JP7474188B2 - Information processing device, information processing method, and program - Google Patents

Description

The present invention relates to an information processing device, an information processing method, and a program, and in particular to a technology for estimating the direction and position of a transmitting station that transmits radio waves in a frequency band that can be used for mobile communications.

Conventionally, a wave source location estimation technology for estimating the location of a transmitting station (wave source) that transmits radio waves in a frequency band that can be used for mobile communications is described, for example, in Non-Patent Document 1. In the wave source location estimation technology described in Non-Patent Document 1, multiple terminals (sensor nodes) that detect the received signal strength (Received Signal Strength Indicator: RSSI) of radio waves transmitted from a transmitting station are placed in a search area, and the location of each terminal is weighted by the RSSI detected by each terminal and averaged to calculate the RSSI center of gravity, and the calculated RSSI center of gravity is used as the estimated location of the transmitting station.

Takuya Wadaka, Toshiyuki Maeyama, Hiroki Matsuno, Hiroyuki Shinbo, "A Study on Estimation of Radio Wave Usage Area in Mobile Distributed Monitoring", 2016 Institute of Electronics, Information and Communication Engineers General Conference, B-17-11

The wave source location estimation technology described in Non-Patent Document 1 above is based on the premise that the radio waves transmitted by the transmitting station are omnidirectional. However, the radio waves transmitted by some transmitting stations are often directional, and there may be cases where there is no information on whether the radio waves transmitted by a transmitting station are directional, or, if they are, their direction. In such cases, the above technology may reduce the accuracy of estimating the direction and position of the transmitting station.

The present invention has been made in consideration of these points, and aims to provide a technology that improves the accuracy of estimating the direction in which a transmitting station is located.

The first aspect of the present invention is an information processing device. This device includes a power center of gravity calculation unit that calculates a power center of gravity by averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighted by the power detected by each of the radio wave sensors, and an area setting unit that sets a sub-area that is an area including the power center of gravity, and sets a plurality of sub-areas whose setting positions are changed by rotating the sub-areas at a plurality of different rotation angles with the power center of gravity as a rotation center. The power center of gravity calculation unit calculates a plurality of sub-area centers of gravity by averaging the position coordinates of each of the plurality of radio wave sensors included in each of the plurality of sub-areas, weighted by the power detected by each of the radio wave sensors. The information processing device further includes a distance calculation unit that calculates a center-of-gravity distance, which is the distance between the power center of gravity and each of the plurality of sub-area centers of gravity calculated by the power center of gravity calculation unit, and an estimation unit that estimates the direction of the transmitting station as viewed from the power center of gravity based on the relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.

The area setting unit may set, as the sub-area, an area having a shape with a line-symmetric structure and in which the power center of gravity is located on the line-symmetric axis.

The area setting unit may set a sector-shaped area centered on the power center of gravity or an isosceles triangular area with the power center of gravity as a vertex as the sub-area.

The estimation unit may estimate the direction based on the symmetry of a graph in which the rotation angle is a first axis and the distance between the centers of gravity corresponding to the rotation angle is a second axis.

The estimation unit may estimate the direction based on the rotation angle when the correlation between the graph and a symmetric function of the graph takes an extreme value.

The second aspect of the present invention is an information processing method. In this method, a processor executes the steps of: calculating a power center of gravity by averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighting the position coordinates of each of the plurality of radio wave sensors by the power detected by each of the radio wave sensors; setting a sub-area that is an area including the power center of gravity; setting a plurality of sub-areas in which the sub-areas are rotated at a plurality of different rotation angles with the power center of gravity as a rotation center to change the setting position; calculating a plurality of sub-area centers of gravity by averaging the position coordinates of each of the plurality of radio wave sensors included in each of the plurality of sub-areas, weighting the position coordinates of each of the plurality of radio wave sensors included in each of the plurality of sub-areas by the power detected by each of the radio wave sensors; calculating a center-of-gravity distance, which is the distance between the power center of gravity and each of the calculated plurality of sub-area centers of gravity; and estimating the direction of the transmitting station as viewed from the power center of gravity based on the relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.

The third aspect of the present invention is a program. This program causes a computer to perform the following functions: Calculate a power center of gravity by averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighted by the power detected by each of the radio wave sensors; set a sub-area that is an area including the power center of gravity; set a plurality of sub-areas in which the sub-areas are rotated at a plurality of different rotation angles with the power center of gravity as a rotation center to change the set position; Calculate a plurality of sub-area centers of gravity by averaging the position coordinates of each of a plurality of radio wave sensors included in each of the plurality of sub-areas, weighted by the power detected by each of the radio wave sensors; calculate a center-of-gravity distance between the power center of gravity and each of the calculated sub-area centers of gravity; and estimate the direction of the transmitting station as viewed from the power center of gravity based on the relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.

To provide this program or to update a portion of the program, a computer-readable recording medium having this program recorded thereon may be provided, or this program may be transmitted over a communication line.

In addition, any combination of the above components, and any conversion of the present invention between methods, devices, systems, computer programs, data structures, recording media, etc., are also valid aspects of the present invention.

The present invention can improve the accuracy of estimating the direction in which a transmitting station is located.

1 is a diagram for explaining an overview of a direction estimation process executed by an information processing device according to an embodiment; FIG. 2 is a diagram illustrating a functional configuration of an information processing device according to an embodiment. 10A and 10B are diagrams for explaining a distance between centers of gravity calculated by a distance calculation unit according to an embodiment; 11A and 11B are diagrams illustrating an example of a shape of a sub-area set by a region setting unit in the embodiment. 1 is a diagram illustrating a graph in which a first axis represents a rotation angle and a second axis represents a distance between centers of gravity corresponding to the rotation angle; 11A and 11B are diagrams illustrating simulation results of a direction estimation process executed by the information processing device according to the embodiment. 10 is a flowchart illustrating a flow of a direction estimation process executed by an information processing device according to an embodiment. 11A and 11B are diagrams for explaining a process of specifying a radius of a sub-area executed by the information processing device according to the embodiment; 11A and 11B are diagrams for explaining a process of specifying a central angle of a sub-area executed by the information processing device according to the embodiment; 10 is a flowchart for explaining the flow of a position estimation process executed by an information processing device according to an embodiment. 13 is a diagram for explaining a position estimation process of a transmitter station performed by an estimation unit according to a second modified example. FIG.

<Outline of Estimation of Direction of Transmitter B>
1A to 1F are diagrams for explaining an overview of a direction estimation process executed by an information processing device 1 according to an embodiment. Hereinafter, an overview of the estimation process of the direction in which a transmitting station B exists will be explained with reference to FIG. 1A to 1F.

1(a) is a diagram for explaining the position estimation of a transmitting station B according to the prior art. In FIG. 1(a), a circle C indicated by a dashed line indicates the range in which the radio waves transmitted by transmitting station B can be observed by a radio wave sensor. Specifically, FIG. 1(a) shows an example in which transmitting station B transmits non-directional radio waves. The multiple white or black circles in FIG. 1(a) each indicate a radio wave sensor. Among these, the white circle indicates a radio wave sensor in which the radio waves transmitted by transmitting station B are below the receiving sensitivity, and the black circle indicates a radio wave sensor receiving the radio waves transmitted by transmitting station B. The size of the black circle indicates the power of the radio waves received by each sensor, and specifically, the larger the radius of the circle, the stronger the power of the radio waves received by the corresponding radio wave sensor. As shown in FIG. 1(a), the closer the radio wave sensor is installed to transmitting station B, the stronger the power of the radio waves it receives.

1(a), the position coordinates of N radio wave sensors (N is an integer equal to or greater than 1) receiving radio waves transmitted by transmitting station B are (x _i , y _i ), where i=1,...,N, and indicates the i-th radio wave sensor receiving radio waves transmitted by transmitting station B. In estimating the position of transmitting station B according to the prior art, an estimate of the position (X _b , Y _b ) of transmitting station B is calculated based on the following formula (1).

Here, P _i indicates the power of the radio wave detected by the i-th radio wave sensor.

Equation (1) shows that the position coordinates of each radio wave sensor receiving radio waves transmitted by transmitting station B are calculated as a weighted average using the power of the radio waves detected by that radio wave sensor, that is, the center of power of the position coordinates of each radio wave sensor is calculated (hereinafter referred to as "power center of gravity G"). In FIG. 1(a), the open triangle marked with the symbol G is the power center of gravity G calculated based on equation (1). The closer the radio wave sensor is installed to transmitting station B, the stronger the power of the radio waves it receives. Therefore, if the radio waves transmitted by transmitting station B are omnidirectional, the position coordinates calculated based on equation (1) are considered to be highly accurate as an estimate of the position coordinates of transmitting station B.

Figure 1(b) is a diagram showing an example of calculating the position of transmitting station B based on formula (1) when transmitting station B transmits directional radio waves. In Figure 1(b), the sector indicated by the symbol A indicates area A where the radio waves transmitted by transmitting station B reach. As shown in Figure 1(b), only radio wave sensors present within area A can receive the radio waves transmitted by transmitting station B, so the position of the power center of gravity G shifts from the position of transmitting station B. Therefore, the information processing device according to the embodiment estimates the direction in which transmitting station B is located in the order shown in Figures 1(c) to (f).

As shown in FIG. 1(c), the information processing device according to the embodiment calculates the power center of gravity G by averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from transmitting station B, weighted by the power detected by each radio wave sensor. In the example shown in FIG. 1(c), the radio waves transmitted by transmitting station B are directional, so the location of transmitting station B is different from the location of power center of gravity G.

Then, the information processing device according to the embodiment sets a plurality of subareas S, which are regions including the power center of gravity G. In the example shown in FIG. 1(d), three sector-shaped subareas S are illustrated: a first subarea S1, a second subarea S2, and a third subarea S3. The second subarea S2 and the third subarea S3 are subareas S in which the setting positions are changed by rotating the first subarea S1 at different rotation angles around the power center of gravity G as the rotation center. For example, in FIG. 1(d), the second subarea S2 is a subarea in which the setting position is changed by rotating the first subarea S1 by an angle θ.

The information processing device according to the embodiment calculates multiple subarea centroids Gs by weighting and averaging the position coordinates of each of the multiple radio wave sensors included in each of the multiple subareas S by the power detected by each of the radio wave sensors. In FIG. 1(d), the open circles included in the first subarea S1, the second subarea S2, and the third subarea S3 respectively indicate the first subarea centroid Gs1, the second subarea centroid Gs2, and the third subarea centroid Gs3, which are the subarea centroids Gs of each subarea S.

Figure 1(e) shows the trajectory T of the subarea center of gravity Gs calculated by changing the setting position while rotating the first subarea S1 at multiple different rotation angles. As will be described in detail later, the trajectory T of the subarea center of gravity Gs has a line-symmetric shape. Also, as shown in Figure 1(f), the transmitting station B exists on a line segment that is the axis of symmetry of the trajectory T of the subarea center of gravity Gs (the dashed line shown in Figure 1(f) (hereinafter, sometimes referred to as the "axis of symmetry L")). By utilizing this property, the information processing device according to the embodiment can accurately estimate the direction in which the transmitting station B exists.

<Functional configuration of information processing device 1 according to embodiment>
FIG. 2 is a diagram showing a schematic functional configuration of an information processing device 1 according to an embodiment. The information processing device 1 includes a storage unit 2 and a control unit 3. In FIG. 2, arrows indicate main data flows, and data flows not shown in FIG. 2 may exist. In FIG. 2, each functional block indicates a functional unit configuration, not a hardware (device) unit configuration. Therefore, the functional blocks shown in FIG. 2 may be implemented in a single device, or may be implemented separately in multiple devices. Data may be exchanged between functional blocks via any means, such as a data bus, a network, or a portable storage medium.

The storage unit 2 is a large-capacity storage device such as a ROM (Read Only Memory) that stores the BIOS (Basic Input Output System) of the computer that realizes the information processing device 1, a RAM (Random Access Memory) that serves as the working area of the information processing device 1, an HDD (Hard Disk Drive) or an SSD (Solid State Drive) that stores the OS (Operating System), application programs, and various information referenced when the application programs are executed.

The control unit 3 is a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit) of the information processing device 1, and functions as a power center of gravity calculation unit 30, an area setting unit 31, a distance calculation unit 32, and an estimation unit 33 by executing the programs stored in the memory unit 2.

Note that FIG. 2 shows an example in which the information processing device 1 is configured as a single device. However, the information processing device 1 may be realized by multiple processors, memory, and other computing resources, for example, as in a cloud computing system. In this case, each part constituting the control unit 3 is realized by at least one of the multiple different processors executing a program.

The power center of gravity calculation unit 30 calculates the power center of gravity G by averaging the position coordinates of each of the multiple radio wave sensors that detect the power of the radio waves transmitted from the transmitting station B, weighting them by the power detected by each radio wave sensor.

The area setting unit 31 sets a sub-area S, which is an area including the power center of gravity G, and sets multiple sub-areas S with different setting positions by rotating the sub-area S at multiple different rotation angles around the power center of gravity G. The shape of the sub-area S set by the area setting unit 31 will be described later.

The power center of gravity calculation unit 30 calculates the subarea center of gravity Gs by averaging the position coordinates of each of the multiple radio wave sensors included in each of the multiple subareas S, weighted by the power detected by each radio wave sensor. Here, the power center of gravity calculation unit 30 may sequentially calculate the subarea center of gravity Gs of the subarea S each time the area setting unit 31 sets a new subarea S. Alternatively, the power center of gravity calculation unit 30 may calculate the subarea center of gravity Gs for each of the multiple subareas S set in advance by the area setting unit 31.

The distance calculation unit 32 calculates the center-of-gravity distance d, which is the distance between the power center of gravity G and each of the multiple sub-area centers of gravity Gs calculated by the power center of gravity calculation unit 30.

Figures 3(a)-(d) are diagrams for explaining the center-to-center distance d calculated by the distance calculation unit 32 according to the embodiment. Figure 3(a) shows that the area setting unit 31 has set a sector-shaped first sub-area S1 centered on the power center of gravity G. Also, the second sub-area S2, third sub-area S3, and fourth sub-area S4 shown in Figures 3(b), 3(c), and 3(d), respectively, show that the area setting unit 31 has set the first sub-area S1 shown in Figure 3(a) by rotating it at different angles around the power center of gravity G.

In Fig. 3(a)-(d), the black rectangle indicated by the symbol B indicates the transmitting station B, and the triangular area indicated by the symbol A indicates the area A where the radio waves transmitted by the transmitting station B reach, but the position of the transmitting station B and the size and shape of the area A are unknown. The first sub-area S1 shown in Fig. 3(a) is included in the area A, but a part of the second sub-area S2 shown in Fig. 3(b) is set to be located outside the area A. Therefore, the second sub-area centroid Gs2, which is the sub-area centroid Gs of the second sub-area S2, is present in the area where the second sub-area S2 and the area A overlap, and the second sub-area centroid Gs2 approaches the power centroid G. Therefore, the first centroid distance d1, which is the distance between the power centroid G and the first sub-area centroid Gs1, is longer than the second centroid distance d2, which is the distance between the power centroid G and the second sub-area centroid Gs2.

The third subarea S3 shown in FIG. 3(c) shows a diagram in which transmitting station B is located on the bisector of the central angle of the third subarea S3. In this case, the third subarea center of gravity Gs3 is located on the line segment connecting the power center of gravity G and transmitting station B, and the third center-of-gravity distance d3, which is the distance between the power center of gravity G and the third subarea center of gravity Gs3, is longer than the distance between transmitting station B and the third subarea center of gravity Gs3.

The fourth sub-area S4 shown in FIG. 3(d) has the narrowest overlapping area with area A. Therefore, the fourth sub-area centroid Gs4, which is the sub-area centroid Gs of the fourth sub-area S4, is closest to the power centroid G.

In this way, the relationship between the rotation angle θ and the distance between the centers of gravity d for each of the multiple subareas S changes depending on the direction of the transmitting station B as seen from the power center of gravity G. The estimation unit 33 estimates the direction of the transmitting station B as seen from the power center of gravity G based on the relationship between the rotation angle θ and the distance between the centers of gravity d for each of the multiple subareas S. This allows the information processing device 1 to accurately estimate the direction in which the transmitting station B is located.

(Shape of sub-area S)
The shape of the sub-area S set by the region setting unit 31 according to the embodiment will be described.
4(a) to 4(c) are diagrams showing examples of the shapes of the sub-areas S set by the region setting unit 31 according to the embodiment. Specifically, the shape of the sub-area S shown in Fig. 4(a) is a sector, the shape of the sub-area S shown in Fig. 4(b) is an isosceles triangle, and the shape of the sub-area S shown in Fig. 4(c) is a rhombus.

As shown in FIG. 4(a)-(c), the subarea S set by the area setting unit 31 according to the embodiment is an area having a shape with a line-symmetric structure. The area setting unit 31 sets the subarea S3 so that the power center of gravity G is on the axis of symmetry L of the line symmetry. More specifically, when the shape of the subarea S is a sector, the area setting unit 31 sets the subarea S so that the power center of gravity G is the center of the sector. When the shape of the subarea S is an isosceles triangle, the area setting unit 31 sets the subarea S so that the power center of gravity G is the apex of the isosceles triangle. The same applies when the shape of the subarea S is a rhombus. By setting the subarea S as described above by the area setting unit 31, the locus T of the subarea center of gravity Gs also has a line-symmetric shape as shown in FIG. 1(f). Note that, in the following description, it is assumed that the shape of the subarea S is a sector, but as described above, the shape of the subarea S is not limited to a sector.

(Estimation of the direction in which transmitting station B exists)
Next, the estimation of the direction in which the transmitting station B exists by the estimation unit 33 according to the embodiment will be described.

As described above, the estimation unit 33 according to the embodiment estimates the direction of the transmitting station B as seen from the power center of gravity G based on the relationship between the rotation angle θ and the center-to-center distance d of each of the multiple subareas S. More specifically, the estimation unit 33 estimates the direction of the transmitting station B as seen from the power center of gravity G based on the symmetry of a graph in which the rotation angle θ is the first axis and the center-to-center distance d corresponding to the rotation angle θ is the second axis.

Figure 5 is a diagram that shows a graph in which the rotation angle θ is the first axis and the center-of-gravity distance d corresponding to the rotation angle θ is the second axis. In Figure 5, the arrows marked with the symbol (a), the arrows marked with the symbol (b), the arrows marked with the symbol (c), and the arrows marked with the symbol (d) correspond to Figures 3(a), 3(b), 3(c), and 3(d), respectively.

Figures 3(a) and 3(c) show the case where the bisector of the central angle of sub-area S overlaps with the axis of symmetry L shown in Figure 1(f). As shown in Figure 5, a graph in which the rotation angle θ is the first axis and the distance between the centers of gravity d corresponding to the rotation angle θ is the second axis becomes symmetrical at the point where the bisector of the central angle of sub-area S overlaps with the axis of symmetry L shown in Figure 1(f). The estimation unit 33 can estimate the direction of transmitting station B as seen from the power center of gravity G based on this symmetry.

Specifically, the estimation unit 33 estimates the direction based on a graph in which the rotation angle θ is the first axis and the distance between the centers of gravity d corresponding to the rotation angle θ is the second axis, and based on the rotation angle when the correlation with the symmetric function of the graph takes an extreme value.

Now, the distance between the centers of gravity d is expressed as a function d(θ) of the rotation angle θ, and the rotation angle at which d(θ) is maximum is θ _max . In this case, the symmetric function d'(θ) of the function d(θ) is defined by the following formula (2).
d'(θ)=d(θ _max −θ) (2)

The estimation unit 33 calculates the correlation between the function d(θ) and the function d′(θ+δθ) and calculates the angle δθ _max at which the correlation is maximum. Specifically, the estimation unit 33 calculates δθ _max shown in the following formula (3).

Here, the symbol corr. denotes the correlation of the function.

Since the directivity of the radio wave transmitted by the transmitting station B is linearly symmetric, the angle _θmax and the angle _θmax + _δθmax are symmetric about the directivity direction. Since the function d(θ) is maximum in the directivity direction as viewed from the power center of gravity G, the directivity direction _θd as viewed from the power center of gravity G is expressed by the following equation (4).

Moreover, the direction _θb of the transmitting station B as viewed from the power center G is expressed by the following equation (5).

The estimation unit 33 can estimate the direction _θb of the transmitting station B as viewed from the power center of gravity G by calculating the formula (5).

Figures 6(a)-(b) are diagrams showing simulation results of the direction estimation process executed by the information processing device 1 according to the embodiment. Specifically, Figure 6(a) is a diagram showing the trajectory T of the sub-area centroid Gs when the direction of the radio wave transmitted by the transmitting station B is 80 degrees and the beam spread is 120 degrees. Also, Figure 6(b) is a diagram showing the function R(δθ) that indicates the correlation between the function d(θ) and the function d'(θ+δθ).

As shown in FIG. 6(a), transmitting station B and trajectory T are set on a two-dimensional XY Cartesian coordinate system. In FIG. 6(a), the angle is set based on line segment P that passes through power center of gravity G and is parallel to the Y axis. Therefore, the direction rotated 80 degrees clockwise from line segment P with power center of gravity G as the center (the direction when looking at point U from power center of gravity G in FIG. 6(a)) is the direction of the radio waves transmitted by transmitting station B.

In addition, in FIG. 6(a), the direction indicated by the solid arrow indicates the direction in which the distance between the centers of gravity d is maximum (the direction of 30 degrees), and the dashed arrow indicates the direction in which the function R(δθ), which shows the correlation between the function d(θ) and the function d'(θ+δθ), is maximum (δθ=103 degrees).

Figure 6(b) is a schematic diagram showing a graph in which the value of function R(δθ), which shows the correlation between function d(θ) and function d'(θ+δθ), is on the vertical axis and the value of δθ is on the horizontal axis. As shown in Figure 6(b), when the value of δθ is 103 degrees, function R(δθ) is at its maximum, i.e., the correlation is 1.

At this time, the estimation unit 33 estimates the direction _θd of the transmitting station B as _θd = 30° + 103° / 2 = 81.5° based on equation (4). Since Fig. 6 is a simulation in which the direction of the radio wave transmitted by the transmitting station B is 80 degrees, it can be seen that the estimation unit 33 can accurately estimate the direction _θd of the transmitting station B. Furthermore, the estimation unit 33 estimates the direction _θb of the transmitting station B as seen from the power center G as _θb = 81.5° + 180° = 261.5° based on equation (5).

<Processing flow of direction estimation method executed by information processing device 1>
7 is a flowchart for explaining the flow of a direction estimation process executed by the information processing device 1 according to the embodiment. The process in this flowchart starts, for example, when the information processing device 1 is started.

The power center of gravity calculation unit 30 calculates the power center of gravity G by averaging the position coordinates of each of the multiple radio wave sensors that detect the power of the radio waves transmitted from the transmitting station B, weighted by the power detected by each radio wave sensor (S2).

The area setting unit 31 sets a rotation angle θ for defining the sub-area S (S4). The area setting unit 31 sets the sub-area S by rotating the sub-area S at the set rotation angle (S6).

The power center of gravity calculation unit 30 calculates the subarea center of gravity Gs by averaging the position coordinates of each of the multiple radio wave sensors included in the subarea S set by the area setting unit 31, weighted by the power detected by each of the radio wave sensors (S8). The distance calculation unit 32 calculates the center-of-gravity distance d, which is the distance between the power center of gravity G and the subarea center of gravity Gs calculated by the power center of gravity calculation unit 30 (S10).

Until the region setting unit 31 finishes setting the new rotation angle θ (No in S12), the region setting unit 31 sets the new rotation angle θ (S14), and the information processing device 1 repeats the processes of steps S6 to S10 described above. When the region setting unit 31 finishes setting the new rotation angle θ (Yes in S12), the estimation unit 33 estimates the direction θ _b of the transmitting station B as viewed from the power center of gravity G based on the calculations of equations (2) to (5) (S16). When the estimation unit 33 estimates the direction θ _b of the transmitting station B as viewed from the power center of gravity G, the process in this flowchart ends.

As described above, according to the information processing device 1 according to the embodiment, it is possible to improve the accuracy of estimating the direction _θb in which the transmitting station B exists as viewed from the power center of gravity G.

<Estimation of the location of transmitting station B>
From the above, the information processing device 1 according to the embodiment can estimate the direction _θb in which the transmitting station B is located as viewed from the power center of gravity G. There is a high probability that the transmitting station B is located on a line segment that passes through the power center of gravity G and points toward the direction _θb . Below, a technique for estimating the position of the transmitting station B will be described on the assumption that the direction _θb is known.

(Specifying the Radius of the Sub-area S)
First, the power center of gravity calculation unit 30 calculates the power center of gravity by averaging the position coordinates of each of the multiple radio wave sensors that detect the power of the radio waves transmitted from the transmitting station B, weighted by the power detected by each of the radio wave sensors. Next, the estimation unit 33 estimates the direction _θb of the transmitting station B as seen from the power center of gravity G. After that, the area setting unit 31 sets a sub-area S, which is a sector-shaped area centered on the power center of gravity G and in which a line segment from the power center of gravity _G toward the direction θb forms the bisector of the central angle.

8(a)-(b) are diagrams for explaining the process of specifying the radius r of the sub-area S executed by the information processing device 1 according to the embodiment. Specifically, FIG. 8(a) shows a diagram in the case where the sub-area S is set in the direction θ _b in which the transmitting station B is located as viewed from the power center of gravity G. As shown in FIG. 8(a), the region setting unit 31 sets the sub-area S so that the bisector of the central angle of the sub-area S faces the direction θ _b in which the transmitting station B is located as viewed from the power center of gravity G.

In FIG. 8(a), the open circle indicates the position of the radio wave sensor that received the radio wave transmitted by transmission station B. The size of the open circle indicates the power of the radio wave received by the radio wave sensor, and more specifically, the larger the open circle, the greater the power of the received radio wave. As shown in FIG. 8(a), the closer the radio wave sensor is to transmission station B, the greater the power of the received radio wave.

Here, the area setting unit 31 sets multiple different subareas S while changing the radius of the subarea S. The power center of gravity calculation unit 30 calculates multiple subarea centers of gravity Gs by weighting the position coordinates of each of the multiple radio wave sensors included in each of the multiple subareas S by the power detected by each radio wave sensor and averaging them. In FIG. 8(a), the first subarea center of gravity Gs1 indicated by the symbol Gs1 indicates the subarea center of gravity Gs when the area setting unit 31 sets the first subarea S1, which is a subarea with a radius r1. In addition, the second subarea center of gravity Gs2 indicated by the symbol Gs2 indicates the subarea center of gravity Gs when the area setting unit 31 sets the second subarea S2, which is a subarea with a radius r2. As shown in FIG. 8(a), when the area setting unit 31 changes the radius r of the subarea S, the position of the subarea center of gravity Gs calculated by the power center of gravity calculation unit 30 also changes. Therefore, below, when the radius of the subarea S is r, the subarea center of gravity Gs is expressed as Gs(r) as a function of the radius r.

Figure 8 (b) is a diagram showing a schematic relationship between the radius r of the subarea S and the distance R (Gs (r)) between the subarea center of gravity Gs (r) and the power center of gravity G. As shown in Figure 8 (b), as the area setting unit 31 sets the radius r to be longer, the distance Gs (r) between the power center of gravity G and the subarea center of gravity Gs becomes longer. On the other hand, as the radius r of the subarea S becomes longer, the increase in the distance R (Gs (r)) between the subarea center of gravity Gs (r) and the power center of gravity G decreases. This is because, although the number of radio wave sensors included in the subarea S increases as the radius r increases, the power of the radio waves received by the newly included radio wave sensors becomes smaller by increasing the radius r.

Therefore, the region setting unit 31 changes the radius r of the subarea S until the radius r reaches a threshold length rth at which the ratio of the amount of change in the distance R(Gs(r)) between the power center of gravity G and the subarea center of gravity Gs(r) to the amount of change in the radius _r becomes a predetermined threshold amount. Here, the ratio of the amount of change in the distance R(Gs(r)) between the power center of gravity G and the subarea center of gravity Gs(r) to the amount of change in the radius r is the slope of the graph shown in FIG. 8(b), and more specifically, is expressed as the tangent (tan(ξ)) of the angle ξ in FIG. 8.

The "predetermined threshold" is the "threshold for stopping radius change" that the area setting unit 31 refers to in deciding whether or not to stop the change in the radius r of the subarea S. Specific values for the predetermined threshold can be determined by experiment taking into account the placement of the radio wave sensor and the accuracy of the position estimation of the transmitting station B, and an example is tan(ξ) = 0.05, ξ = 2.5 degrees. This indicates that the change in the distance R(Gs(r)) between the power center of gravity G and the subarea center of gravity Gs(r) relative to the change in radius r is 5%.

The estimation unit 33 outputs the sub-area S, whose radius r is a threshold length r _th , as an estimated area including the transmitting station B. In this manner, the estimation unit 33 can narrow the sub-area S, which is an area estimated to include the transmitting station B.

(Determination of central angle φ of sub-area S)
Next, the region setting unit 31 narrows the central angle φ of the sub-area S whose radius r is the threshold length r _th , thereby further narrowing the sub-area S.

9 is a diagram for explaining the process of specifying the central angle φ of the sub-area S executed by the information processing device 1 according to the embodiment. As shown in Fig. 9, the area setting unit 31 narrows the sub-area S by changing the central angle φ1 of the sub-area S to φ2, which is an angle smaller than φ1. Specifically, the area setting unit 31 reduces the central angle φ of the sub-area S until the central angle φ of the sub-area S reaches a threshold angle _φth at which the number of radio wave sensors included in the sub-area S becomes a predetermined threshold number.

The "predetermined threshold number" here refers to the "threshold number for stopping the decrease of the central angle" that the area setting unit 31 refers to in order to determine whether or not to stop the decrease of the central angle φ of the subarea S. The specific value of the predetermined threshold number can be determined by experiment, taking into consideration the placement of the radio wave sensors and the accuracy of the position estimation of the transmitting station B, and one example is "3," which is the minimum number required to calculate the center of gravity of the radio wave sensors. In other words, the predetermined threshold number is determined by experiment as an integer of 3 or more.

The estimation unit 33 outputs a subarea S having a radius r equal to a threshold length r _th and a central angle φ equal to a threshold angle φ _th centered on the power center of gravity G as an estimated area including the transmitting station B. This further narrows the subarea S, which is an area estimated to include the transmitting station B.

Next, the power center of gravity calculation unit 30 calculates the subarea center of gravity _Gth by averaging the position coordinates of each of the multiple radio wave sensors included in the subarea _Sth , which is centered on the power center of gravity G, has a central angle φ of a threshold angle _φth , and a radius r of a threshold length rth, weighted by the power detected by each of the radio wave sensors. The estimation unit 33 outputs _the center of gravity _Gsth of the subarea _Sth as the estimated position of the transmitting station B. This allows the estimation unit 33 to accurately estimate the position of the transmitting station B.

<Processing flow of the position estimation method executed by the information processing device 1>
10 is a flowchart for explaining the flow of the position estimation process executed by the information processing device 1 according to the embodiment. The process in this flowchart starts, for example, when the information processing device 1 is started.

The power center of gravity calculation unit 30 calculates the power center of gravity G by averaging the position coordinates of each of the multiple radio wave sensors that detect the power of the radio waves transmitted from the transmitting station B (S20). The estimation unit 33 estimates the direction _θb of the transmitting station B as viewed from the power center of gravity G (S22).

The area setting unit 31 sets a radius r of the sub-area S, which is a sector-shaped area having the power center of gravity G as its center and a line segment extending from the power center of gravity G in the direction _θb as the bisector of the central angle (S24). The power center of gravity calculation unit 30 calculates the sub-area center of gravity Gs by averaging the position coordinates of each of the multiple radio wave sensors included in the sub-area S, weighted by the power detected by each of the radio wave sensors (S26).

The area setting unit 31 calculates the ratio of the change in the distance R between the power center of gravity G and the sub-area center of gravity Gs to the change in the radius r of the sub-area S (S28). Until the ratio of change calculated by the area setting unit 31 becomes equal to or less than a predetermined threshold (No in S30), the information processing device 1 repeats the processes from step S24 to step S28.

When the ratio calculated by the region setting unit 31 reaches a threshold length that is a predetermined threshold amount (Yes in S30), the region setting unit 31 sets the central angle φ of the sub-area (S32). While the number of radio wave sensors included in the sub-area S exceeds the threshold (No in S34), the region setting unit 31 reduces the central angle φ by a predetermined amount and sets a new central angle φ. When the number of radio wave sensors included in the sub-area S falls below the threshold (Yes in S34), the power center of gravity calculation unit 30 calculates the sub-area center of gravity Gs by averaging the position coordinates of each of the multiple radio wave sensors included in the sub-area S weighted by the power detected by each radio wave sensor (S36). The estimation unit 33 outputs the calculated center of gravity Gs of the sub-area S as the estimated position of the transmitting station B (S38). When the estimation unit 33 outputs the estimated position of the transmitting station B, the processing in this flowchart ends.

<Effects of the information processing device 1 according to the embodiment>
As described above, the information processing device 1 according to the embodiment can improve the estimation accuracy of the direction _θb in which the transmitting station B exists as viewed from the power center of gravity G. Furthermore, the information processing device 1 according to the embodiment can accurately estimate the area in which the transmitting station B exists, on the premise that the direction in which the transmitting station B exists as viewed from the power center of gravity G is known.

In particular, the information processing device 1 according to the embodiment can accurately estimate the direction θb and the area and position of the transmitting station B even if it is unknown whether the radio wave transmitted by the transmitting station _B has directivity, and if it has directivity, even if the directional direction and the spread angle of the beam are unknown.

Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the invention. For example, all or part of the device can be configured by distributing or integrating functionally or physically in any unit. In addition, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effect of the new embodiment resulting from the combination also has the effect of the original embodiment. Such modifications are described below.

<First Modification>
In the above description, the estimation unit 33 estimates the direction θb of the transmitting station B as seen from the power center of gravity G based on the symmetry of a graph in which the rotation angle θ is the first axis and the center-to-center distance _d corresponding to the rotation angle θ is the second axis. However, the method of estimating the direction _θb by the estimation unit 33 is not limited to this, and other methods may be used.

1(f) , the locus T of the sub-area center of gravity Gs has a line-symmetric shape. The estimation unit 33 may estimate the direction θ _b by finding the axis of symmetry L of the locus T by utilizing the fact that the locus T of the sub-area center of gravity Gs has a line-symmetric shape.

Specifically, utilizing the property that the center of gravity of a line-symmetric figure exists on the axis of symmetry L, the estimation unit 33 first calculates the center of gravity G _T of the locus T. Next, the estimation unit 33 divides the locus T into two regions with a line segment passing through the center of gravity G _T , and calculates the area of each region. Utilizing the fact that the axis of symmetry L of a line-symmetric figure divides the area of the figure equally, the estimation unit 33 changes the inclination of the line segment passing through the center of gravity G _T until the areas of the two regions obtained by dividing the line-symmetric figure become equal. In this way, the estimation unit 33 can find the axis of symmetry L of the locus T.

<Second Modification>
In the above description, the estimation unit 33 outputs the center of gravity _Gs of the sub-area _S as the estimated position of the transmitting station B. Alternatively, when the radius r of the sub-area S is the threshold length _r , it is possible to estimate the position of the transmitting station B by using the threshold length _r and the direction _θb , assuming that the transmitting station B is located in the vicinity of an arc of the sub-area S.

Fig. 11 is a diagram for explaining the position estimation process of the transmission station B by the estimation unit 33 according to the second modified example. As shown in Fig. 11, in a two-dimensional XY orthogonal coordinate system formed by the X axis and the Y axis, when the coordinates of the power center of gravity G are (Xg, Yg), the radius of the sub-area S is r _th , the angle in the two-dimensional XY orthogonal coordinate system in which the transmission station B is viewed from the power center of gravity G is θ _b , and the coordinates of the estimated position of the transmission station B are (Xb, Yb), the estimation unit 33 calculates the coordinates (Xb, Yb) of the estimated position of the transmission station B based on the following formula (6).

The estimation unit 33 can estimate the position of the transmitting station B without the above-mentioned process of identifying the central angle φ of the subarea S by calculating the coordinates (Xb, Yb) of the estimated position of the transmitting station B based on the formula (6). As a result, the estimation unit 33 can reduce the calculation resources required for estimating the position of the transmitting station B.

The present invention may be specified by the following items.
[Item 1-1]
An information processing device,
a power center of gravity calculation unit that calculates a power center of gravity by averaging position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighted by the power detected by each of the radio wave sensors;
a region setting unit that sets a sub-area that is a region including the power center of gravity, and sets a plurality of sub-areas in which the sub-area is rotated at a plurality of different rotation angles around the power center of gravity as a rotation center to change the set positions,
the power center of gravity calculation unit calculates a plurality of subarea centers of gravity by weighting and averaging position coordinates of each of the plurality of radio wave sensors included in each of the plurality of subareas by power detected by each of the radio wave sensors;
The information processing device includes:
a distance calculation unit that calculates a distance between the power center of gravity and each of the plurality of sub-area centers of gravity calculated by the power center of gravity calculation unit;
and an estimation unit that estimates a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
Information processing device.
[Item 1-2]
the area setting unit sets, as the sub-area, an area having a shape having a line symmetric structure and having the power center of gravity existing on a line symmetric symmetry axis;
Item 1-1. The information processing device according to item 1-1.
[Item 1-3]
the area setting unit sets, as the sub-area, a sector-shaped area having the power center of gravity as a center or an isosceles-triangular area having the power center of gravity as a vertex;
3. The information processing device according to item 1-2.
[Item 1-4]
the estimation unit estimates the direction based on symmetry of a graph having the rotation angle as a first axis and the distance between the centers of gravity corresponding to the rotation angle as a second axis.
4. The information processing device according to any one of items 1-1 to 1-3.
[Item 1-5]
the estimation unit estimates the direction based on the rotation angle when a correlation between the graph and a symmetric function of the graph takes an extreme value;
5. The information processing device according to any one of items 1 to 4.
[Item 1-6]
The processor:
calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
A step of setting a sub-area that is an area including the power center of gravity;
A step of setting a plurality of sub-areas whose setting positions are changed by rotating the sub-areas by a plurality of different rotation angles around the power center of gravity as a rotation center;
calculating a plurality of subarea centroids by weighting and averaging the position coordinates of the plurality of radio wave sensors included in each of the plurality of subareas by the power detected by each of the radio wave sensors;
Calculating a distance between the power center of gravity and each of the calculated sub-area centers of gravity;
and estimating a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
Information processing methods.
[Item 1-7]
On the computer,
A function of calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
A function of setting a sub-area that is an area including the power center of gravity;
A function of setting a plurality of sub-areas whose setting positions are changed by rotating the sub-areas at a plurality of different rotation angles with the power center of gravity as a rotation center;
a function of calculating a plurality of sub-area centroids by weighting and averaging the position coordinates of each of the plurality of radio wave sensors included in each of the plurality of sub-areas by the power detected by each of the radio wave sensors;
A function of calculating a distance between the power center of gravity and each of the calculated sub-area centers of gravity;
and estimating a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
program.

[Item 2-1]
An information processing device,
a power center of gravity calculation unit that calculates a power center of gravity by averaging position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighted by the power detected by each of the radio wave sensors;
an estimation unit that estimates a direction of the transmitting station from the power center of gravity;
a region setting unit that sets a sub-area that is a sector-shaped region having the power center of gravity as a center and a line segment extending from the power center of gravity in the direction of the power center of gravity as a bisector of a central angle,
the power center of gravity calculation unit calculates a sub-area center of gravity by weighting and averaging position coordinates of each of the plurality of radio wave sensors included in the sub-area by power detected by each of the radio wave sensors;
the region setting unit changes a radius of the sub-area until the radius reaches a threshold length at which a ratio of an amount of change in a distance between the power center of gravity and the sub-area center of gravity to an amount of change in the radius becomes a predetermined threshold amount;
The estimation unit outputs the sub-area whose radius is the threshold length as an estimated region including the transmitter station.
Information processing device.
[Item 2-2]
the area setting unit reduces a central angle of the sub-area until the central angle becomes a threshold angle at which the number of the radio wave sensors included in the sub-area becomes a predetermined threshold number;
The estimation unit outputs, as the estimation region, the sub-area having the power center of gravity as a center, a radius of the threshold length, and a central angle of the threshold angle.
The information processing device according to item 2-1.
[Item 2-3]
the power center of gravity calculation unit calculates a subarea center of gravity by weighting and averaging position coordinates of each of the plurality of radio wave sensors included in a subarea having the power center of gravity as a center, a central angle of the threshold angle, and a radius of the threshold length by power detected by each of the radio wave sensors;
The estimation unit outputs a center of gravity of the sub-area as an estimated position of the transmitting station.
Item 2-2. The information processing device.
[Item 2-4]
When the coordinates of the power center of gravity G of the estimation area in a two-dimensional XY orthogonal coordinate system that defines the position coordinates are (Xg, Yg), the radius of the estimation area is r _th , the angle in the two-dimensional XY orthogonal coordinate system in which the transmission station is viewed from the power center of gravity G is θ _b , and the coordinates of the estimated position of the transmission station are (Xb, Yb), the estimation unit estimates the value of Xb to be Xg+r _th cos(θ _b ) and the value of Yb to be Yg+r _th sin(θ _b ).
Item 2-2. The information processing device.
[Item 2-5]
the predetermined threshold number is 3 or greater;
The information processing device according to any one of items 2-2 to 2-4.
[Item 2-6]
The processor:
calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
estimating the direction of the transmitting station with respect to the power centroid;
A step of setting a sub-area that is a sector-shaped region having the power center of gravity as a center and a line segment extending from the power center of gravity in the direction of the power center of gravity as a bisector of a central angle;
calculating a plurality of sub-area centroids by weighting and averaging the position coordinates of each of the plurality of radio wave sensors included in the sub-area by the power detected by each of the radio wave sensors;
Varying the radius of the subarea until the radius reaches a threshold length where a ratio of a change in the radius to a change in the center of gravity of the subarea is a predetermined threshold amount;
and outputting the sub-area whose radius is the threshold length as an estimated region in which the transmitting station is included.
Information processing methods.
[Item 2-7]
On the computer,
A function of calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
a function of estimating a direction of the transmitting station with respect to the power center of gravity;
A function of setting a sub-area that is a sector-shaped area having the power center of gravity as a center and a line segment extending from the power center of gravity in the direction of the power center of gravity as a bisector of a central angle;
a function of calculating a plurality of sub-area centroids by weighting and averaging the position coordinates of each of the plurality of radio wave sensors included in the sub-area by the power detected by each of the radio wave sensors;
a function of changing the radius of the sub-area until the radius of the sub-area reaches a threshold length at which a ratio of a change in the radius to a change in the center of gravity of the sub-area becomes a predetermined threshold amount;
and outputting the sub-area, the radius of which is the threshold length, as an estimated area including the transmitting station.
program.

1: Information processing device 2: Memory unit 3: Control unit 30: Power center of gravity calculation unit 31: Area setting unit 32: Distance calculation unit 33: Estimation unit B: Transmitting station

Claims (6)

An information processing device,
a power center of gravity calculation unit that calculates a power center of gravity by averaging position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station, weighted by the power detected by each of the radio wave sensors;
a region setting unit that sets a sub-area having a shape with a line symmetric structure and a shape in which the power center of gravity exists on a symmetry axis of the line symmetry, and sets a plurality of sub-areas in which the setting positions are changed by rotating the sub-area by a plurality of different rotation angles around the power center of gravity as a rotation center,
the power center of gravity calculation unit calculates a plurality of subarea centers of gravity by weighting and averaging position coordinates of each of the plurality of radio wave sensors included in each of the plurality of subareas by power detected by each of the radio wave sensors;
The information processing device includes:
a distance calculation unit that calculates a distance between the power center of gravity and each of the plurality of sub-area centers of gravity calculated by the power center of gravity calculation unit;
and an estimation unit that estimates a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
Information processing device. the area setting unit sets, as the sub-area, a sector-shaped area having the power center of gravity as a center or an isosceles-triangular area having the power center of gravity as a vertex;
The information processing device according to claim 1 . the estimation unit estimates the direction based on symmetry of a graph having the rotation angle as a first axis and the distance between the centers of gravity corresponding to the rotation angle as a second axis.
3. The information processing device according to claim 1 or 2 . the estimation unit estimates the direction based on the rotation angle when a correlation between the graph and a symmetric function of the graph takes an extreme value;
The information processing device according to claim 3 . The processor:
calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
A step of setting a sub-area having a shape with a line symmetric structure and a shape in which the power center of gravity exists on a line symmetric symmetry axis;
A step of setting a plurality of sub-areas whose setting positions are changed by rotating the sub-areas by a plurality of different rotation angles around the power center of gravity as a rotation center;
calculating a plurality of subarea centroids by weighting and averaging the position coordinates of the plurality of radio wave sensors included in each of the plurality of subareas by the power detected by each of the radio wave sensors;
Calculating a distance between the power center of gravity and each of the calculated sub-area centers of gravity;
and estimating a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
Information processing methods. On the computer,
A function of calculating a power center of gravity by weighting and averaging the position coordinates of each of a plurality of radio wave sensors that detect the power of radio waves transmitted from a transmitting station by the power detected by each of the radio wave sensors;
A function of setting a sub-area having a shape with a line symmetric structure and a shape in which the power center of gravity exists on a line symmetric symmetry axis ;
A function of setting a plurality of sub-areas whose setting positions are changed by rotating the sub-areas at a plurality of different rotation angles with the power center of gravity as a rotation center;
a function of calculating a plurality of sub-area centroids by weighting and averaging the position coordinates of each of the plurality of radio wave sensors included in each of the plurality of sub-areas by the power detected by each of the radio wave sensors;
A function of calculating a distance between the power center of gravity and each of the calculated sub-area centers of gravity;
and estimating a direction of the transmitting station from the power center of gravity based on a relationship between the rotation angle and the center-of-gravity distance for each of the plurality of sub-areas.
program.

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