Information processing device, information processing system, and computer program

Abstract

This invention provides an information processing device, an information processing system, and a computer program that enable expanded search range and highly accurate position estimation using a single receiving antenna. [Solution] An information processing device comprising a calculation unit for estimating the position of a radio wave source, wherein the calculation unit acquires detected values ​​of the radio waves received by an aircraft equipped with an antenna having a plurality of antenna elements flying over a target area, calculates the direction of arrival of the radio waves based on the plurality of detected values ​​received by the plurality of antenna elements and the arrangement of the plurality of antenna elements, calculates the coordinates of the intersection of the virtual line and the virtual plane based on the altitude distance between a virtual plane set in the target area and the aircraft, and a virtual line along the direction of arrival from the position of the aircraft, and calculates the position of the source located in the target area based on the coordinates.

Description

Technical Field

[0001] The present invention relates to an information processing apparatus, an information processing system, and a computer program for estimating the position of a radio wave transmission source.

Background Art

[0002] Monitoring of illegal radio waves and identification of the transmission source have been carried out. When monitoring radio waves on the ground, the radio waves are affected by diffraction, reflection, interference, transmission, etc. in the propagation path. Therefore, monitoring of radio waves on the ground may result in a decrease in accuracy. For example, Patent Document 1 proposes an arithmetic device for monitoring radio waves in the air where the influence of radio wave interference is small. According to the technique described in Patent Document 1, the arithmetic device is configured to execute machine learning using teacher data in advance and calculate the position of the radio wave transmission source based on the radio wave intensity received in the air and the position of the aircraft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, research has been conducted on estimating the transmission position based on radio waves transmitted from mobile terminals or the like during a disaster. Receiving radio waves transmitted from mobile terminals or the like on an aircraft and estimating the transmission position can be applied to rapid rescue activities during a disaster.

[0005] An object of the present invention is to provide an information processing apparatus, an information processing system, and a computer program capable of expanding the search range of position estimation and achieving high-precision position estimation using a single receiving antenna.

Means for Solving the Problems

[0006] One aspect of the present invention is an information processing device comprising a calculation unit for estimating the position of a radio wave source, wherein the calculation unit acquires detected values ​​of the radio waves received by an aircraft equipped with an antenna having a plurality of antenna elements flying over a target area, calculates the direction of arrival of the radio waves based on the plurality of detected values ​​received by the plurality of antenna elements and the arrangement of the plurality of antenna elements, calculates the coordinates of the intersection of the virtual line and the virtual plane based on the altitude distance between a virtual plane set in the target area and the aircraft, and a virtual line along the direction of arrival from the position of the aircraft, and calculates the position of the source located in the target area based on the coordinates. [Effects of the Invention]

[0007] According to the present invention, it is possible to expand the search range and achieve highly accurate position estimation using a single receiving antenna. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram showing the configuration of an information processing system according to an embodiment. [Figure 2] This is a block diagram showing the configuration of an information processing system. [Figure 3] This is a perspective view showing the configuration and operation of the antenna. [Figure 4] This diagram shows a method for estimating the direction of arrival of radio waves in the horizontal direction. [Figure 5] This diagram shows a method for estimating the direction of arrival of radio waves in the vertical direction. [Figure 6] This diagram shows the state of adjusting the deployment angle of the antenna unit. [Figure 7] This diagram shows a method for estimating the location of the source of an event. [Figure 8] This figure shows the simulation results. [Figure 9] This figure shows the simulation results. [Figure 10]This is a diagram showing the simulation status. [Figure 11] This figure shows the simulation results. [Figure 12] This figure shows the simulation results. [Figure 13] This figure shows the simulation results. [Figure 14] This figure shows the simulation results. [Figure 15] This figure shows the simulation results. [Figure 16] This flowchart shows the processing flow of the radio wave position estimation method executed in the information processing device. [Modes for carrying out the invention]

[0009] As shown in Figure 1, the information processing system S consists of a flyable aircraft 1 and an information processing device 10 capable of communicating with the aircraft 1. The aircraft 1 flies above a target area G of the Earth's surface to be observed. The aircraft 1 is equipped with an antenna A that receives radio waves emitted from a source H located within the target area G. The information processing device 10 is configured to estimate the position of the source H based on the detected value of the radio waves received by antenna A.

[0010] As shown in Figures 2 and 3, the aircraft 1 is equipped with flight devices 2 necessary for flight operation. The flight devices 2 are configured according to the flight mode of the aircraft 1. The flight devices 2 are composed of a combination of propulsion sources such as jet engines, rocket engines, internal combustion engines, motors, propellers, wings, and balloons, as well as power sources, lift generators, buoyancy generators, etc. Other devices may be used in the flight devices 2 as long as they enable flight.

[0011] The flying object 1 includes a direction adjustment unit 3 for adjusting the flight direction. The direction adjustment unit 3 includes mechanisms such as jet ejection direction, propeller pitch angle, wing adjustment, airbag adjustment, etc., or a combination of these mechanisms, according to the flight mode. The flying object 1 according to the embodiment is, for example, a communication platform (e.g., HAPS (High Altitude Platform Station)) flying in the stratosphere. The flying object 1 flies, for example, at an altitude of 10 km or more above the ground surface.

[0012] The flying object 1 includes a control device 4 that integrally executes flight control, antenna control, communication control, etc. The control device 4 is realized, for example, by an information processing device such as a computer. The control device 4 includes a control unit 5 that executes arithmetic processing necessary for control. The control device 4 includes a storage unit 6 in which data and computer programs necessary for arithmetic are stored. The control unit 5 is configured to execute, for example, a computer program stored in the storage unit 6 by a hardware processor such as a CPU (Central Processing Unit).

[0013] The control unit 5 may be realized by hardware (including a circuit part; circuitry) such as LSI (Large Scale Integration), ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), GPU (Graphics Processing Unit), or may be realized by cooperation of software and hardware. The computer program may be stored in a storage device such as an HDD (Hard Disk Drive) or flash memory that the storage unit 6 has in advance, or may be stored in a removable storage medium such as a DVD or CD-ROM, and may be installed by mounting the storage medium on a drive device.

[0014] The control device 4 includes a communication unit 7 that can be communicatively connected to the network W. The communication unit 7 is constituted by, for example, a wireless communication device. The flying object 1 further includes a three-dimensional position detection sensor such as GPS (Global Positioning System) necessary for flight.

[0015] The flying object 1 includes an antenna A for receiving radio waves. The antenna A is provided on the lower surface side of the flying object 1. A plurality of antenna elements are provided on the antenna A. The antenna A is, for example, a cylinder antenna formed in a cylindrical shape. The antenna A includes a plurality of antenna units An (n: natural number) arranged along the side surface of the cylinder. The antenna unit An has a receiving surface formed on the outer surface side.

[0016] On the receiving surface side of the antenna unit An, a predetermined number of antenna elements Bnm (m: natural number) are arranged in a matrix. In the antenna unit An according to the embodiment, m antenna elements Bnm arranged in a matrix of m rows × 1 column are provided. The antenna unit An may have antenna elements arranged in a matrix of m rows × multiple columns. Each antenna element Bnm receives the incoming radio waves. The plurality of antenna units An include, for example, a hinge mechanism at the lower end. The plurality of antenna units An are configured to be radially deployable by the hinge mechanism.

[0017] The plurality of antenna units An include a drive unit C for driving them to be radially deployable. The drive unit C includes a plurality of drive parts Cn for driving each antenna unit An. One drive part Cn is provided, for example, at the hinge part of the corresponding one antenna unit An. One drive part Cn rotationally drives the receiving surface of the corresponding one antenna unit An, for example. The drive unit C controls each drive part Cn, drives the plurality of antenna units An to face the target area G, and radially deploys them. The drive unit C is controlled by the information processing device 10 as will be described later.

[0018] With the above configuration, antenna A is configured as an array antenna in which multiple antenna elements Bnm are arranged three-dimensionally on the side surface of a cylinder. The control unit 5 stores the detected values ​​detected by the multiple antenna elements Bnm in the storage unit 6. The control unit 5 transmits the detected values ​​to the information processing device 10 via the network W at a predetermined timing.

[0019] The information processing device 10 performs calculations based on the acquired detection values. The information processing device 10 is implemented by an information processing device such as a personal computer. The information processing device 10 includes an arithmetic unit 11 that performs calculations. The information processing device 10 includes a storage unit 12 that stores data and computer programs necessary for calculations. The arithmetic unit 11 is configured so that a hardware processor such as a CPU executes the computer programs stored in the storage unit 12. The arithmetic unit 11 may be implemented by hardware (including circuitry) such as an LSI, ASIC, FPGA, or GPU, or it may be implemented by the cooperation of software and hardware.

[0020] The computer program may be stored in advance in a storage device such as an HDD or flash memory in the storage unit 12, or it may be stored in a removable storage medium such as a DVD, CD-ROM, or card-type memory, and installed when the storage medium is inserted into the drive device. The information processing device 10 includes a communication unit 13 that can communicate with the network W. The communication unit 13 is configured, for example, by a wireless communication device.

[0021] The calculation unit 11 acquires detected radio wave values ​​from antenna A of an aircraft flying above the target region G. Based on the detected values, the calculation unit 11 performs a process to calculate the position of the radio wave source H present in the target region G. Based on the multiple detected values ​​received by multiple antenna elements Bnm and the arrangement of the multiple antenna elements Bnm, the calculation unit 11 calculates the direction of arrival of the radio waves.

[0022] As shown in Figure 4, the calculation unit 11 estimates the direction of arrival of radio waves in the horizontal plane at antenna A. Antenna A receives radio waves from source H. In this case, antenna A receives radio waves on half of its receiving surface on the side of source H when viewed in a cross-sectional direction along the vertical direction (z-axis direction in the figure). The calculation unit 11 calculates the direction of arrival of radio waves in the horizontal plane (xy-plane in the figure) based on multiple detection values ​​received at multiple antenna elements Bnm and the arrangement of the multiple antenna elements Bnm. The calculation unit 11 individually analyzes the detection values ​​obtained from the multiple antenna elements Bnm arranged at antenna A.

[0023] The calculation unit 11 adjusts the phase difference of multiple detected values ​​based on the arrangement of multiple antenna elements Bnm. The calculation unit 11 calculates the direction of radio wave arrival using an estimation model based on the multiple detected values ​​with adjusted phases. The estimation model used is, for example, a known Beamformer method or MUSIC (Multiple Signal Classification) method that can estimate the direction of radio wave arrival of an array antenna.

[0024] The calculation unit 11, for example, based on an estimation model using the Beamformer method, scans the main lobe V1 of the receiving beam V with the highest receiving sensitivity of antenna A in all directions (all around in the illustrated example) of antenna A, and estimates the direction in which the detected received power is greatest as the direction of arrival of the radio wave. The calculation unit 11 estimates the direction of arrival of the radio wave by scanning the null point N1, which is the valley between the main lobe V1 and the side lobe V2, based on an estimation model using the MUSIC method. Since the null point N1 is more sensitive than the main lobe V1 and side lobe V2, which have beam widths, the resolution can be improved when using the MUSIC method.

[0025] The calculation unit 11 decomposes the eigenvalues ​​and eigenvectors of the correlation matrix representing the phase difference of the received signals between multiple antenna elements Bnm. The calculation unit 11 calculates an eigenvalue equal to the thermal noise power generated in the receiving circuit based on the detected value. The calculation unit 11 calculates the angular spectrum of the detected value based on a subspace method that utilizes the fact that all eigenvectors corresponding to the eigenvalues ​​are orthogonal to the direction vector of the arriving wave. The calculation unit 11 calculates the direction vector of the arriving wave based on the phase difference between the phase reference point of antenna A and antenna element Bnm. The estimation model executed by the calculation unit 11 may use other methods as long as it is possible to calculate the direction of arrival of the radio wave.

[0026] As shown in Figure 5, the calculation unit 11 estimates the direction of arrival of radio waves in the vertical plane at antenna A. For example, after estimating the direction of arrival of radio waves in the horizontal plane, the calculation unit 11 estimates the direction of arrival of radio waves in the vertical plane (xz plane in the figure) at antenna A. The calculation unit 11 scans the received beam V in the same way as the method used to estimate the direction of arrival of radio waves in the horizontal plane. Similar to the horizontal plane, the calculation unit 11 calculates the direction of arrival of radio waves based on estimation models using the Beamformer method or the MUSIC method.

[0027] As shown in Figure 6, the calculation unit 11 may control the drive unit C provided on antenna A to adjust the deployment angle of multiple antenna units An, thereby improving the reception sensitivity of the detected value. In addition to scanning the received beam V, the calculation unit 11 controls the drive unit C to adjust the deployment angle of multiple antenna units An, adjusting the deployment angle of the drive unit C so that the received power of the radio waves increases. The calculation unit 11 calculates the direction of arrival of the radio waves based on the deployment angle at which a predetermined or higher received power is obtained and the detected value of the multiple antenna elements Bnm.

[0028] The calculation unit 11 may adjust the deployment angle so that the direction of arrival of the radio waves calculated based on the scanning of the received beam V matches the normal direction of the antenna unit An. When the antenna unit An is deployed radially based on the deployment angle, the calculation unit 11 transforms the coordinates of the multiple antenna elements Bnm. The calculation unit 11 calculates the direction of arrival of the radio waves based on the transformed coordinates of the multiple antenna elements Bnm and the detected values ​​of the multiple antenna elements Bnm. The calculation unit 11 may adjust the deployment angle by controlling the drive unit C based on the altitude distance of the aircraft 1.

[0029] As shown in Figure 7, the aircraft 1 flies over the target area G and receives radio waves transmitted from the source H at antenna A. The calculation unit 11 calculates the average height U of buildings T surrounding the source H from the ground surface and sets a virtual plane K at the average height U. Based on the detection values ​​of the position detection sensor, the calculation unit 11 calculates the altitude distance D between the virtual plane set in the target area G and the aircraft 1. The calculation unit 11 obtains the detection values ​​of radio waves received from the aircraft 1 at multiple antenna elements Bnm.

[0030] The calculation unit 11 calculates the vector of the incoming direction P of the radio waves using an estimation model, based on multiple detection values ​​received at multiple antenna elements Bnm and the arrangement of the multiple antenna elements Bnm. The calculation unit 11 sets a virtual straight line F along the incoming direction P of the radio waves from the position of the aircraft 1 at an altitude distance D between the virtual plane K set in the target region G and the aircraft 1. Based on the altitude distance D and the virtual straight line F, the calculation unit 11 calculates the three-dimensional coordinate Q of the intersection point of the virtual straight line F and the virtual plane K. Based on the calculated coordinate Q, the average altitude U, and the virtual straight line F, the calculation unit 11 calculates the position X of the source H located in the target region G.

[0031] The calculation unit 11 may use the horizontal two-dimensional position of coordinate Q as the position X of the source H in the target region G if the altitude distance D is sufficiently large compared to the average height U, and the magnitude of the average height U has little effect on the calculation of position X. The calculation unit 11 may also use the horizontal two-dimensional position of coordinate Q as the position X of the source H in the target region G if the angle θ between the direction of arrival P and the vertical direction is sufficiently small, and has little effect on the calculation of position X.

[0032] Figures 8 and 9 show the comparison results of the accuracy of the location of the source H calculated based on simulations in the information processing device 10. In the simulation, 1000 patterns of source locations were set. The source was set to a radio wave output of 40 dBm. According to the calculation results, the average error was sufficient for distances of about 40 km. The estimated probability was sufficient up to about 20 km. Beyond 60 km, correction is necessary because it is affected by the curvature of the Earth.

[0033] Figure 10 shows an example of a simulation to calculate the locations of 10 signal sources. Figures 11 and 12 show the results of a simulation to calculate the locations of 10 signal sources (40 dBm). As shown in Figure 10, the target area G was divided into a mesh-like area in the calculation. As shown in Figures 11 and 12, the calculation results were sufficiently accurate in areas with a side length of 3 km or more. In areas with a side length of 1 km, the calculation results were less accurate because the distance between signal sources H was small.

[0034] Figures 13 and 14 show the simulation results when the distance between antenna elements Bnm is changed in antenna A. In the simulation, the area G was defined as having a side length of 1km. The simulation showed that the calculation results were highly accurate even when the source H was in close proximity. As the distance between elements increases, the accuracy increases, but the weight of antenna A also increases, so it is necessary to design antenna A while considering the balance between weight and required performance.

[0035] Figure 15 shows the results of the MUSIC spectrum obtained from antenna A. As shown in the figure, the calculation results showed that each peak became sharper as the distance between antenna elements Bnm increased. The calculation results showed sufficient accuracy even when the source was close, as the distance between antenna elements Bnm increased.

[0036] Figure 16 shows the processing flow of the radio wave source location estimation method executed in the information processing device 10. The location estimation method is executed based on a computer program installed on the computer mounted in the information processing device 10. The computer program causes the computer to perform the following processes.

[0037] The calculation unit 11 acquires detected values ​​of radio waves received by an aircraft equipped with an antenna having multiple antenna elements flying over the target area (S100). The calculation unit 11 calculates the direction of arrival of the radio waves based on the multiple detected values ​​received by the multiple antenna elements and the arrangement of the multiple antenna elements (S102). The calculation unit 11 calculates the altitude distance between the virtual plane set in the target area and the aircraft, and a virtual straight line along the direction of arrival from the position of the aircraft (S104). The calculation unit 11 calculates the coordinates of the intersection point between the virtual straight line and the virtual plane based on the virtual straight line (S106). The calculation unit 11 calculates the position of the source present in the target area based on the coordinates (S108).

[0038] As described above, the information processing device 10 can estimate the location of the radio wave source by calculating the direction of arrival of the radio waves received by the aircraft 1. The information processing device 10 can reduce the effects of diffraction, reflection, interference, and transmission of radio waves by having the aircraft 1 receive radio waves in the airspace above the target area. [Explanation of Symbols]

[0039] 1. Aircraft, 2. Flight device, 3. Direction adjustment unit, 4. Control device, 5. Control unit, 6. Memory unit, 7. Communication unit, 10. Information processing unit, 11. Calculation unit, 12. Memory unit, 13. Communication unit, A. Antenna, An. Antenna unit, B. Antenna element, C. Drive unit, C. Drive unit, D. Altitude distance, F. Virtual line, G. Target area, H. Source, K. Virtual plane, N1. Null point, P. Direction of arrival, Q. Coordinates, S. Information processing system, T. Building, U. Mean height, V. Received beam, V1. Main lobe, V2. Side lobe, W. Network, X. Position.

Claims

1. It includes a calculation unit that estimates the location of the radio wave source, The aforementioned arithmetic unit, An aircraft equipped with an antenna having multiple antenna elements flies over the target area and acquires the detected value of the radio waves received. Based on the multiple detection values ​​received by the multiple antenna elements and the arrangement of the multiple antenna elements, the direction of arrival of the radio wave is calculated. Based on the altitude distance between the virtual plane set in the target area and the aircraft, and a virtual straight line along the direction of arrival from the position of the aircraft, the coordinates of the intersection point between the virtual line and the virtual plane are calculated. Based on the aforementioned coordinates, the position of the source located in the target area is calculated. Information processing device.

2. The aforementioned antenna is a cylindrical antenna, comprising a plurality of antenna units arranged along the side surface of the cylinder, Each of the aforementioned antenna units is equipped with a drive unit that is driven to be able to be deployed radially so as to face the receiving surface toward the target area. The antenna unit has a predetermined number of the antenna elements arranged in a matrix, The aforementioned arithmetic unit, The detected values ​​obtained from the plurality of antenna elements arranged in the cylinder antenna are individually analyzed, The drive unit is controlled to adjust the deployment angle of the multiple antenna units, The deployment angle is adjusted so that the received power of the aforementioned radio waves increases. The direction of arrival is calculated based on the deployment angle at which the received power of a predetermined level or higher is obtained and the detected values ​​of the plurality of antenna elements. The information processing apparatus according to claim 1.

3. The aforementioned arithmetic unit, The drive unit is controlled according to the altitude distance to adjust the deployment angle. The information processing apparatus according to claim 2.

4. The aforementioned arithmetic unit, The average height of the buildings surrounding the aforementioned source is calculated, The virtual plane is set at the aforementioned average height. The information processing apparatus according to claim 1.

5. An aircraft equipped with an antenna having multiple antenna elements, flying in the airspace above the target area, The system includes an information processing device that calculates the position of a radio wave source present in the target area based on a detection value obtained from the antenna, The aforementioned information processing device is The detected value of the radio wave is obtained from the aforementioned flying object. Based on the multiple detection values ​​received by the multiple antenna elements and the arrangement of the multiple antenna elements, the direction of arrival of the radio wave is calculated. Based on the altitude distance between the virtual plane set in the target area and the aircraft, and a virtual straight line along the direction of arrival from the position of the aircraft, the coordinates of the intersection point between the virtual line and the virtual plane are calculated. Based on the aforementioned coordinates, the position of the source located in the target area is calculated. Information processing system.

6. A computer program installed on a computer mounted on an information processing device that estimates the location of a radio wave source, An aircraft equipped with an antenna having multiple antenna elements flies over the target area and acquires the detected value of the radio waves received. Based on the multiple detection values ​​received by the multiple antenna elements and the arrangement of the multiple antenna elements, the direction of arrival of the radio wave is calculated. Based on the altitude distance between the virtual plane set in the target area and the aircraft, and a virtual straight line along the direction of arrival from the position of the aircraft, the coordinates of the intersection point between the virtual line and the virtual plane are calculated. The computer is instructed to perform a process to calculate the position of the source located in the target area based on the aforementioned coordinates. Computer program.

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