KR20230077237A - Apparatus and method for detecting errors in IoT sensors - Google Patents

Abstract

A detection device is provided. The detection device may include: a collection unit that collects first observation data of a first module for observing the weather and observation data of other modules existing around the first module; an inspection unit that calculates an observation range of the first module using observation data of the other module; A detection unit configured to detect an error of the first module by comparing the observation range with the first observation data.

Description

IoT sensor error detection device and method {Apparatus and method for detecting errors in IoT sensors}

The present invention relates to a device and method for detecting or detecting errors and abnormalities of various measurement modules such as IoT sensors that measure weather conditions and the like.

With the popularization of IoT (Internet of Things) technology, various IoT devices that measure weather conditions are appearing. The corresponding devices can measure the weather environment and transmit the measured results to the server through the IoT-related communication network.

As the corresponding device can be installed not only by various organizations that want to observe the meteorological environment, but also by individuals, if the installation of these devices is accelerated, an environment capable of measuring the meteorological environment in every corner can be prepared. However, in order to prevent damage due to the measurement result of a specific device with low reliability, it is necessary to filter out devices with problems in measurement accuracy.

Korean Registered Patent Publication No. 2169452 discloses that meteorological data collected through IoT sensors is not good for data analysis and utilization when it is necessary to create alternative data due to equipment and network failures and communication failures, or because errors are recorded in the collected data. When it affects, a technology to solve it is being disclosed.

Korean Registered Patent Publication No. 2169452

The present invention is to provide a detection device and method for identifying errors and abnormalities of various measurement modules such as IoT sensors that measure weather conditions and the like.

The detection device of the present invention includes a collection unit for collecting first observation data of a first module for observing weather and observation data of other modules existing around the first module; an inspection unit that calculates an observation range of the first module using observation data of the other module; A detection unit configured to detect an error of the first module by comparing the observation range with the first observation data.

The detection method of the present invention includes a collection step of collecting first observation data of a first module for observing weather and observation data of other modules existing around the first module; an inspection step of calculating an observation range of the first module using observation data of the other module; and a detection step of detecting an error of the first module through comparison of the observation range and the first observation data.

The detection device of the present invention can detect an observation device that outputs an error value or an outlier value that is distinguished from other observation devices. The corresponding detection result can be used in various systems that determine the meteorological environment by collecting data from various observation devices.

According to the present invention, it is possible to extract an observation device with high accuracy in a situation where a number of meteorological environment observation devices are appearing due to the development of IoT technology, and to monitor the meteorological environment using the data of the device. In other words, according to the present invention, it is possible to provide a basis for normally utilizing rapidly increasing observation devices based on IoT technology.

The detection device of the present invention can test each of a plurality of observation devices (modules). As a result of the test, the detection device may detect that an error exists in an observation device that exhibits an observation tendency different from that of other nearby devices or that exhibits an observation tendency that is different from that of the surrounding reference device.

The error may be an error of the observation instrument or may be due to an actual meteorological anomaly local to the area. This can be judged in the post-processing device, and based on the judgment result, whether the corresponding observation device is normal can be determined. Observation devices determined to be normal through normality determination may form one of a plurality of nodes forming a weather environment observation network.

1 is a schematic diagram showing a detection device of the present invention.
2 is a schematic diagram showing the operation of the collection unit.
3 is a schematic diagram showing the operation of the inspection unit.
4 is a chart showing the ratio of the number of second modules for each radius of the first module.
5 is a chart showing the accumulation of the number of second modules for each radius of the first module.
6 is a flowchart showing the detection method of the present invention.
7 is a diagram illustrating a computing device according to an embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, the present invention may be embodied in many different forms and is not limited to the embodiments described herein. And in order to clearly explain the present invention in the drawings, parts irrelevant to the description are omitted, and similar reference numerals are attached to similar parts throughout the specification.

In this specification, redundant descriptions of the same components are omitted.

In addition, in this specification, when a component is referred to as being 'connected' or 'connected' to another component, it may be directly connected or connected to the other component, but another component in the middle It should be understood that may exist. On the other hand, in this specification, when a component is referred to as 'directly connected' or 'directly connected' to another component, it should be understood that no other component exists in the middle.

In addition, terms used in this specification are only used to describe specific embodiments and are not intended to limit the present invention.

Also, in this specification, a singular expression may include a plurality of expressions unless the context clearly indicates otherwise.

In addition, in this specification, terms such as 'include' or 'having' are only intended to designate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more It should be understood that the presence or addition of other features, numbers, steps, operations, components, parts, or combinations thereof is not precluded.

Also in this specification, the term 'and/or' includes a combination of a plurality of listed items or any item among a plurality of listed items. In this specification, 'A or B' may include 'A', 'B', or 'both A and B'.

Also, in this specification, detailed descriptions of well-known functions and configurations that may obscure the subject matter of the present invention will be omitted.

Fine dust exists in the air, moves along with the flow of air, and is locally created and destroyed. If the air flow is smooth, the spatial distribution of fine dust will take a gentle shape without large fluctuations.

Therefore, by collecting the fine dust data of spatially close observatories and comparing their distributions, it is possible to select an observatories showing a different distribution from neighboring observatories. In addition, additional analysis may be performed later by determining the value as an error value according to the degree of deviation from the distribution and correcting the value, or determining as a local phenomenon and an outlier value requiring additional analysis.

Spatiality checks for modules such as sensors corresponding to observation devices that measure weather conditions may be to determine whether each module has a measurement result that is different from that of other adjacent modules.

Spatiality test is performed in two ways, one is the independent spatiality test of the data of the data generating agency, and the other is the integrated spatiality test of the data of a plurality of data generating agencies. Intra-institutional spatiality inspection may be to derive inspection results by calculating a reference range using only observation station data of each institution operating the observation network.

The self-spatiality inspection of the data of the data generating institution may be performed by the first inspection unit 131 of the detection device. The data creation agency data integration spatiality inspection may be performed by the first inspection unit 131 and the second inspection unit 132 of the detection device.

1 is a schematic diagram showing a detection device of the present invention.

The detection device shown in FIG. 1 may include a collection unit 110, a test unit 130, and a detection unit 150.

The collecting unit 110 may collect first observation data of a first module that observes the weather and observation data of other modules existing around the first module.

The first module may be one of a plurality of modules for weather observation. The modules described in this specification (including the first module, the second module, and the reference module) measure meteorological information such as fine dust, temperature, humidity, daily bridge, rainfall, and snowfall, or measure environmental information such as vibration, earthquake, and electric current. It may include various sensors for measuring. In other words, 'weather' described in this specification may mean meteorological information such as fine dust, temperature, humidity, daily bridge amount, rainfall, and snowfall, and environmental information such as vibration, earthquake, and electric current.

In addition, the module may be provided with a wired or wireless first communication means capable of communicating with the collection unit 110 . Correspondingly, a second communication means for communicating with the corresponding first communication means may be provided in the collecting unit 110 as well.

For IoT (Internet of Things), a first communication means capable of low power wide area (LPWA) communication such as WiFi, Bluetooth, etc., and LoRa (Long Range) is available for each module can be provided in The second communication unit of the collection unit 110 may directly communicate with each module or communicate with a relay unit communicating with each module through a communication network such as a local area wireless network, a low-power long-distance communication network, or a wired network.

The collection unit 110 may collect observation data including various weather information from each module using the second communication means.

The inspection unit 130 may calculate the permitted observation range of the first module using observation data of other modules.

The detection unit 150 may detect an error of the first module by comparing the permitted observation range with the first observation data.

Other observation data that is a source for generating the observation range of the first module may be a result of observation through a module other than the first module (excluding the first module). It may be realistically contradictory that the observation range of the first module present at a specific location is determined by another module present at a location on the other side of the globe, for example. Therefore, it is preferable that observation data for generating an observation range of the first module be collected for other modules existing around the first module.

At this time, a problem may arise as to how far to set the range around the first module. This will be described later.

2 is a schematic diagram showing the operation of the collection unit 110.

The collecting unit 110 may collect second observation data from a plurality of second modules a existing within a first set distance from the first module t.

The collection unit 110 may collect third observation data from the reference module o existing within a second set distance from the first module.

In FIG. 2, two concentric circles centered on the first module t to be detected are drawn. In this case, the inner circle (red circle) may mean the first set distance (radius). An outer circle (blue circle) may mean a second set distance (radius). The first set distance and the second set distance may be set differently as shown in the drawing, but may be set equal to each other depending on circumstances.

A first inspection unit 131 and a second inspection unit 132 may be provided in the inspection unit 130 .

The first inspection unit 131 may calculate the first allowable range of the first module t using the plurality of second observation data collected from the plurality of second modules a. The second observation data used by the first inspection unit 131 to calculate the first allowable range may be collected from all second modules existing within the first set distance. Alternatively, the second observation data used by the first inspection unit 131 to calculate the first allowable range is a set number, for example, according to an order close to the first module among a plurality of second modules existing within the first set distance. It may be collected from nine second modules.

The second inspection unit 132 may calculate the second allowable range of the first module t using the third observation data. The reference module o generating the third observation data may correspond to an expensive module with high accuracy of observation data and a module continuously managed by a manager. For example, the reference module o may include a module installed by an authorized institution such as the Korea Meteorological Administration.

The detection unit 150 may output an alarm signal when the observation data is out of any one of the first allowable range and the second allowable range. The alarm signal may indicate an abnormality of the corresponding first module t. Alternatively, the alarm signal may mean a meteorological abnormality in the region where the corresponding first module t is disposed. What the alarm signal means can be signaled by a post-processing device provided at a rear end of the detection device. A detection result of the detection unit may be provided to a post-processing device.

3 is a schematic diagram showing the operation of the inspection unit 130.

3 shows first observation data collected from the first module, a set number that satisfies the first set distance and is close to the first module, for example, nine second observation data collected from module a, nine second Observational data collected from the reference module o, which is separate from the module, is tabulated.

The second module a and the reference module o can be clearly distinguished. For example, even if a reference module is included among modules included within the first set distance and the reference module is closest to the first module, the reference module may be excluded from the second module serving as a source for calculating the first allowable range. . The criteria module can only be used to calculate the second acceptable range. Similarly, the second module, which is distinguished from the reference module, is used only for calculating the first tolerance range and may be excluded from the calculation process of the second tolerance range.

As shown in FIG. 3 , the first allowable range may have additional upper and lower ranges based on a plurality of second observation data. The upper and lower ranges at a specific time point may include a range having a maximum value max and a minimum value min. The second observation data may be located between the maximum value max and the minimum value min. The second allowable range may also have additional upper and lower ranges based on the third observation data. It is recalled that the second allowable range is not separately shown in FIG. 3 .

According to the detection device of the present invention, an alarm signal is not generated simply because the first observation data of the first module t is different from the second observation data or the third observation data. Instead, an alarm signal is generated when the first observation data is outside the first tolerance range in which the upper and lower ranges are added based on the second observation data, or the upper and lower ranges are added based on the third observation data. It can be. In FIG. 3 , a value e outside the first allowable range among the first observation data may be identified as an error.

When the detection of the specific first module is completed, the collection unit 110 selects one of the other modules (including the second module) as the first module again, and first observes the first module based on the newly selected first module. Data, second observation data, and third observation data may be collected.

A first set distance, a second set distance, a first allowable range, and a second allowable range necessary for the inspection unit 130 to function normally will be described in detail.

The detection unit 150 may output an alarm signal when the first observation data is out of the first allowable range.

In this case, the collection unit 110 may set a minimum distance in which a specific module equal to or greater than a set ratio includes other modules of a set number among a plurality of modules for observing the weather as the first set distance.

4 is a chart showing the ratio of the number of second modules for each radius of the first module. 5 is a chart showing the accumulation of the number of second modules for each radius of the first module.

For example, the number of set ratios may be 99% and the number of sets may be 9.

If the set ratio number is 99%, it may mean 198 when the total number of modules present in the target area is 200.

In this case, when each of 198 modules out of a total of 200 is set as the first module, the minimum distance (radius) at which at least 9 second modules can be selected based on the first module is set as the first set distance. can

When the module distribution is as shown in FIGS. 4 and 5, 2 km may be set as the first set distance. In other words, if 2 km is selected as the first set distance, even if any one of 198 modules corresponding to the number of 99% ratio is selected as the first module, at least 9 second modules may exist within the first set distance. There may be more than nine second modules within the first set distance. In this case, the first allowable range may be calculated using second observation data of more than nine second modules. However, as the number of comparison objects increases, the amount of calculation increases and exception processing becomes complicated, so it may be difficult to determine the first allowable range.

Meanwhile, it is preferable that the minimum distance is determined within the first threshold distance.

If the setting ratio, eg 99%, and the setting number, eg 9, are maintained, the first set distance may become unreasonably long. Setting the first allowable range of the first module using the observation data of the second module that is too far away goes against the logic, and may be far from verifying the accuracy of the first module in reality. Therefore, it is preferable that the minimum distance for determining the first set distance is determined within a range that satisfies the first threshold distance set in advance.

When a situation occurs in which the minimum distance exceeds the first threshold distance under conditions of the set ratio and the set number, the collection unit 110 may lower at least one of the set ratio and the set number so that the minimum distance is within the first threshold distance. . Preferably, the collection unit 110 may lower the set number among the set ratio and the set number.

When the setting ratio is lowered, the number of modules for which error detection by the detection device is not performed may increase. According to this, the inconvenience of having to additionally check whether or not error detection is performed for the corresponding module may increase. Therefore, it is recommended that the set ratio be maintained above the set value. In this case, the user can deal with each module, recognizing that error detection has been performed without much concern. This is because there is no problem as long as only a few modules for which error detection has not been performed are recognized.

The collection unit 110 may lower the set ratio only when a situation occurs in which the minimum distance exceeds the first threshold distance despite lowering the set number to four. The reason why the set number is limited to 4 or more is that a standard deviation is used to calculate the first allowable range. In order for the standard deviation to have meaning, it is preferable that the number of second modules is 4 or more.

The first inspection unit 131 may calculate a first median value by using a plurality of second observation data collected from a plurality of second modules. The second inspection unit 132 may calculate the first allowable range by adding upper and lower ranges based on the first intermediate value.

In this case, the first inspection unit 131 may additionally calculate a first standard deviation by using a plurality of second observation data. The first inspection unit 131 may set the upper and lower ranges by using at least one of a function proportional to the first median value and a function proportional to the first standard deviation.

For example, the first inspection unit 131 may calculate an upper and lower range or a first allowable range according to Equation 1 using a first median value, a first standard deviation, and a first constant.

...수학식 1

...Equation 1

Here, median is a first intermediate value, and may be a criterion for an upper and lower range or a first allowable range.

f(median) may be a function that increases as the first median value increases.

stdev can be standard deviation.

g(stdev) may be a function that increases with increasing standard deviation.

c in Equation 1 may be a first constant.

부분이 상하 범위에 해당될 수 있다. 제1 검사부(131)는 제1 중간값을 기준으로 상하 범위를 추가하여 제1 허용 범위를 산정할 수 있다.The functions f (median), g (stdev), and the first constant c may be set differently according to the criteria for determining the error value and the criterion for determining the abnormal value requiring additional analysis. Equation 1 shows the first allowable range, and in Equation 1

The part may correspond to the upper and lower ranges. The first inspection unit 131 may calculate the first allowable range by adding the upper and lower ranges based on the first intermediate value.

The detection unit 150 may generate and output an alarm signal when the value of the first observation data is out of the first allowable range. The first observation data and the first allowable range may be physical quantities of the same type and unit. As an example, FIG. 3 targets concentrations of fine dust over time.

Let's take a look at the second allowable range. When the third observation data is collected by the collection unit 110, the second inspection unit 132 may calculate the second allowable range of the first module using the corresponding third observation data. The detection unit 150 may output an alarm signal when the first observation data is out of the second allowable range.

At this time, the collection unit 110 may set a second set distance within the second threshold distance. Like the second module, if the second reference module is too far from the first module, it loses its meaning as data for determining whether the first module is normal. Therefore, it is advantageous that the second set distance is determined within the second threshold distance, and if there is no reference module within the second threshold distance, it may be reasonable to detect an error in the first module using only the first allowable range. Of course, in this case, there must be a second module that satisfies both the set ratio and the set number within the first threshold distance. The first threshold distance and the second threshold distance may be different from or the same as each other.

Conversely, if there is no second module that satisfies both the set ratio and the set number within the first threshold distance and the reference module exists within the second threshold distance, it is reasonable to detect the error of the first module using only the second allowable range. can do.

If a plurality of reference modules o exist within the second set distance, the collecting unit 110 may collect third observation data from a specific reference module closest to it while excluding other reference modules. In other words, if the second allowable range is a estimable environment, the second allowable range may have third observation data collected from only one reference module as a source.

The second inspection unit 132 may calculate the second allowable range by adding the upper and lower ranges based on the third observation data.

As shown in Equation 2, the second inspection unit 132 may calculate the upper and lower ranges using a function proportional to the third observation data and a second constant.

...수학식 2

...Equation 2

Here, Y may be third observation data.

f(Y) may be a function that increases as the third observation data increases.

c in Equation 2 may be a second constant.

부분이 상하 범위에 해당될 수 있다. 제2 검사부(132)는 제3 관측 데이터 Y를 기준으로 상하 범위를 추가하여 제2 허용 범위를 산정할 수 있다.The function f(Y) and the second constant c may be set differently according to the criterion for determining an error value and the criterion for determining an outlier requiring additional analysis. Equation 2 shows the second allowable range, and in Equation 2

The part may correspond to the upper and lower ranges. The second inspection unit 132 may calculate the second allowable range by adding the upper and lower ranges based on the third observation data Y.

The detection unit 150 may generate and output an alarm signal when the value of the first observation data is out of the second allowable range. The first observation data and the second allowable range may be physical quantities of the same type and unit.

6 is a flowchart showing the detection method of the present invention.

The detection method of FIG. 6 may be performed by the detection device shown in FIG. 1 .

The detection method may include a collection step (S 510), an inspection step (S 520), and a detection step (S 530).

In the collecting step ( S510 ), first observation data of a first module that observes weather and observation data of other modules existing around the first module may be collected. The collecting step (S510) may be performed by the collecting unit 110.

In the inspection step (S520), the observation range of the first module may be calculated using observation data of other modules. The inspection step (S520) may be performed by the inspection unit 130. The inspection unit 130 may include at least one of the first inspection unit 131 and the second inspection unit 132 .

In the detection step ( S530 ), an error of the first module may be detected by comparing the permitted observation range with the first observation data. The detection step (S530) may be performed by the detection unit 150. The observation tolerance range may include at least one of the first tolerance range and the second tolerance range.

The inspection step (S520) may include a first inspection step and a second inspection step.

In the first inspection step, a first allowable range of the first module may be calculated using a plurality of second observation data collected from a plurality of second modules existing within a first set distance from the first module.

The second inspection step may include a second inspection step of calculating a second allowable range of the first module using third observation data collected from a reference module existing within a second set distance from the first module.

In the detecting step, an alarm signal may be output when the observation data is out of any one of the first allowable range and the second allowable range.

7 is a diagram illustrating a computing device according to an embodiment of the present invention. The computing device TN100 of FIG. 7 may be a device (eg, a detection device, etc.) described in this specification.

In the embodiment of FIG. 7 , the computing device TN100 may include at least one processor TN110, a transceiver TN120, and a memory TN130. In addition, the computing device TN100 may further include a storage device TN140, an input interface device TN150, and an output interface device TN160. Elements included in the computing device TN100 may communicate with each other by being connected by a bus TN170.

The processor TN110 may execute program commands stored in at least one of the memory TN130 and the storage device TN140. The processor TN110 may mean a central processing unit (CPU), a graphics processing unit (GPU), or a dedicated processor on which methods according to embodiments of the present invention are performed. Processor TN110 may be configured to implement procedures, functions, methods, and the like described in relation to embodiments of the present invention. The processor TN110 may control each component of the computing device TN100.

Each of the memory TN130 and the storage device TN140 may store various information related to the operation of the processor TN110. Each of the memory TN130 and the storage device TN140 may include at least one of a volatile storage medium and a non-volatile storage medium. For example, the memory TN130 may include at least one of read only memory (ROM) and random access memory (RAM).

The transmitting/receiving device TN120 may transmit or receive a wired signal or a wireless signal. The transmitting/receiving device TN120 may perform communication by being connected to a network.

Meanwhile, the embodiments of the present invention are not implemented only through the devices and/or methods described so far, and may be implemented through a program that realizes functions corresponding to the configuration of the embodiments of the present invention or a recording medium in which the program is recorded. And, such implementation can be easily implemented by those skilled in the art from the description of the above-described embodiment.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also provided. belong to the scope of the invention.

110 ... Collection unit 130 ... Inspection unit
131 ... first inspection unit 132 ... second inspection unit
150 ... detection department

Claims (15)

a collection unit that collects first observation data of a first module that observes the weather and observation data of other modules existing around the first module;
an inspection unit that calculates an observation range of the first module using observation data of the other module;
a detector configured to detect an error of the first module by comparing the observation range with the first observation data;
Detection device comprising a.
According to claim 1,
The collecting unit collects second observation data from a plurality of second modules existing within a first set distance from the first module,
The collecting unit collects third observation data from a reference module existing within a second set distance from the first module,
A first inspection unit is provided that calculates a first allowable range of the first module using a plurality of second observation data collected from a plurality of second modules,
A second inspection unit for calculating a second allowable range of the first module using the third observation data is provided;
The detection unit outputs an alarm signal when the observation data is out of any one of the first allowable range and the second allowable range.
According to claim 1,
The collecting unit collects second observation data from a plurality of second modules existing within a first set distance from the first module,
A first inspection unit is provided that calculates a first allowable range of the first module using a plurality of second observation data collected from a plurality of second modules,
The detection unit outputs an alarm signal when the first observation data is out of the first allowable range.
According to claim 3,
The detection device of claim 1 , wherein the collection unit sets, as the first set distance, a minimum distance in which a specific module having a set ratio or more among a plurality of modules for observing the weather includes a set number of other modules.
According to claim 3,
The minimum distance is determined within a first threshold distance,
The collection unit, when a situation occurs in which the minimum distance exceeds the first threshold distance under conditions of the set ratio and the set number, at least one of the set ratio and the set number is such that the minimum distance is within the first threshold distance. A detection device that lowers one.
According to claim 3,
Wherein the collection unit lowers the set number among the set ratio and the set number when a situation occurs in which the minimum distance exceeds a first threshold distance under conditions of the set ratio and the set number.
According to claim 6,
The detection device of claim 1 , wherein the collection unit lowers the set ratio only when a situation occurs in which the minimum distance exceeds a first threshold distance even though the set number is lowered to four.
According to claim 3,
The first inspection unit calculates a first median using a plurality of second observation data collected from a plurality of second modules,
The detection device of claim 1 , wherein the second inspection unit calculates the first allowable range by adding an upper and lower range based on the first intermediate value.
According to claim 8,
The first inspection unit additionally calculates a first standard deviation using a plurality of the second observation data,
wherein the first inspection unit sets the upper and lower ranges by using at least one of a function proportional to the first intermediate value and a function proportional to the standard deviation.
According to claim 3,
The first inspection unit calculates a first median and a first standard deviation using a plurality of second observation data collected from a plurality of second modules,
The first inspection unit selects an upper and lower range using the first median value, the first standard deviation, and the first constant;
The detection device of claim 1 , wherein the first inspection unit calculates the first allowable range by adding the upper and lower ranges based on the first intermediate value.
According to claim 1,
The collecting unit collects third observation data from a reference module existing within a second set distance from the first module,
A second inspection unit for calculating a second allowable range of the first module using the third observation data is provided;
The detection unit outputs an alarm signal when the first observation data is out of the second allowable range.
According to claim 11,
Wherein the collection unit sets the second set distance within a second threshold distance.
According to claim 11,
If a plurality of reference modules exist within the second set distance, the collection unit excludes other reference modules and collects the third observation data from the closest specific reference module.
According to claim 11,
The second inspection unit calculates the second allowable range by adding an upper and lower range based on the third observation data,
The second inspection unit calculates the upper and lower ranges using a function proportional to the third observation data and a second constant.
In the detection method performed by the detection device,
a collection step of collecting first observation data of a first module that observes the weather and observation data of other modules existing around the first module;
an inspection step of calculating an observation range of the first module using observation data of the other module;
A detection step of detecting an error of the first module through comparison of the observation allowed range and the first observation data;
In the inspection step,
A first inspection step of calculating a first allowable range of the first module using a plurality of second observation data collected from a plurality of second modules existing within a first set distance from the first module;
A second inspection step of calculating a second allowable range of the first module using third observation data collected from a reference module existing within a second set distance from the first module,
Wherein the detecting step outputs an alarm signal when the observation data is out of any one of the first allowable range and the second allowable range.

Images