JP7478213B1 - Grid sensor network system and signal source location estimation method - Google Patents

Abstract

[Problem] To provide a lattice sensor network system and a signal source position estimation method capable of improving position estimation accuracy while reducing the processing load related to position estimation of a desired signal source. [Solution] The lattice sensor network system 1 is configured with a plurality of sensor devices 10 (10-11 to 10-88) that estimate the arrival direction of a signal coming from a signal source 110, arranged in a lattice shape so as to form a predetermined number of lattice squares within a monitoring area 8, a lattice mass estimation unit 51 that estimates the position of the lattice mass in which the desired signal source 110 is located based on the arrival direction estimation results of the signal from the signal source 110 by each sensor device 10, and a signal source position estimation unit 52 that estimates the position of the desired signal source 110 within the monitoring area 8 based on the arrival direction estimation results by a predetermined number of sensor devices 10 in the vicinity of the lattice mass in which the signal source 110 is located. [Selected Figure] Figure 3

Description

Article 30, paragraph 2 of the Patent Act applies [Poster presentation] Workshop on Signal Source Localization in Lattice Sensor Networks - Workshop on Signal Source Localization in Lattice Sensor Networks Program - 2022-10 - MIKA

Article 30, paragraph 2 of the Patent Act applies [Poster presentation] Workshop on Signal Source Localization in Lattice Sensor Networks - Workshop on Signal Source Localization in Lattice Sensor Networks Program - 2022-10 - MIKA

The present invention relates to a lattice sensor network system and a signal source position estimation method that estimates the position of a desired signal source based on the signal arrival direction estimation results of a signal monitoring device in the vicinity of the signal source among multiple radio wave condition monitoring devices arranged in a lattice pattern, and monitors the radio wave conditions at that position.

As the next-generation communications standard 5G begins to be put into practical use, consideration is being given to local 5G, which can be flexibly built and used by various entities such as local governments and local companies, in order to meet the wide-ranging needs of 5G.

In order to cope with the further rapid increase in mobile traffic, the application of InBand Full-Duplex (IBFD), a highly efficient frequency utilization technology, is being considered.

IBFD can ideally double the frequency utilization efficiency compared to existing duplex methods, but there is an issue of a lot of new interference occurring, so a control technology is needed to obtain various interference amounts and determine whether IBFD can be applied based on the results. To achieve this, interference monitoring technology is needed to grasp the wireless conditions in time and space of, for example, 5G wireless terminals or terminals of various other standards, and to measure the interference conditions of radio waves emitted into space from multiple terminals at high speed and with high accuracy, and as part of this, a system is needed to estimate the direction of arrival of electromagnetic waves at any point.

Conventional systems that estimate the direction of arrival include, for example, systems that estimate the direction of arrival of electromagnetic waves based on signals received at the same position by multiple antennas that each receive three orthogonal polarized signals (e.g., Patent Document 1, etc.).

JP 2021-96191 A

In the radio wave arrival direction estimation system described in Patent Document 1, for example, three antennas are moved sequentially to the same measurement position, and the electric field strength is calculated as each received signal is acquired sequentially, and the arrival direction of the radio wave is estimated based on the electric field strength by applying a detection method such as the beamforming method or the MUSIC (Multiple Signal Classification) method.

This conventional radio wave arrival direction estimation system uses all polarized components received at the same location to accurately estimate the arrival direction of electromagnetic waves at that location, but does not disclose any technology for detecting the arrival direction of signals at various locations in a monitored area and monitoring the radio wave conditions within the monitored area based on the detection results.

On the other hand, in recent years, in order to promote the development of next-generation wireless stations, wireless communication systems, and wireless communication technologies, there has been an increasing demand for monitoring technology that can detect (estimate) the direction of arrival of signals emitted from multiple signal sources (wireless stations) at various locations within a monitored area, and use the estimation results to grasp the radio wave conditions of each signal source.

As an example of such monitoring technology, a lattice sensor network system has been proposed in which multiple radio wave condition monitoring devices (hereafter referred to as sensor devices), which have the function of separating signals mixed in with received signals and estimating the direction of arrival of those signals, are arranged in a lattice pattern within a monitoring area, and the radio wave conditions of a signal source can be monitored without moving the sensor devices to follow the signal source moving on the lattice plane.

In a lattice sensor network system, the position of a desired signal source within a monitoring area is estimated based on the direction of arrival estimation results of the incoming signal from each signal source at each sensor device placed within the monitoring area, making it possible to monitor the radio wave conditions at that location. In conventional lattice sensor network systems, the detailed position of the signal source is estimated using the direction of arrival estimation results of all sensor devices without distinguishing the distance between the desired signal source and the sensor devices, and the processing load increases when all sensor devices are used. In addition, when the distance between the desired signal source and the center device is long, the system is significantly affected by direction of arrival estimation errors, resulting in a problem of reduced accuracy in estimating the position of the desired signal source.

The present invention has been made to solve these problems in the past, and aims to provide a lattice sensor network system and a signal source location estimation method that can improve location estimation accuracy while reducing the processing load related to estimating the location of a desired signal source.

In order to solve the above problem, the lattice sensor network system according to claim 1 of the present invention is a lattice sensor network system in which a plurality of sensor devices (10) that estimate the arrival direction of a signal are arranged in a lattice pattern within a monitoring area (8), the position of a desired signal source (110) within the monitoring area is estimated based on the arrival direction estimation result of each of the sensor devices, and radio wave conditions at that position are monitored. The lattice mass estimation means (51) estimates the lattice mass (81a) in which the desired signal source is located among the lattice masses (81) formed in the monitoring area by the lattice arrangement, one section for each of the four sensor devices, based on the arrival direction estimation result by each of the sensor devices, and a signal source position estimation means (52) estimates the position of the desired signal source within the monitoring area based on the arrival direction estimation result by a predetermined number of the sensor devices in the vicinity of the lattice mass in which the desired signal source is located.

With this configuration, the lattice sensor network system according to claim 1 of the present invention can perform processing to estimate the position of a desired signal source based on the direction of arrival estimation results from a preset number of sensor devices in the vicinity of the lattice mass in which the desired signal source is located, and compared to a case in which a detailed position estimation of the desired signal source is performed based on the direction of arrival estimation results from all sensor devices without distinguishing the distance from the signal source, it is possible to reduce the amount of data and processing load related to the position estimation, and to improve the accuracy of the position estimation of the desired signal source by keeping the influence of direction of arrival estimation errors low. In addition, by using the direction of arrival estimation results in estimating the lattice mass, it is possible to improve the accuracy of the position estimation using only existing information.

In addition, in the lattice sensor network system according to claim 2 of the present invention, the lattice mass estimation means performs a vertical search process for searching for the arrival direction of the signal estimated by the sensor device in each row in which the sensor device is arranged, and a horizontal search process for searching for the arrival direction of the signal estimated by the sensor device in each column in which the sensor device is arranged, and in the vertical search process, the sensor device in the row is moved from the bottom row to the upper row one by one to determine whether the arrival direction is up or down. The direction of arrival may be determined by majority decision between the direction of arrival estimation results, and a row of lattice masses between the row where the direction of arrival has changed from top to bottom and the row immediately preceding it may be identified as a vertical lattice mass candidate; in the horizontal search process, whether the direction of arrival is right or left may be determined by majority decision between the direction of arrival estimation results of the sensor device in that row, while moving from the leftmost column to the right column one column at a time; a row of lattice masses between the column where the direction of arrival has changed from right to left and the column immediately preceding it may be identified as a horizontal lattice mass candidate; and the lattice mass in which the desired signal source is located may be estimated based on the vertical lattice mass candidates and the horizontal lattice mass candidates.

With this configuration, the lattice sensor network system according to claim 2 of the present invention can easily estimate the lattice mass in which the desired signal source is located by performing a vertical search process and a horizontal search process using a simple algorithm.

In addition, in the lattice sensor network system according to claim 3 of the present invention, the lattice mass estimation means may be configured to, if it is determined in the vertical search process that the arrival direction of the signal is horizontal, transition to the row one level up and execute the vertical search process for that row, and, if it is determined in the horizontal search process that the arrival direction of the signal is vertical, transition to the column one level to the right and execute the horizontal search process for that column.

With this configuration, the lattice sensor network system according to claim 3 of the present invention can smoothly continue the vertical or horizontal search process by transitioning to the next row or column when it is determined during the vertical search process that the incoming direction of the signal is horizontal, or when it is determined during the horizontal search process that the incoming direction of the signal is vertical, and can smoothly proceed to the location estimation process of the desired signal source.

In addition, in the lattice sensor network system according to claim 4 of the present invention, the signal source position estimation means may be configured to estimate the position of the desired signal source based on the arrival direction estimation results from either 4 or 16 sensor devices within an area (82) near the lattice mass in which the desired signal source is located.

With this configuration, the lattice sensor network system according to claim 4 of the present invention does not need to use the direction of arrival estimation results of all sensor devices for detailed position estimation, and can accurately estimate the position of the desired signal source with a small processing load based on the direction of arrival estimation results of either 4 or 16 sensor devices in the area near the lattice square in which the desired signal source is located.

In order to solve the above problem, the signal source location estimation method according to claim 5 of the present invention is a signal source location estimation method for a lattice sensor network system in which a plurality of sensor devices (10) that estimate the arrival direction of a signal are arranged in a lattice pattern within a monitoring area (8), the location of a desired signal source (110) within the monitoring area is estimated based on the arrival direction estimation results of the signal from each of the sensor devices, and the radio wave conditions at that location are monitored. The method includes a lattice mass estimation step (S53) of estimating the lattice mass (81a) in which the desired signal source is located among the lattice masses (81) formed in the monitoring area by the lattice arrangement, one section for each of the four sensor devices, based on the arrival direction estimation results from each of the sensor devices, and a signal source location estimation step (S7) of estimating the location of the desired signal source within the monitoring area based on the arrival direction estimation results from a predetermined number of the sensor devices in the vicinity of the lattice mass in which the desired signal source is located.

With this configuration, the signal source location estimation method according to claim 5 of the present invention can be applied to a lattice sensor network system having the configuration according to any one of claims 1 to 4 to perform processing to estimate the location of a desired signal source based on the direction of arrival estimation results from a preset number of sensor devices in the vicinity of the lattice mass in which the desired signal source is located. This makes it possible to reduce the amount of data and processing load related to location estimation compared to a case in which detailed location estimation of a signal source is performed based on the direction of arrival estimation results from all sensor devices, and to improve the accuracy of estimating the location of the desired signal source by suppressing the influence of direction of arrival estimation errors. In addition, by using the direction of arrival estimation results in estimating the lattice mass as well, it is possible to improve the accuracy of location estimation using only existing information.

The present invention provides a lattice sensor network system and a signal source location estimation method that can improve location estimation accuracy while reducing the processing load associated with estimating the location of a desired signal source.

1 is a diagram showing the overall configuration of a lattice sensor network system according to an embodiment of the present invention; 1 is a block diagram showing a functional configuration of a sensor device in a lattice sensor network system according to an embodiment of the present invention; 1 is a block diagram showing the overall functional configuration of a lattice sensor network system according to an embodiment of the present invention; 5 is a flowchart showing a signal source location estimation process operation in the lattice sensor network system according to an embodiment of the present invention. 5 is a flowchart showing a signal arrival direction estimation process operation in each sensor device in step S4 of FIG. 4. 5 is a flowchart showing the lattice mass estimation process operation in step S6 of FIG. 4. FIG. 7 is a state transition diagram in the lattice mass estimation processing operation of FIG. 6 . 1 is a graph showing an example of a MUSIC angular spectrum generated by a sensor device of a lattice sensor network system according to an embodiment of the present invention. 1 is a graph showing an example of a beamforming angular spectrum generated by a sensor device of a lattice sensor network system according to an embodiment of the present invention. 1 is a table illustrating an example of direction-of-arrival estimation result data collected from sensor devices in a lattice sensor network system according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing the arrangement of sensor devices in a lattice sensor network system according to one embodiment of the present invention, and the radio wave monitoring state after estimating the position of a desired signal source based on the direction of arrival estimation results of sensor devices near the lattice square in which the signal source is located.

Below, an embodiment of the lattice sensor network system and signal source location estimation method according to the present invention will be described with reference to the drawings.

(overview)
As shown in Figures 1 and 11, the lattice sensor network system 1 of this embodiment is configured by arranging multiple sensor devices 10-11, 10-12, 10-13, ..., 10-18, 10-21, 10-22, 10-23, ..., 10-28, 10-31, 10-32, 10-33, ..., 10-38, ..., 10-81, 10-82, 10-83, ..., 10-88 in a lattice pattern within a predetermined monitoring area 8. In the following description, sensor devices 10-11, 10-12, 10-13, ..., 10-18, 10-21, 10-22, 10-23, ..., 10-28, 10-31, 10-32, 10-33, ..., 10-38, ..., 10-81, 10-82, 10-83, ..., 10-88 may be collectively referred to as sensor device 10.

In the examples of Figures 1 and 11, a configuration example is given in which 64 sensor devices 10 are arranged in 8 rows and 8 columns (8 x 8), but the present invention is not limited to this, and it is possible to construct a configuration in which, for example, n x n (n = 5, 6, 7, ...) or n x m (m ≠ n) sensor devices 10 are arranged in a lattice pattern.

Each of the sensor devices 10 described above receives incoming signals from the surrounding wireless environment at its location, for example, as shown in FIG. 11, a mixture of wireless signals sent from multiple signal sources 110-1, 110-2, and 110-3 (collectively sometimes referred to as signal sources 110) present within the monitoring area 8, using multiple antenna elements, and separates the signals (incoming signals) sent from each signal source 110 by processing the received signals of each antenna element, and analyzes the separated incoming signals to estimate the direction of arrival of the incoming signals for each signal source 110.

In the process of estimating the direction of arrival of the incoming signal separated for each signal source 110, each sensor device 10 generates an angular spectrum using two analysis methods, the MUSIC method and the beamforming method, and then performs a process of deriving one (single) direction of arrival estimation result for each signal source 110 from these two angular spectra, i.e., a unification process of unifying the angles (directions of arrival) estimated based on the above two analysis methods.

Regarding the above unification process, for example, focusing on one of the characteristics of the MUSIC method, "high angular resolution of the peak," and one of the characteristics of the beamforming method, "the peak reflects the received signal level," the unification process condition is defined as "the peak angle of the angular spectrum obtained by the MUSIC method that is closest to the maximum level (peak angle) of the angular spectrum obtained by the beamforming method," and the process of unifying the direction of arrival estimation results based on the MUSIC method and the beamforming method is carried out based on the unification process condition.

The unified direction of arrival estimation results (unified direction of arrival estimation results) for each signal source 110 derived by each sensor device 10 are sent to the control unit 30 (see Figures 1 and 3). The control unit 30 receives the unified direction of arrival estimation results for the signals from each signal source 110 at each placement position sent from all sensor devices 10 in the monitoring area 8. Furthermore, the control unit 30 compiles the unified direction of arrival estimation results for each signal source 110 at each placement position of each sensor device 10 received and stores them in a database (indicated by reference symbol 35 in Figure 3), and performs signal processing related to monitoring the radio wave conditions of the desired signal source 110 in the monitoring area 8 based on the stored unified direction of arrival estimation results for each signal source 110.

To monitor the radio wave conditions at the location of the desired signal source 110, it is necessary to estimate the location of the signal source 110, and to estimate the location of the signal source 110, it is necessary to estimate the direction of arrival of the direct wave from the signal source 110. Since direct waves generally have a maximum reception level, the above-mentioned unified direction of arrival estimation results are collected from each sensor device 10 as the direction of arrival estimation results of the signal (direct wave) and stored in the database 35. The control unit 30 performs processing to estimate the location of the desired signal source 110-1 within the monitoring area 8, for example, as shown in FIG. 11, based on the unified direction of arrival estimation results collected from each sensor device 10. Furthermore, the control unit 30 also performs signal processing, etc. to monitor (monitor) the status of the signals sent by other signal sources 110-2 and 110-3 at the location (location) of the signal source 110-1.

In this way, according to the lattice sensor network system 1 of this embodiment in which multiple sensor devices 10 are arranged in a lattice pattern, each sensor device 10 can monitor the radio wave conditions at the location of the target signal source TG, i.e., the conditions of the signals sent out by other signal sources 110-2 (hereinafter, NTG1) and 110-3 (hereinafter, NTG2), without moving to follow the movement of the desired signal source 110-1 (see FIG. 11; hereinafter, also referred to as the target signal source TG) moving on the lattice plane (monitoring area 8).

In addition, in the lattice sensor network system 1 according to this embodiment, each sensor device 10 arranged in a lattice derives a single direction of arrival estimation result for each signal source 110 from two angular spectra generated using the MUSIC method and the beamforming method for the incoming signals separated for each signal source 110, and passes this to the control unit 30. This makes it possible for the lattice sensor network system 1 according to this embodiment to compensate for the fact that "the angular spectrum of the MUSIC method does not reflect reception level information, and the angular spectrum of the beamforming method has low angular resolution," thereby improving the angular resolution compared to the direction of arrival estimation result based on the analysis result when the beamforming method is used alone.

Furthermore, in the lattice sensor network system 1 according to this embodiment, the control unit 30 estimates the location of the desired signal source 110 using only the arrival direction estimation results of a preset number of sensor devices 10 in the vicinity of the desired signal source 110, among the arrival direction estimation results derived with high accuracy by the above-mentioned unification process for all sensor devices 10 arranged in the monitoring area 8. In order to identify the sensor device 10 close to the desired signal source 110, the control unit 30 of the lattice sensor network system 1 according to this embodiment is provided with a lattice mass estimation unit 51 as a lattice mass estimation function that estimates the lattice mass 81a (see FIG. 11) in which the desired signal source 110 is located based on the arrival direction estimation results of each sensor device 10.

The lattice mass will be described. According to the arrangement of the sensor devices 10 in the lattice sensor network system 1 of this embodiment, for example, the arrangement shown in FIG. 11, a square surrounded by the four sensor devices 10 is formed for each of the four sensor devices 10 arranged in a lattice. In this embodiment, in FIG. 11, one square surrounded by four sensor devices 10 is referred to as a lattice mass 81. As shown in FIG. 11, according to the arrangement in which 64 sensor devices 10 are arranged in a lattice at equal intervals in a square monitoring area 8, a total of 49 square lattice masses 81 are formed, seven vertically and seven horizontally. Among the lattice masses 81, the lattice mass 81 in which the desired signal source 110-1 (target signal source TG) is located is denoted by the symbol 81a. In addition, the area 82 in the vicinity of the lattice mass 81a in which the desired signal source 110-1 (target signal source TG) is located includes, for example, 16 sensor devices 10.

In the lattice sensor network system 1 according to this embodiment, by using the direction of arrival estimation results of a predetermined number of sensor devices 10 in an area 82 near the lattice mass 81a in which the target signal source TG is located, it is possible to reduce the amount of data processing required for estimating the position of the target signal source TG compared to using the direction of arrival estimation results of all sensor devices 10. Also, compared to using the direction of arrival estimation results of all sensor devices 10, it is possible to reduce the influence of direction of arrival estimation errors and improve the accuracy of estimating the position of the desired signal source. Furthermore, by using the direction of arrival estimation results for estimating the lattice mass 82a as well, it is possible to improve the accuracy of position estimation using only existing information.

The lattice sensor network system 1 according to this embodiment further includes a signal source position estimation unit 52 as a component of the data control unit 50 shown in FIG. 3. The signal source position estimation unit 52 realizes a signal source position estimation function that estimates the position of the desired signal source 110-1 located in the lattice mass 81a estimated by the lattice mass estimation unit 51 in the monitoring area 8 based on the arrival direction estimation results by a predetermined number of sensor devices 10 in the area 82 near the lattice mass 81a. FIG. 11 shows the radio wave monitoring state in the monitoring area 8 after the position of the desired signal source 110-1 is estimated based on the arrival direction estimation results by 16 sensor devices 10 arranged in the area 82 near the lattice mass 81a. The signal source position estimation unit 52 constitutes the signal source position estimation means of the present invention.

As described above, the lattice sensor network system 1 according to this embodiment has a first processing function for estimating the lattice mass 81a in which the signal source 110 is located using the arrival direction estimation results of all sensor devices 10, and a second processing function for estimating the position of the desired signal source 110 using the arrival direction estimation results of the sensor devices 10 in the vicinity of the lattice mass 81a, in order to estimate the position of the desired signal source 110. By performing a rough position estimation (lattice mass estimation) process using the first processing function and then performing a detailed position estimation process using the second processing function, it is possible to realize a highly accurate position estimation using only the arrival direction estimation results of the sensor devices 10 that are close to the desired signal source 110 (without using the arrival direction estimation results of the sensor devices 10 that are far away).

The lattice sensor network system 1 according to this embodiment can be used, for example, in a local 5G environment, and the frequency bands of the incoming signals to be captured are assumed to be, for example, 4.6 GHz to 4.8 GHz and 28.2 GHz to 29.1 GHz. The lattice sensor network system 1 is not limited to use in a local 5G environment, and can also be used in other wireless systems such as Wi-Fi.

Next, the configuration of a lattice sensor network system 1 according to one embodiment of the present invention will be described with reference to Figures 1 to 3.

As shown in FIG. 1, the lattice sensor network system 1 according to this embodiment is configured to include, for example, 64 sensor devices 10 arranged in a lattice pattern, and a control unit 30 communicatively connected to the sensor devices 10 via a network 9. In this lattice sensor network system 1, each sensor device 10 has a functional configuration, for example, as shown in FIG. 2, and each sensor device 10 is controlled by a control unit 30 having a functional configuration, for example, as shown in FIG. 3.

First, the configuration of the sensor device 10 will be described. As shown in FIG. 2, the sensor device 10 is configured to include an antenna device 11, a frequency conversion unit 12, an AD conversion unit 13, a signal separation unit 14, a signal analysis unit 15, an arrival direction estimation unit 17, and an external interface (I/F) unit 18.

The antenna device 11 receives mixed radio signals sent from multiple signal sources 110 (see FIG. 11) at various locations within a predetermined space that constitutes the monitoring area 8 (see FIG. 1). Specific configurations of the antenna device 11 include, for example, a configuration in which three antennas capable of receiving three orthogonal polarized waves are rotated on a rotating body as multiple antenna elements as described in Patent Document 1, or an array antenna composed of multiple antenna elements.

The antenna device 11 is not limited to the configuration described above. As long as it is capable of estimating the direction of arrival of an incoming signal in the above-mentioned frequency band and passing the result to a downstream circuit, various methods can be applied in terms of the type, number, arrangement, driving method, etc. of the antenna.

The frequency conversion unit 12 inputs the received signal (radio signal) received by the antenna device 11 and converts the received signal into an intermediate frequency band signal (IF signal).

The AD conversion unit 13 converts the received signal, frequency-converted by the frequency conversion unit 12, from an analog signal to a digital signal and outputs it to the signal separation unit 14. The AD conversion unit 13, together with the antenna device 11 and the frequency conversion unit 12 described above, constitutes the receiving unit 20a.

The signal separation unit 14 performs signal separation processing to separate the digital signal input from the AD conversion unit 13, i.e., the mixed radio signals at each measurement point within a specific space of the above-mentioned monitoring area 8, into signals sent from one of the multiple signal sources 110.

The signal analysis unit 15 inputs the signals separated by the signal separation unit 14 (the signals arriving at the measurement point from each signal source 110) and performs the signal analysis processing required to estimate the direction of arrival of the arriving signals. Specifically, the signal analysis unit 15 has multiple analysis processing units 15a, 15b, ..., 15n that individually process the arriving signals from the multiple signal sources 110 input from the signal separation unit 14. Each analysis processing unit 15a, 15b, ..., 15n performs analysis processing for estimating the direction of arrival for each signal source 110, and each has the same configuration, i.e., a MUSIC analysis processing unit 16a and a beamforming analysis processing unit 16b.

Here, the MUSIC analysis processing unit 16a is a processing circuit that generates a MUSIC angle spectrum (see Figure 8) of each signal (input signal) separated by the signal separation unit 14, and the beamforming analysis processing unit 16b is a processing circuit that generates a beamforming angle spectrum (see Figure 9) of each of the above-mentioned signals (input signals).

The direction of arrival estimation unit 17 corresponds to the direction of arrival estimation means of the present invention, and is configured to have unification processing units 17a, 17b, ..., 17n provided corresponding to the analysis processing units 15a, 15b, ..., 15n, respectively. The unification processing units 17a, 17b, ..., 17n respectively perform unification processing to combine the direction of arrival estimation results for each signal source 110 based on the MUSIC angle spectrum obtained by the MUSIC analysis processing unit 16a of the analysis processing units 15a, 15b, ..., 15n and the beamforming angle spectrum obtained by the beamforming analysis processing unit 16b of the analysis processing units 15a, 15b, ..., 15n, and output the combined direction of arrival estimation results as a unified direction of arrival estimation result.

Specifically, for example, the unification processing unit 17a outputs, as the unified direction of arrival estimation result, the peak closest to the maximum level in the beamforming angle spectrum obtained by the beamforming analysis processing unit 16b of the analysis processing unit 15a, among the peaks of the MUSIC angle spectrum obtained by the MUSIC analysis processing unit 16a of the analysis processing unit 15a from the input signal corresponding to the first signal source 110 separated by the signal separation unit 14. Similarly, the unification processing units 17b, ..., 17n output, as the unified direction of arrival estimation result, the peak closest to the maximum level in the beamforming angle spectrum obtained by the beamforming analysis processing unit 16b of the analysis processing unit 15b, ..., 15n, among the peaks of the MUSIC angle spectrum obtained by the MUSIC analysis processing unit 16a of the analysis processing unit 15b, ..., 15n from the input signal corresponding to each signal source 110 separated by the signal separation unit 14.

The external I/F unit 18 is an interface function unit for sequentially transmitting the unified arrival direction estimation results of each signal source 110 derived by the unification processing units 17a, 17b, ..., 17n to the control unit 30 via the network 9. The unified arrival direction estimation results of each signal source 110 transmitted to the control unit 30 here include, for example, position information (see FIG. 10) of each measurement point (location of the sensor device 10). In the sensor device 10, the signal separation unit 14, signal analysis unit 15, arrival direction estimation unit 17, and external I/F unit 18 constitute the arrival direction analysis unit 20b.

Next, the configuration of the control unit 30 will be described. The control unit 30 is, for example, configured by a computer device such as a PC (personal computer). As shown in FIG. 3, this computer device has, for example, a CPU (Central Processing Unit) 31, a ROM (Read Only Memory) 32, a RAM (Random Access Memory) 33, an external I/F unit 34, a database 35, a non-volatile storage medium such as a hard disk device (not shown), and various input/output ports.

The CPU 31 performs overall control related to the position estimation process of the desired signal source 110 in the lattice sensor network system 1. The ROM 32 stores the OS (Operating System) for starting up the CPU 31, other programs, and control parameters. The RAM 33 stores the OS and application execution codes and data used by the CPU 31 for operation.

The external I/F unit 34 has an input interface function for inputting a specific signal and an output interface function for outputting a specific signal. The external I/F unit 34 is communicatively connected to the above-mentioned multiple sensor devices 10 via the network 9. The network 9 is not limited to being connected to the sensor devices 10 by wire (see Figures 1 to 3), but may also be connected wirelessly.

An input unit 36 and a display unit 37 are connected to the input/output port of the computer device.

The input unit 36 is a functional unit for inputting various information such as commands, and is composed of input devices such as a keyboard and a mouse. In this embodiment, the input unit 36 may have a function for inputting settings (model, frequency range, etc.) of the signal source 110 to be subjected to position estimation, i.e., the target signal source TG, and commands for starting or ending the position estimation process.

The display unit 37 is a functional unit for displaying various information, such as an input screen for various information (commands, etc.) related to the operation of the lattice sensor network system 1 and measurement results. The display unit 37 may be configured with a touch panel or the like that allows various information to be input from a displayed screen, such as the input screen.

The computer device described above functions as the control unit 30 when the CPU 31 executes a program stored in the ROM 32 using the RAM 33 as a working area. As shown in FIG. 3, the control unit 30 has a device control unit 40 and a data control unit 50. The device control unit 40 and the data control unit 50 are also realized when the CPU 31 executes a predetermined program stored in the ROM 32 in the working area of the RAM 33.

The device control unit 40 controls the entire device related to the signal source position estimation process based on preset monitoring conditions, and also remotely controls each sensor device 10. To achieve this, the device control unit 40 has a monitoring condition setting function, a communication control function, and an antenna control function.

The monitoring condition setting function is a functional unit that sets monitoring conditions (various setting items) related to the signal source position estimation process targeting the monitoring area 8 based on user operation. The setting items include, for example, the frequency range of the signal whose direction of arrival is estimated by the sensor device 10 (frequency band for which direction of arrival is estimated), the signal source 110 that is to be the target signal source TG among the signal sources 110 that are sending the signal whose direction of arrival is estimated, and the number of sensor devices 10 in the vicinity of the lattice mass 81a used for detailed position estimation of the target signal source TG. For example, the monitoring condition setting function may be configured to set any one of the 3.7 GHz band, the 4.7 GHz band, and the 28 GHz band as the frequency band for which direction of arrival is estimated, taking into account the operation of 5G.

The communication control function is a functional unit that controls communication between the control unit 30 and each sensor device 10. For example, the communication control function sends an instruction to the sensor device 10 to start a signal arrival direction estimation operation, and starts a reception operation at the sensor device 10.

The communication control function also controls communication to receive the estimated results of the direction of arrival from the sensor device 10 when the sensor device 10 starts a receiving operation and estimates the direction of arrival for each signal separated from the mixed wireless signals received by the antenna device 11. When reception of the direction of arrival estimation results is completed, the communication control function, for example, sends an instruction to the sensor device 10 to end the signal direction of arrival estimation operation and stops the receiving operation. In addition, the communication control function controls the sending and receiving of control data for controlling each part of the sensor device 10 (receiving unit 20a, direction of arrival analysis unit 20b, etc.) as necessary.

The antenna control function performs mechanical control such as the antenna direction of the antenna device 11 of the sensor device 10 through communication control by the communication control function.

The data control unit 50 has a data management function, a lattice mass estimation function, a signal source position estimation function, and a display control function. The data management function executes a process of receiving the unified direction of arrival estimation results sent from each sensor device 10 and storing them in the database 35, and a process of reading the stored unified direction of arrival estimation results from the database 35 and passing them to the signal source position estimation function.

The data management function here may have a control function for consolidating the unified arrival direction estimation results, etc. sent from each sensor device 10 as arrival direction estimation result data 56 with the above-mentioned location information (the placement position of each sensor device 10) added, for example as shown in FIG. 10, and storing it in the database 35 or performing a read process.

The arrival direction estimation result data 56 shown in FIG. 10 has a configuration in which information such as the placement position, number of incoming signal sources, signal arrival direction, and incoming signal information is stored for each of the 64 sensor devices 10 described above. In the arrival direction estimation result data 56 shown in FIG. 10, the number of incoming signal sources differs for each placement position of the sensor device 10. Also, even for the same signal, the arrival direction differs depending on the placement location. For example, as shown in FIG. 11, where a circular diagram showing the arrival direction is added using sensor device 10-11 as an example (the same applies to the other sensor devices 10), the arrival direction of the signal is estimated in a range from 0° (degrees) to 360°. Various information such as reception level is stored as the arrival signal information.

According to the example of arrival direction estimation result data 56 shown in FIG. 10, for example, sensor devices 10-11 and 10-12 receive three signals coming from signal sources A, B, and C, respectively, which are incoming signal sources, sensor devices 10-53, 10-54, 10-63, and 10-64 receive three signals coming from signal sources F, G, and H, respectively, which are incoming signal sources, and sensor device 10-88 receives two signals coming from signal sources J and K, respectively, which are incoming signal sources, and the arrival direction of each signal is estimated.

The data management function also has a function of managing information identifying each signal source 110 so that the user can arbitrarily set a target signal source TG or other signal source NTG from among the multiple signal sources 110 prior to the start of the direction of arrival estimation process by each sensor device 10. As a method of managing information identifying each signal source 110, for example, an attribute information management table that stores attribute information such as the model and frequency band of each signal source 110 may be stored in advance in the ROM 32, and the data management function may have a functional configuration of identifying a signal source 110 that matches the attribute information input by the user and setting the signal source 110 as the target signal source TG.

The lattice mass estimation function estimates the lattice mass 81a in which the desired signal source 110 (target signal source TG) set by the user within the monitoring area 8 is located based on the arrival direction estimation result data 56 acquired from the data management function, i.e., it is a functional unit that performs the rough position estimation process described above, and corresponds to the lattice mass estimation unit 51 in the data control unit 50 in Figure 3. The lattice mass estimation unit 51 constitutes the lattice mass estimation means of the present invention.

As will be described in detail later with reference to Figures 6 and 7, the lattice mass estimation unit 51 performs a vertical search process (see "Vertical Estimation" in step S51 of Figure 6) to search for the direction of arrival estimation results by the sensor device 10 in each row in which the sensor device 10 is arranged, and a horizontal search process (see "Horizontal Estimation" in step S52 of Figure 6) to search for the direction of arrival estimation results by the sensor device 10 in each column in which the sensor device 10 is arranged.

In the vertical search process, the arrival direction of the signal from the desired signal source 110 is determined by majority vote between the arrival direction estimation results of the sensor device 10 on that row, moving row by row from the bottom row, and the lattice cell of the row between the row where the arrival direction has changed from top to bottom and the row immediately before it is identified as a vertical lattice cell candidate (see steps S61 to S63 in Figure 7). In the horizontal search process, the arrival direction is determined by majority vote between the row at the left end and the row at the right, moving row by row from the left end. The direction of arrival estimation results of the sensor devices 10 in the column are determined by majority vote, and a row of lattice cells between the column in which the direction of arrival has changed from right to left and the column immediately preceding it is identified as a horizontal lattice cell candidate (see steps S64 to S66 in FIG. 7). Then, based on the row of vertical lattice cell candidates and the column of horizontal lattice cell candidates, the location of the desired signal source 110 is estimated, for example, lattice cell 82a shown in FIG. 11 (see step S53 in FIG. 6, step S67 in FIG. 7, and FIG. 11).

The lattice mass estimation unit 51 may be configured such that, if it is determined in the vertical search process that the incoming direction of the signal is horizontal, it transitions to the next row and executes the vertical search process for that row, and, if it is determined in the horizontal search process that the incoming direction of the signal is vertical, it transitions to the next column and executes the horizontal search process for that column.

The signal source position estimation function is a functional unit that estimates the location of the desired signal source 110 within the monitoring area 8 based on the direction of arrival estimation results corresponding to a predetermined number of sensor devices 10 within the area 82 near the lattice mass 81a estimated by the lattice mass estimation unit 51 described above, out of the direction of arrival estimation result data 56 acquired from the data management function described above. In other words, it is a functional unit that performs the detailed position estimation process described above, and corresponds to the signal source position estimation unit 52 in the data control unit 50 of the control unit 30 in FIG. 3.

Specifically, in a configuration in which 64 sensor devices 10 are arranged in 8 rows and 8 columns as shown in FIG. 11, and 49 lattice squares 81 can be formed with 4 sensor devices 10 surrounding each other, the signal source position estimation unit 52 estimates the position of the target signal source TG within the monitoring area 8 based on the arrival direction estimation results of any of a preset number of sensor devices 10, for example 4, 16, or 36, in the vicinity of the lattice square 81a in which the desired signal source 110 (target signal source TG) is located, estimated by the lattice square estimation unit 51, and the position information of each of the sensor devices 10, etc.

The display control function is a functional unit that performs display control to display various information on the display unit 37. As an example of the display control, the display control function may be configured to display a mark indicating that it is the target signal source TG at a location corresponding to the location of the target signal source TG on a monitoring map simulating the monitoring area 8, in order to clearly indicate to the user the location of the target signal source TG estimated by the signal source location estimation unit 52.

Next, the signal source position estimation process operation of the lattice sensor network system 1 according to this embodiment will be described with reference to the flowchart shown in FIG. 4. Here, the system configuration (see FIG. 11) in which 64 sensor devices 10 are arranged in 8 rows and 8 columns will be described as an example.

In the lattice sensor network system 1 according to this embodiment, prior to the start of a signal source location estimation process, a pre-start setting process is performed to set the setting items required for the signal source location estimation process (step S1). The pre-start setting process can be performed, for example, by displaying a setting screen on the display unit 37 and accepting input of setting values from the input unit 36 into the setting fields of each setting item displayed on the setting screen. Here, in the control unit 30, the monitoring condition setting function of the device control unit 40 accepts input (setting operations) of setting items such as the target signal source TG, the frequency band for direction of arrival estimation, and the number of sensor devices included in the area 82 (see FIG. 11) by the user, and performs processing to set each of the input items.

Next, the control unit 30 accepts an operation by the user to start the signal source position estimation process, for example, on the input unit 36 (step S2). This start operation can be performed, for example, by pressing the "Start" button displayed on the setting screen described above.

When an operation to start the signal source position estimation process is accepted in step S2, the device control unit 40 in the control unit 30 sends an instruction to each sensor device 10 to start the signal arrival direction estimation operation (step S3).

When each sensor device 10 receives an instruction from the control unit 30 to start the signal arrival direction estimation operation, it performs a process to estimate the arrival direction of the signal received at each placement location (step S4). The signal arrival direction estimation process in each sensor device 10 in step S4 is performed by remote control by the device control unit 40 of the control unit 30. By this remote control, each sensor device 10 performs a process to estimate the arrival direction of the signal received at each placement location, i.e., the signal arriving from the signal source 110 present in the vicinity of the placement location, for each signal source 110.

The direction-of-arrival estimation process in step S4 will be described in detail with reference to FIG. 5. As shown in FIG. 5, in the direction-of-arrival estimation process, the control unit 30 remotely controls the antenna device 11 in the receiving unit 20a of each sensor device 10 using the antenna control function, and causes the antenna device 11 to receive a radio signal in a frequency band previously set using the monitoring condition setting function as an arriving signal at the location where each sensor device 10 is installed (step S40).

Next, in the receiving unit 20a of each sensor device 10, the incoming signal (received signal) to the placement point received by the antenna device 11 is frequency converted by the frequency conversion unit 12, and the frequency-converted radio signal is further converted from an analog signal to a digital signal by the AD conversion unit 13 and input to the signal separation unit 14 of the arrival direction analysis unit 20b. The signal separation unit 14 performs signal separation processing to separate from the input radio signal a number of signal source components (signals sent from each signal source 110) arriving from the surroundings at the placement point (step S41), and inputs the separated signal source components to the signal analysis unit 15.

In the signal analysis unit 15, each signal source component separated by the signal separation unit 14 is input to analysis processing units 15a, 15b, ..., 15n for each signal source 110. Here, the analysis processing units 15a, 15b, ..., 15n take in each signal source component input from the signal separation unit 14 and perform analysis processing to estimate the direction of arrival of each signal component (step S42).

For the analysis process to estimate the direction of arrival in step S42, the sensor device 10 performs analysis process using the MUSIC method (step S43) and analysis process using the beamforming method (step S44).

Specifically, in step S43, the analysis processing units 15a, 15b, ..., 15n generate a MUSIC analysis processing unit 16a that generates a MUSIC angle spectrum (see Figure 8) of the input signal.

On the other hand, in step S44, the beamforming analysis processing unit 16b of the analysis processing units 15a, 15b, ..., 15n generates a beamforming angle spectrum (see FIG. 9) of the input signal. The MUSIC analysis processing unit 16a and the beamforming analysis processing unit 16b input the MUSIC angle spectrum and the beamforming angle spectrum for each signal source 110 that they have generated to the unification processing units 17a, 17b, ..., 17n of the direction of arrival estimation unit 17, respectively.

The unification processing units 17a, 17b, ..., 17n then perform a unification process to derive one direction-of-arrival estimation result (angle) from the analysis results by the MUSIC method and the analysis results by the beamforming method (step S45). For this unification process, the above-mentioned unification process condition, i.e., "the peak angle of the angle spectrum by the MUSIC method closest to the maximum level (peak angle) of the angle spectrum by the beamforming method" is set in advance. In step S45, the unification processing units 17a, 17b, ..., 17n derive a unified direction-of-arrival estimation result that satisfies the above-mentioned unification process condition from the MUSIC angle spectrum and the beamforming angle spectrum for each signal source 110 input from the analysis processing units 15a, 15b, ..., 15n, respectively.

The unification process in step S45 will be described in more detail with reference to Figures 8 and 9. Figure 8 shows an example of the MUSIC angle spectrum of an incoming signal analyzed by the MUSIC method, and Figure 9 shows an example of the beamforming angle spectrum of an incoming signal analyzed by the beamforming method.

As shown in Figures 8 and 9, both the MUSIC angle spectrum and the beamforming angle spectrum have the angle on the horizontal axis and the signal level on the vertical axis, and show the direction of arrival (angle) of the incoming signal in relation to the signal level. From the MUSIC angle spectrum and the beamforming angle spectrum, the peak of the signal level on the vertical axis can be read, and the angle on the horizontal axis corresponding to said peak can be estimated as the direction of arrival (angle) of the incoming signal having that angle spectrum.

Comparing the MUSIC angle spectrum (see Figure 8) and the beamforming angle spectrum (see Figure 9), the former has the characteristic of having a higher angular resolution of the peak compared to the latter, and the latter has the characteristic of reflecting the reception level while the former does not. Taking this into consideration, the lattice sensor network system 1 of this embodiment applies an estimation processing method as a unification processing method for unifying the signal arrival direction based on the signal analysis results in the signal analysis unit 15, in which the peak on the MUSIC angle spectrum closest to the maximum level that appears on the beamforming angle spectrum is found, and the angle corresponding to that peak is estimated as the arrival direction.

As a specific example of the signal arrival direction unification process in the arrival direction estimation unit 17, for example, for signal source #0 of signal sources #0 and #1 shown in Figures 8 and 9, the unification processing units 17a, 17b, ..., 17n read the angle (-10°) corresponding to the maximum level from the beamforming angle spectrum in Figure 9, and then perform a process of estimating the peak (=-9°) closest to the above-mentioned angle (-10°) in the MUSIC angle spectrum in Figure 8 as the arrival direction of the signal from signal source #0.

Similarly, for signal source #1, the unification processing units 17a, 17b, ..., 17n read the angle (5°) corresponding to the maximum level from the beamforming angle spectrum in Figure 9, and then perform a process to estimate the peak (= 5°) closest to the above-mentioned angle (5°) in the MUSIC angle spectrum in Figure 8 as the arrival direction of the signal from signal source #1.

In this way, the direction of arrival estimation unit 17 of each sensor device 10 has a unification processing function that derives a single direction of arrival estimation result from the two direction of arrival estimation results, the beamforming angle spectrum and the MUSIC angle spectrum, for signal source #0 or #1, respectively. This unification processing is performed by the unification processing units 17a, 17b, ..., 17n for each signal source 110 input thereto. As a result, in step S45 of FIG. 5, each sensor device 10 can obtain a unified direction of arrival estimation result for, for example, the above-mentioned signal sources #0 and #1.

The direction of arrival estimation unit 17 sends the unified direction of arrival estimation results for each signal source 110 derived by the unification processing units 17a, 17b, ..., 17n in step S45 to the control unit 30 via the external I/F unit 18 (step S46).

Now, returning to FIG. 4, the operation of the position estimation process for the desired signal source 110 will be described. In step S3, the control unit 30 instructs each sensor device 10 to start the signal arrival direction estimation process, and then receives the unified arrival direction estimation results sent from the unification processing units 17a, 17b, ..., 17n of each sensor device 10 that performs the signal arrival direction estimation process in response to the instruction via the external I/F unit 34, and stores them in the database 35 after consolidating them as arrival direction estimation result data 56 (see FIG. 10) (step S5).

Next, in the control unit 30, for example, the lattice mass estimation unit 51 provided in the data control unit 50 executes a process of estimating the lattice mass 81a in which the target signal source TG set in step S1 is located (step S6).

The lattice mass estimation process in step S6 will be described in more detail with reference to Figs. 6 and 7. Fig. 6 is a flowchart showing the lattice mass estimation process operation in the control unit 30 in step S6 in Fig. 4. Fig. 7 shows state transitions in the lattice mass estimation process operation in Fig. 6.

In the lattice mass estimation process in step S6, the lattice mass estimation unit 51 of the data control unit 50 searches the arrival direction estimation result data 56 stored in the database 35 in step S5, and executes a vertical search process (vertical estimation) for each row of the sensor devices 10 arranged in the monitoring area 8 to search for the estimated result of the arrival direction of the signal emitted by the desired signal source 110 set as the target signal source TG in step S1 (step S51).

In the vertical search process, the lattice cell estimation unit 51 determines whether the arrival direction is up or down by majority vote among the eight sensor devices 10 on the row, moving from the bottom row in the monitoring area 8 to the upper rows one row at a time, and identifies the seven lattice cells 81 in one row between the row where the majority vote has changed from up to down and the row immediately before it as candidates for vertical lattice cells.

After the vertical search process is completed, the lattice mass estimation unit 51 then executes a horizontal search process (horizontal estimation) for searching for an estimated direction of arrival of a signal emitted by a desired signal source 110, for each column of sensor devices 10 arranged in the monitoring area 8 (step S52). In the horizontal search process, the lattice mass estimation unit 51 determines whether the direction of arrival is right or left by majority decision among the eight sensor devices 10 on the column, while moving from the left end of the monitoring area 8 to the right column one column at a time, and identifies the seven lattice masses 81 in one column between the column where the majority decision has changed from right to left and the column immediately before it as horizontal lattice mass candidates.

When the horizontal search process is completed, the lattice mass estimation unit 51 further performs a process of estimating the lattice mass 81 where the row of the vertical lattice mass candidate identified in step S51 and the column of the horizontal lattice mass candidate identified in step S52 intersect as the lattice mass 81a in which the desired signal source 110 is located (step S53).

After steps S51 to S53, when the process of estimating the lattice mass 81a in which the desired signal source 110 is located is completed, the process proceeds to step S7 and subsequent steps in FIG. 4.

The processing of steps S51, S52, and S53 will be explained in more detail with reference to Figures 7 and 11.

Figure 7 shows state transitions in the lattice mass estimation process of Figure 6. In Figure 7, steps S61 to S63 show state transitions in the vertical estimation process (vertical search process) of step S51 in Figure 6, and steps S64 to S66 show state transitions in the horizontal estimation process (horizontal search process) of step S52 in Figure 6. Step S67 corresponds to the process of step S53 in Figure 6.

Figure 11 is a schematic diagram showing the arrangement of the sensor devices 10 in the lattice sensor network system 1 according to this embodiment, and the radio wave monitoring state after the position of the target signal source TG is estimated based on the arrival direction estimation results of the sensor devices 10 near the lattice mass 81a in which the desired signal source 110-1 (target signal source TG) is located. In Figure 11, 64 sensor devices 10 are arranged in a lattice of 8 rows and 8 columns, and 49 lattice masses 81 are formed in the monitoring area 8 by the arrangement of these sensor devices 10.

In FIG. 11, the arrangement of the sensor devices 10 is referred to as the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, and 8th rows from the top row to the bottom row, and as the 1st, 2nd, 3rd, 4th, 5th, 6th, 7th, and 8th columns from the leftmost column to the right column in FIG. 11. In particular, FIG. 11 shows the lattice square 81 at the intersection of the lattice square row between the 6th and 5th rows and the lattice square column between the 3rd and 4th columns, which is recognized as the lattice square 81a where the target signal source TG is located, and shows the result of estimating the position of the target signal source TG based on the direction of arrival estimation results of 16 sensor devices 10 in the vicinity of the lattice square 81a (shaded circle in the figure).

As shown in FIG. 7, the lattice mass estimation process (steps S51 to S53) in FIG. 6 starts from the initial step of the vertical search (step S61). In step S61, the lattice mass estimation unit 51 searches the arrival direction estimation result data 56 to determine whether the arrival direction estimated by each of the eight sensor devices 10 in the eighth row of the monitoring area 8 (see FIG. 11) is up, down, or horizontal, and determines whether the arrival direction is up, down, or horizontal based on the search results by majority vote (in this example, the arrival direction is determined to be up or down if there are more up and down directions, respectively, and the arrival direction is determined to be horizontal when there are an equal number of up and down directions).

If the majority decision determines that the direction of arrival is downward ("Down" in step S61), the lattice mass estimation unit 51 ends the process.

If the majority decision determines that the direction of arrival is horizontal ("horizontal" in step S61), the lattice mass estimation unit 51 proceeds to step S62.

Also, if the majority decision in the initial vertical search processing in step S61 determines that the direction of arrival is up ("up" in step S61), the lattice mass estimation unit 51 proceeds to step S62. In step S62, the lattice mass estimation unit 51 performs processing to continue the vertical search. Here, the lattice mass estimation unit 51 searches the arrival direction estimation result data 56 to determine whether the arrival direction estimated by each of the eight sensor devices 10 in the seventh row of the monitoring area 8 is up, down, or horizontal, and determines by majority decision whether the arrival direction is up, down, or horizontal based on the search results (step S62).

If the result of the direction of arrival estimation is determined to be up or horizontal in the majority decision in step S62 ("up and horizontal" in step S62), the lattice mass estimation unit 51 advances the search target row to the row one level up and continues the process in step S62.

That is, in step S62, the grid mass estimation unit 51 performs a majority vote determination on the arrival direction estimation result data 56 using the arrival directions estimated by each sensor device 10 in the following order of the 7th, 6th, 5th, 4th, 3rd, 2nd, and 1st rows of the monitoring area 8.

During that time, if the majority decision for each row determines that the direction of arrival is upward, or horizontal ("upward and horizontal" in step S62), the lattice mass estimation unit 51 advances the search target row one step upward and continues the process in step S62.

In contrast, if the majority decision for each row determines that the direction of arrival is downward (step S62: "Down"), the lattice cell estimation unit 51 stops searching the row to the row above, and determines the seven lattice cells 81 arranged horizontally between the row determined to have a downward direction of arrival and the row preceding it as candidates for vertical lattice cells (step S63).

In this way, the lattice mass estimation unit 51 performs a majority decision using the arrival direction estimation results of the eight sensor devices 10 from the eighth row to the first row of the lattice arrangement through a series of operational transitions in steps S61 to S63 described above, and selects the seven lattice masses 81 in one row between the row in which the majority decision result has shifted from top to bottom and the row before that as vertical lattice mass candidates. As an example, for example, if the signal source 110-1 in the monitoring area 8 is assumed to be the target signal source TG as shown in FIG. 11 and the lattice mass 81a in which the target signal source TG is located is estimated, in the majority decision on the fifth row, the result of the majority decision shifts from top to bottom, and the seven lattice masses 81 lined up horizontally between the sixth and fifth rows are selected as vertical lattice mass candidates.

After determining the vertical lattice mass candidates in step S63, the lattice mass estimation unit 51 proceeds to the initial step of the horizontal search (step S64). In step S64, the lattice mass estimation unit 51 searches the arrival direction estimation result data 56 to determine whether the arrival direction estimated by each of the eight sensor devices 10 in the leftmost column of the monitoring area 8 is right, left, or vertical, and determines by majority vote whether the arrival direction is right, left, or vertical based on the search results (in this example, the more right and left are determined to be the arrival direction as right and left, respectively, and when the number of right and left is the same, the arrival direction is determined to be vertical).

If the majority decision determines that the direction of arrival is left ("Left" in step S64), the lattice mass estimation unit 51 ends the process.

Also, if the majority decision in the initial processing of the horizontal search in step S64 determines that the direction of arrival is vertical ("vertical" in step S64), the lattice mass estimation unit 51 proceeds to step S65.

Also, if the majority decision in step S64 determines that the direction of arrival is to the right (step S64: "Right"), the lattice mass estimation unit 51 transitions to step S65. In step S65, the lattice mass estimation unit 51 performs processing to continue the horizontal search. Here, the lattice mass estimation unit 51 searches the direction of arrival estimation result data 56 to determine whether the direction of arrival estimated by each of the eight sensor devices 10 in the second row of the monitoring area 8 is to the right, left, or vertical, and determines by majority decision whether the direction of arrival is to the right, left, or vertical based on the search results (step S65).

If the result of the direction of arrival estimation is determined to be right in the majority decision in step S65, or if the result is determined to be vertical ("right/vertical" in step S65), the lattice mass estimation unit 51 advances the column to be searched to the next column to the right and continues the process in step S65.

That is, in step S65, the grid mass estimation unit 51 performs a majority vote determination on the arrival direction estimation result data 56 using the arrival directions estimated by each sensor device 10 in each column in the order of the second column, third column, fourth column, fifth column, sixth column, seventh column, and eighth column of the monitoring area 8.

During that time, if the majority decision for each column determines that the direction of arrival is right, or vertical (step S65: "right/vertical"), the lattice mass estimation unit 51 advances the search target column one step further to the right and continues the process of step S65.

In contrast, if the majority decision for each column determines that the direction of arrival is to the left (step S65: "left"), the lattice cell estimation unit 51 stops moving the search target column to the right, and determines the seven lattice cells 81 aligned vertically between the column determined to have the direction of arrival to the left and the column immediately preceding it as horizontal lattice cell candidates (step S66).

In this way, the lattice mass estimation unit 51 performs majority decision using the arrival direction estimation results of the eight sensor devices 10 from the first column to the eighth column of the lattice arrangement through a series of operational transitions from steps S64 to S66, and selects a row of seven lattice masses 81 between the column where the majority decision result shifts from right to left and the column before that as horizontal lattice mass candidates. As an example, for example, if the signal source 110-1 in the monitoring area 8 is assumed to be the target signal source TG as shown in FIG. 11 and the lattice mass 81a in which the target signal source TG is located is estimated, in the majority decision for the fourth column, the result of the majority decision shifts from right to left, and the seven lattice masses 81 lined up vertically between the third and fourth columns are selected as horizontal lattice mass candidates.

After determining the horizontal lattice mass candidates in step S66, the lattice mass estimation unit 51 proceeds to a step (step S67) of estimating the position of the lattice mass 81 in which the desired signal source 110 (e.g., signal source 110-1 in FIG. 11) is located.

Here, the lattice mass estimation unit 51 performs a process of estimating the position of the lattice mass 81a in which the target signal source TG is located based on the vertical lattice mass candidate determined in step S63 and the horizontal lattice mass candidate determined in step S66 (step S67). Using FIG. 11 as an example, the lattice mass estimation unit 51 identifies the lattice mass 81 at the position where the third lattice mass row from the bottom, which is a vertical lattice mass candidate, and the third lattice mass column from the left, which is a horizontal lattice mass candidate, intersect in the monitoring area 8, and estimates that lattice mass 81 as the lattice mass 81a in which the target signal source TG is located.

As described above, in step S6 in FIG. 4, the process of estimating the lattice mass 81a in which the desired signal source 110 is located is performed by the process of steps S51 to S53 in FIG. 6 according to the series of state transitions shown in FIG. 7. When the process of estimating the lattice mass 81a is completed, the control unit 30 continues the process from step S7 in FIG. 4 onwards.

Returning now to FIG. 4, the processing operations from step S7 onwards will be described. After the lattice mass estimation unit 51 of the data control unit 50 estimates the lattice mass 81a in which the target signal source TG is located in step S6 (see FIGS. 6 and 7), the signal source position estimation unit 52 subsequently executes a process of estimating the position of the desired signal source 110 in the monitoring area 8, i.e., the target signal source TG previously set in step S1, based on the arrival direction estimation result data 56 stored in the database 35 in step S5 and the estimation result of the lattice mass 81a in step S6 (step S7).

In step S7, the signal source position estimation unit 52 first searches the above-mentioned arrival direction estimation result data 56 and identifies a predetermined number of sensor devices 10 in the vicinity of the lattice mass 81a in which the target signal source TG estimated in step S6 is located (step S7a). The "number of sensor devices 10 in the vicinity of the lattice mass 81a" to be identified here can be set in advance by the user in the above step S1, for example. In a system configuration in which 64 sensor devices 10 are arranged (see FIG. 11), the "number of sensor devices 10 in the vicinity of the lattice mass 81a" that can be set here can be, for example, 4, 16, 36, etc. However, the "number of sensor devices 10 in the vicinity of the lattice mass 81a" that can be set is not limited to these numbers, and an appropriate number can be set depending on the number of sensor devices 10, etc.

The signal source position estimation unit 52 then reads out the direction of arrival estimation results for each of the predetermined number of sensor devices 10 identified in step S7a from the direction of arrival estimation result data 56, and performs a process of estimating the position of the target signal source TG within the monitoring area 8 based on the direction of arrival estimation results for the predetermined number of sensor devices 10 that have been read out (step S7b).

When the position estimation process for the target signal source TG in step S7 is completed, the data management function of the data control unit 50 stores the position estimation result of the target signal source TG, for example, in a predetermined storage area of the database 35 (step S8). After storing the position estimation result of the target signal source TG, the series of processes related to the position estimation of the target signal source TG is terminated.

Next, the position estimation process of the desired signal source 110 in step S7 of FIG. 4 will be described in more detail with a specific example. Here, the lattice sensor network system 1 is configured by arranging 64 sensor devices 10 as shown in FIG. 11, and in step S1 of FIG. 4, for example, the signal source 110-1 (see FIG. 11) is designated (set) as the target signal source TG, and the number of target signal sources TG in the vicinity of the lattice mass 81a in which the target signal source TG is located is set to "16". In addition, in step S5 of FIG. 4, the database 35 of the control unit 30 stores, for example, the arrival direction estimation result data 56 having the configuration shown in FIG. 10, and the signal source 110-1 set as the target signal source TG corresponds to the signal source F in the arrival direction estimation result data 56.

In this case, in step S7a of FIG. 4, the signal source position estimation unit 52 recognizes from the lattice mass estimation result in step S6 that the lattice mass 81 in which the target signal source TG (in this example, signal source F) is located is lattice mass 81a (see FIG. 11), and then identifies the 16 sensor devices 10-42, 10-43, 10-44, 10-45, 10-52, 10-53, 10-54, 10-55, 10-62, 10-63, 10-64, 10-65, 10-72, 10-73, 10-74, and 10-75 in the area 82 around the lattice mass 81a, shown by the dotted line in FIG. 11, as sensor devices 10 in the vicinity of the lattice mass 81a (target signal source TG).

Next, in step S7b of FIG. 4, the signal source position estimation unit 52 searches the arrival direction estimation result data 56 for the arrival direction estimation results of the arrival signals from the signal source F of each of the 16 sensor devices 10 (near the target signal source TG) identified in step S7a, and estimates the position of the target signal source TG based on the arrival direction estimation results of the arrival signals from the signal source F of each of these 16 sensor devices 10.

At that time, the signal source position estimation unit 52 estimates the position of the target signal source TG by tracing in reverse the direction of arrival of the incoming signal from the signal source F of each of the 16 sensor devices 10.

For simplicity's sake, here we will use as an example a case in which the position of the target signal source TG is estimated based on the results of estimating the direction of arrival of the incoming signal from the signal source F of the four sensor devices 10-53, 10-54, 10-63, and 10-64 that define the lattice mass 81a out of the 16 sensor devices 10.

In this case, the signal source position estimation unit 52 searches for the signal source F from the arrival direction estimation result data 56 using the attribute information of the target signal source TG set in step S1 as a key, and further identifies the four sensor devices 10-53, 10-54, 10-63, and 10-64 that are closest to the above-mentioned lattice mass 81a among all the sensor devices 10 that are receiving the signal sent by the signal source F as an arriving signal. Furthermore, the signal source position estimation unit 52 locates the position of the signal source F that is transmitting the arriving signal by comprehensively taking into account the arrival direction of the arriving signal from the signal source F by the identified sensor devices 10-53, 10-54, 10-63, and 10-64.

When performing the process of identifying the position of the signal source F described above, the signal source position estimation unit 52 searches the arrival direction estimation result data 56 and recognizes that the arrival direction of the signal from the target signal source TG, that is, the signal source F, is the lower right direction (first direction: 307 degrees) for the sensor device 10-53, the lower left direction (second direction: 210 degrees) for the sensor device 10-54, the upper right direction (third direction: 63 degrees) for the sensor device 10-63, and the upper left direction (fourth direction: 139 degrees) for the sensor device 10-64.

Then, the signal source position estimation unit 52 recognizes the positions (position information) of the sensor devices 10-53, 10-54, 10-63, and 10-64 from the arrival direction estimation result data 56. As shown in Figures 10 and 11, the positions of the sensor devices 10-53, 10-54, 10-63, and 10-64 within the monitoring area 8 are known in advance. As a result, the signal source position estimation unit 52 determines the position indicated by the above-mentioned four directions (first direction to fourth direction) from the positions of the sensor devices 10-53, 10-54, 10-63, and 10-64, and detects this position as the position of the signal source F, which is the target signal source TG.

Here, for simplicity's sake, we have described a case where the position of the target signal source TG is estimated by comprehensively taking into account the results of estimating the direction of arrival of the signal from signal source F at each of the sensor devices 10-53, 10-54, 10-63, and 10-64 closest to the lattice mass 81a in which the target signal source TG is located. However, the position of the target signal source TG can also be estimated by similar processing when referring to the results of estimating the direction of arrival of the signal from signal source F at, for example, 16 sensor devices 10-42, 10-43, 10-44, 10-45, 10-52, 10-53, 10-54, 10-55, 10-62, 10-63, 10-64, 10-65, 10-72, 10-73, 10-74, and 10-75 in the area 82 surrounding the lattice mass 81a.

In this way, in the lattice sensor network system 1 according to this embodiment, in the position estimation process of the desired signal source 110 (target signal source TG) in step S7 of FIG. 4, the position indicated by the shaded circle in the lattice cell 81a, for example as shown in FIG. 11, can be identified as the position of the target signal source TG (signal source 110-1) while referring to the arrival direction estimation results of a preset limited number of sensor devices 10 in the vicinity of the lattice cell 81a in which the previously estimated target signal source TG is located.

As shown in FIG. 11, in addition to the target signal source TG (signal source 110-1) given as an example, other signal sources 110-2 (NTG1), 110-3 (NTG2), etc. may exist within the monitoring area 8. In the lattice sensor network system 1 according to this embodiment, by referring to the arrival signal information from the other signal sources NTG1, NTG2 in the arrival direction estimation result data 56 described above, it is also possible to recognize the interference situation from the other signal sources NTG1, NTG2 at the location of the target signal source TG. Note that the other signal sources 110-2 (NTG1) and 110-3 (NTG2) can also be set as target signal sources TG (see step S1 in FIG. 4) and used as targets for position estimation.

As described above, the lattice sensor network system 1 of this embodiment arranges multiple sensor devices 10, each having a direction-of-arrival estimation unit 17 that estimates the direction of arrival of a signal sent from a signal source 110, in a lattice pattern within a monitoring area 8, estimates the position of a desired signal source 110 (target signal source TG) within the monitoring area 8 based on the result of the direction-of-arrival estimation of the signal from the sensor devices 10 in the vicinity of the desired signal source 110, and monitors the radio wave conditions at that position.

The lattice sensor network system 1 according to this embodiment is configured to include a lattice mass estimation unit 51 that estimates the lattice mass 81a in which the desired signal source 110 is located among the lattice masses 81 formed in a monitoring area 8 by a lattice arrangement, one section for every four sensor devices 10, based on the arrival direction estimation results from each sensor device 10, and a signal source position estimation unit 52 that estimates the position of the desired signal source 110 in the monitoring area 8 based on the arrival direction estimation results from a preset number of sensor devices 10 in the vicinity of the lattice mass 81a in which the desired signal source 110 is located.

With this configuration, the lattice sensor network system 1 according to this embodiment can estimate the position of the desired signal source 110 based on the direction of arrival estimation results from a preset number of sensor devices 10 in the vicinity of the lattice mass 81a in which the desired signal source 110 is located. Compared to a case in which a detailed position estimation of the desired signal source 110 is performed based on the direction of arrival estimation results from all sensor devices 10 without distinguishing the distance from the signal source, the amount of data and processing load related to the position estimation can be reduced, and the influence of direction of arrival estimation errors can be kept low to improve the accuracy of the position estimation of the desired signal source 110. In addition, by using the direction of arrival estimation results to estimate the lattice mass 81a, it is possible to improve the accuracy of the position estimation using only existing information.

In addition, in the lattice sensor network system 1 according to this embodiment, the lattice mass estimation unit 51 performs a vertical search process for searching for the arrival direction of the signal estimated by the sensor device 10 in each row in which the sensor device 10 is arranged, and a horizontal search process for searching for the arrival direction of the signal estimated by the sensor device 10 in each column in which the sensor device 10 is arranged, for the arrival direction of the signal estimated by the sensor device 10 in each column in which the sensor device 10 is arranged. In the vertical search process, the sensor device 1 in the row is moved from the bottom row to the upper row one by one, and the arrival direction of the signal estimated by the sensor device 10 in the row is determined to be up or down. 0 arrival direction estimation results by majority decision, and a row of lattice masses between the row where the arrival direction has changed from top to bottom and the row immediately preceding it are identified as vertical lattice mass candidates, and in the horizontal search process, whether the arrival direction is right or left is determined by majority decision between the arrival direction estimation results of the sensor devices 10 in that row, moving from the leftmost column to the right column one column at a time, and a row of lattice masses between the column where the arrival direction has changed from right to left and the column immediately preceding it are identified as horizontal lattice mass candidates, and the lattice mass 81a in which the desired signal source 110 is located is estimated based on the vertical lattice mass candidates and the horizontal lattice mass candidates.

With this configuration, the lattice sensor network system 1 according to this embodiment can easily estimate the lattice mass in which the desired signal source is located by performing a vertical search process and a horizontal search process using a simple algorithm.

In addition, in the lattice sensor network system 1 according to this embodiment, if the vertical search process determines that the incoming direction of the signal is horizontal, the lattice mass estimation unit 51 transitions to the row above and executes the vertical search process for that row, and if the horizontal search process determines that the incoming direction of the signal is vertical, it transitions to the column one column to the right and executes the horizontal search process for that column.

With this configuration, the lattice sensor network system 1 of this embodiment can smoothly continue the vertical or horizontal search process by transitioning to the next row or column when it is determined during the vertical search process that the incoming direction of the signal is horizontal, or when it is determined during the horizontal search process that the incoming direction of the signal is vertical, and can smoothly proceed to the position estimation process of the desired signal source 110.

In addition, in the lattice sensor network system 1 according to this embodiment, the signal source position estimation unit 52 is configured to estimate the position of the desired signal source 110 based on the arrival direction estimation results from either 4 or 16 sensor devices 10 within the area 82 in the vicinity of the lattice mass 81a in which the desired signal source 110 is located.

With this configuration, the lattice sensor network system 1 according to this embodiment does not need to use the direction of arrival estimation results of all sensor devices 10 for detailed position estimation, and can accurately estimate the position of the desired signal source 110 with a small processing load based on the direction of arrival estimation results of either 4 or 16 sensor devices 10 within the area 82 near the lattice mass 81a in which the desired signal source 110 is located.

The signal source position estimation method according to this embodiment is a signal source position estimation method for a lattice sensor network system in which a plurality of sensor devices 10 having a direction of arrival estimation unit 17 that estimates the direction of arrival of a signal sent from a signal source 110 are arranged in a lattice pattern in a monitoring area 8, the position of a desired signal source (TG) in the monitoring area 8 is estimated based on the direction of arrival estimation results of the signal from the sensor devices 10 in the vicinity of the desired signal source 110 (target signal source TG), and the radio wave situation at that position is monitored. The method includes a lattice mass estimation step (S53) of estimating the lattice mass 81a in which the desired signal source (target signal source TG) is located among the lattice masses 81 formed in the monitoring area 8 by the lattice arrangement, one section for each of the four sensor devices 10, based on the direction of arrival estimation results from each sensor device 10, and a signal source position estimation step (S7) of estimating the position of the desired signal source 110 in the monitoring area 8 based on the direction of arrival estimation results from a predetermined number of sensor devices 10 in the vicinity of the lattice mass 81a in which the desired signal source 110 is located.

With this configuration, the signal source location estimation method according to this embodiment can be applied to a lattice sensor network system 1 having any of the configurations described above to estimate the location of the desired signal source 110 based on the direction of arrival estimation results from a preset number of sensor devices 10 in the vicinity of the lattice mass 81a in which the desired signal source 110 is located. This makes it possible to reduce the amount of data and processing load related to location estimation compared to a case in which detailed location estimation of the signal source 110 is performed based on the direction of arrival estimation results from all sensor devices 10, and to improve the accuracy of location estimation of the desired signal source 110 by suppressing the influence of direction of arrival estimation errors. In addition, by using the direction of arrival estimation results to estimate the lattice mass 81a, it is possible to improve the accuracy of location estimation using only existing information.

As described above, the present invention has the effect of improving the accuracy of position estimation while reducing the processing load associated with estimating the position of a desired signal source, and is useful for lattice sensor network systems in which sensor devices are arranged in a lattice pattern, and for signal source position estimation methods in general.

1 Lattice sensor network system 8 Monitoring area 9 Network 10, 10-11, 10-12, 10-13, ..., 10-18, 10-21, 10-22, 10-23, ..., 10-28, 10-31, 10-32, 10-33, ..., 10-38, ..., 10-81, 10-82, 10-83, ..., 10-88 Radio wave condition monitoring device (sensor device)
REFERENCE SIGNS LIST 11 Antenna device 12 Frequency conversion unit 13 AD conversion unit 14 Signal separation unit 15 Signal analysis unit 15a, 15b, ..., 15n Analysis processing unit 16a MUSIC analysis processing unit 16b Beamforming analysis processing unit 17 Arrival direction estimation unit (arrival direction estimation means)
17a, 17b, ..., 17n unification processing unit 30 control unit 36 input unit 37 display unit 40 device control unit 50 data control unit 51 lattice mass estimation unit (lattice mass estimation means)
52 Signal source position estimation unit (signal source position estimation means)
81 Grid (grid)
81a: Lattice cell in which the target signal source TG is located; 82: Area in the vicinity of the lattice cell 81a; 110, 110-1, 110-2, 110-3: Signal source TG: Signal source to be localized; NTG1, 2: Other signal sources

Claims (5)

A lattice sensor network system in which a plurality of sensor devices (10) for estimating a direction of arrival of a signal are arranged in a lattice pattern within a monitoring area (8), a position of a desired signal source (110) within the monitoring area is estimated based on the result of estimating the direction of arrival of the signal from each of the sensor devices, and radio wave conditions at that position are monitored,
a lattice mass estimation means (51) for estimating, based on the arrival direction estimation results by each of the sensor devices, a lattice mass (81 a) in which the desired signal source is located, out of lattice masses (81) formed in the surveillance area by the lattice arrangement, each of which is formed for each of the four sensor devices;
a signal source position estimation means (52) for estimating a position of the desired signal source within the monitoring area based on the arrival direction estimation results by a preset number of the sensor devices in the vicinity of the grid cell in which the desired signal source is located;
A lattice sensor network system comprising: The lattice mass estimation means
For the direction of arrival estimation results by each of the sensor devices, a vertical search process is performed to search for the direction of arrival of the signal estimated by the sensor device of the row in unit of a row in which the sensor device is arranged, and a horizontal search process is performed to search for the direction of arrival of the signal estimated by the sensor device of the column in unit of a column in which the sensor device is arranged,
In the vertical search process, while moving from the bottom row to the upper rows one by one, it is determined whether the arrival direction is up or down by majority decision between the arrival direction estimation results of the sensor devices in the row, and a lattice cell in one row between the row in which the arrival direction has changed from up to down and the row immediately before it is identified as a vertical lattice cell candidate;
In the horizontal search process, while moving from the leftmost column to the right column one column at a time, it is determined whether the arrival direction is right or left by majority decision between the arrival direction estimation results of the sensor devices in the column, and a lattice cell in one column between the column in which the arrival direction has changed from right to left and the column immediately before it is identified as a horizontal lattice cell candidate;
The lattice sensor network system according to claim 1 , wherein the lattice mass in which the desired signal source is located is estimated based on the vertical lattice mass candidates and the horizontal lattice mass candidates. The lattice mass estimation means
if it is determined in the vertical search process that the arrival direction of the signal is horizontal, transition to the next row up and perform the vertical search process on that row;
3. The grid sensor network system of claim 2, wherein if the horizontal search process determines that the arrival direction of the signal is vertical, the grid sensor network system transitions to the next right column and executes the horizontal search process for that column. The grid sensor network system according to claim 1, characterized in that the signal source location estimation means estimates the location of the desired signal source based on the arrival direction estimation results from either 4 or 16 of the sensor devices within an area (82) near the grid mass in which the desired signal source is located. A signal source position estimation method for a lattice sensor network system, in which a plurality of sensor devices (10) for estimating a direction of arrival of a signal are arranged in a lattice pattern within a monitoring area (8), a position of a desired signal source (110) within the monitoring area is estimated based on the signal arrival direction estimation results of each of the sensor devices, and radio wave conditions at that position are monitored,
a lattice mass estimation step (S53) of estimating a lattice mass (81 a) in which the desired signal source is located among lattice masses (81) formed in the surveillance area by the lattice arrangement, each of which is formed for each of the four sensor devices, based on the arrival direction estimation results by each of the sensor devices;
a signal source position estimation step (S7) of estimating the position of the desired signal source within the monitoring area based on the arrival direction estimation results by a preset number of the sensor devices in the vicinity of the lattice mass in which the desired signal source is located;
13. A signal source location estimation method comprising:

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