KR20080113536A - System and method for localization - Google Patents

Abstract

A system for determining position using wireless sensor network and method thereof are provided to easily calculate a distance between moving bodies in which a reference node and a position are not known by using signal strength attenuation model in an indoor/outdoor. A system for determining location using wireless sensor network comprises a first position decision reference part(110), a second position decision reference part(120), and a position tracking unit. The first position decision reference part includes a first transmitter(111) and a first receiver(113). The first transmitter transmits an electric wave. The first receiver provides an electric wave transmitted from the first transmitter and signal strength index measured after receiving an electric wave from outside. The second position decision reference part includes a second transmitter(121) and a second receiver(123). The second transmitter transmits an electric wave to the first receiver. The second receiver provides an electric wave transmitted from the second transmitter and signal strength index measured after receiving an electric wave from the first transmitter. The position tracking unit determines a location of a moving body through a signal strength attenuation model.

Description

Positioning system and method {SYSTEM AND METHOD FOR LOCALIZATION}

1 is a block diagram of a positioning system using radio signal modeling according to an embodiment of the present invention;

2 is a flowchart illustrating a positioning method through radio signal modeling according to an embodiment of the present invention;

3 is a block diagram of a positioning system showing a signal flow when determining a position of a tag by synchronizing two reference node units according to another embodiment of the present invention.

<Explanation of symbols for main parts of the drawings>

110, 120, 410, 420: reference node

111, 121, 411, 421: transmitter

113, 123, 413, 423: receiver

200, 500: Tags

415, 425: clock

The present invention relates to a system and method for determining a location of an object using a wireless sensor network.

As a related art related to the tracking of the position of an object, Korean Patent Laid-Open Publication No. 2007-0019953, "A device and method for indicating the position of a relative moving object", describes a method of calculating the relative motion of an object using the strength of the radio signal or the propagation time. Presented.

"High resolution localization for indoor environments" of US Patent Publication 20060217132 proposed a method for determining the position of an object indoors using the signal strength, the direction of reception of the signal.

"Location determination and location tracking in wireless networks" of US Patent Publication 20050246334 proposed a method of determining the indoor location using the signal strength by creating a radio map in advance.

However, the related arts related to the tracking of the object using the radio wave strength have not been able to determine the absolute position of the object by determining the position by using the relative movement of the object, or have to use the signal reception direction as well as the signal strength. Could determine the location. Alternatively, there is a problem in that a radio wave map must be prepared in advance even when the location of an object is determined using signal strength.

The present invention has been proposed to solve such a conventional problem, and the first object is to accurately measure the transmission and reception radio wave intensity in real time by using a transceiver (Transceiver) that performs the role of radio transmission and reception, and precisely model the radio wave through this To make a precise decision.

A second object of the present invention is to determine the position of an object by measuring the difference in the time of arrival of the radio wave or measuring the propagation travel time by using a transceiver that plays a role of radio wave transmission and reception.

As a first aspect of the present invention, a positioning system includes a first transmitter for transmitting radio waves and a first receiver for providing radio wave strengths measured by receiving radio waves transmitted from the first transmitter and radio waves from outside. A first positioning reference body; A second transmitter for transmitting a radio wave so that the first receiver can receive; and a second receiver for receiving and measuring a radio wave transmitted from the second transmitter and a radio wave transmitted from the first transmitter. A second positioning reference body; Position tracking means for determining the position of the moving object through the radio signal modeling using the radio wave strength measured by receiving the radio wave transmitted from the first and second transmitters and the radio wave strength provided from the first and second receivers.

As a second aspect of the present invention, a positioning system includes a first transmitter for transmitting radio waves, a first receiver for receiving radio waves from the outside, a radio wave transmission time by the first transmitter, and a first receiver. A first positioning reference body including a first clock for measuring radio wave reception time; A second transmitter for transmitting radio waves so that the first receiver can receive; a second receiver for receiving radio waves transmitted from the first transmitter; and a radio wave transmission time by the second transmitter and radio waves by the second receiver A second positioning reference body comprising a second clock for measuring a reception time; The radio wave is transmitted to the first and second positioning reference bodies to determine the position of the moving object using the difference in radio wave arrival time measured by the first and second clocks, or by using the propagation travel time measured by the first and second clocks. And position tracking means.

According to a third aspect of the present invention, a positioning method includes a first positioning reference having a first transmitter and a first receiver for transmitting and receiving radio waves, and a second positioning reference having a second transmitter and a second receiver for transmitting and receiving radio waves. A method of determining the position of the position tracking means in a positioning system comprising a sieve and a position tracking means, the method comprising the steps of: (a) transmitting the radio waves transmitted from the first transmitter to the first and second receivers; (B) receiving radio waves transmitted from the second transmitter at the first and second receivers and the location tracking means, and (c) the first and second receivers and the location tracking means Measuring received radio wave strength respectively, (d) providing the radio wave strength measured by the first and second receivers to the location tracking means, and (e) the location tracking means itself. And determining the position of the moving object through the propagation signal modeling using the propagation strength measured from the radio wave strength and the radio wave strengths provided from the first and second receivers.

According to a fourth aspect of the present invention, a positioning method includes a first positioning reference having a first transmitter, a first receiver, and a clock for transmitting and receiving radio waves, and a second transmitter, a second receiver, and a clock, for transmitting and receiving radio waves. A method for determining the position of the position tracking means in a positioning system including a positioning reference body and a position tracking means that does not know the position, the method comprising: (a) the time at which the radio wave is transmitted by the first transmitter and the radio wave receiving the radio wave; Measuring the radio wave arrival time to the second transmitter, or measuring the radio wave transmission time by the second transmitter and the radio wave arrival time to the first transmitter that receives the radio wave; and (b) the radio wave transmission time and Obtaining a time difference between the first and second positioning reference bodies using the radio wave arrival time; and (c) propagating to the first and second positioning reference bodies. Measuring the difference in the radio wave arrival time to the first and second positioning reference bodies or by measuring the propagation travel time to the first and second positioning reference bodies; and (d) in the step (b). Determining the position of the moving object by using the obtained time difference of the first and second positioning reference bodies and the time difference of the radio wave arrival, or by using the time difference of the first and second positioning reference bodies and the propagation movement time. Include.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a block diagram of a positioning system using radio signal modeling according to an embodiment of the present invention.

Referring to FIG. 1, the positioning system receives a plurality of reference node units 110 and 120 that transmit and receive radio signals and signals transmitted from the plurality of reference node units 110 and 120 in real time. It comprises a tag 200 that calculates its position using the calculated propagation model constant.

The tag 200 is attached to the moving object to be tracked, and the reference node parts 110 and 120 are attached to the point to be a reference point of the triangulation method for calculating the position of the moving object.

The tag 200 measures the intensity of radio waves and calculates the distance between the tag 200 and the reference node units 110 and 120 using the intensity.

The reference node unit 110, 120 includes a transmitter (111, 121) for transmitting the radio wave, and a receiver (113, 123) for receiving the radio wave transmitted from the transmitter (111, 121).

The receivers 113 and 123 calculate the propagation model constants used in the triangulation method in real time by calculating the characteristics of the radio signal in real time.

As indicated by the solid line in FIG. 1, the radio wave transmitted from the reference node unit 110 is transmitted to the receiver 113 mounted inside the same reference node unit 110, the tag 200, and another reference node unit ( Another receiver 123 mounted on 120 is reached. In addition, as indicated by a dotted line in FIG. 1, the radio wave transmitted from the reference node unit 120 includes a receiver 123, a tag 200, and another reference node unit mounted inside the same reference node unit 120. Another receiver 113 mounted at 110 is reached. That is, the plurality of reference node units 110 and 120 transmit and receive radio waves to each other, and the tag 200 receives these signals.

In FIG. 1, two reference node parts 110 and 120 are shown to help understand the description, but the number of reference node parts 110 and 120 is considered to be extended to N (where N is a natural number greater than 2). . Hereinafter, for convenience of description, the reference node units 110 and 120 are divided into reference node units #i (110) and reference node units #j (120).

In the present invention, since the position of the tag 200 is determined by using the intensity of the radio wave, the relationship between the radio wave intensity and the distance as shown in Equation 1 below is used.

In Equation 1, I (r) represents the strength of the radio wave c measured at the distance r, the index a is a constant to be determined.

In general, if the constant c and the index a are known, the distance r can be easily calculated by measuring the intensity I. However, in most cases, the propagation attenuation index a is sensitive to the environment and thus varies according to the environment in which the system is used, and the initial strength c sent by the transmitters 111 and 121 varies over time and therefore may be regarded as a fixed value. Can't. Therefore, there are many errors when the distance is measured using the fixed propagation model constants a and c.

The present invention precisely determines the position of a tag by determining constants a and c in real time using the positioning system shown in FIG.

로 측정하였고, 기준노드부 #j(120)의 발신기(121)에서 송신한 신호를 기준노드부 #i(110)의 수신기(113)에서 수신하였을 때 이 강도를

로 관측하였다고 하자. 태그(200)가 기준노드부 #i(110)의 발신기(111)에서 송신한 신호를 수신하였고 이의 강도는

로 관측하였다고 가정한다. 기준노드부 #i(110)와 태그(200) 사이의 거리를

이라 하고 전파 감쇄 지수를

라 하면 모르는 변수는

와

가 되고 관측된 값들은

와

가 된다. 결국 문제는 관측된

와

를 이용하여

와

를 실제값(True value)에 가까운 값으로 최적으로 추정하는 것이다. 이를 위한 간단한 방법은 기준노드부 #i(110)와 기준노드부 #j(120) 사이의 거리 정보를 이용하는 것이다. 즉, 기준노드부 #i(110)와 기준노드부 #j(120)의 위치는 알고 있기 때문에 이들 사이의 거리는 고정되어 있고 이 때

와

를 이용하면 기준노드부 #i(110)를 기준으로 다음의 수학식 2와 같은 관계식을 얻을 수 있다.The signals transmitted from the transmitters 111 and 121 of the reference node #i 110 and the reference node #j 120 have a unique identity, and the reference node #i 110 and the reference node have their own identity. Since the position of the sub #j 120 is known, the receivers 113 and 123 and the tag 200 may know at which position the received signal is transmitted. For convenience, the signal transmitted from the transmitter 111 of the reference node unit #i (110) is received by the receiver 113 of the reference node unit #i (110).

When the signal transmitted from the transmitter 121 of the reference node #j (120) is received by the receiver 113 of the reference node #i (110), this strength is measured.

Assume that we observed The tag 200 receives a signal transmitted from the transmitter 111 of the reference node unit #i 110 and its strength is

Assume that we observed The distance between the reference node #i (110) and the tag (200)

Called the radio wave attenuation index

If you don't know

Wow

And the observed values

Wow

Becomes Eventually the problem was observed

Wow

Using

Wow

Is optimally estimated to be close to the true value. A simple method for this is to use the distance information between the reference node unit #i (110) and the reference node unit #j (120). That is, since the positions of the reference node unit #i (110) and the reference node unit #j (120) are known, the distance between them is fixed.

Wow

By using Equation 2, a relational expression as shown in Equation 2 can be obtained based on the reference node unit #i (110).

는 기준노드부 #i(110)와 기준노드부 #j(120) 사이의 거리이고,

는 기준노드부 #i(110)에서 수신한 기준노드부 #j(120)의 신호 강도다. 따라서 알고자 하는

는 다음과 같은 수학식 3을 통해 구할 수 있다.In Equation 2 above

Is a distance between the reference node unit #i (110) and the reference node unit #j (120),

Is the signal strength of the reference node unit #j (120) received by the reference node unit #i (110). So you want to know

Can be obtained from Equation 3 below.

, i=1, …,N를 구할 수 있고 수학식 1과 태그에서 관측된 수신 강도

를 이용하면 기준노드부(110)와 태그(200) 사이의 거리

, i=1, …,N를 구할 수 있다.In the end, using the above Equation 3, the unknown attenuation index

, i = 1,… , N can be found and the received strength observed in Equation 1 and tags

By using the distance between the reference node 110 and the tag 200

, i = 1,… , N can be obtained.

를 다음의 수학식 4와 같이 계산할 경우에는 잡음의 효과를 상쇄할 수 있다.However, the above method has the advantage of being able to calculate the attenuation index simply, but has the disadvantage of being sensitive to noise. Therefore, as a method of overcoming this, a method of receiving the radio waves transmitted from the reference node unit #j 120 at the N reference node units and averaging them may be designed to remove noise. In other words,

When calculating as shown in Equation 4 below can cancel the effect of noise.

The overall flow of positioning through the propagation signal modeling will be described with reference to FIG. 2 as follows.

First, in order to determine the position of the tag 200, the transmitters 111 and 121 of each reference node unit 110 and 120 transmit radio waves (S301), and in the receivers 113 and 123 and the tag 200, the transmitter ( The radio wave transmitted by 111 and 121 is received (S303).

In addition, the receivers 113 and 123 and the tag 200 measure a received signal strength index (RSI), respectively (S305), and the receivers 113 and 123 measure the measured radio wave strength through radio wave communication. The tag 200 transmits to the tag 200 (S307).

를 수학식 3이나 수학식 4에 의해서 계산한다(S309).Next, the tag 200 uses the radio wave strength measured by itself and the radio wave strength received from the receivers 113 and 123 to attenuate the index.

Is calculated by the equation (3) or (4) (S309).

Finally, the calculated attenuation index calculates the distance between the tag 200 and the reference node units 110 and 120 through Equation 1 (S311). After the distance is calculated, the position of the tag 200 can be easily obtained by triangulation (S313). The positioning process by triangulation is well known in the art, and thus detailed description thereof will be omitted.

Until now, as a method for creating an accurate attenuation model of radio signals, transmitters 111 and 121 and receivers 113 and 123 are mounted together in reference node units 110 and 120 to receive radio wave strengths of receivers 113 and 123. The process of calculating the position of the tag 200 by the method of use has been described.

In the above-described embodiment, the position of the movable body is calculated by using the radio wave transmission / reception strength between the reference node unit and the tag of the movable body, but the position of another movable body whose position is unknown may be regarded as the reference node unit. At this time, the moving body used as a reference for calculating the position of the other moving body will be referred to as a substantial reference node. In addition, the position of another tag whose location is unknown may be calculated by using the reference node and a tag whose position is known. That is, the reference node unit in the embodiment may be an embodiment of the positioning reference body that knows the position, and the tag may be an embodiment of the position tracking means that does not know the position.

On the other hand, based on the method of determining the position using the propagation intensity as described above, it is possible to easily derive a method of determining the position using the propagation travel time or the radio arrival time difference.

FIG. 3 is a block diagram of a positioning system showing a signal flow when determining a position of a tag by synchronizing two reference node units according to another embodiment of the present invention by using a propagation movement time or a propagation time difference.

Referring to FIG. 3, the positioning system includes a plurality of reference node units 410 and 420 that know a location and a tag 500 that does not know a location.

The reference node unit 410 provides a transmitter 411 for transmitting radio waves, a receiver 413 for receiving radio waves from the outside, and a radio wave transmission time by the transmitter 411 and a radio wave arrival time to the receiver 413. It includes the clock 415 to measure.

The reference node unit 420 includes a transmitter 421 that transmits radio waves so that the receiver 413 can receive, a receiver 423 that receives radio waves from the transmitter 411, and a radio wave transmission time by the transmitter 421. And a clock 425 for measuring the radio wave arrival time to the receiver 423.

The tag 500 uses the radio wave transmission time measured by the clock 415 and the radio wave arrival time measured by the clock 425, or the radio wave transmission time measured by the clock 425 and the radio wave arrival measured by the clock 415. The two clocks 415 and 425 are synchronized using the time, and the radio waves are transmitted to the reference node unit 410 and 420 to use the difference in the radio wave arrival time measured by the two clocks 415 and 425 or the two clocks 415 and 425. The position of the moving object is determined using the propagation movement time measured by 425.

에 전파를 발신하여 기준노드부 #j(420)에서 기준노드부 #j(420)에 장착된 시계(425)를 기준으 로 시각

에 수신하였다고 하자(S601).Looking at the positioning process in more detail with reference to Figure 3, the time based on the clock mounted on the reference node #i (410) in the reference node #i (410)

The radio wave is sent to the time based on the clock 425 mounted on the reference node #j (420) from the reference node #j (420).

Let's say that (S601).

로 계산할 수 있다. 결국 두 시계(415, 425) 사이에는

만큼 시각 차이(off-set)가 존재하게 됨을 알 수 있다.In this case, since the distance between these two reference node parts 410 and 420 is constant and the time it takes for radio waves to reach between them is also constant, the clocks 415 and 425 of the two reference node parts 410 and 420 may be synchronized. Can be. That is, if the distance between them is d, the time it takes for the radio waves to reach can be calculated as d · c = Δt when the speed of light is c. Therefore, when the clock of the reference node #j (420) is viewed as a reference, the time at which the radio wave is transmitted from the reference node #i (410) is

Can be calculated as Finally, between the two clocks (415, 425)

As can be seen, there is an off-set.

에 전파를 발신하여 기준노드부 #i(410)에서 기준노드부 #i(410)에 장착된 시계(415)를 기준으로 시각

에 수신하였다고 하면 두 시계(415, 425) 사이의 시각 차이를

와 같이 구할 수 있다(S603).On the contrary, the time based on the clock 425 mounted on the reference node #j 420 in the reference node #j 420.

The radio wave is sent to the time based on the clock 415 mounted on the reference node #i 410 from the reference node #i 410.

The time difference between the two clocks (415, 425)

It can be obtained as (S603).

In the same principle, the difference between the time at which the radio wave is transmitted by the tag 500 and the time received by the reference node unit #i 410 and the reference node unit #j 420 is obtained (S605 and S607).

Finally, the time-difference of arrival (TDOA) method uses the time difference between the two clocks 415 and 425 and the arrival time difference received from the two reference node units 410 and 420. By the position of the tag 500 can be calculated. Since the TDOA method is well known in the art, a detailed description thereof will be omitted.

On the other hand, as shown in steps S605 and S607 that the arrival time difference between the reference node unit #i 410 and the reference node unit #j 420 can be obtained, the tag 500 transmits a radio wave to transmit the reference node unit #i (410). ) And propagation movement time, which means time to reach the reference node unit #j 420, can be obtained. Accordingly, the position of the tag 500 may be calculated by a time of flight (TOF) method using a propagation movement time without using the TDOA method.

In the above-described embodiments, the position of the movable body is calculated using the propagation movement time or the radio wave arrival time difference between the reference node unit and the tag of the movable body, but the movable body that knows the position is regarded as the reference node unit. You can also calculate the location. At this time, the moving body used as a reference for calculating the position of the other moving body will be referred to as a substantial reference node. In addition, the position of another tag whose location is unknown may be calculated by using the reference node and a tag whose position is known. That is, the reference node unit in the embodiment may be an embodiment of the positioning reference body that knows the position, and the tag may be an embodiment of the position tracking means that does not know the position.

It has been described so far limited to one embodiment of the present invention, it is obvious that the technology of the present invention can be easily modified by those skilled in the art. Such modified embodiments should be included in the technical spirit described in the claims of the present invention.

In the present invention, it is possible to precisely measure the position of an object by calculating propagation characteristics in real time.

The present invention accurately and easily calculates the distance between a reference node and a moving object whose location is not known by using a signal strength attenuation model indoors or outdoors, or uses a position difference using a propagation time difference or propagation travel time of the reference node. The precision and accuracy of the decision is improved.

Claims (22)

A first positioning reference body comprising a first transmitter for transmitting a radio wave and a first receiver for providing a radio wave intensity measured by receiving radio waves transmitted from the first transmitter and radio waves from the outside; A second transmitter for transmitting a radio wave so that the first receiver can receive; and a second receiver for receiving and measuring a radio wave transmitted from the second transmitter and a radio wave transmitted from the first transmitter. A second positioning reference body; Position tracking means for determining the position of the moving object through radio signal modeling using the radio wave strength measured by receiving the radio wave transmitted from the first and second transmitters and the radio wave strengths provided from the first and second receivers. Positioning system comprising a. The method of claim 1, The first and second positioning reference bodies may be implemented as reference node parts attached to a point that becomes a reference point of triangulation for calculating the position of the moving object. The position tracking means is attached to the moving body implemented by a tag for calculating the distance to each of the reference node portion Positioning system. The method of claim 2, The tag may determine the radio wave attenuation index in real time using the radio wave strength measured by receiving the radio wave transmitted from the first and second transmitters and the radio wave strengths provided from the first and second receivers, and then, respectively, the reference node Used to calculate distance from wealth Positioning system. The method of claim 2, The positioning system includes at least N positioning reference bodies including at least the first and second positioning reference bodies, where N is a natural number greater than two, The tag removes noise using radio wave strengths provided from receivers of the N positioning reference bodies to determine a propagation attenuation index in real time and calculates a distance from each of the reference node units. Positioning system. The method of claim 2, The reference node unit may be implemented by another moving object having a known position. Positioning system. The method of claim 1, Any one of the first and second positioning reference bodies may be implemented as a reference node part attached to a point which becomes a reference point of triangulation for calculating the position of the moving object, and the other may be a first tag attached to the moving object whose position is known. Implement The position tracking means is implemented by a second tag attached to a moving body and calculating a distance between the reference node and the first tag. Positioning system. A first clock for transmitting radio waves, a first receiver for receiving radio waves from the outside, and a first clock for measuring radio wave transmission time by the first transmitter and radio wave arrival time to the first receiver; 1 positioning reference body; A second transmitter for transmitting radio waves so that the first receiver can receive; a second receiver for receiving radio waves transmitted from the first transmitter; and a radio wave transmission time by the second transmitter and radio waves to the second receiver A second positioning reference body comprising a second clock for measuring arrival time; The radio wave is transmitted to the first and second positioning reference bodies to determine the position of the moving object using the difference in radio wave arrival time measured by the first and second clocks, or by using the propagation travel time measured by the first and second clocks. Location tracking means Positioning system comprising a. The method of claim 7, wherein The position tracking means uses radio wave transmission time measured by the first clock and radio wave arrival time measured by the second clock, or radio wave transmission time measured by the second clock and radio wave measured by the first clock. To synchronize the first and second clocks using the arrival time. Positioning system. The method of claim 7, wherein The first and second positioning reference bodies may be implemented as reference node parts attached to a point that becomes a reference point of triangulation for calculating the position of the moving object. The position tracking means is attached to the moving body implemented by a tag for calculating the distance to each of the reference node portion Positioning system. The method of claim 9, The reference node unit may be implemented by another moving object having a known position. Positioning system. The method of claim 7, wherein Any one of the first and second positioning reference bodies may be implemented as a reference node part attached to a point which becomes a reference point of triangulation for calculating the position of the moving object, and the other may be a first tag attached to the moving object whose position is known. Implement The position tracking means is implemented by a second tag attached to a moving body and calculating a distance between the reference node and the first tag. Positioning system. A first positioning reference body having a first transmitter and a first receiver for transmitting and receiving radio waves, a second positioning reference body having a second transmitter and a second receiver for transmitting and receiving radio waves, a position including a position tracking means A method for determining the position of said position tracking means in a determination system, (a) receiving, at the first and second receivers and the location tracking means, radio waves transmitted from the first transmitter; (b) receiving radio waves transmitted from the second transmitter at the first and second receivers and the location tracking means; (c) measuring the received radio wave strength by the first and second receivers and the location tracking means, respectively; (d) providing said position tracking means with said propagation intensity measured by said first and second receivers; (e) determining the position of the moving object through the propagation signal modeling using the propagation intensity measured by the position tracking means and the propagation strengths provided from the first and second receivers; Position determination method comprising a. The method of claim 12, The first and second positioning reference bodies may be implemented as reference node parts attached to a point that becomes a reference point of triangulation for calculating the position of the moving object. The position tracking means is attached to the moving body implemented by a tag for calculating the distance to each of the reference node portion Positioning method. The method of claim 13, In the step (e), the tag determines the radio wave attenuation index in real time by using the radio wave strength measured by the tag and the radio wave strengths provided from the first and second receivers, and then uses the distance to the reference node unit. To calculate Positioning method. The method of claim 13, Wherein the positioning method comprises N positioning references, wherein the positioning system includes at least the first and second positioning reference bodies, where N is a natural number greater than two; In the step (e), the tag removes noise using radio wave strengths provided from receivers of the N positioning reference bodies to determine a radio wave attenuation index in real time, and then uses the tag to determine the radio wave attenuation index in real time. To calculate distance Positioning method. The method of claim 13, The positioning method may be implemented by the reference node unit of another moving object having a known position. Positioning method. The method of claim 12, In the positioning method, any one of the first and second positioning reference bodies is used as a reference node part attached to a point which becomes a reference point of triangulation for calculating the position of the moving body, and the other is connected to a moving body whose position is known. Used as the attached first tag, In the step (e), the second tag implementing the position tracking means calculates a distance between the reference node unit and the first tag. Positioning method. A first positioning reference body having a first transmitter and a first receiver and a clock for transmitting and receiving radio waves, a second positioning reference body having a second transmitter, a second receiver and a clock for transmitting and receiving radio waves, a position tracking means A method of determining the position of the position tracking means in a positioning system comprising: (A) measuring the radio wave transmission time by the first transmitter and the radio wave arrival time to the second transmitter that receives the radio wave, or the radio wave transmission time by the second transmitter and the first transmitter that receives the radio wave; Measuring the radio wave arrival time until (B) obtaining a time difference between the first and second positioning reference bodies using the radio wave transmission time and the radio wave arrival time; (C) The radio wave is transmitted to the first and second positioning reference bodies to measure the difference in the radio wave arrival time to the first and the second positioning reference bodies, or the propagation movement time to the first and the second positioning reference bodies. Measuring the (D) use the time difference between the first and second positioning reference bodies and the radio wave arrival time difference obtained in step (b), or use the time difference and the propagation travel time of the first and second positioning reference bodies. Determining the position of the moving object Position determination method comprising a. The method of claim 18, The positioning method may include synchronizing the clocks of the first and second positioning reference bodies before performing the step (c). Positioning method. The method of claim 18, The positioning method may be implemented by each of the first and second positioning reference bodies attached to a reference node attached to a point that becomes a reference point of triangulation for calculating the position of the moving object. The position tracking means is attached to the moving body implemented by a tag for calculating the distance to each of the reference node portion Positioning method. The method of claim 20, The positioning method may be implemented by the reference node unit of another moving object having a known position. Positioning method. The method of claim 18, In the positioning method, any one of the first and second positioning reference bodies is used as a reference node part attached to a point which becomes a reference point of triangulation for calculating the position of the moving body, and the other is connected to a moving body whose position is known. Used as the attached first tag, In the step (d), the second tag implementing the position tracking means calculates a distance between the reference node unit and the first tag. Positioning method.

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