KR20060134271A - Localization method using moving object - Google Patents

Abstract

A locating method using a movable reference device is provided to improve accuracy of the location result by using a short-range location technology using a small number of mobile reference device. At least one reference device(200a,200b,200c,200d) is used to determine the position of an object(202) to be found. The region where the reference device is within a recognizable distance is determined, and the object is recognized. The distance between the recognized object and the reference device is measured. Preceding processes are repeated, until the reference device moves to more than three points and the distances from the points are measured. A triangular algorithm is used on the position information of the reference device and the measured distance, so that the position of the object is calculated.

Description

LOCALIZATION METHOD USING MOVING OBJECT}

1 is a diagram illustrating the generation of a virtual image in a three-dimensional space during triangulation according to the prior art.

2 is a view for explaining a location tracking method according to a preferred embodiment of the present invention.

3 is a view for explaining a location tracking method according to another embodiment of the present invention.

The present invention relates to a method for tracking the position of a fixture, and more particularly, to a location tracking method for tracking the location of a location tracking target device by trigonometry while the location tracking reference device is moving.

The method of tracking the position of an object uses a method of calculating a position relative to other objects having the position information of the object. As such a method, the most widely used method is a method of calculating the absolute coordinates of an arbitrary object using a distance relationship with a satellite whose absolute coordinates are known by GPS (Global Positioning Systems). However, GPS is expensive and requires a view of at least four satellites and can only be used in applications where a tolerance of 10m is usually acceptable.

On the other hand, the most commonly used method of tracking location indoors is a method called cricket. Cricket is a technique of placing three or more beacons that simultaneously generate ultrasonic waves and radio waves. Since these beacons know their absolute coordinates, the signal receiver calculates the distance between the beacons and the receiver by measuring the difference in the arrival time of the ultrasonic waves and radio waves arriving from the beacons. Therefore, the signal receiver can calculate its position through trigonometry.

Other methods are based on a range of distance measurement techniques, such as measuring the distance using the UWB signal's arrival time, or measuring the distance through the signal attenuation between the transmitter and receiver. Location tracking techniques exist, and these techniques generally use trigonometry.

The trigonometric method used as the base technology of the position tracking in the prior art will be described with reference to FIG. 1. 1 is a diagram illustrating the generation of a virtual image in a three-dimensional space during triangulation according to the prior art. Referring to FIG. 1, triangulation means that there are three reference points 100a, 100b, and 100c in which a location is known in three dimensions, and that there is a specific object 102 whose location is unknown. It is a technique for calculating the position of the particular object 102 by measuring the distance between the and three reference points (100a, 100b, 100c). However, at this time, the virtual image 104 is additionally generated in addition to one actual image as the position of the individual. In this case, the virtual image can be removed if the virtual position is known in advance, but when the virtual image cannot be removed, another reference point 100d capable of tracking the distance, that is, a total of four reference points is required. do.

If the distance between a particular entity and the other three reference points is unknown, but the difference between the distances is known, real and false images can be obtained if the number of entities that can know the position is four. This is the case with GPS, and the virtual image is removed using the fact that the position of the object to be measured is similar to that of the earth.

The commonality between these techniques is that triangulation can be used to track the position of an object whose location is to be tracked by having at least three or four devices with absolute coordinates within the receiving distance. However, these limitations cause various implementation difficulties.

First, if the limit distance that can measure the distance between objects is relatively small compared to the space where the position should be measured, there is a problem that a large number of devices that know absolute coordinates are required.

Second, the distribution of a device that knows absolute coordinates must completely dominate the space to be measured, and the distance from the required number of points (3 to 5) can be measured anywhere in the space where all measurements should be possible. To this end, there is a problem in that the distribution of the device needs to be carefully calculated and arranged.

Third, there is a problem that the continuous operation of the energy source must be supplied to the device that knows the absolute coordinates, so that the continuous operation can be ensured and the maintenance cost is high when the number is large.

Fourth, when there are a plurality of devices that know the absolute coordinates, the signal synchronization between each device can be prevented to prevent the inability of the position measurement due to the collision, which increases the implementation cost of the location tracking system.

The present invention has been made in view of the above, and aims to reduce the cost of the configuration of the location tracking system and to facilitate maintenance by reducing the number of devices serving as reference points in the location tracking system.

One aspect of the present invention for achieving the above object is a method for tracking the location of the location tracking target device using at least one movable location tracking reference device, (a) the location tracking reference area within the recognition distance; Recognizing a location tracking target device by searching for (b) measuring a distance between the recognized location tracking target device and a location tracking reference device, and (c) moving the location tracking reference device at three or more points while moving the location tracking reference device. Repeating the steps (a) and (b) until the measurement; and (d) the position tracking target using the triangulation method using the position information of the position tracking reference device at each point and the distance measured at each point. Calculating the position of the device.

In this case, in the step (a), searching for the area within the recognition distance by the positioning reference device may be performed by using the positioning reference device as the center of a circle or sphere whose recognition distance is a radius, and when the positioning reference device moves. It is desirable to search for the sphere's trajectory to cover the entire area where the location target device can exist.

Recognizing the location tracking target device in step (a) includes: continuously emitting the beacon message by the location tracking reference device, receiving the beacon message by the location tracking target device, and responding by the location tracking target device; Preferably, the step of transmitting a signal to the positioning reference device.

Furthermore, the location information of the location tracking reference device is preferably obtained using GPS.

Another aspect of the present invention for achieving the above object is a method for tracking the location of a location tracking target device distributed in space using at least one movable location tracking reference device, (a) location tracking reference device Moving the existing area of the location tracking target device into a triangle or a tetrahedron with the position of the location tracking reference device as a vertex, and (b) when one location tracking device is found, the location tracking object in the existing area. Measuring a distance between a device and each vertex of each triangle or tetrahedron comprising the same; (c) trigonometry using location information of a location tracking reference device at each vertex and the measured distance at each vertex Calculating the location of the location tracking target device through (d) if another location tracking target device exists in the existing area. Characterized in that it comprises the step of repeating said (a) to (c) step.

In this case, the length of one side of the triangle or tetrahedron is preferably the smaller of the measurable distance and the recognition distance of the position tracking reference device.

In addition, the location information of the location reference device is preferably obtained by using the GPS.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the following embodiments are provided to those skilled in the art to fully understand the present invention, and may be modified in various forms, and the scope of the present invention is limited to the embodiments described below. It doesn't happen.

(Example)

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

2 is a view for explaining a location tracking method according to a preferred embodiment of the present invention. Referring to FIG. 2, the location tracking apparatuses 200a, 200b, 200c, and 200d should be able to know their absolute coordinates as a device serving as a reference point when tracking an object. As a method of obtaining the absolute position of the position tracking reference apparatuses 200a, 200b, 200c, and 200d, GPS or the like can be used as a known method.

In addition, the location tracking reference devices 200a, 200b, 200c, and 200d may be configured to be movable on their own, or may be mounted on the movable equipment, and as shown in FIG. 2, for example, may be mounted on a helicopter. . Since the location tracking reference apparatus 200a, 200b, 200c, 200d needs only one quantity due to the characteristics of the present invention, there is no problem in using a costly technology because there is little restriction on energy supply. have. Thus, for example, an additional technique of increasing accuracy may be used in addition to the GPS used for the positioning reference devices 200a, 200b, 200c, and 200d. Of course, one or more positioning reference devices 200a, 200b, 200c, and 200d may be used according to embodiments, but reference numerals 200a, 200b, 200c, and 200d of FIG. 2 eventually move one positioning reference device. In this case, it refers to the same positioning reference device at each reference point.

In FIG. 2, the location tracking target device 202 is a fixture to be tracked from a location, and the location tracking reference devices 200a, 200b, 200c, and 200d are used to track the location of the location tracking target device 202. The tracking target device 202 has a function of measuring the distance between each other.

In addition, the location reference apparatuses 200a, 200b, 200c, and 200d need to know in advance information about an area where the location tracking target apparatus 202 is distributed. That is, the location tracking target device 202 should not exist outside the area known by the location tracking reference devices 200a, 200b, 200c, and 200d. Specifically, between the location tracking reference devices 200a, 200b, 200c, and 200d and the location tracking target device 202, if the location tracking reference devices 200a, 200b, 200c, and 200d are closer to each other than a predetermined distance, There is a mechanism for recognizing the presence of the location tracking target device 202, the recognition distance of such a location tracking reference device may be named d. Several mechanisms have already been disclosed for this mechanism, for example, the positioning reference apparatus 200a, 200b, 200c, 200d continuously generates a beacon message and responds when the positioning target device 202 recognizes this. The location tracking reference devices 200a, 200b, 200c, and 200d may recognize the existence of the location tracking target device 202. This method is the same as the technique used in RFID, which is beyond the scope of the present invention and thus the detailed description is omitted.

As a method of tracking the location of the location tracking target device 202 by using the location tracking devices 200a, 200b, 200c, and 200d, the location tracking devices 200a, 200b, 200c, and 200d may have a predetermined distance range. After moving to three or more locations within the device to measure the distance to the location tracking target device 202 at each location, the bilateral distance information at each location of the location tracking reference devices 200a, 200b, 200c, and 200d is obtained. It is possible to use the calculation of the position of the position tracking target device 202 by the trigonometric method. The position tracking reference devices 200a, 200b, 200c, and 200d have a function of measuring a distance from the position tracking target device 202 within a predetermined distance l, and a method of measuring the distance is also disclosed in the related art. Methods, that is, a method using a speed difference between ultrasonic waves and radio waves can be used. Although the position tracking reference devices 200a, 200b, 200c, and 200d satisfy the requirements of the present invention with only one device, one or more may be used. One or more location tracking target devices 202 may be present. The more location tracking target devices 202, the higher the effect of the invention.

Hereinafter, a method of recognizing a location for each object of the location tracking target device 202 using the movable location tracking reference devices 200a, 200b, 200c, and 200d as described above will be described.

The location tracking apparatus 200a, 200b, 200c, or 200d searches the entire area where the location tracking target device 202 may exist. In this case, the location tracking apparatuses 200a, 200b, 200c, and 200d search the entire area that can be searched by the recognition distance d of the location tracking target device 202. Such a search algorithm may also use a conventional method. For example, the location tracking target device 202 may exist when the path of the location tracking devices 200a, 200b, 200c, and 200d follows a circle or sphere having a radius d. Orbital methods may be used to cover the entire possible area.

At this time, if the location tracking target device 202 is recognized, the distance between the location tracking reference device (200a, 200b, 200c, 200d) and the location tracking target device 202 is measured at three or four points. In this case, the distance between three or four different points and the location tracking target device 202 should be smaller than l. Since the location tracking reference apparatus 200a, 200b, 200c, or 200d does not know the exact location of the location tracking target device 202 when it first recognizes the location tracking target device 202, the distance from the location tracking target device 202 at once. Cannot find another point less than l as many times as necessary. Therefore, the search method is repeated to narrow the distribution range of the location tracking target device 202 and to continue the measurement until the required number of points are found.

When the distance information between the location tracking target device 202 and the location tracking reference devices 200a, 200b, 200c, and 200d is obtained at the point 3 or 4, the location tracking target device 202 is triangulated using the distance information. Can pinpoint the exact location of the. If another location tracking target device 202 exists, the location tracking reference devices 200a, 200b, 200c, and 200d may continue to search the area again after the location measurement of the first location tracking target device 202 is finished. If the reference device 200a, 200b, 200c, or 200d knows the number of the location tracking target devices 202 and finds the location tracking target device 202 by the number, the location tracking may be stopped.

Next, a description will be given of a method for the movable location tracking reference device to recognize the location of the location tracking target device through space occupation.

3 is a view for explaining a location tracking method according to another embodiment of the present invention, when it knows the area in which the object to be tracked is distributed, it is possible to cover the entire area tightly (300a, 300b) , ..., 300n) can be used to track the position of the object through the triangle. Specifically, referring to FIG. 3, the center hatched area 302 is an area of the location tracking target device, and each point 300a, 300b, ..., 300n is a reference point for distance measurement when one location tracking reference device moves. Indicates the position of the position tracking reference device.

As shown in FIG. 3, the presence area 302 of the location tracking target device may be covered with a triangle having a length of min (l, d) (when the existence area is three-dimensional, the length of the corner is min). (l, d) tetrahedron). In this case, the length min (l, d) of one side of the triangle or tetrahedron means a smaller value of the measurable distance l and the recognition distance d of the position tracking reference device 300. Therefore, all objects in the existence area 302 of the location tracking target device can be measured at three points in two-dimensional space and at four points in three-dimensional space.

Since this point satisfies the number of reference points necessary for the location tracking of the location tracking device, the location tracking reference device 300 measures the distance from the location tracking device in all the triangles or vertices of the tetrahedron. The distance is stored internally and keeps moving. The location tracking device measured more than the number of times (three or four times) requiring distance measurement can be notified of the calculated position immediately after the distance measurement. The location tracking reference device 300 should measure distances from all reference points, but if the number of location tracking target devices is known and the location measurement of all location tracking devices is completed, even if the distance measurement is not performed at all reference points, I can finish.

As described above, according to the present invention, since a movable location tracking reference device is used, it is not necessary to use a large number of location tracking reference devices, and thus a cost reduction effect can be obtained, and a cost burden for one movable location tracking reference device is required. It is possible to use high-precision technology without any cost, and to use the low-cost short-range location tracking technology for the location reference device.

As mentioned above, although preferred embodiment of this invention was described in detail, this invention is not limited to the said embodiment, A various deformation | transformation by a person of ordinary skill in the art within the scope of the technical idea of this invention is carried out. This is possible.

Claims (7)

A method for tracking the location of a location tracking target device using at least one movable location reference device, (a) the location tracking apparatus recognizes the location tracking target device by searching an area within the recognition distance; (b) measuring a distance between the recognized location tracking target device and the location tracking reference device; (c) repeating steps (a) and (b) until the position tracking reference device measures the distance at three or more points; and (d) calculating a position of the location tracking target device by trigonometry using the location information of the location tracking reference device at each point and the distance measured at each point. The method of claim 1, wherein in the step (a), the location tracking apparatus searches for an area within the recognition distance, using the location tracking reference apparatus as a center of a circle or sphere having a radius of recognition distance and moving the location reference apparatus. A location tracking method characterized in that the trajectory of a circle or sphere is searched to cover the entire area where the location tracking target device can exist. According to claim 1, Recognizing the location tracking target device in the step (a), Continuously radiating a beacon message by the location reference apparatus; Receiving, by the location tracking target device, a beacon message; And positioning the response signal by the location tracking target device to the location tracking reference device. The location tracking method of claim 1, wherein the location information of the location tracking reference device is obtained by using a GPS. A method for tracking the location of a location tracking target device distributed in space using at least one movable location tracking reference device, the method comprising: (a) moving the location tracking reference device while dividing the existence area of the location tracking target device into a triangle or a tetrahedron having the position of the location tracking reference device as a vertex; (b) when one location tracking target device is found, measuring a distance between the location tracking target device in the presence area and each vertex of each triangle or tetrahedron including the location tracking target device; (c) calculating the position of the location tracking target device by triangulation using the location information of the location tracking reference device at each vertex and the measured distance at each vertex; and (d) repeating steps (a) to (c) if another location tracking target device exists in the presence area. 6. The method of claim 5, wherein the length of one side of the triangle or tetrahedron is the smaller of the measurable distance and the perceived distance of the positioning reference device. The location tracking method of claim 5, wherein the location information of the location tracking reference device is obtained by using a GPS.

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