JP2008008780A - Position estimation system and position estimation method - Google Patents

Abstract

An object of the present invention is to realize simple and economical position detection in a closed space such as an indoor or underground mall.
A mobile terminal 1 that transmits unmodulated radio waves, a plurality of fixed receivers 2 to 4 that simultaneously receive radio waves transmitted from the mobile terminal 1, and an arbitrary one of a plurality of fixed receivers 2 to 4 Phase comparators 5 and 6 for comparing and measuring the relative phase difference of radio waves generated with the movement of the mobile terminal 1 and the phase comparators 5 and 6. A position calculator 7 is connected for estimating the arrival direction of the radio wave based on the relative phase difference of the radio wave compared by the phase comparators 5 and 6 and calculating the position of the mobile terminal from the result.
[Selection] Figure 1

Description

  The present invention relates to a position estimation system and a position estimation method for estimating an arrival wave direction using a mobile terminal such as a mobile phone and estimating its position.

GPS (Global Positioning System) is most widely used for position estimation using radio waves, and GPS covers the world with 24 satellites. However, it is limited to outdoor use, and it is impossible for others to know the position of the GPS terminal owner unless it has communication means.
For this reason, there is a technique for obtaining a distance from the propagation delay of radio waves using a wireless LAN and detecting the position based on the principle of triangulation. Although this technology can be used indoors, it has a special system configuration and is expensive.

Further, a method of receiving radio waves in the vicinity and knowing the position using RFID (Radio Frequency IDentification) is being studied. According to this method, it is effective only for positioning at discrete points, but it has been found that a huge amount of RFID is required for linear or planar positioning.
Further, in Patent Document 1, the configuration is greatly complicated by measuring the phase difference of the wave signal arriving from the transmission side at two different positions individually for two pairs of two different positions. A position estimation device capable of estimating the position of the transmitting end with high accuracy, stability, and low cost is described, and in Patent Document 2, the direction estimation device radiates a directional transmission wave, and the received transmission wave A direction estimation system, a direction estimation device, and a direction estimation terminal that can be used in places where there are obstacles by comparing signal levels are described.
JP 2004-333252 A JP 2005-318393 A

However, in the device described in Patent Document 1 described above, in a small terminal in which only one receiving antenna such as a mobile phone can be arranged, the receiver has a small shape. It is difficult to arrange the radio waves, and therefore, it is impossible to estimate the arrival direction and the position of the radio wave.
Also, as in the MUSIC (Multiple Signal Classic) method, in order to calculate the frequency component of a signal, a process such as calculating a pseudo spectrum using a Schmidt eigenspace analysis method from the signal or signal correlation matrix is performed. It was necessary to apply a difficult algorithm, and it was difficult to estimate its position easily.

In addition, the device described in Patent Document 2 can be used only in places where there are obstacles such as receivers. Further, in an enclosed space such as an indoor or underground mall, the cost increases or separate communication is required. It was difficult for others to know the position of the GPS terminal owner, such as requiring a means.
The present invention has been made in view of the above-described circumstances, and can be applied to a small terminal such as a mobile phone in which only one receiving antenna can be arranged. An object of the present invention is to provide a position estimation system and a position estimation method based on the direction of an incoming wave that can realize economical position detection.

In order to solve the above-mentioned problem, the position estimation system according to claim 1 comprises:
A mobile terminal having a transmitting antenna for transmitting radio waves;
A plurality of fixed receivers that simultaneously receive radio waves transmitted from the mobile terminal;
A plurality of phase comparators that are arranged between any pair of fixed reception devices among the plurality of fixed reception devices, and that compare and measure the relative phase difference of radio waves generated with the movement of the mobile terminal;
A position calculator connected to the phase comparator, estimating the arrival direction of the radio wave based on the relative phase difference of the radio wave compared by the phase comparator, and calculating the position of the mobile terminal from the result;
It is characterized by having.

According to this configuration, in the indoor position detection, the fixed receiving device does not need a plurality of antennas, so that it is possible to form an infrastructure at a low cost.
According to a second aspect of the present invention, in the position estimation system according to the first aspect, the position calculator calculates the position of the mobile terminal after the movement of the phase difference between the plurality of fixed reception devices. It is characterized by estimating based on the change of the relative phase difference in.
According to this configuration, the position after movement of the mobile terminal can be estimated by converting the relative phase difference before and after the movement of the phase difference between the plurality of fixed reception devices into a distance using a simple conversion formula. An effect is obtained.

According to a third aspect of the present invention, in the position estimation system according to the first aspect, the plurality of fixed reception devices are four, and the relative phase difference between the fixed reception devices before and after the mobile terminal moves is calculated. The absolute position of the mobile terminal is obtained from the condition that the intersections of the three equiphase difference curves drawn on the basis of them match.
According to this configuration, even when the initial position of the mobile terminal is not known, the absolute position of the mobile terminal can be obtained.

According to a fourth aspect of the present invention, in the position estimation system according to the third aspect, the position calculator uses the wave number from the mobile terminal to each fixed reception device as an unknown number, and the estimated position of the mobile terminal and the position Estimating the absolute position of the mobile terminal by building simultaneous equations from unknowns, extracting three intersections from the wave numbers obtained each time the vehicle moves, and finding the wave number that satisfies the condition that minimizes the difference between them. It is a feature.
According to this configuration, there is an effect that the position of the mobile terminal can be obtained as an absolute position by a simple simultaneous equation.

According to a fifth aspect of the present invention, in the position estimation system according to the first aspect, the position calculator includes a table indicating a relationship between a phase difference between the fixed reception devices and a position of the mobile terminal, Collating means for collating the phase difference measured by the phase comparator and the phase difference shown in the table is provided, and the position where they are most matched is estimated as the position of the mobile terminal.
According to this configuration, since the table is used, an effect that the calculation process is fast and the position can be estimated with high accuracy is obtained.

The invention according to claim 6 is the position estimation system according to claim 1, wherein the mobile terminal transmits an unmodulated radio wave from the transmission antenna.
According to this configuration, there is an effect that the position of the mobile terminal can be estimated with a simple system.
According to a seventh aspect of the present invention, in the position estimation system according to the first aspect, the mobile terminal transmits a radio wave of a modulated wave of a cellular phone from the transmission antenna.
According to this configuration, it is possible to easily estimate the position using radio waves from a mobile phone or the like.

Moreover, the position estimation system according to claim 8 comprises:
An oscillation splitting device that divides by dividing by oscillating radio waves,
A plurality of fixed transmission devices that radiate radio waves distributed by the oscillation division device into space;
A mobile terminal that receives and separates radio waves transmitted by the fixed transmission device, detects each relative phase difference or phase difference, and estimates its own position from the amount of change,
It is characterized by having.
According to this structure, the effect that the mobile terminal itself can estimate the position is acquired.

The position estimation method according to claim 9 is:
A transmission step of transmitting radio waves from the mobile terminal;
A reception step of simultaneously receiving radio waves transmitted from the mobile terminal using a plurality of fixed reception devices;
A comparison step of comparing and measuring the relative phase difference of radio waves generated with the movement of the mobile terminal using a plurality of phase comparators arranged between any pair of fixed reception devices of the plurality of fixed reception devices;
Using a position calculator connected to the phase comparator, the arrival direction of the radio wave is estimated based on the relative phase difference of the radio wave compared by the phase comparator, and the position of the mobile terminal is calculated from the result A calculation step to
It is characterized by including.
According to this configuration, in the indoor position detection, the fixed receiving device does not need a plurality of antennas, so that it is possible to form an infrastructure at a low cost.

As described above, in the position estimation system and the position estimation method of the present invention, the position is specified by measuring the relative phase change and the phase difference of the unmodulated wave. Position estimation can be performed.
In addition, indoor position detection requires a huge amount of infrastructure because measurement devices must be installed in all areas of interest, but the application of the present invention reduces the cost. Infrastructure can be formed.

Hereinafter, a preferred embodiment of a position estimation system of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a schematic diagram showing a basic configuration example of a position estimation system of the present invention.
The position estimation system 10 includes a mobile terminal 1, a plurality of fixed reception devices 2 to 4, phase comparators 5 and 6, and a position calculator 7.
The mobile terminal 1 can be applied to any general mobile device such as a mobile phone, an in-vehicle device, and a mobile.
The fixed reception devices 2 to 4 are wireless communication devices that simultaneously receive radio waves transmitted from the mobile terminal 1 with the same content.

The phase comparators 5 and 6 measure and compare the phase difference between the radio waves received by the fixed receiving devices 2 to 4. Here, the phase comparator 5 compares the phases between the fixed receiver 2 and the fixed receiver 3, and the phase comparator 6 compares the phases between the fixed receiver 3 and the fixed receiver 4. .
The position calculator 7 is an apparatus that is connected to the phase comparators 5 and 6 and calculates the position of the mobile terminal 1 based on the relative phase difference compared by the phase comparators 5 and 6.

  In FIG. 1, the radio waves transmitted from the mobile terminal 1 are received by the fixed receivers 2 to 4, and the phase comparators 5 and 6 measure the phase difference between the radio waves received by the fixed receivers. That is, assuming that the phase of the radio wave received by the fixed receiver 2 before the movement of the mobile terminal 1 is φ2 (t1) and the phase of the radio wave received by the fixed receiver 3 is φ3 (t1), the phase comparator 5 at this time Detects the phase difference φ2 (t1) −φ3 (t1). If the phase of the radio wave received by the fixed receiver 2 after the movement of the mobile terminal 1 is φ2 (t2) and the phase of the radio wave received by the fixed receiver 3 is φ3 (t2), the phase comparator 5 at this time is The phase difference to be detected is φ2 (t2) −φ3 (t2).

Here, if the change in the phase difference before and after the movement of the mobile terminal 1 is defined as a relative phase change Δφ,
Δφ = {φ2 (t1) −φ3 (t1)} − {φ2 (t2) −φ3 (t2)}
It can be expressed as. When this relative phase change Δφ is divided by 2π (radian) and multiplied by wavelength λ, the distance change Δd is
Δd = Δφ × λ / 2π
It becomes. For example, when the phase is measured by the fixed receiving device 2 and the fixed receiving device 3, the distance change Δd includes the distance that the mobile terminal 1 has moved away from the fixed receiving device 2 and the distance that has approached the fixed receiving device 3. It corresponds to the difference.

Next, a method for estimating the position of the mobile terminal using this configuration will be described below.
When the initial position of the mobile terminal 1 is known, a method for obtaining the distance change Δd of the fixed receivers 2 to 4 from the mobile terminal 1 and measuring the position of the mobile terminal 1 will be described below with reference to FIG. State.
FIG. 2 is a diagram illustrating a method for estimating a position from the intersection of hyperbolic curves.
After the movement of the mobile terminal 1, the difference x between the distance from the mobile terminal 1 to the fixed reception device 2 and the distance from the mobile terminal 1 to the fixed reception device 3 at the position (initial position) before the movement of the mobile terminal 1 When the distance change Δd obtained by the above measurement is added, the difference (x + Δd) between the distance from the mobile terminal 1 to the fixed receiver 2 after movement and the distance from the mobile terminal 1 to the fixed receiver 3 is obtained. From this distance difference (x + Δd), a hyperbola 101 including a position where the mobile terminal 1 exists is defined. By performing the same operation by defining the hyperbola 102 from the fixed receiver 4 and the fixed receiver 2 and the hyperbola 103 from the fixed receiver 4 and the fixed receiver 3, three hyperbolas are newly defined as shown in FIG. Is done.

The intersection P of these hyperbolas is the estimated position of the mobile terminal 1 after movement. In addition, although an intersection can be obtained even with two hyperbola, there may be a plurality of intersections as shown in FIG. That is, the intersection of the hyperbola 101 and the hyperbola 102 is two points P and Q. Therefore, it can be seen that three hyperbolas are required to correctly obtain the position.
As described above, when the initial position of the mobile terminal 1 is known, the locus of the mobile terminal 1 can be obtained by repeating the above operation using the three fixed reception devices 2 to 4.

[Second Embodiment]
Next, a method for obtaining the absolute position of the mobile terminal will be described with reference to FIG.
The method according to the first embodiment requires an initial position, but if this method is applied, information on the initial position is not necessary.
FIG. 3 is a schematic diagram showing the basic principle of the position estimation system according to the second embodiment of the present invention.
In the present embodiment, four fixed reception devices are required to obtain the absolute position of the mobile terminal 1. That is, in the case where the distance difference is calculated for the three fixed receivers 2 to 4, there is a position of the mobile terminal where the distance difference of all the fixed receivers is exactly the same. Since the position of the mobile terminal cannot be estimated, four fixed receiving apparatuses are required.

Here, the reason why four fixed reception devices are required to obtain the absolute position of the mobile terminal 1 will be described in detail below.
In the figure, R (t1) is the position (initial position) of the mobile terminal at time t1, and R (t2) is the position of the mobile terminal (position after movement) at time t2.
Here, defining “distance between fixed reception device A and R (t1) = distance between fixed reception device B and R (t1) = x”, the fixed reception device and the mobile terminal according to the time change The difference in distance is as follows.
“Change in distance to the fixed receiver A when the mobile terminal moves from R (t1) to R (t2)” and “Fixed reception when the mobile terminal moves from R (t1) to R (t2)” The difference from “change in distance to device B” is

“Change in distance to fixed receiver B when mobile terminal moves from R (t1) to R (t2)” and “Fixed reception when mobile terminal moves from R (t1) to R (t2)” The difference from “change in distance to device C” is

“Change in distance to the fixed receiver C when the mobile terminal moves from“ R (t1) ”to R (t2)” and “Fixed when the mobile terminal moves from R (t1) to R (t2)” The difference from the “change in distance to the receiving device A” is

It becomes.
On the other hand, in the second embodiment, since the position (initial position) of the mobile terminal at time t1 is unknown, there is a possibility that the position of S (t1 ′) is the initial position.
Here, in FIG. 3, S (t1 ′) is the position (initial position) of the mobile terminal at time t1, and S (t2 ′) is the position of the mobile terminal (position after movement) at time t2. the distance between t2 ′) and the fixed receiver C is a ′, the distance between S (t1 ′) and the fixed receiver C is b ′, and
Distance between fixed receiver A and S (t1 ′) = xy
Distance between fixed receiver B and S (t1 ′) = x + y,
Distance between fixed receiver B and S (t2 ′) = z,
The distance between the fixed receiver A and S (t2 ′) is defined as z ₂ .

At this time, the difference in the distance between the fixed reception device and the mobile terminal accompanying the change in time is as follows.
・ "Change in distance to fixed receiver A when the mobile terminal moves from S (t1 ') to S (t2')" and "The mobile terminal moves from S (t1 ') to S (t2') The difference with "change in distance with respect to the fixed receiver B when"
_{= {Z 2 - (x-} y)} - {z- (x + y)} = 2y-z + z 2 ... (4)
・ "Change in distance to fixed receiver B when the mobile terminal moves from S (t1 ') to S (t2')" and "The mobile terminal moves from S (t1 ') to S (t2') The difference with "change in distance with respect to the fixed receiver C when"
= {Z− (x + y)} − (a′−b ′) = − x−y + z−a ′ + b ′ (5)
・ "Change in distance to the fixed receiver C when the mobile terminal moves from S (t1 ') to S (t2')" and "The mobile terminal moves from S (t1 ') to S (t2') The difference with the “change in distance relative to the fixed receiver A” is
= (A′−b ′) − {z ₂ − (xy)} = xy−z ₂ + a′−b ′ (6)
It becomes. In the above formula,
Formula (1) = Formula (4), that is,

  Formula (2) = Formula (5), that is,

  Formula (3) = Formula (6), that is,

If there is a condition that becomes as follows, it cannot be determined which of the positions (R (t1) and S (t1)) of the two mobile terminals at the time t1 is the initial position. That is, the three fixed receivers A, B, and C cannot determine the position at time t1.
Therefore, when one more fixed receiving apparatus is added, it can be determined which of the initial positions is.

In this case, first, an initial position of the mobile terminal 1 is assumed, and a distance difference (x + Δd) is obtained from the relative phase change between the fixed receiving apparatuses obtained after the movement from the initial position, and three hyperbolas are drawn. If the assumed initial position is correct, the intersections coincide. If they do not match, 3-6 intersections will appear. Out of these intersections, three intersections are extracted and converged so as to minimize the difference between the distances as an evaluation function, and the position of the mobile terminal when the evaluation function is minimum is the absolute position. . At this time, when more than three intersections appear, as a method of extracting three intersections, after arbitrarily extracting three intersections, calculate the area of a triangle having the three points as vertices, What is necessary is just to take the method of extracting the intersection which the area becomes the minimum.
For the above reasons, when there is no initial position, at least four fixed receivers are required.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.
The present embodiment is a method for obtaining the position with higher accuracy. In the method of the first embodiment and the second embodiment, the distance change Δd of each fixed reception device is obtained from the mobile terminal by the relative phase change Δφ, but in this embodiment, the value of the phase difference itself is particularly focused. Not. Here, paying attention to the value of the phase difference itself, the distance D from the mobile terminal 1 to the fixed receivers 2 to 4 is:
D = (measured phase difference + 2πn) × λ / 2π (n is an integer)
It is. If n is obtained, the error in the distance from the mobile terminal to the fixed receiver is equal to or less than the wavelength (phase difference measurement error × λ / 2π), and a very accurate distance can be obtained.

  When calculating n backward from the distance D, if the phase difference can be measured accurately and the accurate distance D can be estimated, the correct n can be obtained. If accurate measurement of the phase difference is possible and n is an incorrect value, circles drawn at distance D from each fixed receiving device (hereinafter, distance circles) do not intersect at one point. On the other hand, the estimated values before and after n (eg, n + 1, n−1, etc.) are used instead of n to estimate the distance, and as a result, the distance circles from each fixed receiving device can intersect at one point. The value is correct. However, since the measurement always includes an error, the correct n is not always obtained by such a procedure. Therefore, the operation for searching for the optimum n is repeated as the mobile terminal moves. If n is correct, the distance circles from the fixed receiving apparatuses always intersect at almost one point, but if n is incorrect, it does not converge to one point. By this comparison, the most correct value of n can be found. For example, n is obtained by providing a threshold value (for example, the distance estimation error from the fixed reception device to the estimated position is always equal to or less than ¼ wavelength) to the extent that the distance from each fixed reception device converges to one point. Once n is obtained, the subsequent positional accuracy is equal to or less than the wavelength (phase difference measurement error × λ / 2π). For example, if the phase measurement error is π / 4 at 2, 45 GHz, the position error is about 3 cm. Among the above methods, the method for estimating the distance D using n is effective even if the initial position is known. If the initial position is known, n has already been given. Therefore, for example, when one phase of the phase changes in accordance with the change in the phase accompanying the movement, 1 is added to (subtracted from) n. If it goes, accurate measurements can be maintained.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described.
The present embodiment is a method for estimating the position using the Euclidean distance. A table as a database is required first, but after the table is created, the calculation process is fast. FIG. 4 shows an example of the database. The element number corresponding to the position is divided into N × M (N and M are integers), and a table for each divided element (N × M page measurement range as a total) is created. Here, element numbers (1, 1), (1, 2), (2, 1) are given as an example for the position (N, M). The vertical axis of the table represents the azimuth angle in the direction of travel (0 to 360 degrees is equally divided into L: L is an integer), and the horizontal axis is filled with the relative phase change φ measured between each fixed receiver. Yes. For example, in this table, in the case of the element number (1, 1), if the azimuth angle in the traveling direction is 0 °, the fixed reception devices 2 and 3 are 300 °, the fixed reception devices 2 and 4 are 200 °, and the fixed number is fixed. The angle between the receiving devices 3 and 4 is 100 °. Note that the movement amount of the mobile terminal at this time is set to a unit length (for example, 1 m).

  In actual measurement, first, a table of pages corresponding to the position (element) of the mobile terminal before moving is prepared. Next, the relative phase change φ measured between the fixed receivers after the movement of the mobile terminal is normalized. For example, each relative phase change φ is divided by the sum of absolute values of the relative phase changes φ. Similarly, the relative phase change φ on the table is also normalized. Next, the Euclidean distance (the difference between the two values is squared to obtain the square root of the sum) between the normalized table value and the actual measurement value is calculated. The direction in which the Euclidean distance is the minimum is the direction in which the mobile terminal has advanced. The movement distance is obtained by taking the ratio of the actually measured phase amount and the phase amount on the table and multiplying by the unit length.

[Fifth Embodiment]
FIG. 5 is a diagram showing a basic configuration of the fifth embodiment of the present invention.
In the present embodiment, the mobile terminal 11 measures the position by itself using the fixed transmission devices 12 to 14 and the oscillation / division device 15 that distributes radio waves.
The fixed transmission devices 12 to 14 are wireless communication devices that simultaneously transmit the same content to the mobile terminal 11.
The radio waves distributed by the oscillating / dividing device 15 are radiated into the space from the fixed transmitting devices 12, 13, and 14. The mobile terminal 11 separates these radio waves after receiving them, detects each relative phase difference or phase difference, and estimates the position from the amount of change. In this way, the mobile terminal 11 can know its own position by transmitting with the fixed transmission devices 12 to 14 and receiving with the mobile terminal 1.

[Modification]
Next, a modified example of the present invention will be described.
In the above-described embodiment, an example using an unmodulated wave has been described. However, in the method using a modulated wave, for example, a radio wave of a mobile phone can be used, and a special device for this positioning is not required. Is a feature.
The present invention has been described above by the preferred embodiments of the present invention. While the invention has been described with reference to specific embodiments, various modifications and changes may be made to these embodiments without departing from the broad spirit and scope of the invention as defined in the claims. Obviously you can. In other words, the present invention should not be construed as being limited by the details of the specific examples and the accompanying drawings.

It is the schematic which shows the basic structural example of the position estimation system which concerns on 1st Embodiment. It is a figure which estimates a position from the intersection of a hyperbola. It is the schematic which shows the reason why four fixed receivers are required in the position estimation system which concerns on 2nd Embodiment. It is a figure which shows the example of the table for calculating Euclidean distance in order to estimate a moving direction in the position estimation system which concerns on 4th Embodiment. It is the schematic which shows the structural example which made the fixed side oscillate and received the mobile terminal in the position estimation system which concerns on 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,11 ... Mobile terminal, 2, 3, 4 ... Fixed receiver, 5, 6 ... Phase comparator, 7 ... Position calculator, 10 ... Position estimation system, 12, 13, 14 ... Fixed transmitter, 15 ... Oscillation・ Split device

Claims (9)

A mobile terminal having a transmitting antenna for transmitting radio waves;
A plurality of fixed receivers that simultaneously receive radio waves transmitted from the mobile terminal;
A plurality of phase comparators that are arranged between any pair of fixed reception devices among the plurality of fixed reception devices, and that compare and measure the relative phase difference of radio waves generated with the movement of the mobile terminal;
A position calculator connected to the phase comparator, estimating the arrival direction of the radio wave based on the relative phase difference of the radio wave compared by the phase comparator, and calculating the position of the mobile terminal from the result;
A position estimation system comprising:   The position estimation system according to claim 1, wherein the position calculator estimates the position of the mobile terminal after movement based on a change in relative phase difference before and after movement of the phase difference between the plurality of fixed reception devices. A position estimation system characterized by:   The position estimation system according to claim 1, wherein the plurality of fixed reception apparatuses are four, and three equal phase difference curves drawn based on a relative phase difference between the fixed reception apparatuses before and after the mobile terminal moves. A position estimation system, wherein an absolute position of the mobile terminal is obtained from a condition in which intersections of the mobile terminals coincide with each other.   4. The position estimation system according to claim 3, wherein the position calculator uses the wave number from the mobile terminal to each fixed reception device as an unknown number, and creates a simultaneous equation from the estimated position of the mobile terminal and the unknown number, and moves A position estimation system, wherein three intersections are extracted from wave numbers obtained each time, and an absolute position of the mobile terminal is estimated by finding a wave number that satisfies a condition that the difference between them is minimized.   2. The position estimation system according to claim 1, wherein the position calculator includes a table indicating a relationship between a phase difference between the fixed reception apparatuses and a position of the mobile terminal, a phase difference measured by the phase comparator, and the A position estimation system comprising: a collating unit that collates with a phase difference indicated in a table, and estimating a position where they are most consistent as a position of a mobile terminal.   The position estimation system according to claim 1, wherein the mobile terminal transmits an unmodulated radio wave from the transmission antenna.   The position estimation system according to claim 1, wherein the mobile terminal transmits a radio wave of a modulated wave of a mobile phone from the transmission antenna. An oscillation splitting device that divides by dividing by oscillating radio waves,
A plurality of fixed transmission devices that radiate radio waves distributed by the oscillation division device into space;
A mobile terminal that receives and separates radio waves transmitted by the fixed transmission device, detects each relative phase difference or phase difference, and estimates its own position from the amount of change,
A position estimation system comprising: A transmission step of transmitting radio waves from the mobile terminal;
A reception step of simultaneously receiving radio waves transmitted from the mobile terminal using a plurality of fixed reception devices;
A comparison step of comparing and measuring the relative phase difference of radio waves generated with the movement of the mobile terminal using a plurality of phase comparators arranged between any pair of fixed reception devices of the plurality of fixed reception devices;
Using a position calculator connected to the phase comparator, the arrival direction of the radio wave is estimated based on the relative phase difference of the radio wave compared by the phase comparator, and the position of the mobile terminal is calculated from the result A calculation step to
The position estimation method characterized by including.

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