors, other technologies are used to locate objects indoors. There is a technique for finding the location of an anchor node or tag node using communication between the anchor node and the tag node. This technique estimates the absolute coordinates of a tag node by installing a plurality of anchor nodes indoors and communicating with the tag node.

The above-described background technology is possessed or acquired by the inventor during the derivation process of the present invention, and is not necessarily a known technology disclosed to the public before the filing of the present invention.

The present invention provides a method and apparatus for estimating the position of an anchor node at a low cost by estimating the relative position of an anchor node and a tag node.

The method for estimating a location according to an embodiment includes calculating displacements at at least three locations where tag nodes are located, calculating distances between the tag nodes and anchor nodes at the at least three locations, and the at least three locations. And estimating the position of the anchor node based on the above position and the distance corresponding to each of the positions.

The step of calculating the displacement includes measuring acceleration and angular velocity at the at least three locations using an inertial sensor, and calculating displacement at the at least three locations based on the acceleration and the angular velocity. can do.

In the calculating of the displacement, the displacement may be calculated by combining the result of integrating each of the accelerations with an angular velocity corresponding to each of the accelerations.

The calculating of the displacement includes measuring a number of steps, a walking direction and a stride at the at least three positions using a pedometer, and calculating the displacement based on the number of steps, the walking direction, and the step length can do.

When the tag node is moved by an object using a motor, the calculating of the displacement may include measuring a rotation angle of the motor and a direction of the motor at the three or more positions, and a rotation angle of the motor and And calculating the displacement based on the direction of the motor.

The calculating of the distance may include receiving an electromagnetic wave from the anchor node and calculating a distance between the tag node and the anchor node at the at least three locations based on the strength of the received electromagnetic wave. have.

The calculating of the distance may include: transmitting electromagnetic waves to the anchor node and receiving electromagnetic waves from the anchor node; and at least three or more based on the transmitted electromagnetic waves and the time of flight (TOF) of the received electromagnetic waves. And calculating a distance between the tag node and the anchor node at a location.

The step of estimating the position of the anchor node includes: calculating a center position of at least three circles from the calculated displacement, calculating a radius of at least three circles from the calculated distance, and the at least three circles. It may include the step of estimating the intersection of the center position and the radius of the circle as the position of the anchor node.

A location estimation apparatus including a tag node according to an embodiment includes at least one processor and at least one memory storing instructions to be executed by the processor, wherein the processor includes: Calculate displacements at at least three locations, calculate distances between the tag node and anchor nodes at the at least three locations, and place the anchors based on the at least three locations and the distance corresponding to each of the locations You can estimate the location of the node.

According to an embodiment, the position estimation apparatus may estimate the position of the anchor node at a low cost by estimating the relative position of the anchor node and the tag node.

1 is a diagram showing the overall configuration of a system for measuring the position of an anchor node indoors according to an embodiment.
2 is a flowchart illustrating an operation of a location estimation method according to an embodiment.
3A is a diagram illustrating an example in which a plurality of anchor nodes are arranged according to the prior art.
FIG. 3B is a diagram illustrating a graph of estimating the position of the tag node using circles indicating the position of the tag node with respect to the anchor node measured at different positions according to the prior art.
4 is a diagram illustrating a graph for estimating the position of an anchor node by a position estimation apparatus according to an embodiment.
5 is a diagram illustrating a detailed configuration of a location estimation apparatus according to an embodiment.

Specific structural or functional descriptions of the embodiments are disclosed for illustrative purposes only, and may be implemented in various forms. Accordingly, the embodiments are not limited to a specific disclosure form, and the scope of the present specification includes modifications, equivalents, or substitutes included in the technical spirit.

The terms first or second may be used to describe various components, but these terms should be interpreted only for the purpose of distinguishing one component from other components. For example, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

When an element is said to be "connected" to another element, it should be understood that other elements may be present, either directly connected to or connected to the other element.

Singular expressions include plural expressions unless the context clearly indicates otherwise. In this specification, terms such as “include” or “have” are intended to designate the existence of a described feature, number, step, action, component, part, or combination thereof, one or more other features or numbers, It should be understood that the existence or addition possibilities of steps, actions, components, parts or combinations thereof are not excluded in advance.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person skilled in the art. Terms such as those defined in a commonly used dictionary should be interpreted as having meanings consistent with meanings in the context of related technologies, and should not be interpreted as ideal or excessively formal meanings unless explicitly defined herein. Does not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. In describing with reference to the accompanying drawings, the same reference numerals are assigned to the same components regardless of reference numerals, and duplicate descriptions thereof will be omitted.

1 is a diagram showing the overall configuration of a system for measuring the position of an anchor node indoors according to an embodiment.

According to an embodiment, the position estimation apparatus 110 may estimate a relative distance and direction from the anchor node 120. The user 100 can easily estimate the location of the anchor node 120 indoors using the location estimation device 110. Since the location estimation apparatus 110 estimates a relative location, the location estimation apparatus 110 relative to the anchor node 120 itself may be estimated by estimating the location of the anchor node 120.

The position estimation apparatus 110 may be applied to a problem of estimating the position of the anchor node 120 indoors. The position estimation apparatus 110 may be applied to the field of the Internet of Things (IoT) using a wireless sensor network (WSN). The location estimation apparatus 110 may be used to easily estimate the location of an object to which the anchor node 120 is attached indoors (Indoor Localization). For example, the location estimation device 110 may find a lost item in the room (Lost Items Problem), augmented reality (Augmented Reality, AR), a problem in the location of a vehicle in a parking lot, a problem in the location of a product in a store, etc. , It can be applied to solve the problem of finding an access point (AP) of Wi-Fi.

Referring to FIG. 1, the location estimation device 110 may include a smart phone, but is not limited thereto. For example, the location estimation apparatus 110 may include a wearable device. The position estimation device 110 may be a device worn on an arm or leg, or may be implemented in the form of a helmet.

According to an embodiment, the location estimation apparatus 110 may estimate a relative location with the anchor node 120. Here, the location estimation apparatus 110 may be referred to as a tag node. Alternatively, the location estimation device 110 may include a tag node. The position estimation device 110 may calculate displacements and distances for the anchor node 120 at different positions. The position estimation apparatus 110 may estimate the relative position of the anchor node 120 using the displacement and distance to the anchor node 120 calculated from at least three or more positions.

The location estimation apparatus 110 may intuitively inform the user of the location of the anchor node by estimating the direction and distance of the anchor node with respect to the tag node and providing it to the user 100. The user 100 may determine whether it is close to the anchor node 120 by receiving information about the relative position in real time from the location estimation device 110.

The position estimation apparatus 110 may estimate the position of the anchor node 120 using one or a small number of anchor nodes 120. Since the position estimation apparatus 110 uses the relative positions of the tag node 110 and the anchor node 120, it is less than the position estimation method of the absolute coordinate method using a plurality of anchor nodes 120 (for example, Also, the position of the anchor node 120 can be easily estimated with the anchor node 120 of one anchor node). As such, the position estimation apparatus 110 can estimate the position of the anchor node 120 at a small cost by reducing the cost of installing the plurality of anchor nodes 120.

2 is a flowchart illustrating an operation of a location estimation method according to an embodiment.

According to an embodiment, the location estimation apparatus 110 may calculate displacement at at least three or more locations where the tag node is located. The position estimation apparatus 110 may calculate a direction and a moving distance from the first location to the second location according to the movement of the tag node. The position estimation apparatus 110 may calculate a direction and a moving distance from the second position to the third position according to the movement of the tag node. The position estimation apparatus 110 may calculate a direction and a moving distance from the third position to the fourth position according to the movement of the tag node.

According to an embodiment, the position estimation device 110 may measure acceleration and angular velocity at at least three positions using an inertial sensor. For example, the inertial sensor may include an inertial measurement unit (IMU). The inertial sensor can measure acceleration and angular velocity at regular intervals. The inertial sensor can store the measured acceleration and angular velocity over time in memory.

According to an embodiment, the position estimation device 110 may calculate displacement at at least three positions based on acceleration and angular velocity. The position estimation apparatus 110 may calculate a direction and a moving distance of the tag node during each time period using the measured acceleration and angular velocity. The position estimation device 110 may determine the position of the position estimation device 110 or the tag node moved according to each displacement.

According to an embodiment, the position estimation apparatus 110 may calculate displacement by combining the result of integrating each acceleration with an angular velocity corresponding to each acceleration. The position estimation apparatus 110 may calculate the moving distance by integrating the acceleration measured for each time section twice with time. The position estimation apparatus 110 may calculate the moving direction by integrating the angular velocity measured for each time section once with time. The position estimation apparatus 110 may calculate the movement distance of the tag node based on the movement distance and the movement direction.

According to another embodiment, the position estimation apparatus 110 may measure the number of steps, the walking direction, and the stride at at least three positions using a pedometer. The position estimation apparatus 110 may measure the number of steps, the step direction, and the step length for each of the plurality of time sections. The location estimation device 110 may store the number of steps, the direction of walking, and the step length measured for each time section in the memory.

The position estimator 110 may calculate displacement based on the number of steps, the direction of walking, and the step length. The position estimation apparatus 110 may calculate the displacement by calculating the step direction and the step length for each step. The position estimation apparatus 110 may calculate displacements for the total steps by summing each displacement.

According to another embodiment, when the tag node moves by an object using a motor, the position estimation apparatus 110 may measure the rotation angle of the motor and the direction of the motor at at least three positions. The position estimation apparatus 110 may measure the rotation angle of the motor and the direction of the motor at a constant time period. For example, the position estimation device 110 may include a wheeled mobile device. The position estimation apparatus 110 may store the rotation angle and rotation direction of the motor over time in memory as encoded data. The encoded data may be referred to as encoder data.

The position estimation apparatus 110 may calculate displacement based on the rotation angle of the motor and the direction of the motor. The position estimation apparatus 110 may calculate the movement distance of the tag node by using the rotation angle of the motor for each time section. The location estimation apparatus 110 may calculate the direction of the tag node for each time period.

As described above, the position estimation apparatus 110 may determine the position after the movement by calculating the displacement of the tag node according to each time section in various ways.

According to an embodiment, the location estimation apparatus 110 may calculate a distance between the tag node and the anchor node at at least three locations. Here, three or more positions where the distance is calculated may correspond to a position where the displacement is calculated, respectively.

According to an embodiment, the location estimation apparatus 110 may receive electromagnetic waves from an anchor node. The anchor node may periodically emit electromagnetic waves of a constant intensity. Here, electromagnetic waves within an allowed bandwidth may be used. For example, the electromagnetic wave may include electromagnetic waves having a bandwidth not used indoors. According to another embodiment, the anchor node may emit electromagnetic waves of a certain intensity when a request signal is received from the tag node.

The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node based on the received signal strength indicator (RSSI). The distance between the tag node and the anchor node can be calculated at at least three locations based on the intensity of electromagnetic waves. The intensity of the electromagnetic wave may decrease as the distance between the tag node and the anchor node increases, and as the distance between the tag node and the anchor node decreases. The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node based on the intensity of electromagnetic waves received from the anchor node using this principle.

The position estimation apparatus 110 may correspond to the displacement calculated for each position and the distance between the tag node and the anchor node. The position estimation apparatus 110 may store a correspondence relationship between displacement and distance in memory for each time.

According to another embodiment, the position estimation apparatus 110 may transmit electromagnetic waves to the anchor node and receive electromagnetic waves from the anchor node. The position estimation device 110 may periodically radiate electromagnetic waves. The position estimation apparatus 110 may broadcast electromagnetic waves or propagate electromagnetic waves in a specific direction. The anchor node may receive electromagnetic waves and radiate electromagnetic waves to the tag nodes correspondingly. The anchor node can emit electromagnetic waves to the tag node immediately or at regular time intervals.

The location estimation apparatus 110 may calculate the distance between the tag node and the anchor node at at least three locations based on the time of flight (TOF) of the electromagnetic wave and the received electromagnetic wave. The position estimation apparatus 110 may store the speed of electromagnetic waves in the memory in advance in the room. The position estimation apparatus 110 may measure the round trip time of electromagnetic waves between the tag node and the anchor node. The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node based on the round trip time of the electromagnetic wave and the speed of the electromagnetic wave. For example, the position estimation apparatus 110 may calculate the distance between the tag node and the anchor node by integrating the velocity of the electromagnetic wave over time during the round trip time of the electromagnetic wave.

Inertial sensors and distance sensors using RSSI are usually built into smartphones. Therefore, when the position estimation device 110 is implemented as an inertial sensor and a distance sensor using RSSI, there is an advantage in that no separate hardware is required.

According to an embodiment, the location estimation apparatus 110 may estimate the location of the anchor node based on at least three locations and a distance corresponding to each of the locations. Here, the three or more locations may refer to locations where the tag node has changed from the previous viewpoint. Here, the distance may refer to a distance between the tag node and the anchor node.

According to an embodiment, the location estimation apparatus 110 may estimate the intersection of at least three or more circles as the location of the anchor node. The position estimation apparatus 110 may estimate the position of the anchor node through triangulation based on three or more relative positions between the anchor node and the tag node. To this end, the position estimation apparatus 110 may calculate the center position and radius of at least three circles.

The position estimation apparatus 110 may calculate the center position of at least three or more circles from the calculated displacement. The position estimation apparatus 110 may calculate a radius of at least three or more circles from the calculated distance.

According to another embodiment, the location estimation apparatus 110 may estimate the intersection of at least three or more spheres as the location of the anchor node. The position estimation apparatus 110 may estimate the position of the anchor node using triangulation in three dimensions based on three or more relative positions between the anchor node and the tag node.

To this end, the position estimation apparatus 110 may calculate the center position of at least three or more spheres from the calculated displacement. The position estimation apparatus 110 may calculate a radius of at least three or more spheres from the calculated distance.

3A is a diagram illustrating an example in which a plurality of anchor nodes are arranged according to the prior art.

According to this method, a plurality of anchor nodes are installed in a lattice shape in the building. In addition, the absolute coordinates of each anchor node must be set, and in the process of exchanging coordinate data, the location information of the tag node holder can be easily exposed. Since installing a plurality of anchor nodes for each building requires a high cost, a technique for estimating absolute coordinates is an obstacle to constructing a ubiquitous environment for providing a location based service (LBS).

FIG. 3B is a diagram illustrating a graph of estimating the position of the tag node using circles indicating the position of the tag node with respect to the anchor node measured at different positions according to the prior art.

좌표에 있고 사용자의 위치는

에 있다는 정보가 사용자에게 제공된다. Since the Global Positioning System (GPS) cannot be used in an indoor environment, at least three anchor nodes are usually installed, and the position of the tag node is estimated through triangulation using a positional relationship with the tag node to locate. . As an example, if you use absolute coordinates, the lost item is in the current building.

Coordinates and the user's location

Information is provided to the user.

Referring to FIG. 3B, a graph for locating a tag node from three anchor nodes is shown. P1, P2 and P3 indicate the position of the anchor node. The distance from the position of each anchor node to the position of the tag node is measured. A circle with each distance as a radius is set around the position of each anchor node. It can be estimated that the tag node is located at the intersection of the circles set around the three anchor nodes.

4 is a diagram illustrating a graph for estimating the position of an anchor node by a position estimation apparatus according to an embodiment.

The position estimation apparatus 110 may determine the position of the tag node and the distance between the anchor node and the tag node, and estimate the position of the anchor node using triangulation from each position of the tag node.

The position estimation device 110 may calculate the position change of the tag node using the inertial sensor. The location estimation apparatus 110 may determine three different locations of the tag node. Referring to FIG. 4, the location estimation apparatus 110 may track the process of moving the tag node to P1, P2 and P3.

The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node at P1. The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node at P2. The position estimation apparatus 110 may calculate the distance between the tag node and the anchor node at P3. Since the position estimation apparatus 110 calculates only the distance between the tag node and the anchor node and does not know the direction, the position of the anchor node can be estimated using triangulation.

The position estimation apparatus 110 may set each position as the center of the circle in P1, P2, and P3, and set the distance from the corresponding position to the anchor node as the radius of the circle. The position estimation apparatus 110 may estimate a point at which each circle intersects as the position of the anchor node.

According to another embodiment, the location estimation apparatus 110 may set each location as the center of the sphere in P1, P2, and P3, and set the distance from the location to the anchor node as the radius of the sphere. The position estimation apparatus 110 may estimate the point at which each sphere intersects as the position of the anchor node.

5 is a diagram illustrating a detailed configuration of a location estimation apparatus according to an embodiment.

According to an embodiment, the position estimation apparatus 500 may include a processor 501, a memory 503, a displacement sensor 505 and a distance sensor 507. The location estimation apparatus 500 may be referred to as a tag node. Alternatively, the location estimation apparatus 500 may include a tag node.

The memory 503 can store instructions to be executed by the processor 501. The memory 503 may store the signal received from the anchor node by time. The memory 503 may store signals received from the displacement sensor 505 and the distance sensor 507 for each time. The memory 503 may store the calculated position of the tag node and the distance between the tag node and the anchor node by time.

The displacement sensor 505 may calculate the displacement of the tag node at a constant time period. In one example, the displacement sensor 505 may include an inertial sensor or a pedometer.

The distance sensor 507 may calculate the distance between the tag node and the anchor node at a constant time period. Here, three or more positions where the distance is calculated may correspond to a position where the displacement is calculated, respectively. In one example, the distance sensor 507 may measure the strength of the received signal received from the anchor node or calculate the distance using TOF.

The processor 501 may calculate displacement at at least three locations where the tag node is located. The processor 501 may calculate the distance between the tag node and the anchor node at at least three locations. The processor 501 may estimate the location of the anchor node based on at least three locations and a distance corresponding to each location.

The embodiments described above may be implemented with hardware components, software components, and / or combinations of hardware components and software components. For example, the devices, methods, and components described in the embodiments include, for example, processors, controllers, arithmetic logic units (ALUs), digital signal processors (micro signal processors), microcomputers, and field programmable gates (FPGAs). Arrays, programmable logic units (PLUs), microprocessors, or any other device capable of executing and responding to instructions can be implemented using one or more general purpose computers or special purpose computers. The processing device may run an operating system (OS) and one or more software applications running on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of the software. For convenience of understanding, a processing device may be described as one being used, but a person having ordinary skill in the art, the processing device may include a plurality of processing elements and / or a plurality of types of processing elements. It can be seen that may include. For example, the processing device may include a plurality of processors or a processor and a controller. In addition, other processing configurations, such as parallel processors, are possible.

The components described in the embodiments may include one or more digital signal processors (DSPs), processors, controllers, application specific integrated circuits (ASICs), programmable logic elements such as field programmable gate arrays (FPGAs), other electronic devices, and the like. It may be implemented by hardware components including one or more of the combinations. At least some of the processes or functions described in the embodiments may be implemented by software, and the software may be recorded on a recording medium. The components, functions, and processes described in the embodiments may be implemented by a combination of hardware and software.

The software may include a computer program, code, instruction, or a combination of one or more of these, and configure the processing device to operate as desired, or process independently or collectively You can command the device. Software and / or data may be interpreted by a processing device, or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. , Or may be permanently or temporarily embodied in the transmitted signal wave. The software may be distributed on networked computer systems, and stored or executed in a distributed manner. Software and data may be stored in one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. Computer-readable media may include program instructions, data files, data structures, or the like alone or in combination. The program instructions recorded on the computer-readable medium may be specially designed and configured for the embodiments, or may be known and usable by those skilled in the computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs, DVDs, and magnetic media such as floptical disks. Includes hardware devices specifically configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of program instructions include high-level language code that can be executed by a computer using an interpreter, etc., as well as machine language codes produced by a compiler. The hardware device described above may be configured to operate as one or more software modules to perform the operations of the embodiments, and vice versa.

As described above, although the embodiments have been described with limited drawings, those skilled in the art can apply various technical modifications and variations based on the above. For example, the described techniques are performed in a different order than the described method, and / or the components of the described system, structure, device, circuit, etc. are combined or combined in a different form from the described method, or other components Alternatively, even if replaced or substituted by equivalents, appropriate results can be achieved.

100: user
110: position estimation device
120: anchor node

Claims (10)

Calculating displacement at at least three or more locations where the tag node is located;
Calculating a distance between the tag node and the anchor node at the at least three locations; And
Estimating the position of the anchor node based on the at least three positions and the distance corresponding to each of the positions
Including,
When the tag node is moved by an object using a motor,
The step of calculating the displacement,
Measuring a rotation angle of the motor and a direction of the motor at each of the at least three positions for each time period;
Storing the measured rotation angle and direction as encoded data; And
And calculating the displacement based on the rotation angle of the motor and the direction of the motor.
According to claim 1,
The step of calculating the displacement,
Measuring acceleration and angular velocity at the at least three locations using an inertial sensor; And
Calculating displacement at the at least three or more locations based on the acceleration and the angular velocity
Location estimation method comprising a. According to claim 2,
The step of calculating the displacement,
Calculating the displacement by combining the result of integrating each of the accelerations with an angular velocity corresponding to each of the accelerations,
Location estimation method. According to claim 1,
The step of calculating the displacement,
Measuring a number of steps, a walking direction and a stride at the at least three positions using a pedometer; And
Calculating the displacement based on the number of steps, the direction of walking and the step length
Location estimation method comprising a. delete According to claim 1,
The step of calculating the distance,
Receiving electromagnetic waves from the anchor node; And
Calculating a distance between the tag node and the anchor node at the at least three locations based on the received electromagnetic wave strength.
Location estimation method comprising a. According to claim 1,
The step of calculating the distance,
Transmitting electromagnetic waves to the anchor node and receiving electromagnetic waves from the anchor node; And
Calculating a distance between the tag node and the anchor node at the at least three locations based on the transmitted electromagnetic wave and the time of flight (TOF) of the received electromagnetic wave.
Location estimation method comprising a. According to claim 1,
Estimating the position of the anchor node,
Calculating a center position of at least three or more circles from the calculated displacement;
Calculating a radius of at least three circles from the calculated distance; And
Estimating the intersection of the center position and radius of the at least three circles as the position of the anchor node.
Location estimation method comprising a. A computer-readable recording medium recording a program for executing the method of claim 1 on a computer. In the position estimation apparatus comprising a tag node,
At least one processor and
And at least one memory for storing instructions to be executed by the processor,
The processor,
The displacement is calculated at least three or more locations where the tag node is located,
Calculating a distance between the tag node and the anchor node at the at least three locations,
Estimate the position of the anchor node based on the at least three positions and the distance corresponding to each of the positions,
When the tag node is moved by an object using a motor,
The processor measures the rotation angle of the motor and the direction of the motor at the at least three locations for each time period, stores the measured rotation angle and direction as encoded data, and rotates the rotation angle of the motor and Calculating the displacement based on the direction of the motor,
Position estimation device.

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