JP2017151007A - Wave source position estimation device, program for execution of computer, and computer readable recording medium holding program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wave source position estimation device capable of easily estimating a wave source position while suppressing the calculation amount.SOLUTION: When dispersion Var of the distribution of a plurality of terminal devices is a threshold Var_th or more, the estimation device estimates, as a wave source position, the center of gravity of the plurality of terminal devices weighted by a received power (S3 and S4). When the dispersion Var is less than the threshold Var_th, the estimation device estimates, as a wave source position, an average value of the internal division points obtained by internally dividing the distance between two positions of two terminal devices or an average value of the external division points obtained by externally dividing the distance between the two positions (S7-S11).SELECTED DRAWING: Figure 9

Description

  The present invention relates to a wave source position estimation device, a program for causing a computer to execute, and a computer-readable recording medium on which the program is recorded.

  The secondary use of the frequency can be used within a range that does not affect the primary user. Therefore, in order to increase the frequency use efficiency, studies on secondary use of the frequency are underway.

  In order to determine whether or not the secondary use of the frequency is possible, it is necessary to detect the presence or absence of the primary use of the frequency. And in order to detect the presence or absence of the primary use of a frequency, it is necessary to estimate a wave source position.

  Conventionally, a method described in Non-Patent Document 1 is known as a method of estimating a wave source position. In the method described in Non-Patent Document 1, the wave source position is estimated using TDoA (Time Differential of Arrival).

  More specifically, a radio wave from a wave source is received using a highly accurate sensor called a long distance sensor, and the wave source is estimated from the arrival time differences of radio waves to a plurality of sensors.

That is, the arrival time difference | t _a −t _b | when the radio wave arrives at the two sensors S _A and S _B from the wave source is calculated. Then, the arrival time difference _| t a -t _{b |} with propagation distance difference when the radio wave arrives from the wave source sensor _S A, the _{S B |} L a -L _{b |} is calculated.

Similarly, the propagation distance difference | L _b −L _c | when the radio wave arrives from the wave source to the sensors S _B and S _C and the propagation distance difference when the radio wave arrives from the wave source to the sensors S _C and S _A | L _c −L _a | is calculated.

Then, three hyperbola | L _a -L _b |, | L _b -L _c |, | L _c -L _a | are drawn, and the intersection of the three hyperbola is estimated as the wave source position.

Kenji Horibata, Kazuo Kanno, Satoshi Furukawa, Goro Hasegawa, Yoshio Takeuchi, "Study on elemental technology for local white space estimation using heterogeneous sensors," 2014 IEICE General Conference, Communications Lectures Collection 1, B- 17-28, p607.

  However, in the estimation method described in Non-Patent Document 1, there is a problem that it is necessary to synchronize the sensors and a high-function system is required. In addition, there is a problem that the calculation amount becomes large for wave source position estimation.

  The above problem becomes more prominent as the monitoring area and frequency range become wider.

  Therefore, according to the embodiment of the present invention, there is provided a wave source position estimation device that can easily estimate the wave source position while suppressing the amount of calculation.

  In addition, according to the embodiment of the present invention, there is provided a program for causing a computer to execute simple estimation of a wave source position while suppressing a calculation amount.

  Furthermore, according to the embodiment of the present invention, there is provided a computer-readable recording medium on which a program for suppressing a calculation amount and causing a computer to execute a simple estimation of a wave source position is recorded.

  According to the embodiment of the present invention, the wave source position estimation apparatus includes a reception unit, a calculation unit, and an estimation unit. The receiving means receives terminal information including the position information of the terminal device composed of a mobile terminal or a stationary terminal and the received power in the terminal device from a plurality of terminal devices. The calculation means calculates a variance in the distribution of the positions of the plurality of terminal devices based on the plurality of pieces of position information included in the plurality of pieces of terminal information of the plurality of terminal devices. When the calculated variance is greater than or equal to the first threshold value, the estimation means is weighted by the received power based on the plurality of position information and the plurality of received power included in the plurality of terminal information. Is estimated as the wave source position, and when the calculated variance is smaller than the first threshold, the two positions indicated by the position information of the two terminal devices out of the plurality of terminal devices are externally divided. A process of obtaining an internal dividing point that internally divides a dividing point or two positions is executed for all two terminal devices among a plurality of terminal devices, and the obtained outer dividing point or inner dividing point is averaged. The estimated position is estimated as the wave source position.

  According to the embodiment of the present invention, the wave source position estimation device is configured such that the center of gravity of a plurality of terminal devices weighted by received power, the average value of internal dividing points obtained by internally dividing two positions of two terminal devices, or two The average value of the external dividing points obtained by dividing the position is estimated as the wave source position. As a result, the wave source position estimation apparatus can estimate the wave source position using four arithmetic operations.

  Therefore, it is possible to easily estimate the wave source position while suppressing the calculation amount.

  In addition, since the wave source position estimation apparatus estimates the average value of the internal dividing points or the average value of the external dividing points as the wave source position, the wave source position can be accurately estimated even when the position of the terminal device is biased.

  According to the embodiment of the present invention, the program for causing the computer to execute is a program for causing the computer to perform estimation of the wave source position, and the receiving means is a terminal device comprising a mobile terminal or a stationary terminal. A first step of receiving terminal information including the position information of the terminal and the received power at the terminal device from the plurality of terminal devices, and the calculating means based on the plurality of position information included in the plurality of terminal information of the plurality of terminal devices. A second step of calculating the variance in the distribution of the positions of the plurality of terminal devices, and the estimating means, when the calculated variance is greater than or equal to the first threshold value, the plurality of position information and the plurality of terminal information Based on the plurality of received powers included, the center of gravity of the plurality of terminal devices weighted by the received power is estimated as the wave source position, and the calculated variance is calculated based on the first threshold value. A plurality of terminal devices for obtaining an external dividing point that divides two positions indicated by position information of two terminal devices out of a plurality of terminal devices or an internal dividing point that internally divides two positions. And the third step of estimating a position obtained by averaging the obtained outer dividing points or inner dividing points as a wave source position.

  By executing the program, the center of gravity of the plurality of terminal devices weighted by the received power, the average value of the internal dividing points obtained by internally dividing the two positions of the two terminal devices, or the outer dividing point obtained by dividing the two positions externally The average value is estimated as the wave source position. As a result, the wave source position can be estimated using four arithmetic operations.

  Therefore, it is possible to easily estimate the wave source position while suppressing the calculation amount.

  Furthermore, according to an embodiment of the present invention, the computer-readable recording medium on which the program is recorded is a computer-readable recording medium on which the program according to any one of claims 6 to 10 is recorded. is there.

  The wave source position can be easily estimated while suppressing the amount of calculation.

It is a figure which shows the radio | wireless communications system in embodiment of this invention. It is the schematic of the wave source position estimation apparatus shown in FIG. It is a figure which shows the relationship between received power and the distance from a wave source. The center of gravity (x _{G, y G)} is a diagram showing a calculation result in the estimation method to the wave source position. The center of gravity (x _{G, y G)} are diagrams for explaining a problem of the estimation method and the wave source position. The center of gravity (x _{G, y G)} is another diagram for explaining a problem of the estimation method and the wave source position. 4 is a diagram for explaining a method for estimating a wave source position when the wave source position is biased to one side with respect to the distribution region of the terminal device 2. FIG. It is a figure for demonstrating the discrimination | determination method of using either an outer dividing point or an inner dividing point. It is a flowchart for demonstrating operation | movement of the wave source position estimation apparatus shown in FIG. It is a flowchart for demonstrating another operation | movement of the wave source position estimation apparatus shown in FIG. It is the schematic which shows the other structure of the wave source position estimation apparatus shown in FIG. It is a conceptual diagram which shows the fluctuation | variation of the reception power by time. It is a figure which shows the relationship between the classification of an error, and the required reliability. It is a figure which shows the relationship between the magnitude | size n of a sample, and the error range e. It is a figure which shows the sample in the case of determining whether receiving power is correct data. It is a flowchart for demonstrating operation | movement of the wave source position estimation apparatus shown in FIG.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram showing a radio communication system according to an embodiment of the present invention.

  With reference to FIG. 1, a wireless communication system 10 includes a wave source position estimation device 1 and a plurality of terminal devices 2.

  The wave source position estimation device 1 and the plurality of terminal devices 2 are arranged in a wireless communication space. The plurality of terminal devices 2 and the wave source S are arranged in the observation area REG. The observation area REG has a circular shape centered on the wave source S.

  Each of the plurality of terminal devices 2 includes a mobile terminal or a stationary terminal. Then, each of the plurality of terminal devices 2 detects its own position by, for example, GPS (Global Positioning System).

Each of the plurality of terminal devices 2 receives a radio wave from the wave source S and detects received power P _i (i = 1, 2, 3,...) When the radio wave is received.

Further, each of the plurality of terminal devices 2 detects the time when the received power P _i is detected.

Each of the plurality of terminal devices 2 includes position information (x _i , y _i ) indicating its own position, received power P _i, and time information indicating a time when the received power P _i is detected. Terminal information is generated, and the generated terminal information is transmitted to the wave source position estimation apparatus 1 by wireless communication.

  The wave source position estimation apparatus 1 receives a plurality of terminal information from a plurality of terminal apparatuses 2 and estimates a wave source position that is the position of the wave source S by a method described later based on the received plurality of terminal information.

  FIG. 2 is a schematic diagram of the wave source position estimation apparatus 1 shown in FIG. With reference to FIG. 2, the wave source position estimation apparatus 1 includes an antenna 11, a reception unit 12, a storage unit 13, a calculation unit 14, and an estimation unit 15.

  The receiving means 12 receives a plurality of terminal information from the plurality of terminal devices 2 via the antenna 11 and stores the received plurality of terminal information in the storage means 13.

  The storage unit 13 stores a plurality of terminal information received from the reception unit 12.

  The calculating unit 14 reads a plurality of terminal information from the storage unit 13 and calculates the variance Var in the position distribution of the plurality of terminal devices 2 based on the plurality of position information included in the read plurality of terminal information. Then, the calculation unit 14 outputs the calculated variance Var to the estimation unit 15.

The estimation unit 15 receives the variance Var from the calculation unit 14 and reads a plurality of terminal information from the storage unit 13. Then, the estimation unit 15 compares the variance Var with the threshold value Var_th, and according to the comparison result, a plurality of pieces of position information (x _i , y _i ) included in the plurality of terminal information and a plurality of received powers P _i. The wave source position is estimated based on

  A method for estimating the wave source position will be described.

The estimation means 15 calculates the centroids (x _G , y _G ) of the plurality of terminal devices 2 by the following formula.

In equation (1), w _i represents the weight of the i-th terminal device 2 and is composed of the received power P _{i at the} i-th terminal device 2.

The estimation unit 15 estimates the center of gravity calculated by the equation _{(1) (x G, y} G) as wave source position. That is, the estimation unit 15 estimates the center of gravity (x _G , y _G ) of the plurality of terminal devices 2 weighted by the received power P _i as the wave source position.

  FIG. 3 is a diagram illustrating the relationship between the received power and the distance from the wave source. In FIG. 3, the vertical axis represents the received power, and the horizontal axis represents the distance from the wave source S.

Referring to FIG. 3, received power P _i attenuates in inverse proportion to the distance from wave source S. As a result, the received power P _i increases as it approaches the wave source S, so that the weighting effect by the received power P _i is greater near the wave source S. Therefore, the estimated value estimated by the estimation method using the center of gravity (x _G , y _G ) as the wave source position approaches the vicinity of the wave source.

FIG. 4 is a diagram illustrating a calculation result in the estimation method using the center of gravity (x _G , y _G ) as the wave source position.

  The wave source S was disposed at the position (300, 300) in the xy coordinates. The number of terminal devices 2 is 50. A white circle in FIG. 4 represents the terminal device 2. The radius of the observation area is 1000 m.

The position of the center of gravity (x _G , y _G ) calculated using Equation (1) was (295,306).

Therefore, it was found that the estimated value is located in the vicinity of the wave source S by setting the center of gravity (x _G , y _G ) calculated using the equation (1) as the wave source position.

FIG. 5 is a diagram for explaining the problems of the estimation method in which the center of gravity (x _G , y _G ) is used as the wave source position.

  In FIG. 5, the circle represents the position of the center of gravity, and the square represents the wave source position.

  With reference to (a) of FIG. 5, when the distribution of the terminal device 2 is uniform, the position of the center of gravity is accurately positioned in the vicinity of the wave source position.

On the other hand, when the distribution of the terminal device 2 is biased, the position of the center of gravity is greatly different from the wave source position. The center of gravity (x _G , y _G ) calculated using the equation (1) is located at the center of the region where the terminal device 2 is distributed, so the distribution region of the plurality of terminal devices 2 is located at the wave source position. On the other hand, when it is biased to one side, the position of the center of gravity is not located in the vicinity of the wave source position.

FIG. 6 is another diagram for explaining the problem of the estimation method using the center of gravity (x _G , y _G ) as the wave source position.

  In FIG. 6, the position of the terminal device 2, the wave source position, and the center of gravity position are shown in the x-axis direction, and changes in received power in the x-axis direction are shown.

  FIG. 6A shows a case where the wave source position exists between two terminal apparatuses, and FIG. 6B shows a case where the wave source position exists on one side of the two terminal apparatuses 2.

  6A and 6B, the received power attenuates in inverse proportion to the distance from the wave source position.

  When the wave source position exists between two terminal devices, the barycentric position exists in the vicinity of the wave source position.

  On the other hand, when the wave source position exists on one side of the two terminal devices 2, the gravity center position exists between the two terminal devices, and is greatly deviated from the wave source position.

  Thus, even in one dimension, when the wave source position is biased toward one side of the terminal device, the position of the center of gravity greatly deviates from the wave source position.

  FIG. 7 is a diagram for explaining a method of estimating the wave source position when the wave source position is biased to one side with respect to the distribution region of the terminal device 2.

When the positions of the terminal device 2-1 and the terminal device 2-2 are close to each other, the position (x ₁ , y ₁ ) of the terminal device 2-1 and the position (x ₂ , y ₂ ) of the terminal device 2-2 A point (x _E , y _E ) that divides and into w ₁ : w ₂ is estimated as a wave source position.

In this case, x _E and y _E are expressed by the following equations.

  Referring to the distribution of the received power according to the distance, the wave source is biased to the right of the terminal devices 2-1 and 2-2 on the paper surface of FIG. It is larger than the received power of 2-1.

Therefore, among the received power of the terminal devices 2-1 and 2-2, the position (x ₁ , y ₁ ) of the terminal device 2-1 and the terminal device 2-2 on the terminal device 2-2 side having a large received power. The position (x ₂ , y ₂ ) is externally divided into w ₁ : w ₂ to obtain an external dividing point (x _E , y _E ).

When x _E and y _E become negative values, it is not calculated as a simple sum. Therefore, any two terminal devices are extracted from a plurality of terminal devices, and the two positions of the extracted two terminal devices are divided. The process of obtaining the outer dividing point is executed for all the two terminal devices, and the average value of the obtained outer dividing points is estimated as the wave source position.

When the total number of terminal devices 2 is N, the average values x _{E_ave} and y _{E_ave} of the outer _dividing points are determined by the following equations.

In the equation (3), _{w i} is made i-th received power _{P i} of the terminal device 2, _{w j} consists received power _{P j} of the j-th terminal device 2.

  FIG. 8 is a diagram for explaining a method of determining which of the outer dividing point and the inner dividing point is used.

  Referring to FIG. 8, when the diameter of the observation area REG is D and the distance between the two terminal devices 2 is d, when d is equal to or larger than the radius of the observation area (= D / 2), the wave source S is It exists between the two terminal devices 2. This is because the observation area REG has a circular shape centered on the wave source S as described above.

  On the other hand, when d is smaller than the radius (= D / 2), the wave source S exists at a position biased to one side of the two terminal devices 2.

  Therefore, when the distance d between the two terminal devices 2 is equal to or larger than the radius (= D / 2) of the observation area REG, an internal dividing point obtained by internally dividing the positions of the two terminal devices is estimated as a wave source position. When the distance d between the terminal devices 2 is smaller than the radius (= D / 2) of the observation area REG, an external dividing point obtained by dividing the position of the two terminal devices is estimated as the wave source position.

  That is, the wave source position is estimated by the following equation.

In Equation (4), x _Est and y _Est indicate the estimated value of the wave source position. Further, x _th shown in Expression (4) is a radius in the x-axis direction of the observation area REG, and y _th is a radius in the y-axis direction of the observation area REG.

  FIG. 9 is a flowchart for explaining the operation of the wave source position estimation apparatus 1 shown in FIG.

  Referring to FIG. 9, when the operation of wave source position estimation device 1 is started, calculation unit 14 calculates a variance Vari of distributions of a plurality of terminal devices 2 (step S1), and estimates the calculated variance Var. Output to means 15.

  Then, the estimation unit 15 receives the variance Var from the calculation unit 14, and determines whether or not the received variance Var is equal to or greater than the threshold value Var_th (step S2).

When it is determined in step S2 that the variance Var is equal to or greater than the threshold value Var_th, the estimation unit 15 applies all the position information (x _i , y _i ) read from the storage unit 13 and all the received powers P _i . Based on the equation (1), the center of gravity (x _G , y _G ) of the plurality of terminal devices 2 weighted by the received power P _i is calculated (step S3), and the calculated center of gravity (x _G , y _G ) is estimated as the wave source position (step S4).

On the other hand, when it is determined in step S2 that the variance Var is not equal to or greater than the threshold value Var_th, the estimation unit 15 selects any two points out of all the position information (x _i , y _i ) read from the storage unit 13. And the distance between the two points is calculated (step S5).

  And the estimation means 15 determines whether the distance between two points is more than a threshold value (= radius of observation area) (step S6).

  When it is determined in step S6 that the distance between the two points is not equal to or greater than the threshold value (= the radius of the observation area), the estimating means 15 calculates two external dividing points (step S7).

  On the other hand, when it is determined in step S6 that the distance between the two points is equal to or greater than the threshold value (= the radius of the observation area), the estimating means 15 calculates two internal dividing points (step S8).

  Then, after step S7 or step S8, the estimating means 15 determines whether or not evaluation of all measurement points has been completed (step S9).

  When it is determined in step S9 that evaluation of all measurement points has not been completed, the series of operations returns to step S5, and in step S9, until it is determined that evaluation of all measurement points has been completed. Steps S5 to S9 described above are repeatedly executed.

  When it is determined in step S9 that the evaluation of all the measurement points has been completed, the estimation means 15 calculates the average value of the inner and outer dividing points using equation (4) (step S10). Then, the calculated average value is estimated as the wave source position (step S11).

  Then, after step S4 or step S11, the operation of estimating the wave source position ends.

  Thus, in the embodiment of the present invention, based on the positional information and received power of a plurality of terminal devices, the center of gravity of the plurality of terminal devices weighted by the received power or the two positions of the two terminal devices. Since the average value of the dividing point or the outer dividing point is estimated as the wave source position, the wave source position can be estimated using four arithmetic operations. Therefore, it is possible to easily estimate the wave source position while suppressing the calculation amount.

  In the flowchart shown in FIG. 9, since the internal dividing point and the external dividing point are selectively used, the wave source position can be accurately estimated even when the position of the terminal device is biased.

  In step S10 of FIG. 9, it has been described that the average value is obtained by simply averaging the inner dividing point or the outer dividing point. However, in the embodiment of the present invention, the inner dividing point or the outer dividing point is not limited thereto. The average value of the inner dividing point or the outer dividing point may be obtained by weighting with the average power of the two received powers of the two terminal devices used to obtain the dividing point.

  That is, the average value of the inner dividing points may be obtained by the following equation (5), and the average value of the outer dividing points may be obtained by the equation (6).

  FIG. 10 is a flowchart for explaining another operation of the wave source position estimation apparatus 1 shown in FIG.

  The flowchart shown in FIG. 10 is the same as the flowchart shown in FIG. 9 except that steps S5 to S8 in the flowchart shown in FIG. 9 are replaced with steps S21 to S28.

  When the operation of the wave source position estimating apparatus 1 is started, the above-described steps S1 to S4 are sequentially executed.

When it is determined in step S2 that the variance Var is smaller than the threshold value Var_th, the estimation unit 15 selects any 2 of the positional information (x _i , y _i ) read from the storage unit 13. A point is extracted, and a distance Lx between two points in the x-axis direction and a distance Ly between two points in the y-axis direction are calculated (step S21).

  Then, the estimating unit 15 determines whether or not the distance Lx in the x-axis direction is greater than or equal to the threshold value L_th_x (step S22). The threshold value L_th_x is set to the radius of the observation area REG in the x-axis direction.

  When it is determined in step S22 that the distance Lx is not equal to or greater than the threshold value L_th_x, the estimation unit 15 further determines whether or not the distance Ly in the y-axis direction is equal to or greater than the threshold value L_th_y (step S23). The threshold value L_th_y is set to the radius of the observation area REG in the y-axis direction.

  On the other hand, when it is determined in step S22 that the distance Lx is greater than or equal to the threshold value L_th_x, the estimation unit 15 further determines whether or not the distance Ly in the y-axis direction is greater than or equal to the threshold value L_th_y (step S22). S24).

  When it is determined in step S23 that the distance Ly is not greater than or equal to the threshold value L_th_y, the estimating unit 15 calculates an outer dividing point between the two points in both the x-axis direction and the y-axis direction (step S25).

  On the other hand, when it is determined in step S23 that the distance Ly is greater than or equal to the threshold value L_th_y, the estimating unit 15 calculates an outer dividing point between two points in the x-axis direction, and two points in the y-axis direction. An internal dividing point is calculated (step S26).

  When it is determined in step S24 that the distance Ly is not equal to or greater than the threshold value L_th_y, the estimating unit 15 calculates an internal dividing point between two points in the x-axis direction, and between the two points in the y-axis direction. Is calculated (step S27).

  On the other hand, when it is determined in step S24 that the distance Ly is greater than or equal to the threshold value L_th_y, the estimating unit 15 calculates an internal dividing point between the two points in both the x-axis direction and the y-axis direction (step S24). S28).

  Then, after any of step S25 to step S28, the process proceeds to step S9, and the above-described steps S21 to S28, S9 are repeatedly executed until it is determined in step S9 that the evaluation of all the measurement points is completed. The

  If it is determined in step S9 that the evaluation of all measurement points has been completed, steps S10 and S11 described above are sequentially executed. In this case, in step S10, the estimation means 15 calculates the average value of the inner dividing point and the outer dividing point in the x-axis direction and the y-axis direction, respectively.

  As described above, according to the flowchart shown in FIG. 10, since either the internal dividing point or the external dividing point is used separately for the x-axis direction and the y-axis direction (refer to step S22 to step S28), the calculation is performed in step S10. The average value obtained is closer to the wave source position.

  Therefore, the wave source position can be estimated more accurately.

  Also, in the flowchart shown in FIG. 10, since the internal dividing point and the external dividing point are selectively used, the wave source position can be accurately estimated even when the position of the terminal device is biased.

  FIG. 11 is a schematic diagram showing another configuration of the wave source position estimation apparatus 1 shown in FIG. In the embodiment of the present invention, the wave source position estimating apparatus 1 may be the wave source position estimating apparatus 1A shown in FIG.

  Referring to FIG. 11, wave source position estimating apparatus 1 </ b> A is obtained by adding estimating means 16 and detecting means 17 to wave source position estimating apparatus 1 shown in FIG. 1, and is otherwise the same as wave source position estimating apparatus 1. .

The estimation unit 16 reads a plurality of pieces of terminal information from the storage unit 13, and records a variation in the received power P _i depending on time based on the plurality of _pieces of received power P _i and the plurality of pieces of time information included in the read pieces of terminal information. To do. Then, the estimation means 16 estimates whether the received power P _i is fluctuating due to noise or fading based on the fluctuation of the received power P _i with time, and detects the estimated error factor. 17 output.

Detection means 17, from the storage unit 13 reads a plurality of received power P _i, receives the error factor from the estimation means 16. Then, the detecting unit 17 detects the received power P _{i_CFD} satisfying the required reliability rate from the plurality of received powers P _i by a method described later, and outputs the detected received power P _{i_CFD} to the estimating unit 15.

In wave source position estimating apparatus 1A, estimating means 15 estimates the wave source position by the method described above based on received power P _{i_CFD} received from detecting means 17.

Figure 12 is a conceptual diagram showing a variation of the received power P _i with time. Referring to FIG. 12, in a propagation environment affected by fading, received power P _i varies as shown by curve k1 with time.

Further, when the propagation environment is a propagation environment that is affected by noise, the received power P _i varies with time so as to differ from the curve k1.

Estimating means 16 holds the variation of the received power P _i over time, the variation characteristics associated with the error factor such as noise and fading. The estimation means 16, the variation with time of the received power P _i read from the storage unit 13, determines whether equal or close any fluctuation characteristics, detects the error factor corresponding to the fluctuation characteristics that match or approximate Thus, the error factor that the received power P _i varies with time is estimated.

  The distribution of errors such as noise and fading is one of a normal distribution, a Rice distribution, and a Rayleigh distribution. The normal distribution is an error distribution when the error factor is noise, and the Rice distribution and the Rayleigh distribution are error distributions when the error factor is fading. The Rayleigh distribution is an error distribution when the scattering is intense.

Therefore, in the embodiment of the present invention, the propagation environment of radio waves is estimated, and according to the estimated propagation environment, the distribution of error factors is determined as one of a normal distribution, a Rice distribution, and a Rayleigh distribution, The received power P _{i_CFD} that satisfies the reliability corresponding to the distribution of the determined error factors is detected.

  Based on the terminal information from the fixed terminal or the terminal information from the mobile terminal having the slowest moving speed, the estimating means 16 detects the variation of the received power with time, and based on the detected variation of the received power with time. The propagation environment such as a fading propagation environment or a noisy propagation environment is estimated.

  Then, the estimation unit 16 determines the distribution of the error factor to be any one of the normal distribution, the Rice distribution, and the Rayleigh distribution according to the estimated propagation environment, and sends the determined distribution of the error factor to the detection unit 17. Output.

  FIG. 13 is a diagram illustrating the relationship between the type of error and the required reliability rate. Referring to FIG. 13, when the type of error is a normal distribution, the required reliability rate is, for example, 0.95, and the distribution point α is a normal distribution point having a reliability rate of 0.95. When the type of error is a Rice distribution, the required reliability rate is, for example, 0.90, and the distribution point β is a Rice distribution point having a reliability rate of 0.90. When the type of error is Rayleigh distribution, the required reliability is, for example, 0.80, and the distribution point γ is a Rayleigh distribution point with a reliability of 0.80.

  The detecting means 17 holds a correspondence table TBL indicating the correspondence between the error types and the required reliability shown in FIG. When receiving the error factor distribution from the estimating unit 16, the detecting unit 17 refers to the correspondence table TBL and detects the reliability corresponding to the received error factor distribution.

Thereafter, the detection unit 17 reads a plurality of _pieces of terminal information, and detects the received power P _{i_CFD} that satisfies the requested reliability rate based on the read _pieces of terminal information.

More specifically, the detection means 17 detects the received power P _{i_CFD} by the following method. The detection unit 17 extracts a plurality of received powers having different times from the received power received from one terminal device 2. For example, the detection unit 17 extracts ten received powers having different times. And the detection means 17 calculates Z by following Formula using ten received power from which time differs.

  In Expression (7), n is the size of the number of samples, e is an allowable error range, and Z is a distribution point having a reliability rate α. P is a ratio of received power used for estimating the wave source position in the population. For example, when the wave source position is estimated using 10 received powers out of 100 received powers, P = 0.1. N is the population.

  FIG. 14 is a diagram showing the relationship between the sample size n and the error range e. FIG. 14 shows the relationship between the sample size n and the error range e when the average received power is −100 dBm and the reliability rate α is 0.95.

  Referring to FIG. 14, the sample size n is, for example, any one of 10, 20, 50, and 100. The error range e is set to, for example, 10% when the sample size n is 10, and is set to, for example, 7% when the sample size n is 20, and the sample size n is 50. Is set to 5%, for example, and is set to 3%, for example, when the sample size n is 100. Thus, the error range e is set so as to decrease as the sample size n increases.

  When the sample size n is 10, there is a true value in the range of −110 to −90 dBm with a probability of 95% (reliability α = 0.95). When the sample size n is 100, there is a true value in the range of −103 to −97 dBm with a probability of 95% (reliability α = 0.95).

  Since the error range e is set to become smaller as the sample size n increases, the error range e becomes smaller and the accuracy improves as the sample size n increases.

  Further, the distribution point of the reliability rate α and the allowable error range e are set according to the required accuracy. If the sample size n does not increase, the restriction on the reliability rate α or the error range e is reduced. This is because when the sample size n does not increase, if the reliability rate α is set high or the error range e is set narrow, there is no received power that satisfies the reliability rate α or the error range e, and the wave source position cannot be estimated. .

N is the total number of received powers P _i , n is 10 received powers with different times (the number of received powers of some of the total received powers P _i ), and e is Since it is set as shown, since it is known and P is also known, the detection means 17 can calculate Z by the equation (7).

  Then, the detection unit 17 determines whether or not the calculated Z satisfies the reliability rate. More specifically, the detection means 17 determines that the received power is correct data when Z satisfies the reliability rate, and determines that the received power is incorrect data when Z does not satisfy the reliability rate.

  Here, whether or not Z satisfies the reliability is determined by whether or not Z falls within a range in which the deviation is ± 0.05 in the normal distribution when the error distribution follows the normal distribution. Then, when Z falls within a range where the deviation is ± 0.05 in the normal distribution, it is determined that Z satisfies the reliability, and when Z does not fall within the range where the deviation is ± 0.05 in the normal distribution, Z Is determined not to satisfy the reliability rate.

  When it is determined that the received power is incorrect data, the detecting unit 17 determines whether the received power is correct data for the other received power by the method described above.

  Even when the error distribution is a Rice distribution or a Rayleigh distribution, the detection unit 17 determines whether or not the received power is correct data, as in the case where the error distribution is a normal distribution.

  The detecting means 17 extracts a plurality of received powers having the same time information from a plurality of received powers received from different terminal devices, and for each of the extracted received powers, the above-described method is used. It may be determined whether the received power is correct.

  FIG. 15 is a diagram illustrating a sample for determining whether or not the received power is correct data.

Referring to (a) of FIG. 15, n (n is an integer satisfying 2 ≦ n <i) received powers P _{1 to} P _n having different time information at position (x ₁ , y ₁ ). Electric power.

Referring to (b) of FIG. 15, n received powers P ′ _{1 to} P ′ _n are received powers having different position information in time information t ₁ .

When determining whether or not the received power is correct data using the _n received powers P _{1 to} P _n , the detection unit 17 determines that the distribution of the _n received powers P _{1 to} P _n is a normal distribution and a rice. It is judged whether it corresponds to distribution or Rayleigh distribution. When the detection unit 17 determines that the normal distribution is satisfied, the detection unit 17 refers to the correspondence table TBL and detects a reliability rate of 0.95 corresponding to the normal distribution.

  Thereafter, the detection means 17 calculates Z using the equation (7), and determines whether or not the calculated Z satisfies the reliability rate by the method described above.

Even when the distribution of the _n received powers P _{1 to} P _n is a Rice distribution or a Rayleigh distribution, the detection unit 17 similarly determines whether or not the calculated Z satisfies the reliability rate by the method described above. .

When the detection unit 17 determines that Z satisfies the reliability rate, that is, when it is determined that the n received powers P _{1 to} P _n are correct data, reception at the position (x ₁ , y ₁ ) is performed. The power is detected as data for wave source position estimation.

As described above, since the estimation unit 15 estimates the wave source position using a plurality of received power detected at different positions, the n received power P ₁ detected at the same position (x ₁ , y ₁ ). This is because ~ _Pn cannot be used as the received power for wave source position estimation.

When determining whether or not the received power is correct data using the _n received powers P ′ _{1 to} P ′ _n , the detection means 17 has a distribution of the _n received powers P ′ _{1 to} P ′ _n . It is determined whether the distribution is normal distribution, Rice distribution, or Rayleigh distribution. When the detection unit 17 determines that the normal distribution is satisfied, the detection unit 17 refers to the correspondence table TBL to detect a reliability rate of 0.95 corresponding to the normal distribution.

  Thereafter, the detection means 17 calculates Z using the equation (7), and determines whether or not the calculated Z satisfies the reliability rate by the method described above.

Even when the distribution of the _n received powers P ′ _{1 to} P ′ _n is a Rice distribution or a Rayleigh distribution, the detection unit 17 similarly determines whether or not the calculated Z satisfies the reliability rate by the method described above. judge.

When the detection unit 17 determines that Z satisfies the reliability rate, that is, when it is determined that the n received powers P ′ _{1 to} P ′ _n are correct data, the n received powers P ′ ₁ ˜P ′ _n is detected as data for wave source position estimation.

This is because the n received powers P ′ _{1 to} P ′ _n are received powers detected at different positions, and can be used as data for estimating the wave source position in the estimating unit 15 if the reliability rate is satisfied.

Therefore, the detection means 17 detects the n received powers P ′ _{1 to} P ′ _n as a correct set of data.

On the other hand, when the detection unit 17 determines that the n received powers P ′ _{1 to} P ′ _n are not correct data, at least one of the _n received powers P ′ _{1 to} P ′ _n is different from another n. The received power is extracted, and it is determined by the above-described method whether or not the extracted n received powers are correct data.

  Detecting the received power satisfying the required reliability rate by the above-described method is equivalent to detecting the received power satisfying the required reliability rate according to the radio wave propagation environment. The estimation means 16 estimates the propagation environment of radio waves, determines the distribution of error factors according to the estimated propagation environment, and the detection means 17 determines the reliability rate (required) corresponding to the determined distribution of error factors. This is because the received power satisfying the (reliability rate) is detected.

  FIG. 16 is a flowchart for explaining the operation of the wave source position estimating apparatus 1A shown in FIG.

  Referring to FIG. 16, when the operation of wave source position estimating apparatus 1A is started, estimating means 16 estimates an error distribution by the above-described method (step S31), and detects the estimated error distribution. 17 output.

  The detection unit 17 receives the error distribution from the estimation unit 16 and reads a plurality of pieces of terminal information from the storage unit 13. That is, the detection means 17 acquires terminal information from the terminal device (step S32). And the detection means 17 calculates Z by the method mentioned above based on terminal information, and determines whether the calculated Z satisfy | fills a reliability rate (step S33).

  When it is determined in step S33 that Z does not satisfy the reliability rate, the series of operations returns to step S32, and steps S32 and S33 are repeatedly executed until it is determined in step S33 that Z satisfies the reliability rate. To do.

  In step S33, when it is determined that Z satisfies the reliability rate, the detection unit 17 outputs the received power that satisfies the reliability rate to Z to the estimation unit 15.

  The estimation means 15 receives the received power with which Z satisfies the reliability rate from the detection means 17, and estimates the wave source position according to the flowchart shown in FIG. 9 or 10 based on the received power with which the received Z satisfies the reliability ratio ( Step S34). Thereby, the operation of the wave source position estimating apparatus 1A is completed.

  As described above, the wave source position estimating apparatus 1A estimates the wave source position using the received power satisfying the required reliability ratio among the received power received from the terminal apparatus 2, and thus there are error factors such as noise and fading. The wave source position can be estimated with high accuracy even in an environment.

  In addition, estimation of the wave source position in the wave source position estimation apparatuses 1 and 1A may be executed by software.

  In this case, each of the wave source position estimation devices 1 and 1A includes a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory).

  The ROM is one of the program Prog_A including the flowchart shown in FIG. 9, the program Prog_B including the flowchart illustrated in FIG. 10, the program Prog_C including the flowchart illustrated in FIGS. 9 and 15, and the program Prog_D including the flowchart illustrated in FIGS. Store

  Then, the CPU reads any one of the programs Prog_A to Prog_D from the ROM, executes the read program (any one of the programs Prog_A to Prog_D), and estimates the wave source position.

  In this case, the RAM is used for storing terminal information received from the terminal device 2 and for various calculations.

  Further, any of the programs Prog_A to Prog_D may be recorded and distributed on a recording medium such as a CD or a DVD. In this case, the CPU reads and executes the program (any one of the programs Prog_A to Prog_D) from the mounted recording medium, and estimates the wave source position. Therefore, a recording medium such as a CD or a DVD on which a program (any one of the programs Prog_A to Prog_D) is recorded is a computer-readable recording medium.

  In the above, wave source position estimation apparatus 1, 1A was demonstrated. That is, when the wave source position is estimated using the received power received from the terminal apparatus 2 as it is, and when the wave source position is estimated using the received power satisfying the required reliability ratio among the received power received from the terminal apparatus 2 And explained.

  Therefore, the wave source position estimation device according to the embodiment of the present invention includes: a receiving unit that receives terminal information including position information of a terminal device composed of a mobile terminal or a stationary terminal and received power in the terminal device from a plurality of terminal devices; Calculating means for calculating a variance in a distribution of positions of a plurality of terminal devices based on a plurality of pieces of position information included in a plurality of pieces of terminal information of the plurality of terminal devices, and the calculated variance is equal to or greater than a first threshold value; The center of gravity of the plurality of terminal devices weighted by the received power is estimated as the wave source position based on the plurality of position information and the plurality of received power included in the plurality of terminal information, and the calculated variance is the first value. When the threshold value is smaller than the threshold value, an outer dividing point that divides the two positions indicated by the position information of two terminal devices out of the plurality of terminal devices or an inner dividing point that divides the two positions is obtained. And an estimation means for estimating a position obtained by averaging the obtained outer dividing point or inner dividing point as a wave source position, for all two terminal devices of the plurality of terminal devices. Just do it.

  Further, a program for causing a computer to execute according to an embodiment of the present invention is a program for causing a computer to perform estimation of a wave source position, and the reception unit is position information of a terminal device including a mobile terminal or a stationary terminal. And a first step of receiving terminal information including the received power in the terminal device from the plurality of terminal devices, and the calculating means includes a plurality of pieces of information based on the plurality of pieces of position information included in the plurality of terminal information of the plurality of terminal devices. A second step of calculating a variance in the distribution of the position of the terminal device, and a plurality of position information and a plurality of terminal information included in the plurality of terminal information when the estimating means has the calculated variance equal to or greater than a first threshold value The center of gravity of the plurality of terminal devices weighted by the received power based on the received power is estimated as the wave source position, and the calculated variance is greater than the first threshold value. In this case, a process for obtaining an external dividing point that divides two positions indicated by position information of two terminal apparatuses among a plurality of terminal apparatuses or an internal dividing point that internally divides two positions is performed by a plurality of terminal apparatuses. If it is executed for all of the two terminal devices, and the computer executes the third step of estimating the obtained outer dividing point or the position obtained by averaging the inner dividing points as the wave source position, Good.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wave source position estimation device, a program for causing a computer to execute, and a computer-readable recording medium on which the program is recorded.

  1, 1A Wave source position estimating device, 2 terminal device, 10 wireless communication system, 11 antenna, 12 receiving means, 13 storing means, 14 calculating means, 15, 16 estimating means, 17 detecting means.

Claims (11)

Receiving means for receiving, from a plurality of terminal devices, terminal information including position information of a terminal device composed of a mobile terminal or a stationary terminal and received power in the terminal device;
Calculating means for calculating a variance in a distribution of positions of the plurality of terminal devices based on a plurality of pieces of position information included in a plurality of terminal information of the plurality of terminal devices;
The plurality of terminals weighted by the received power based on the plurality of position information and the plurality of received powers included in the plurality of terminal information when the calculated variance is equal to or greater than a first threshold value When the center of gravity of the apparatus is estimated as a wave source position and the calculated variance is smaller than the first threshold, two positions indicated by position information of two terminal apparatuses among the plurality of terminal apparatuses are determined. A process for obtaining an external dividing point for dividing externally or an internal dividing point for internally dividing the two positions is executed for all two terminal devices of the plurality of terminal devices, and the obtained external dividing point or internal dividing point is obtained. A wave source position estimation apparatus comprising: an estimation unit that estimates a position obtained by averaging the wave source positions as the wave source position.   The estimating means averages the internal dividing points when the calculated variance is smaller than the first threshold and the distance between the two positions is equal to or larger than a second threshold. When the calculated dispersion is smaller than the first threshold and the distance between the two positions is smaller than the second threshold The wave source position estimating apparatus according to claim 1, wherein a position obtained by averaging the outer dividing points is estimated as the wave source position.   The wave source position estimation apparatus according to claim 2, wherein the estimation unit estimates, as the wave source position, a position obtained by simply averaging the outer dividing point or the inner dividing point.   The said estimation means estimates the position obtained by carrying out the weighted average of the said external dividing point or the said internal dividing point by the average power of the two received powers of the said 2 terminal device as said wave source position. Wave source position estimation device. Among the plurality of received powers, further comprising detection means for detecting received power that satisfies a reliability rate required according to a radio wave propagation environment,
5. The wave source position estimation apparatus according to claim 1, wherein the estimation unit estimates the wave source position using reception power detected by the detection unit. 6. A program for causing a computer to estimate a wave source position,
A first step of receiving, from a plurality of terminal devices, terminal information including position information of a terminal device composed of a mobile terminal or a stationary terminal and received power in the terminal device;
A second step of calculating a variance in a distribution of positions of the plurality of terminal devices based on a plurality of pieces of position information included in a plurality of pieces of terminal information of the plurality of terminal devices;
The estimation unit is weighted by the received power based on the plurality of position information and the plurality of received power included in the plurality of terminal information when the calculated variance is greater than or equal to a first threshold value. When the center of gravity of the plurality of terminal devices is estimated as a wave source position and the calculated variance is smaller than the first threshold value, it is indicated by position information of two terminal devices of the plurality of terminal devices. Processing for obtaining an external dividing point that divides two positions or an internal dividing point that internally divides the two positions is executed for all two terminal devices of the plurality of terminal devices, and the obtained external dividing points Or the program for making a computer perform the 3rd step which estimates the position obtained by averaging an internal dividing point as said wave source position.   In the third step, the estimating means, when the calculated variance is smaller than the first threshold and the distance between the two positions is equal to or greater than a second threshold, A position obtained by averaging the inner dividing points is estimated as the wave source position, the calculated variance is smaller than the first threshold value, and the distance between the two positions is a second value. The program for making a computer run of Claim 6 which estimates the position obtained by averaging the said external dividing point as said wave source position when it is smaller than a threshold value.   8. The computer according to claim 7, wherein in the third step, the estimation unit estimates, as the wave source position, a position obtained by simple averaging of the outer dividing point or the inner dividing point. program.   In the third step, the estimation means estimates, as the wave source position, a position obtained by weighted averaging the outer dividing point or the inner dividing point with an average power of two received powers of the two terminal devices. The program for making the computer of Claim 7 perform. The detection means further causes the computer to execute a fourth step of detecting a received power satisfying a reliability rate required according to a radio wave propagation environment among the plurality of received powers,
10. The computer according to claim 6, wherein, in the third step, the estimation unit estimates the wave source position using the received power detected in the fourth step. 11. A program to be executed.   The computer-readable recording medium which recorded the program of any one of Claims 6-10.

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