Sensor network system and obstacle detection method

Abstract

To provide a sensor network system capable of easily grasping a region, in which a radio wave is not propagated because of an obstacle, so as to more efficiently grasp a radio environment which is useful for developing a next-generation communication technique, and a signal source position estimation method.SOLUTION: A sensor network system 1 comprises: a clustering processing section 53 by which, regarding a signal source 110 of which the position is estimated by a signal source position estimation section 52, clustering processing is performed for dividing path information Pt from the signal source 110 to sensor devices 10 into groups and linking the path information to the sensor devices 10; an obstacle detection section 54 for detecting that an obstacle 8 is present in a region between adjacent sensor devices 10 on the basis of, a comparison result of the path information Pt between the adjacent sensor devices 10; and a display control section 55 for performing a notification of the presence of the detected obstacle 8 (displaying the presense of the detected object, on a display section 37) in relation to the region where the presence of the obstacle 8 is detected.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a sensor network system and an obstacle detection method that estimates the position of a signal source from the signal arrival direction estimation results of a plurality of sensor devices and detects obstacles that hinder radio wave propagation based on the signal source position estimation results. [Background technology]

[0002] The next-generation communications standard, 5G, is beginning to be put into practical use, and in order to meet the wide-ranging needs of 5G, studies are underway on local 5G, which can be flexibly built and used by various entities such as local governments and local companies.

[0003] 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.

[0004] IBFD can ideally double the frequency utilization efficiency compared to existing duplex methods, but it has the problem of generating a lot of new interference, so a control technology is needed to acquire various interference levels and determine whether IBFD is applicable based on the results. To achieve this, an interference monitoring technology is needed that can grasp the wireless conditions in time and space, for example, of 5G wireless terminals or terminals of various other standards, and quickly and accurately measure the interference conditions of radio waves emitted into space from multiple terminals.

[0005] In particular, estimating the direction of arrival of radio waves (signals) emitted in space-time, estimating the location of the signal source that causes radio wave interference based on the estimated direction of arrival, and understanding the area where signal propagation occurs (in other words, the area where signal propagation does not occur) based on the estimated location of the signal source can be important information for promoting efficient radio wave use in determining the suitability of IBFD.

[0006] Known conventional systems for estimating the direction of arrival include those 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 (for example, Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent Publication No. 2021-96191 Summary of the Invention [Problem to be solved by the invention]

[0008] In the conventional 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 at the stage where each received signal is acquired sequentially, and further, based on the electric field strength, a search method such as a beamforming method or a MUSIC (Multiple Signal Classification) method is applied to estimate the arrival direction of the radio wave (signal).

[0009] Conventional radio wave arrival direction estimation systems are limited to technology for estimating the arrival direction of a signal at a desired location, and do not go beyond that and disclose monitoring technology that enables estimation of the position of a signal source based on the result of estimating the arrival direction of the signal, or furthermore, makes it possible to identify areas where no signal propagation is occurring by using the result of estimating the position of the signal source.

[0010] Meanwhile, in recent years, with the hope of realizing IBFD, a sensor network system has been proposed as a monitoring technology to promote the development of next-generation radio stations, wireless communication systems, and wireless communication technologies.This involves placing multiple radio wave condition monitoring devices (hereinafter referred to as sensor devices) within a monitored area, and each sensor device separating signals mixed in with the received signal to estimate the direction of arrival of the signal in question, and analyzing the results of the signal direction estimation by each sensor device, thereby monitoring the radio wave condition based on the location of the signal source.

[0011] However, while conventional sensor network systems can estimate the location of a signal source and monitor the radio wave conditions at that location, they are unable to detect where obstacles exist based on the estimated location of the signal source, nor are they able to identify areas where signals are not propagating due to the influence of obstacles.

[0012] For this reason, conventional sensor network systems of this type had the problem that they were unable to obtain a more efficient understanding of the wireless environment by taking into account areas where radio waves are not propagating due to obstacles, which is information useful for developing next-generation communication technologies, from the radio wave situation monitoring results (signal source location estimation results) based on the signal arrival direction estimation results from each sensor device.

[0013] The present invention has been made to solve these conventional problems, and aims to provide a sensor network system and a signal source location estimation method that can easily grasp areas where radio waves are not propagating due to obstacles, and enable more efficient understanding of the wireless environment, which is useful for the development of next-generation communication technologies. [Means for solving the problem]

[0014] In order to solve the above problem, a sensor network system according to claim 1 of the present invention comprises a plurality of sensor devices (10) that are distributed so as to cover a predetermined area (5) and that estimate the signal arrival direction of a signal arriving at each of the locations of the sensor devices; a signal source location estimation means (52) that analyzes the estimation results of the signal arrival direction of all of the sensor devices to estimate the position of a signal source (110); and a signal source location estimation means (52) that, for the signal sources whose positions have been estimated by the signal source location estimation means, divides path information (Pt) from the signal source to each of the sensor devices into groups and estimates the position of each of the signal sources. The system is characterized by comprising a clustering processing means (53) that performs a clustering process to link each of the sensor devices to the sensor devices, an obstacle detection means (54) that compares the path information between adjacent sensor devices among all the sensor devices and detects the presence of an obstacle (8) that hinders radio wave propagation in the area between the adjacent sensor devices based on the comparison result of the path information, and an obstacle notification means (55) that notifies the presence of the obstacle detected by the obstacle detection means by associating it with the area in which the presence of the obstacle was detected.

[0015] With this configuration, the sensor network system according to claim 1 of the present invention can simultaneously estimate the positions of multiple signal sources by analyzing the directions of arrival of signals received by multiple sensor devices that make up the sensor network. Then, it can detect obstacles through clustering processing using the position estimation information of each signal source. Furthermore, by reporting the obstacles, it is possible to easily identify areas where radio waves are not propagating due to obstacles. This makes it possible to limit currently available propagation paths and prevent invalid transmissions and receptions in advance, thereby enabling more efficient radio wave utilization toward the realization of next-generation communication technologies.

[0016] Furthermore, in the sensor network system according to claim 2 of the present invention, the signal source position estimation means may be configured to calculate, for each of the sensor devices, a straight line along the signal arrival direction estimated by the sensor device, select the coordinates of the intersections where the straight lines intersect as candidates for the position of the signal source, and estimate, as the position of the signal source, an intersection where a number of the straight lines intersect that exceeds a predetermined threshold, from among the intersections selected as candidates for the position of the signal source.

[0017] With this configuration, the sensor network system of claim 2 of the present invention can simultaneously and easily estimate the positions of multiple signal sources by analyzing the direction of arrival of signals received by multiple sensor devices through a process of calculating straight lines along the direction of arrival of each signal and the intersections of those lines.

[0018] Furthermore, the sensor network system according to claim 3 of the present invention may further comprise a setting means (41) for setting an obstacle determination condition for determining the presence of the obstacle, and the obstacle detection means may be configured to determine that the obstacle exists when the path information between the adjacent sensor devices satisfies the obstacle determination condition.

[0019] With this configuration, the sensor network system of claim 3 of the present invention sets the requirement that the path information from the same signal source between adjacent sensor devices does not match as an obstacle determination condition, and when the obstacle determination condition is satisfied, it can easily detect the presence of an obstacle in the area between the two sensor devices.

[0020] Furthermore, the sensor network system according to claim 4 of the present invention A sensor network system according to claim 3. In the above, the setting means may be configured to set, as the obstacle determination condition, a first obstacle determination condition that requires that the path information between the adjacent sensor devices does not completely match, or a second obstacle determination condition that requires that there is no common part in the path information between the adjacent sensor devices.

[0021] With this configuration, the sensor network system according to claim 4 of the present invention can realize a loose obstacle detection function that relatively easily accepts the determination of an obstacle by using the first obstacle determination condition and determining that an obstacle exists if the path information between adjacent sensor devices does not completely match. Also, by using the second obstacle determination condition and determining that an obstacle exists if the path information between adjacent sensor devices has no common part at all, it can realize a more conservative obstacle detection function that does not easily accept the determination of an obstacle compared to when the first obstacle determination condition is used.

[0022] The sensor network system according to claim 5 of the present invention may further include a path information management table (53a) that manages the path information associated with each of the sensor devices by the clustering processing means.

[0023] With this configuration, the sensor network system according to claim 5 of the present invention can easily manage the path information linked to each sensor device as a result of the clustering process, and can also smoothly proceed with the subsequent obstacle detection process.

[0024] Furthermore, in the sensor network system according to claim 6 of the present invention, the obstacle notification means may be configured to be a display control means (55) that displays an obstacle monitoring image (60) in which sensor objects (So) corresponding to the sensor devices on a two-dimensional plane that mimics the arrangement of the sensor devices in the specified area are connected by edges (61), and to notify the presence of the obstacle according to the display state of the edges.

[0025] With this configuration, the sensor network system of claim 6 of the present invention can clearly and easily identify areas where obstacles exist by, for example, changing the display mode of the edges connecting adjacent sensor devices when the presence of an obstacle is detected to a display mode different from that when no obstacle is present.

[0026] In order to solve the above problem, an obstacle detection method according to claim 7 of the present invention is an obstacle detection method using the sensor network system according to claim 1 to detect an obstacle (8) that obstructs radio wave propagation and exists in an area between adjacent sensor devices among a plurality of the sensor devices distributed in a predetermined area (5), the method comprising: a signal source position estimation step (S7) of estimating the position of a signal source (110) by analyzing the estimation results of the signal arrival direction of all the sensor devices; and a signal source position estimation step (S8) of estimating the position of the signal source (110) from the signal source for each of the signal sources whose position is estimated in the signal source position estimation step. The method includes a clustering processing step (S8) for performing a clustering process in which path information (Pt) to the sensor devices is divided into groups and linked to each of the sensor devices; an obstacle detection step (S9) for comparing the path information between adjacent sensor devices among all the sensor devices and detecting the presence of an obstacle in the area between the adjacent sensor devices based on the comparison result of the path information; and an obstacle notification step (S10) for notifying the presence of the obstacle detected in the obstacle detection step by associating it with the area in which the presence of the obstacle was detected.

[0027] With this configuration, the obstacle detection method according to claim 7 of the present invention can be applied to a sensor network system having the configuration described in claim 1, thereby simultaneously estimating the positions of multiple signal sources by analyzing the directions of arrival of signals received by multiple sensor devices. Then, obstacles can be discovered by clustering processing using the position estimation information of each signal source, and by reporting the obstacle, areas where radio waves are not propagating due to obstacles can be easily identified. This makes it possible to limit currently available propagation paths and avoid invalid transmissions and receptions in advance, thereby enabling more efficient use of radio waves toward the realization of next-generation communication technology. [Effects of the Invention]

[0028] The present invention can provide a sensor network system and a signal source location estimation method that can easily identify areas where radio waves are not propagating due to obstacles, enabling more efficient understanding of the wireless environment, which is useful for the development of next-generation communication technologies. [Brief explanation of the drawings]

[0029] [Figure 1] 1A and 1B are schematic diagrams of a sensor network system according to the present invention, in which (a) shows the arrangement of sensor devices and the connection between the sensor devices and the control unit, and (b) shows an example of an obstacle monitoring image that mimics the arrangement of the sensor devices. [Figure 2] 1 is a block diagram showing the functional configuration of a sensor device in a sensor network system according to an embodiment of the present invention; [Figure 3] 1 is a block diagram showing the overall functional configuration of a sensor network system according to an embodiment of the present invention; [Figure 4] 5 is a flowchart showing an obstacle monitoring processing operation in the sensor network system according to the embodiment of the present invention. [Figure 5] 5 is a flowchart showing detailed operations of the signal source position estimation process in step S7 of FIG. 4. [Figure 6] 5 is a flowchart showing detailed operations of the obstacle detection process in step S9 of FIG. 4. [Figure 7] 10 is a diagram showing the distribution of intersections of straight lines along the signal arrival direction in the signal source location estimation process in the sensor network system according to one embodiment of the present invention. FIG. [Figure 8] FIG. 8 is a diagram showing an example of a histogram of intersections of lines having the distribution shown in FIG. 7. [Figure 9] 9 is a table diagram showing an example of a path information management table for managing path information obtained by a clustering process for a signal source estimated based on the histogram shown in FIG. 8. FIG. [Figure 10]7 is a schematic diagram showing a specific processing form in steps S33, S34, and S37 of FIG. 6 when obstacle determination condition A is set during obstacle monitoring processing in the sensor network system according to one embodiment of the present invention. FIG. [Figure 11] 7 is a schematic diagram showing a specific processing form in steps S33, S34, and S37 of FIG. 6 when obstacle determination condition B is set during obstacle monitoring processing in the sensor network system according to one embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0030] A sensor network system and an obstacle detection method according to the present invention will be described below with reference to the drawings.

[0031] (overview) The sensor network system 1 according to the present invention is configured to include, for example, as shown in FIG. 1(a), a plurality of (n) sensor devices 10 (in this example, sensor devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7) distributed within a predetermined area (monitoring area 5) that has been assumed in advance, and a control unit 30 that is connected to the n sensor devices 10, for example, wirelessly.

[0032] In the sensor network system 1 according to the present invention, the number of sensor devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7 is not limited to the number (seven) shown in Figure 1(a) and may be more or less than this number. In the following description, the sensor devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, ... may be collectively referred to as sensor device 10.

[0033] 1(a), each sensor device 10 receives, via multiple antenna elements, incoming signals arriving from the surrounding wireless environment at its respective placement location within the monitoring area 5, for example, mixed wireless signals transmitted from signal sources 110-1, 110-2, 110-3, and 110-4. Each sensor device 10 performs signal processing on the received signals of each antenna element to separate signals (incoming signals) transmitted from each of the signal sources 110-1, 110-2, 110-3, and 110-4 (hereinafter, these may be collectively referred to as signal sources 110), analyze the separated incoming signals, and estimate the direction of arrival of the incoming signals for each signal source 110.

[0034] In the process of estimating the direction of arrival of the incoming signal described above, each sensor device 10 generates an angular spectrum using an analysis method such as the MUSIC method or the beamforming method, and then executes a process of deriving one (single) direction of arrival estimation result from these angular spectra for each signal source 110. The signal direction estimation result from each sensor device 10 is sent to the control unit 30, for example, by wireless communication.

[0035] The control unit 30 stores the signal arrival direction estimation results received wirelessly from each sensor device 10 in a memory unit (see "database 35" in Figure 3), and then performs data processing on the information on the signal arrival direction estimation results (signal arrival direction estimation result data).

[0036] As one of the data processing functions, the control unit 30 has a signal source position estimation function (see signal source position estimation unit 52 in FIG. 3) that estimates the position (coordinates) of the signal source 110 based on the signal arrival direction estimation result data obtained by each sensor device 10. The signal source position estimation function is a function that finds the intersection (see FIG. 7) of lines along the signal arrival directions estimated by each sensor device 10, and recognizes the coordinates of the intersection as the position of the signal source 110.

[0037] As a second data processing function, the control unit 30 has an obstacle detection function (see obstacle detection unit 54 in Figure 3) that detects obstacles 8 (see Figure 1(b)) that hinder the propagation of radio waves based on the results of estimation of the location of each signal source 110 by the signal source location estimation function.

[0038] The obstacle detection function is a function that, based on the estimation results of the location of each signal source 110, groups and links the path information Pt indicating the signal reception path (Path) from each signal source 110 for each sensor device 10 (see Figure 7), and then determines whether an obstacle 8 exists depending on whether the relationship between the path information Pt between adjacent (neighboring) sensor devices 10 (see Figures 10 and 11) satisfies preset obstacle determination conditions.

[0039] Furthermore, the control unit 30 has an obstacle notification function that notifies the presence of an obstacle 8 when the obstacle detection function detects the obstacle 8. In the sensor network system 1 of the present invention, the obstacle notification function is realized by a display control function (see the display control unit 55 in FIG. 3) that displays the presence of an obstacle 8 in the sensor network 63 using an obstacle monitoring image 60 as shown in FIG. 1(b), for example. The display control function displays the obstacle monitoring image 60 by internal processing (software).

[0040] As shown in FIG. 1(b), the obstacle monitoring image 60 is composed of a two-dimensional planar image that imitates the arrangement of the sensor devices 10 in the monitoring area 5, and adjacent sensor devices 10 (in this example, sensor devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7) are connected by their respective sides 61. Note that although the sensor devices 10 are referred to as sensor devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7 in FIG. 1(b), in the obstacle monitoring image 60, each of these sensor devices 10 is displayed (represented) by a sensor object So (figure) that imitates each of the sensor devices 10.

[0041] In the example of the obstacle monitoring image 60 shown in Figure 1(b), three or four adjacent sensor devices 10 are connected by sides 61 to form multiple triangular or rectangular meshes 62, and a collection of these multiple meshes 62 constitutes one large network (sensor network) 63. Here, the shape of the meshes 62, which are components of the sensor network 63, is not limited to the above-mentioned triangle or rectangle, and other shapes may be used as long as they can cover the entire sensor network 63.

[0042] In the sensor network system 1 of the present invention, by defining an edge 61 between adjacent sensor devices 10 in the obstacle monitoring image 60 described above, it is possible to display the area spanning that edge 61 as the location of the obstacle 8.

[0043] In short, the sensor network system 1 of the present invention monitors whether or not an obstacle 8 is present in the area of ​​the edge 61 connecting adjacent sensor devices 10, and if an obstacle 8 is detected, the edge 61 corresponding to the area where the obstacle 8 is present is displayed in a different manner from the edge 61 corresponding to the area where the obstacle 8 is not present.

[0044] As a more specific display mode, for example, it is possible to display the edge 61 connecting adjacent sensor devices 10 in the normal color and form (e.g., a solid black line) when no obstacle 8 is present, and to display it in a different color (e.g., red, blue, etc.) and form (e.g., a dotted line or flashing line, etc.) from the normal state when the presence of an obstacle 8 is detected.

[0045] In this way, the sensor network system 1 of the present invention has a signal source position estimation function that estimates the position of the signal source 110 based on the estimated signal arrival direction obtained from each sensor device 10, an obstacle detection function that detects the location of an obstacle 8 using path information Pt from the signal source 110 whose position has been estimated to each sensor device 10, and an obstacle notification function that notifies the presence of the detected obstacle 8.

[0046] In the sensor network system 1 according to the present invention, which has a signal source position estimation function, an obstacle detection function, and an obstacle notification function, it is possible to easily identify locations within the monitoring area 5 (or outside the monitoring area 5) where there is no radio wave propagation, based on the display mode of the obstacle monitoring image 60. If locations within the monitoring area 5 where there is no radio wave propagation can be identified, it is possible to limit currently possible propagation paths, and by avoiding invalid transmissions and receptions in advance, it becomes possible to achieve more efficient radio wave utilization toward the realization of in-band full-duplex communication, which is the core of 5G, the next-generation communication standard.

[0047] The sensor network system 1 according to the present invention can be used in, for example, a local 5G environment, and the frequency bands of signals for which direction of arrival estimation is to be performed are assumed to be, for example, 4.6 GHz to 4.8 GHz and 28.2 GHz to 29.1 GHz. The sensor network system 1 according to the present invention is not limited to use in a local 5G environment, and can also be used in other wireless systems such as WiFi.

[0048] Next, the configuration of a sensor network system 1 according to one embodiment of the present invention will be described with reference to Figures 2 and 3. In the sensor network system 1 according to one embodiment of the present invention, the sensor device 10 has a functional configuration as shown in Figure 2, for example. Moreover, the sensor network system 1 as a whole is configured by functional blocks as shown in Figure 3, for example.

[0049] As shown in Figure 2, in the sensor network system 1 of this embodiment, 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, an arrival direction estimation processing unit 15, a signal analysis unit 16, and an external interface (I / F) unit 17.

[0050] The antenna device 11 receives mixed radio signals transmitted from a plurality of signal sources 110 at various locations within a predetermined space constituting the monitoring area 5 (see FIG. 1(a)). 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 a plurality of antenna elements, as described in Patent Document 1, or an array antenna composed of a plurality of antenna elements.

[0051] The antenna device 11 is not limited to the above-described configuration. As long as it can estimate the direction of arrival of an incoming signal in the above-described frequency band and pass the result to a subsequent circuit, various methods can be applied in terms of the type, number, arrangement, driving method, etc. of antennas.

[0052] The frequency conversion unit 12 receives a signal (radio signal) received by the antenna device 11 and converts the received signal into an intermediate frequency band signal (IF signal).

[0053] The AD conversion unit 13 converts the received signal, which has been frequency-converted by the frequency conversion unit 12, from an analog signal to a digital signal and outputs the digital signal to the signal separation unit 14. The AD conversion unit 13, together with the antenna device 11 and frequency conversion unit 12 described above, constitutes the receiving unit 20a.

[0054] 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 point within a specified space of the monitoring area 5, into signals sent from any of the multiple signal sources 110.

[0055] The arrival direction estimation processing unit 15 receives the signals separated by the signal separation unit 14 (signals arriving at the location from each signal source 110) and performs signal processing to estimate the arrival direction for each of the arriving signals. In this signal processing, the beamformer method, the MUSIC method, the ESPRIT method, or the like is used as an algorithm for estimating the arrival direction.

[0056] The signal analysis unit 16 receives the signal separated by the signal separation unit 14 (the signal arriving at the location) and performs signal processing to analyze the arriving signal for items required for radio interference monitoring. Items to be analyzed (analysis items) include, for example, field strength, sweep spectrum, constellation, etc.

[0057] The external I / F unit 17 is an interface function unit for sequentially transmitting the signal arrival direction estimation results obtained by the arrival direction estimation processing unit 15 and the signal analysis results for each item obtained by the signal analysis unit 16 to the control unit 30, and is configured by, for example, a wireless I / F unit. The external I / F unit 17 is not limited to a wireless I / F unit, and may instead have a wired interface function between each sensor device 10 and a wired network including the control unit 30. The external I / F unit 17, together with the signal separation unit 14, the arrival direction estimation processing unit 15, and the signal analysis unit 16, configures the arrival direction analysis unit 20b.

[0058] Here, the arrival direction estimation results of each signal source 110 transmitted to the control unit 30 include, for example, position information (see FIG. 9) of each point (position of the sensor device 10) and the like.

[0059] Next, the configuration of the control unit 30 will be described. The control unit 30 is configured by a computer device such as a PC (personal computer). As shown in Fig. 3, this computer device has 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 drive (not shown), and various input / output ports.

[0060] The CPU 31 performs overall control over the estimation of the position of the signal source 110, the detection of the location of the obstacle 8, and the notification process of the detection results in the sensor network system 1. The ROM 32 stores an operating system (OS) and other programs and control parameters for starting up the CPU 31. The RAM 33 stores the OS and application execution codes and data used by the CPU 31 for operation.

[0061] The external I / F unit 34 has an input interface function for inputting a predetermined signal and an output interface function for outputting a predetermined signal. The external I / F unit 34 is, for example, configured by a wireless I / F unit, and is connected to the external I / F unit 17 of each of the sensor devices 10 described above so as to be able to communicate wirelessly. When each of the sensor devices 10 and the control unit 30 are connected via a wired network, both the external I / F unit 34 of the control unit 30 and the external I / F unit 17 of the sensor device 10 can be configured by a wired I / F unit.

[0062] The database 35 is a section for storing various data such as signal arrival direction estimation result data received from each sensor device 10 via the external I / F section 34.

[0063] An input unit 36 ​​and a display unit 37 are connected to the input / output ports of the computer device.

[0064] The input unit 36 ​​is a functional unit for inputting various information such as commands, and is configured with input devices such as a keyboard, a mouse, etc. In this embodiment, the input unit 36 ​​may have a function for inputting commands to start or end the process of estimating the position of the signal source 110, the process of detecting the location of the obstacle 8, and the process of displaying the results of the position estimation and the location detection.

[0065] The display unit 37 is a part for displaying various information such as measurement results and an input screen for various information (commands, etc.) related to the operation of the sensor network system 1. The display unit 37 may be configured with a touch panel or the like that allows various information to be input from a currently displayed screen such as the input screen.

[0066] 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 work 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 using the RAM 33 as a work area.

[0067] The device control unit 40 controls the entire device related to signal source position estimation processing 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 unit 41, a communication control unit 42, and an antenna control unit 43.

[0068] The monitoring condition setting unit 41 is a functional unit that sets, based on a user operation, obstacle monitoring conditions (various setting items) related to obstacle monitoring estimation processing for the monitoring area 5. Examples of the setting items include the frequency range of a signal for which the direction of arrival is estimated by the sensor device 10 (frequency band for direction of arrival estimation target), the number of intersections as the threshold n used in the processing for estimating the position of the signal source 110 by the signal source position estimation unit 52 (see step S23 in FIG. 5), and obstacle determination condition A or B used in the obstacle determination processing by the obstacle detection unit 54 (see step S32 in FIG. 6).

[0069] The monitoring condition setting unit 41 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 estimation is to be performed, taking into consideration, for example, 5G operation. The monitoring condition setting unit 41 constitutes the setting means of the present invention.

[0070] The communication control unit 42 is a functional unit that controls communication between the control unit 30 and each sensor device 10. For example, the communication control unit 42 sends an instruction to the sensor device 10 to start a signal arrival direction estimation process, and causes the sensor device 10 to start a reception operation.

[0071] Furthermore, when the sensor device 10 starts receiving operations and estimates the direction of arrival for each signal separated from the mixed wireless signals received by the antenna device 11, the communication control unit 42 performs communication control to receive the estimated results of the direction of arrival from the sensor device 10. When reception of the direction of arrival estimation results is completed, the communication control unit 42 sends, for example, an instruction to the sensor device 10 to end the signal direction estimation operation, causing the receiving operation to be stopped. In addition, the communication control unit executes control to send and receive control data for controlling each unit of the sensor device 10 (receiving unit 20a, direction of arrival analysis unit 20b, etc.) as necessary.

[0072] The antenna control unit 43 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 unit 42.

[0073] The data control unit 50 includes a data management unit 51 , a signal source position estimation unit 52 , a clustering processing unit 53 , an obstacle detection unit 54 , and a display control unit 55 .

[0074] The data management unit 51 performs a process of storing the arrival direction estimation result data, etc. sent from each sensor device 10, together with the aforementioned location information (the placement position of each sensor device 10) added thereto, in the database 35, and a process of reading out the stored arrival direction estimation result data, etc. from the database 35 and passing it to the signal source position estimation unit 52, etc.

[0075] The arrival direction estimation result data is configured to store information such as the placement position, number of incoming signal sources, signal arrival direction, and incoming signal information for each of the n sensor devices 10. In the arrival direction estimation result data, the number of incoming signal sources differs depending on the placement position of each sensor device 10. Furthermore, even for the same signal, the arrival direction differs depending on the placement location. The arrival direction of the signal is information indicating, for example, an angle within a range of 0° to 360° when the x-axis is set to 0° (degrees) on a two-dimensional plane (see FIG. 1(b)) that simulates the monitoring area 5. Various information such as reception level is stored as the incoming signal information.

[0076] The signal source position estimation unit 52 is a functional unit that estimates the position of the signal source 110 that is the source of the signal received by each sensor device 10, based on the arrival direction estimation result data acquired from the data management unit 51. The signal source position estimation unit 52 constitutes the signal source position estimation means of the present invention.

[0077] Specifically, the signal source position estimation unit 52 calculates straight lines along the directions of arrival estimated by each sensor device 10 based on the direction of arrival estimation result data (see FIG. 7), selects the intersection of these lines as a candidate for the position of the signal source 110, and then executes a signal source position estimation process to estimate the coordinates of the intersection of lines of more than a preset threshold n among the candidate candidates as the position of the signal source 110 (signal source 110-1 and signal source 110-2 in the example of FIG. 7) as the detection result.

[0078] The clustering processing unit 53 is a functional unit that performs clustering processing, in which, for a signal source 110 whose position has been estimated by the signal source position estimation unit 52, path information Pt indicating the signal reception path at each sensor device 10 that originates from that signal source 110 is grouped, and the path information Pt of each group is associated (linked) with each sensor device 10.

[0079] According to this clustering process, for example, when n signal sources 110 are estimated, at least one of the n groups of path information Pt grouped for each signal source 110 (in the example of FIG. 7, path information Pt11 grouped for signal source 110-1 and path information Pt12 grouped for signal source 110-2) is associated with each sensor device 10. The clustering processing unit 53 constitutes the clustering processing means of the present invention.

[0080] The obstacle detection unit 54 is a functional unit that detects the position of an obstacle 8 using the path information Pt clustered for the signal source 110 by the clustering processing unit 53. Specifically, the obstacle detection unit 54 compares the path information Pt associated with each of the adjacent sensor devices 10, and determines that an obstacle 8 exists in the area between the sensor devices 10 when a relationship that satisfies a preset obstacle discrimination condition is established between the path information Pt. As the obstacle discrimination condition, for example, obstacle discrimination condition A or B, which will be described later, can be set. The obstacle detection unit 54 constitutes the obstacle detection means of the present invention.

[0081] The display control unit 55 is a functional unit that performs display control to display various information on the display unit 37. In this embodiment, the display control unit 55 performs control to display the presence of an obstacle 8 using an obstacle monitoring image 60 (see FIG. 1(b)) that imitates the arrangement of each sensor device 10 in the monitoring area 5, based on the detection result of an obstacle 8 by the obstacle detection unit 54. The display control unit 55 constitutes the obstacle notification means of the present invention.

[0082] Specifically, when the obstacle detection unit 54 determines that an obstacle 8 exists in the area between adjacent sensor devices 10, the display control unit 55 displays the presence of the obstacle 8 by displaying the edge 61 connecting the adjacent sensor devices 10 in the obstacle monitoring image 60 (see Figure 1 (b)).

[0083] As a display mode of the edge 61 when displaying the presence of an obstacle 8, the display control unit 55 can, for example, display the edge 61 in different colors when the obstacle 8 is not detected and when it is detected (for example, black when the obstacle 8 is not detected, and red or yellow when the obstacle 8 is detected), or can display the edge 61 as a solid line when the obstacle 8 is not detected, and switch to a dotted line or a flashing solid or dotted line when the obstacle 8 is detected. In any display mode, the user can be effectively notified that an obstacle 8 is present in the area corresponding to the edge 61.

[0084] Next, the obstacle monitoring processing operation of the sensor network system 1 according to this embodiment will be described with reference to the flowcharts shown in Figures 4, 5, and 6. Figure 4 shows the overall flow of the obstacle detection processing operation, and Figure 5 shows details of the position estimation processing operation of the signal source 110 in step S7 of Figure 4. Also, Figure 6 shows details of the obstacle detection processing operation in step S9 of Figure 4.

[0085] In the sensor network system 1 according to this embodiment, a setting process for setting obstacle monitoring conditions is performed at the start of the obstacle monitoring process shown in Fig. 4 (step S1). This setting process can be performed, for example, by the monitoring condition setting unit 41 of the device control unit 40. Here, the monitoring condition setting unit 41 displays a setting screen on the display unit 37, accepts input of setting values ​​from the input unit 36 ​​for setting fields for each setting item displayed on the setting screen, and performs a process of setting the input values ​​for each setting item.

[0086] The setting items for the obstacle monitoring conditions include, for example, the frequency band for which the sensor device 10 estimates the direction of arrival, the threshold value n (number of intersections) used in the position estimation process of the signal source 110 in step S7 (more specifically, step S23 in Figure 5), and the obstacle determination conditions used in the obstacle determination process in step 9 in Figure 4 (more specifically, step S32 in Figure 6).

[0087] Of these obstacle determination conditions, the sensor network system 1 according to this embodiment is configured to set an obstacle determination condition A or an obstacle determination condition B. The obstacle determination condition A, for example, specifies the condition that "the path information Pt between adjacent sensor devices 10 does not completely match" (see FIG. 10). The obstacle determination condition B, for example, specifies the condition that "the path information Pt between adjacent sensor devices 10 has absolutely no common part" (see FIG. 11). The obstacle determination condition A and the obstacle determination condition B correspond to the first obstacle determination condition and the second obstacle determination condition, respectively, in the present invention.

[0088] When the setting of the obstacle monitoring conditions in step S1 is completed, the control unit 30 accepts an obstacle monitoring start operation by the user, for example, via the input unit 36 ​​(step S2). The obstacle monitoring operation can be performed, for example, by pressing the "Start" button displayed on the setting screen described above.

[0089] When an obstacle monitoring start operation is accepted in step S2, the control unit 30 causes the communication control unit 42 of the device control unit 40 to send an instruction to each sensor device 10 to start a signal arrival direction estimation operation (step S3).

[0090] When each sensor device 10 receives an instruction to start the signal arrival direction estimation operation from the control unit 30, it performs a process of estimating the arrival direction of the signal received at its respective placement location (step S4). The signal arrival direction estimation process in each sensor device 10 in step S4 is performed by remote control from the device control unit 40 of the control unit 30. Through this remote control, each sensor device 10 performs a process of estimating the arrival direction of the signal received at its respective 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.

[0091] In more detail regarding the signal arrival direction estimation process in step S4, the control unit 30 remotely controls the antenna device 11 in the receiving unit 20a of each sensor device 10 using the antenna control unit 43, and causes the antenna device 11 to receive a radio signal of a frequency band previously set by the monitoring condition setting unit 41 as an arriving signal at the location where each sensor device 10 is installed.

[0092] Next, in the receiving unit 20a of each sensor device 10, the incoming signal (received signal) received by the antenna device 11 at the placement point 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.

[0093] The signal separation unit 14 performs signal separation processing to separate from the input radio signal a plurality of signal source components (signals transmitted from each signal source 110) arriving from the surroundings at the placement point, and inputs the separated signal source components to the arrival direction estimation processing unit 15 and the signal analysis unit 16.

[0094] The direction-of-arrival estimation processor 15 takes in each signal source component separated by the signal separator 14 and performs processing to estimate the direction of arrival of each signal component. Here, the direction-of-arrival estimation processor 15 performs analysis processing using, for example, the MUSIC method to generate a MUSIC angle spectrum of the input signal and derive a direction-of-arrival estimation result based on the MUSIC angle spectrum. The direction-of-arrival estimation processing in the direction-of-arrival estimation processor 15 is not limited to the MUSIC method, and other analysis methods such as a beamforming method may be applied to derive the direction-of-arrival estimation result.

[0095] The signal analysis unit 16 performs analysis processing of various items related to the input signal from the signal separation unit 14 in accordance with the signal arrival direction estimation processing by the arrival direction estimation processing unit 15. The arrival direction estimation result of the arrival signal by the arrival direction estimation processing unit 15 and the analysis result of the input signal by the signal analysis unit 16 are sent to the control unit 30 via the external I / F unit 17.

[0096] Meanwhile, after instructing the control unit 30 to start the signal arrival direction estimation process in step S3, the control unit 30 receives the signal arrival direction estimation results from each sensor device 10 sent from the respective sensor device 10 via the external I / F unit 34 (step S5).

[0097] Next, in the control unit 30, the data management unit 51 performs processing to store the arrival direction estimation results received from each sensor device 10 in step S5 in the database 35 as arrival direction estimation result data in association with each sensor device 10 (step S6). The arrival direction stored in association with each sensor device 10 in the arrival direction estimation result data can serve as an index indicating that the signal source 110 is located on a straight line (see FIG. 7) along that arrival direction.

[0098] Subsequently, in the control unit 30, the signal source position estimation unit 52 carries out a process of estimating the position of the signal source 110 based on the arrival direction estimation result data stored in the database 35 (step S7).

[0099] More specifically, the process of estimating the position of the signal source 110 in step S7 is performed according to the flowchart shown in Fig. 5. As shown in Fig. 5, when the process of estimating the position of the signal source 110 starts, the signal source position estimation unit 52 calculates each straight line along the direction of arrival of the signal estimated by each sensor device 10 based on the direction of arrival estimation result data, determines the intersection of these lines, and extracts the intersection of each straight line as a candidate for the position (coordinates) of the signal source 110 (step S21).

[0100] Next, the signal source position estimation unit 52 creates a histogram of the intersections extracted in step S21 (step S22).

[0101] Furthermore, based on the histogram of intersections generated in step S22, the signal source position estimation unit 52 uses the threshold n set in step S1 of Figure 4 to estimate the coordinates of the intersection where lines exceeding the threshold n intersect as the position (coordinates) of the signal source 110 (step S23).

[0102] The processing of steps S21 to S23 will be described in more detail with reference to Fig. 7 and Fig. 8. Fig. 7 is a diagram showing an image of the calculation processing of lines and their intersections when extracting candidates for the position of signal source 110 in step S21. In Fig. 7, the arrangement of sensor devices 10-1, 10-2, 10-3, and 10-4 does not necessarily match the arrangement shown in Fig. 1, and is merely an image.

[0103] When extracting candidate positions of the signal source 110 in step S21, the signal source position estimation unit 52 searches the arrival direction estimation result data to obtain the arrival direction of the signal estimated by each sensor device 10, and determines a straight line along the arrival direction.

[0104] 7, for example, two arrival directions are estimated for sensor device 10-1 among sensor devices 10-1, 10-2, 10-3, and 10-4, and signal source position estimation unit 52 calculates line l11 along one of the arrival directions and line l12 along the other arrival direction. Similarly, for sensor devices 10-2, 10-3, and 10-4, for example, two arrival directions are estimated for each, and signal source position estimation unit 52 calculates line l21, line l31, and line l41 along one of the arrival directions and calculates line l22, line l32, and line l42 along the other arrival direction.

[0105] From the straight line calculation results shown in FIG. 7, the intersections of the eight straight lines l11, l12, l21, l22, l31, l32, l41, and l42 are found, and eight intersections are calculated: intersection P11 of straight lines l11, l21, l31, and l41; intersection P12 of straight lines l12, l22, l32, and l42; intersection P21 of straight lines l12 and l21; intersection P22 of straight lines l12 and l31; intersection P23 of straight lines l12 and l41; intersection P24 of straight lines l22 and l31; intersection P24 of straight lines l22 and l41; and intersection P26 of straight lines l32 and l41.

[0106] Here, intersection points P11 and P12 are respectively intersected by four lines l11, l21, l31, l41 and lines l12, l22, l32, l42, and the other six intersection points P21, P22, P23, P24, P14325, and P26 are respectively intersected by two lines (l12, l21), (l12, l31), (l12, l41), (l22, l31), (l22, l41), and (l32, l41).

[0107] 7, the above-mentioned eight intersection points P11, P12, and P21 to P26 are calculated. Of these, two intersection points P11 and P12 are each intersected by four lines, and the other six intersection points P21 to P26 are each intersected by two lines. It can be seen that intersection points P11 and P12, where a greater number of lines intersect, are more likely to be the location of the true signal source 110, while intersection points where fewer lines intersect, such as two lines, are less likely to be the location of the true signal source 110, such as being the location of a radio wave reflection.

[0108] From this, it can be seen that in the example shown in FIG. 7, in order to estimate the two intersection points P11 and P12 as the true signal source 110, it is sufficient to find the intersection points where four straight lines intersect from the eight intersection points P11, P12, and P21 to P26.

[0109] To achieve this, in the sensor network system 1 of this embodiment, in step S22, the signal source position estimation unit 52 creates a histogram of the coordinates of the intersections and the number of lines intersecting at those intersections based on the intersection calculation results shown in Figure 7, and in step S23, executes a process to determine the position (coordinates) of the signal source 110 from the coordinates of the intersections where four or more lines intersect from the histogram.

[0110] Fig. 8 shows an example of a histogram relating to the coordinates of the intersections and the number of lines intersecting at those intersections based on the intersection calculation results as shown in Fig. 7. In Fig. 8, the horizontal axis represents the coordinates (x, y) of the intersection P extracted by the process shown in Fig. 7 on a two-dimensional plane (XY plane) assuming the monitoring area 5 (see Fig. 1(b)), and the vertical axis represents the number of lines intersecting at each intersection.

[0111] When the histogram shown in FIG. 8 is obtained, the signal source position estimation unit 52 uses a preset threshold n (the number of lines intersecting at an intersection: set in step S1 of FIG. 4) to check whether the number of lines intersecting at each coordinate corresponding to that coordinate exceeds the threshold n, and can estimate the position of the coordinate where the number of lines intersecting exceeds the threshold n as the position of the signal source 110.

[0112] As a result, after generating the histogram shown in FIG. 8 in step S21 of FIG. 5, in step S22, the signal source position estimation unit 52 checks whether or not there is an intersection point where more than the threshold n of straight lines intersect with the histogram, and if there is an intersection point where more than the threshold n of straight lines intersect with the histogram, it estimates the coordinates of the intersection point as the position of the signal source 110.

[0113] Taking the histogram shown in Fig. 8 as an example, by setting the threshold n to, for example, "3," it is possible to estimate the coordinates of two intersections where lines exceeding the threshold n (=3) (i.e., "4" or more) intersect as the positions of the respective signal sources 110. Furthermore, when this estimation process is applied to the example of intersection calculation results shown in Fig. 7, it is possible to estimate the coordinates of two intersections P11 and P21 where lines exceeding the threshold n (=3) intersect, that is, "4" or more, as the positions of the two signal sources 110-1 and 110-2.

[0114] As described with reference to Figures 7 and 8, in the signal source position estimation process in step S7 of Figure 4 (more specifically, steps S21 to S23 of Figure 5), the signal source position estimation unit 52 finds the intersection of lines corresponding to each arrival direction from the arrival direction estimation results of the signals from each sensor device 10, and then estimates, as the position of the signal source 110, the intersection (coordinate) of more lines than the number of which is set in advance as a threshold value n.

[0115] 4, the processing from step S7 onwards will be described. After estimating the position of the signal source 110 within the monitoring area 5 (or outside the monitoring area 5) in step S7 (more specifically, steps S21 to S23 in FIG. 5), the clustering processing unit 53 performs clustering (grouping) processing of the path information Pt between the estimated signal source 110 and each sensor device 10 (step S8).

[0116] The clustering process of path information Pt for signal source 110 in step S8 will be described with reference to Fig. 7. According to the calculation results of the lines and their intersections shown in Fig. 7, as described above, for example, two intersections P11 and P12 where four lines exceeding threshold n (=3) intersect can be estimated as the positions of signal sources 110-1 and 110-2.

[0117] 7, the path information Pt when sensor devices 10-1, 10-2, 10-3, and 10-4 receive signals from signal sources 110-1 and 110-2 can be divided into two groups: path information Pt11 from signal source 110-1 and path information Pt12 from signal source 110-2. In the present invention, the process of dividing the path information Pt for each of sensor devices 10-1, 10-2, 10-3, and 10-4 for signal sources 110-1 and 110-2 into path information Pt11 from signal source 110-1 and path information Pt11 from signal source 110-2 is referred to as clustering processing.

[0118] 4, of signal source 110-1 and signal source 110-2 estimated in step S7, clustering processing unit 53 groups, for signal source 110-1, the reception paths of sensor devices 10-1, 10-2, 10-3, and 10-4 corresponding to four straight lines intersecting at intersection P11 as path information Pt11 indicated by solid lines, and for signal source 110-2, groups, for signal source 110-2, the reception paths corresponding to four straight lines intersecting at intersection P12 as path information Pt12 indicated by dotted lines. Furthermore, clustering processing unit 53 performs processing to associate (link) path information Pt11 grouped for signal source 110-1 and path information Pt12 grouped for signal source 110-2 with sensor devices 10-1, 10-2, 10-3, and 10-4, respectively.

[0119] The path information Pt (Pt11, Pt12) generated by the clustering process in step S8 may be managed by the data management unit 51 using a path information management table 53a shown in FIG.

[0120] As shown in Figure 9, the path information management table 53a has a data structure that stores, for each sensor device 10, the placement position (position coordinates) of each sensor device 10, path information Pt (path 1) from signal source 110-1, and path information Pt (path 2) from signal source 110-2.

[0121] 7 is stored for path 1, and path information Pt12 is stored for path 2. The path information Pt11 and Pt12 for path 1 and path 2 are information (angle information) indicating the angle (for example, in the range of 0° to 360°) of a line connecting each sensor device 10 and signal source 110-1 or signal source 110-2 when the x-axis is set to 0° on a two-dimensional plane (see FIG. 1(b)) that simulates the monitored area 5.

[0122] After generating the path information management table 53a by the clustering process in step S8, the obstacle detection unit 54 then performs a process of detecting an obstacle 8 based on the path information Pt stored in the path information management table 53a (step S9).

[0123] Furthermore, the control unit 30 performs a process of notifying the presence of the obstacle 8 detected by the obstacle detection process in the above step S9 (step S10). As described above, the process of notifying the presence of the obstacle 8 (obstacle notification process) is performed by, for example, causing the display control unit 55 to display an obstacle monitoring image 60 (see FIG. 1(b)) on the display unit 37.

[0124] During the execution of the obstacle notification process in step S10, for example, by accepting an operation to end the obstacle monitoring process at the input unit 36, the control unit 30 ends the series of obstacle monitoring process operations shown in FIG.

[0125] The obstacle 8 detection process in step S9 in Fig. 4 and the obstacle notification process in step S10 are specifically performed according to the flowchart shown in Fig. 6. In Fig. 6, steps S31 to S36 correspond to the obstacle detection process in step S9 in Fig. 4, and step S37 corresponds to the obstacle notification process in step S10 in Fig. 4.

[0126] As shown in Figure 6, when the detection process for an obstacle 8 is started, the obstacle detection unit 54 reads out the path information Pt associated with each of the first sets of adjacent sensor devices 10 from the path information management table 53a (see Figure 9), and compares the path information Pt between these first sets of adjacent sensor devices 10 (step S31).

[0127] Next, the obstacle detection unit 54 determines whether the path information Pt between the first pair of adjacent sensor devices 10 satisfies the obstacle determination condition A or the obstacle determination condition B set in step S1 of Fig. 4 based on the comparison result in step S31 (step S32). If it is determined in step S32 that the path information Pt between the first pair of adjacent sensor devices 10 does not satisfy the obstacle determination condition A or the obstacle determination condition B set in step S1 of Fig. 4 (NO in step S32), the obstacle detection unit 54 maintains the edge 61 (see Fig. 1(b)) connecting the adjacent sensor devices 10 in the obstacle monitoring image 60 (indicating that no obstacle 8 exists between the adjacent sensor devices 10) (step S33), and then proceeds to step S35.

[0128] On the other hand, if it is determined in step S32 that the path information Pt between the first pair of adjacent sensor devices 10 satisfies the obstacle determination condition A or the obstacle determination condition B set in step S1 of FIG. 4 (YES in step S32), the obstacle detection unit 54 cuts the edge 61 connecting the adjacent sensor devices 10 (indicating that an obstacle 8 exists between the adjacent sensor devices 10) (step S33), and then proceeds to step S35.

[0129] In step S35, the obstacle detection unit 54 checks whether the comparison of the path information Pt between all pairs of adjacent sensor devices 10 has been completed.

[0130] Here, if it is determined that the comparison of the path information Pt between all pairs of adjacent sensor devices 10 has not been completed (NO in step S35), the obstacle detection unit 54 compares the path information Pt between the next pair of sensor devices 10 (step S36).

[0131] Thereafter, the obstacle detection unit 54 continues the processing from step S32 onwards. During this time, if it is determined in step S35 that the comparison of the path information Pt between all pairs of adjacent sensor devices 10 has been completed (YES in step S35), the display control unit 55 executes processing to highlight and display the edge 61 cut in the processing of step S34 above in a form that indicates the presence of an obstacle 8 (step S37).

[0132] Specifically, the display control unit 55 controls the display of the edges 61 that are components of the mesh 62 in the obstacle monitoring image 60 (see Figure 1 (b)), which have been cut in the processing of step S34, in a manner different from that of the uncut edges 61 (edges 61 where the presence of an obstacle 8 has not been detected).

[0133] For example, when the display control unit 55 represents the edge 61 where the presence of an obstacle 8 has not been detected as a solid black line, the display control unit 55 displays the edge 61 where the presence of an obstacle 8 has been detected as a color other than black. Furthermore, if the presence of an obstacle 8 is detected while the edge 61 is displayed as a solid black line, the edge 61 may be displayed as a color other than black, as a dotted line, or may be displayed in a flashing manner. Here, as long as it is possible to notify the presence of an obstacle 8, the edge 61 may be displayed in various manners other than the manner described above. The control of the highlighting of the edge 61 that notifies the presence of an obstacle 8 is terminated by receiving an operation to terminate the obstacle monitoring process.

[0134] A specific example of the processing of steps S32, S33, and S34 in the obstacle alarm control (corresponding to step S10 in FIG. 4) shown in FIG. 6 will be described in more detail with reference to FIGS.

[0135] Fig. 10 is a schematic diagram showing an example of the obstacle 8 presence determination process and the display control for notifying the presence of the detected obstacle 8 when obstacle determination condition A is set such that "path information Pt does not completely match between adjacent sensor devices 10." Fig. 11 is a schematic diagram showing an example of the obstacle 8 presence determination process and the display control for notifying the presence of the detected obstacle 8 when obstacle determination condition B is set such that "path information Pt does not have any common part between adjacent sensor devices 10."

[0136] First, the process of determining whether an obstacle 8 exists when obstacle determination condition A is set will be described with reference to Fig. 10. In Fig. 10, adjacent sensor devices 10 are exemplified by a pair of sensor device 10-1 and sensor device 10-2, a pair of sensor device 10-1 and sensor device 10-3, and a pair of sensor device 10-2 and sensor device 10-3.

[0137] Among these, path information Pt11 shown by a solid line and path information Pt12 shown by a dotted line are linked to sensor device 10-1. Path information Pt11 shown by a solid line corresponds to path information Pt from signal source 110-1 located at position P11 in Fig. 7, for example, and path information Pt21 shown by a dotted line corresponds to path information Pt from signal source 110-2 located at position P12 in Fig. 7.

[0138] 10, when the path information Pt between the sensor device 10-1 and the sensor device 10-2 is compared, the path information Pt11 is common to both, but the path information Pt12 exists only in the sensor device 10-1. In other words, the path information Pt between the sensor device 10-1 and the sensor device 10-2 does not completely match, and the obstacle determination condition A is satisfied.

[0139] Therefore, in this case, the edge 61 between the sensor device 10-1 and the sensor device 10-2 is cut (see step S34 in FIG. 6). In FIG. 10, the fact that the edge 61 has been cut, i.e., the presence of an obstacle 8, is indicated by a dotted line, and an x ​​mark is added as obstacle presence indication information 65 indicating that an obstacle 8 is present on the edge 61.

[0140] Next, comparing the path information Pt between the sensor device 10-2 and the sensor device 10-3, it is found that only the path information Pt11 is linked to the sensor device 10-2, whereas both the path information Pt11 and the path information Pt21 are linked to the sensor device 10-2. In other words, the path information Pt between the sensor device 10-2 and the sensor device 10-3 do not completely match, and the obstacle determination condition A is satisfied.

[0141] Therefore, in this case, the side 61 between the sensor device 10-2 and the sensor device 10-3 is cut (see step S34 in FIG. 6). In this case, too, the fact that the side 61 has been cut, i.e., the presence of an obstacle 8, is indicated by a dotted line, and an X mark is added as obstacle presence indication information 65 indicating that an obstacle 8 is present on the side 61.

[0142] Next, when the path information Pt between the sensor device 10-1 and the sensor device 10-3 is compared, both the path information Pt11 and the path information Pt12 are linked. In other words, the path information Pt between the sensor device 10-1 and the sensor device 10-3 is completely identical, and does not satisfy the obstacle determination condition A. Therefore, in this case, the edge between the sensor device 10-1 and the sensor device 10-3 is not cut (see step S33 in FIG. 6). In FIG. 10, the absence of an obstacle 8 is indicated by a solid line.

[0143] In this way, according to the obstacle 8 presence determination process using the obstacle determination condition A, it is possible to realize a relaxed obstacle detection function that relatively easily accepts the determination of an obstacle 8 by determining that an obstacle 8 exists on the condition that the path information Pt between adjacent sensor devices 10 does not completely match.

[0144] Next, the process of determining whether an obstacle 8 exists when the obstacle determination condition B is set will be described with reference to Fig. 11. In Fig. 11, the form is the same as in Fig. 10 except for the path information Pt linked to the sensor devices 10-1, 10-2, and 10-3.

[0145] 11, comparing the path information Pt between sensor device 10-1 and sensor device 10-2 reveals that path information Pt11 is common to both, but path information Pt12 exists only in sensor device 10-1. In other words, path information Pt11 exists as a common portion in the path information Pt between sensor device 10-1 and sensor device 10-2, and does not satisfy obstacle determination condition B. Therefore, in this case, edge 61 between sensor device 10-1 and sensor device 10-2 is not cut (see step S33 in FIG. 6) and is displayed by a solid line.

[0146] Next, comparing the path information Pt between the sensor device 10-2 and the sensor device 10-3, it is found that only the path information Pt11 is linked to the sensor device 10-2, while only the path information Pt12 is linked to the sensor device 10-3. In other words, there are no matching portions in the path information Pt between the sensor device 10-2 and the sensor device 10-3, and the obstacle determination condition B is satisfied.

[0147] Therefore, in this case, the edge 61 between the sensor device 10-2 and the sensor device 10-3 is cut (see step S34 in FIG. 6). In FIG. 11, the fact that the edge 61 has been cut, i.e., the presence of an obstacle 8, is indicated by a dotted line, and an X mark is added as obstacle presence indication information 65 indicating that an obstacle 8 is present on the edge 61.

[0148] Next, comparing the path information Pt between sensor device 10-1 and sensor device 10-3, it is found that path information Pt12 is common to both, but path information Pt11 exists only in sensor device 10-1. In other words, path information Pt12 exists as a common part in the path information Pt between sensor device 10-1 and sensor device 10-2, and therefore does not satisfy obstacle determination condition B. In this case, edge 61 between sensor device 10-1 and sensor device 10-2 is not cut (see step S33 in FIG. 6) and is displayed as a solid line.

[0149] In this way, according to the obstacle 8 presence determination process using obstacle determination condition B, the presence of an obstacle 8 is determined to be present on the condition that there is no common part in the path information Pt between adjacent sensor devices 10, thereby realizing a more conservative obstacle detection function that does not easily accept a determination of an obstacle 8 compared to when obstacle determination condition A is used.

[0150] 10 and 11, the process of determining an obstacle 8 using obstacle determination conditions A and B and adding obstacle presence indication information 65 is also performed between all other adjacent sensor devices 10. As a result, in the sensor network system 1 according to this embodiment, by displaying obstacle presence indication information 65 (such as an X mark) on each edge 61 of a mesh 62 on an obstacle monitoring image 60 that represents one sensor network 63 made up of a collection of meshes 62 connecting the sensor devices 10, it is possible to clearly inform the user that an obstacle 8 is present near that edge 61.

[0151] As described above, the sensor network system 1 of this embodiment is configured to include a plurality of sensor devices 10 that are distributed over the monitoring area 5 and that estimate the signal arrival direction of an incoming signal at each of their locations; a signal source position estimation unit 52 that analyzes the signal arrival direction estimation results of all the sensor devices 10 to estimate the position of the signal source 110; a clustering processing unit 53 that performs clustering processing to divide the path information Pt from the signal source 110 to each sensor device 10 for the signal source 110 whose position has been estimated by the signal source position estimation unit 52 into groups and link them to each sensor device 10; an obstacle detection unit 54 that compares the path information Pt between adjacent sensor devices 10 out of all the sensor devices 10 and detects the presence of an obstacle 8 that obstructs radio wave propagation in the area between the adjacent sensor devices 10 based on the comparison result of the path information Pt; and an obstacle notification means that notifies the presence of the obstacle 8 detected by the obstacle detection unit 54 by associating it with the area in which the obstacle 8 is detected.

[0152] With this configuration, the sensor network system 1 according to this embodiment can simultaneously estimate the positions of multiple signal sources 110 by analyzing the directions of arrival of signals received by multiple sensor devices 10 that make up the sensor network. Then, it is possible to discover obstacles 8 by clustering processing using the position estimation information of each signal source 110, and furthermore, by being notified of the obstacles 8, it is possible to easily identify areas where radio waves are not propagating due to the obstacles 8. This makes it possible to limit currently available propagation paths and avoid invalid transmissions and receptions in advance, thereby enabling more efficient use of radio waves toward the realization of next-generation communication technologies.

[0153] Furthermore, in the sensor network system 1 according to this embodiment, the signal source position estimation unit 52 is configured to calculate, for each sensor device 10, a straight line along the signal arrival direction estimated by the sensor device 10, select the coordinates of the intersections where the straight lines intersect as candidates for the position of the signal source 110, and estimate, as the position of the signal source 110, an intersection where a number of straight lines exceeding a predetermined threshold n intersect among the intersections selected as candidates for the position of the signal source 110.

[0154] With this configuration, the sensor network system 1 of this embodiment can simultaneously and easily estimate the positions of multiple signal sources 110 by analyzing the direction of arrival of signals received by multiple sensor devices 10 through a process of calculating straight lines along the direction of arrival of each signal and the intersections of those straight lines.

[0155] In addition, the sensor network system 1 of this embodiment further has a monitoring condition setting unit 41 that sets obstacle determination conditions for determining whether an obstacle 8 exists, and the obstacle detection unit 54 is configured to determine that an obstacle 8 exists when the path information Pt between adjacent sensor devices 10 satisfies the obstacle determination conditions.

[0156] With this configuration, the sensor network system 1 of this embodiment sets the requirement that the path information Pt from the same signal source 110 between adjacent sensor devices 10 does not match as an obstacle determination condition, and if the obstacle determination condition is satisfied, it can easily detect the presence of an obstacle in the area between the two sensor devices 10.

[0157] In addition, in the sensor network system 1 of this embodiment, the monitoring condition setting unit 41 is configured to set, as an obstacle determination condition, either obstacle determination condition A, which requires that the path information Pt between adjacent sensor devices 10 does not completely match, or obstacle determination condition B, which requires that the path information Pt between adjacent sensor devices 10 has no common parts at all.

[0158] With this configuration, the sensor network system 1 according to this embodiment can realize a loose obstacle detection function that uses obstacle determination condition A to determine that an obstacle 8 exists on the condition that the path information Pt between adjacent sensor devices 10 does not completely match, thereby relatively easily accepting a determination that an obstacle is an obstacle 8. Furthermore, by using obstacle determination condition B to determine that an obstacle 8 exists on the condition that the path information Pt between adjacent sensor devices 10 has no common parts at all, a more conservative obstacle detection function can be realized that does not easily accept a determination that an obstacle is an obstacle 8 compared to when obstacle determination condition A is used.

[0159] The sensor network system 1 according to this embodiment further includes a path information management table 53a that manages the path information Pt associated with each sensor device 10 by the clustering processing unit 53.

[0160] With this configuration, the sensor network system 1 according to this embodiment can easily manage the path information Pt associated with each sensor device 10 as a result of the clustering process, and can also smoothly proceed with the subsequent obstacle detection process.

[0161] In addition, in the sensor network system 1 of this embodiment, the obstacle notification means is composed of a display control unit 55 that displays an obstacle monitoring image 60 in which sensor objects So corresponding to sensor devices 10 on a two-dimensional plane that mimics the arrangement of the sensor devices 10 in the monitoring area 5 are connected by edges 61, and is configured to notify the presence of an obstacle 8 according to the display mode of the edges 61.

[0162] With this configuration, the sensor network system 1 of this embodiment can clearly and easily identify the area in which an obstacle 8 exists by, for example, changing the display mode of the edge 61 connecting adjacent sensor devices 10 when the presence of an obstacle 8 is detected to a display mode different from that when no obstacle 8 is present.

[0163] Furthermore, the obstacle detection method according to this embodiment is an obstacle detection method that uses a sensor network system 1 having the above-described configuration to detect an obstacle 8 that obstructs radio wave propagation and is present in the area between adjacent sensor devices 10 among a plurality of sensor devices 10 distributed in a monitoring area 5, and is characterized by including a signal source position estimation step (S7) that analyzes the estimated signal arrival direction results of all sensor devices 10 to estimate the position of the signal source 110, a clustering processing step (S8) that divides the path information Pt from the signal source 110 to each sensor device for the signal source 110 whose position is estimated in the signal source position estimation step into groups and links them to each sensor device 10, an obstacle detection step (S9) that compares the path information Pt between adjacent sensor devices 10 among all sensor devices 10 and detects the presence of an obstacle 8 in the area between the adjacent sensor devices 10 based on the comparison result of the path information Pt, and an obstacle notification step (S10) that notifies the presence of the obstacle 8 detected in the obstacle detection step by associating it with the area in which the presence of the obstacle 8 was detected.

[0164] With this configuration, by applying the obstacle detection method according to this embodiment to the sensor network system 1 having the above configuration, it is possible to simultaneously estimate the positions of multiple signal sources 110 by analyzing the directions of arrival of signals received by multiple sensor devices 10. Then, it is possible to discover obstacles 8 by performing a clustering process using the position estimation information of each signal source 110, and furthermore, by being notified of the obstacle 8, it is possible to easily grasp areas where radio waves are not propagating due to the obstacle 8. This makes it possible to limit currently available propagation paths and avoid invalid transmissions and receptions in advance, thereby enabling more efficient use of radio waves towards the realization of next-generation communication technology.

[0165] The above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Various modifications or applications of the elements disclosed in the above-described embodiments are possible within the technical scope of the present invention. [Industrial Applicability]

[0166] As described above, the present invention has the effect of making it possible to easily grasp areas where radio waves are not propagating due to obstacles, and to more efficiently grasp the wireless environment, which is useful for the development of next-generation communication technologies. It is also useful for sensor network systems in which multiple sensor devices are distributed, and for obstacle detection methods in general. [Explanation of symbols]

[0167] 1. Sensor network system 5. Monitoring area (prescribed area) 8 Obstacles 10, 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7 Radio wave condition monitoring device (sensor device) 11 Antenna device 12 Frequency conversion section 13 AD conversion section 14 Signal separation section 15 Direction of arrival estimation processing unit 16 Signal analysis section 17, 34 External interface (I / F) section 30 Control Unit 35 databases 36 Input section 37 Display section 40 Device control section 41 Monitoring condition setting unit (setting means) 42 Communication control section 43 Antenna control unit 50 Data control section 51 Data Management Department 52 Signal source position estimation unit (signal source position estimation means) 53 Clustering processing unit (clustering processing means) 53a Path information management table 54 Obstacle detection unit (obstacle detection means) 55 Display control unit (obstacle notification means) 60 Obstacle monitoring images 61 sides 62 Mesh 63 Sensor Network 110, 110-1, 110-2, 110-3, 110-4 signal source So Sensor Object Pt Path Information

Claims

1. a plurality of sensor devices (10) that are distributed and arranged so as to cover a predetermined area (5), and that estimate the direction of arrival of a signal arriving at each of the arranged positions; a signal source position estimation means (52) for estimating the position of a signal source (110) by analyzing the estimation results of the signal arrival directions of all the sensor devices; a clustering processing means (53) for performing a clustering process in which path information (Pt) from the signal source to each of the sensor devices is divided into groups and linked to each of the sensor devices, for the signal source whose position has been estimated by the signal source position estimation means; an obstacle detection means (54) for comparing the path information between adjacent sensor devices among all of the sensor devices and detecting the presence of an obstacle (8) that obstructs radio wave propagation in the area between the adjacent sensor devices based on the comparison result of the path information; an obstacle notification means (55) for notifying the presence of the obstacle detected by the obstacle detection means in association with the area in which the presence of the obstacle is detected; A sensor network system comprising:

2. The signal source position estimation means For all the sensor devices, calculate a straight line along the signal arrival direction estimated by the sensor device, and select the coordinates of the intersection of the straight lines as candidates for the position of the signal source; The sensor network system according to claim 1, characterized in that, of the intersections selected as candidates for the location of the signal source, an intersection at which a number of the lines intersect that exceeds a predetermined threshold is estimated as the location of the signal source.

3. The vehicle further includes a setting means (41) for setting an obstacle determination condition for determining the obstacle, The obstacle detection means 2. The sensor network system according to claim 1, wherein it is determined that the obstacle exists when the path information between the adjacent sensor devices satisfies the obstacle determination condition.

4. The setting means The sensor network system according to claim 3, characterized in that the obstacle determination condition is set to either a first obstacle determination condition that the path information between the adjacent sensor devices does not completely match, or a second obstacle determination condition that the path information between the adjacent sensor devices does not have any common parts.

5. 2. The sensor network system according to claim 1, further comprising a path information management table (53a) for managing the path information linked to each of the sensor devices by the clustering processing means.

6. the obstacle notification means is configured by a display control means (55) that displays an obstacle monitoring image (60) in which sensor objects (So) corresponding to the sensor devices on a two-dimensional plane that simulates the arrangement of the sensor devices in the predetermined area are connected by edges (61); 2. The sensor network system according to claim 1, wherein the presence of the obstacle is notified according to the display mode of the edge.

7. 10. An obstacle detection method for detecting an obstacle (8) that obstructs radio wave propagation and exists in an area between adjacent sensor devices among a plurality of sensor devices distributed in a predetermined area (5) using the sensor network system according to claim 1, a signal source position estimation step (S7) of estimating the position of a signal source (110) by analyzing the estimation results of the signal arrival directions of all the sensor devices; a clustering processing step (S8) of performing a clustering process for dividing path information (Pt) from the signal source to each of the sensor devices into groups and linking the path information (Pt) to each of the sensor devices for the signal source whose position has been estimated in the signal source position estimation step; an obstacle detection step (S9) of comparing the path information between adjacent sensor devices among all the sensor devices and detecting the presence of the obstacle in the area between the adjacent sensor devices based on the comparison result of the path information; an obstacle notification step (S10) of notifying the presence of the obstacle detected in the obstacle detection step in association with the area in which the presence of the obstacle was detected; 1. An obstacle detection method comprising:

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