Magnetic sensor arrangement method, sensing system, and determination device

Abstract

The objective is to provide a technology that can accurately determine the presence or absence of an object. [Solution] The magnetic sensor placement method involves placing a magnetic sensor for measuring the magnetic field in at least one of the first region and the second region. The first region is a region on the ground surface or underground corresponding to the first frame portion or the area around the first frame portion on the magnetic north side of the object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped. The second region is a region on the ground surface or underground corresponding to the second frame portion or the area around the second frame portion on the magnetic south side, which is in the opposite direction to the magnetic north side of the object stopping frame.

Description

Technical Field

[0001] The present disclosure relates to a magnetic sensor arrangement method, a sensing system, and a determination device.

Background Art

[0002] In a parking lot management system, a technique (see, for example, Patent Document 1) has been proposed in which a magnetic sensor is arranged at the center of a parking space, which is a frame-shaped mark indicating the position where a vehicle should be stopped. In this technique, the magnetic sensor can determine the presence or absence of a vehicle in the parking space by detecting a magnetic field (magnetic field) that changes according to the presence or absence of a vehicle directly above the magnetic sensor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the prior art, a magnetic sensor detects a magnetic field (magnetic field) that changes due to a hard magnetic material contained in an engine and an inverter of a vehicle. However, since the size of the hard magnetic material is small, there is a problem that even if a vehicle is present in the parking space, if the hard magnetic material is not directly above the magnetic sensor, an incorrect determination may be made that there is no vehicle in the object stop frame such as the parking space. Therefore, in the technique described in Patent Document 1, in the process of a vehicle entering a parking space, in order to measure the change in the magnetic field when the engine or the like is located directly above the magnetic sensor, the magnetic field must be measured at a high frequency, resulting in new problems such as an increase in the data to be handled and the power consumption.

[0005] Therefore, the present disclosure has been made in view of the above problems, and an object thereof is to provide a technique capable of accurately determining the presence or absence of an object such as a vehicle. [Means for solving the problem]

[0006] The magnetic sensor placement method according to this disclosure involves placing a magnetic sensor for measuring a magnetic field in at least one of the following: a first frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped, or a first region on the ground surface or underground corresponding to the area around the first frame portion; and a second frame portion on the magnetic south side of the object stopping frame, which is opposite to the magnetic north side, or an area around the second frame portion. [Effects of the Invention]

[0007] According to this disclosure, since the magnetic sensor is positioned in at least one of the first region on the magnetic north side of the object stopping frame and the second region on the magnetic south side opposite to the magnetic north side of the object stopping frame, the presence or absence of an object can be determined with high accuracy. [Brief explanation of the drawing]

[0008] [Figure 1] This diagram shows the Earth's magnetic field when no soft magnetic materials are present. [Figure 2] This diagram shows the magnetic field generated by the Earth's magnetic field when an object containing soft magnetic material is present. [Figure 3] This diagram schematically shows the configuration of the sensing system according to Embodiment 1. [Figure 4] This is a top view showing the arrangement of the magnetic sensor according to Embodiment 1. [Figure 5] This is a side view showing the arrangement of the magnetic sensor according to Embodiment 1. [Figure 6] This is a top view showing the arrangement of the magnetic sensor according to Embodiment 1. [Figure 7] This is a top view showing the arrangement of the magnetic sensor according to Embodiment 1. [Figure 8] This diagram schematically shows the configuration of the sensing system according to Embodiment 2. [Figure 9] This is a side view showing the arrangement of the magnetic sensor according to Embodiment 2. [Figure 10] This diagram schematically shows the configuration of the sensing system according to Embodiment 3. [Figure 11] This diagram schematically shows the configuration of the determination device relating to a modified example. [Modes for carrying out the invention]

[0009] Figure 1 shows the geomagnetic field 2 when object 1, which contains a soft magnetic material with high permeability as shown in Figure 2, is not present. The direction of arrival of the geomagnetic field 2 (hereinafter sometimes referred to as the "geomagnetic direction") has an inclination relative to the Earth's surface in Japan, and the magnetic field strength of the geomagnetic field 2 is uniform over a fairly large area, regardless of whether it is in the air, on the Earth's surface, or underground. The direction in which the direction of arrival of the geomagnetic field 2 is projected onto the Earth's surface corresponds to the magnetic north direction.

[0010] Figure 2 shows the magnetic field generated when the Earth's magnetic field 2 is affected by object 1, which contains a soft magnetic material with high magnetic permeability. The values ​​+30μT and -30μT in Figure 2 indicate the magnetic field strength corresponding to the magnetic field strength of the Earth's magnetic field 2.

[0011] When object 1 contains a soft magnetic material, the geomagnetic field 2 arriving with an inclination is affected by the magnetic concentration characteristic of the soft magnetic material, as shown by the dashed arrow. As a result, the magnetic flux is strongly concentrated at the starting end 1A on the side where the geomagnetic field 2 is incident on object 1, and at the ending end 1B on object 1, which is located opposite the starting end 1A in the direction of arrival of the geomagnetic field 2, resulting in a magnetic field stronger than the geomagnetic field 2. On the other hand, at the ends 1C and 1D in the intermediate portion between the starting end 1A and the ending end 1B of object 1, the magnetic flux is dispersed, resulting in a magnetic field weaker than the geomagnetic field 2. Furthermore, as you move away from the starting end 1A, the ending end 1B, and the ends 1C and 1D, the magnetic field strength approaches the magnetic field strength of the geomagnetic field 2.

[0012] As a result, the magnetic field strength in the region on the magnetic north side of object 1, either on the surface or underground, i.e., the region on the terminal 1B side, is stronger than the strength of the geomagnetic field 2. On the other hand, the magnetic field strength in the region on the magnetic south side of object 1, either on the surface or underground, i.e., the region on the end 1C side, is weaker than the strength of the geomagnetic field 2. Thus, when object 1 is within range 3 in Figure 2, the magnetic field strengths in the regions on the terminal 1B side and end 1C side change from the magnetic field strengths of the geomagnetic field 2 in the regions on the terminal 1B side and end 1C side, respectively, when object 1 is not within range 3.

[0013] Therefore, by placing a magnetic sensor in at least one of the regions on the terminal 1B side and the end 1C side, the presence or absence of object 1 within range 3 can be determined based on the magnetic field measured by the magnetic sensor. In this specification, for example, at least one of A, B, C, ..., and Z means any one of all combinations obtained by selecting one or more from the groups A, B, C, ..., and Z. The sensing system and sensing device described below are configured to determine the presence or absence of object 1 using the above principle.

[0014] <Embodiment 1> Figure 3 is a schematic diagram showing the configuration of the sensing system according to this embodiment 1. In the following, we will describe an example in which object 1 is an automobile 6 containing a soft magnetic material such as iron in its body and frame, and object stopping frame is a parking space 7 which is a frame-shaped marker indicating the position where the automobile 6 should be stopped. In other words, we will describe an example in which the sensing system determines the presence or absence of an automobile 6 within the parking space 7. Note that object 1 and object stopping frame are not limited to an automobile 6 and parking space 7, respectively. Object 1 may be, for example, an airplane containing a soft magnetic material in its body and frame, and object stopping frame may be, for example, a frame-shaped marker indicating the position where an airplane should be stopped.

[0015] The sensing system of FIG. 3 includes a sensing device 11 and a determination device 12. The sensing device 11 includes a magnetic sensor 11a and a first communication device 11b, and the determination device 12 includes a second communication device 12a including a receiving unit and a determination processing unit 12b.

[0016] The magnetic sensor 11a measures a magnetic field. FIGS. 4 and 5 are a top view and a side view showing in detail the arrangement of the sensing device 11 including the magnetic sensor 11a according to Embodiment 1. Since the sensing device 11 is schematically illustrated in FIG. 3, the size of the sensing device 11 is illustrated as being relatively large, but as shown in FIG. 4, the actual size of the sensing device 11 is relatively small.

[0017] The sensing device 11 including the magnetic sensor 11a is disposed in a first region 7a on the ground surface or underground corresponding to the first frame portion on the magnetic north side or the periphery of the first frame portion in FIGS. 4 and 5 among the frame portions of the parking space 7. The first region 7a may be a region on the ground surface or underground at the first frame portion on the magnetic north side of the parking space 7, or may be a region on the ground surface or underground around (outside or inside) the first frame portion. Further, by disposing the sensing device 11 at the central portion in the direction perpendicular to the arrival direction of the geomagnetism 2 in the first region 7a, the influence of the magnetic field variation due to the parking position of the automobile 6 can be reduced.

[0018] Preferably, a region where a change in the magnetic field corresponding to the presence or absence of the automobile 6 in the parking space 7 described later can be read by actual measurement of the magnetic field by the magnetic sensor 11a is applied to the first region 7a.

[0019] When the automobile 6 is present in the parking space 7, the positional relationship between the automobile 6 in FIG. 5 and the first region 7a is the same as the positional relationship between the object 1 in FIG. 2 and the region on the terminal 1B side. For this reason, the geomagnetism 2 whose arrival direction has a dip angle with respect to the ground plane is affected by the soft magnetic automobile 6, and the magnetic field intensity of the first region 7a on the ground surface or underground corresponding to the first frame portion on the magnetic north side of the parking space 7 or the periphery of the first frame portion becomes stronger than the intensity of the geomagnetism 2.

[0020] On the other hand, if the car 6 is not present in the parking space 7, the magnetic field strength of the first frame portion on the magnetic north side of the parking space 7, or the first region 7a on the ground surface or underground corresponding to the area around the first frame portion, will be the same as the strength of the Earth's magnetic field 2. From the above, the magnetic field measured by the magnetic sensor 11a placed in the first region 7a will change depending on whether or not the car 6 is present in the parking space 7.

[0021] It should be noted that the positional relationship between the direction of arrival of the geomagnetic field 2 and the parking space 7 is not limited to the positional relationship between the magnetic north direction and the parking space 7 shown in Figure 4. For example, if the positional relationship between the direction of arrival of the geomagnetic field 2 and the parking space 7 is the positional relationship between the magnetic north direction and the parking space 7 shown in Figures 6 and 7, then the first region 7a will be the area on the ground surface or underground corresponding to the first frame portion on the magnetic north side of the parking space 7's frame or the area surrounding the first frame portion.

[0022] The first communication device 11b of the sensing device 11 in Figure 3 transmits magnetic data indicating the magnetic field measured by the magnetic sensor 11a. The second communication device 12a of the determination device 12 receives the magnetic data transmitted from the first communication device 11b. Communication between the first communication device 11b and the second communication device 12a may be via wired communication or wireless communication.

[0023] The determination processing unit 12b may be implemented by the cooperation of hardware such as a CPU (Central Processing Unit) and memory (not shown) and software such as a control program, or it may be implemented by dedicated hardware such as a processing circuit. The determination processing unit 12b determines the presence or absence of a car 6 in the parking space 7 based on the magnetic data received by the second communication device 12a. The determination device 12 outputs the presence or absence of a car 6 in each parking space 7 determined by the second communication device 12a to an output unit such as a display unit (not shown), so that the user can confirm the presence or absence of a car 6 in each parking space 7.

[0024] For example, the determination processing unit 12b determines whether or not there is a car 6 in the parking space 7 based on the result of comparing the magnetic field indicated by the magnetic data with a predetermined threshold value that is greater than the strength of the Earth's magnetic field 2. Specifically, the determination processing unit 12b determines that a car 6 is present in the parking space 7 if the strength of the magnetic field indicated by the magnetic data is equal to or greater than the threshold, and determines that a car 6 is not present in the parking space 7 if the strength of the magnetic field indicated by the magnetic data is less than the threshold.

[0025] Furthermore, the determination of whether or not a car 6 is present in a parking space 7 is not limited to the above determination. For example, the determination processing unit 12b may calculate the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present, and determine whether or not a car 6 is present in a parking space 7 based on the result of comparing that difference with a predetermined threshold. Specifically, the determination processing unit 12b may determine that a car 6 is present in a parking space 7 if the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present is greater than or equal to the threshold, and determine that a car 6 is not present in a parking space 7 if the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present is less than the threshold.

[0026] Furthermore, for example, the determination processing unit 12b may determine the presence or absence of a car 6 in the parking space 7 based on the comparison result between the sequentially measured magnetic field differences indicated by the sequentially received magnetic data and a predetermined threshold. Specifically, the determination processing unit 12b may determine that a car 6 is present in the parking space 7 (changed from not present to present) if the difference between the magnetic field strength at the previous time and the magnetic field strength at the current time is greater than or equal to a threshold in the positive direction, and that a car 6 is not present in the parking space 7 (changed from present to not present) if the difference is greater than or equal to a threshold in the negative direction, and that the presence or absence of a car 6 in the parking space 7 has not changed since the previous time if the difference is less than or equal to a threshold in either the positive or negative direction.

[0027] The threshold value used in the determination processing unit 12b may be the default value, or it may be appropriately changed based on the strength of the magnetic field measured by the magnetic sensor 11a when the car 6 is not in the parking space 7.

[0028] <Summary of Embodiment 1> In conventional technology, a magnetic sensor was placed in the center of the parking space 7 to detect hard magnetic materials such as the engine.

[0029] In contrast, in this embodiment 1, the magnetic sensor 11a is positioned on the ground surface or in a first region 7a underground that corresponds to the first frame portion or the area surrounding the first frame portion on the magnetic north side of the parking space 7. On the other hand, the body and frame of an object 1 such as an automobile 6 are generally made of iron, which is a soft magnetic material. If the hard magnetic material and the soft magnetic material are the same size, the change in the magnetic field due to the soft magnetic material is smaller than the change in the magnetic field due to the hard magnetic material.

[0030] However, since the size of the body and frame made of soft magnetic material is larger than that of a hard magnetic material engine, the soft magnetic body and frame can change the magnetic field over a wider range and more stably than a hard magnetic material engine. For this reason, the sensing system according to this embodiment 1 can accurately determine the presence or absence of a car 6 in the parking space 7 based on the magnetic field measured by the magnetic sensor 11a in the first region 7a. Furthermore, it can suppress the misjudgment that occurred in conventional configurations for detecting hard magnetic materials when the orientation of the car 6 was repeatedly changed.

[0031] Furthermore, in this embodiment 1, the sensing device 11 including the magnetic sensor 11a is installed on the ground surface or underground, so that the movement of the automobile 6 is not obstructed by the sensing device 11. Also, the sensing device 11 including the magnetic sensor 11a is not installed in the center of the parking space 7, but in the first frame portion of the parking space 7 or in the first region 7a corresponding to the area around the first frame portion. For this reason, for example, when wireless communication is used between the first communication device 11b and the second communication device 12a, it is possible to prevent the wireless communication from being blocked by the automobile 6 located within the parking space 7.

[0032] Furthermore, multiple magnetic sensors 11a at different distances from the center of the parking space 7 may be provided in the first region 7a. In this case, if the first region 7a includes areas where small cars and areas where large cars are present, the presence or absence of a car 6 in the parking space 7 can be accurately determined regardless of whether the car 6 is a small car or a large car.

[0033] <Embodiment 2> Figure 8 is a schematic diagram showing the configuration of the sensing system according to this second embodiment, and Figure 9 is a detailed side view showing the arrangement of the sensing device 11 including the magnetic sensor 11a according to this second embodiment. Hereinafter, among the components of this second embodiment, components that are the same as or similar to the components described above will be denoted by the same or similar reference numerals, and the different components will be mainly described.

[0034] In Embodiment 1, as shown in Figure 5, the sensing device 11, including the magnetic sensor 11a, is positioned in the ground surface or underground in a first region 7a corresponding to the first frame portion or the area surrounding the first frame portion on the magnetic north side of the parking space 7. In Embodiment 2, as shown in Figure 9, the sensing device 11, including the magnetic sensor 11a, is positioned in the ground surface or underground in a second region 7b corresponding to the second frame portion or the area surrounding the second frame portion on the magnetic south side of the parking space 7. Except for this point and the determination by the determination processing unit 12b, the configuration of the sensing device 11 in the sensing system of Figure 8 is the same as the configuration of the sensing device 11 in the sensing system of Figure 3.

[0035] When the car 6 is in the parking space 7, the positional relationship between the car 6 and the second region 7b in Figure 9 is the same as the positional relationship between object 1 and the region on the end 1C side in Figure 2. As a result, the geomagnetic field 2, which has an inclination angle with respect to the ground plane in its direction of arrival, is affected by the soft magnetic material of the car 6. Consequently, the magnetic field strength of the second region 7b on the ground surface or underground, corresponding to the second frame portion or the area surrounding the second frame portion on the magnetic south side of the parking space 7, becomes weaker than the strength of the geomagnetic field 2.

[0036] On the other hand, if the car 6 is not present in the parking space 7, the magnetic field strength of the second region 7b on the ground surface or underground, corresponding to the second frame portion or the area surrounding the second frame portion on the magnetic south side of the parking space 7, will be the same as the strength of the geomagnetic field 2. From the above, the magnetic field measured by the magnetic sensor 11a placed in the second region 7b will change depending on whether or not the car 6 is present in the parking space 7.

[0037] The first communication device 11b, the second communication device 12a, and the determination processing unit 12b according to this second embodiment are generally the same as the first communication device 11b, the second communication device 12a, and the determination processing unit 12b according to the first embodiment, respectively. However, the determination processing unit 12b according to this second embodiment determines the presence or absence of an automobile 6 in the parking space 7 based on the result of comparing the magnetic field indicated by the magnetic data with a predetermined threshold value that is smaller than the strength of the Earth's magnetic field 2. Specifically, the determination processing unit 12b determines that an automobile 6 is present in the parking space 7 if the strength of the magnetic field indicated by the magnetic data is less than the threshold, and determines that an automobile 6 is not present in the parking space 7 if the strength of the magnetic field indicated by the magnetic data is equal to or greater than the threshold.

[0038] Furthermore, the determination of whether or not a car 6 is present in a parking space 7 is not limited to the above determination. For example, the determination processing unit 12b may calculate the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present, and determine whether or not a car 6 is present in a parking space 7 based on the result of comparing that difference with a predetermined threshold. Specifically, the determination processing unit 12b may determine that a car 6 is present in a parking space 7 if the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present is greater than or equal to the threshold, and determine that a car 6 is not present in a parking space 7 if the difference between the magnetic field indicated by the magnetic data and the magnetic field measured when no vehicle is present is less than the threshold.

[0039] Furthermore, for example, the determination processing unit 12b may determine the presence or absence of a car 6 in the parking space 7 based on the comparison result between the sequentially measured magnetic field differences indicated by the sequentially received magnetic data and a predetermined threshold. Specifically, the determination processing unit 12b may determine that a car 6 is present in the parking space 7 (changed from not present to present) if the difference between the magnetic field strength at the previous time and the magnetic field strength at the current time is greater than or equal to a threshold in the negative direction, and that a car 6 is not present in the parking space 7 (changed from present to not present) if the difference is greater than or equal to a threshold in the positive direction, and that the presence or absence of a car 6 in the parking space 7 has not changed since the previous time if the difference is less than or equal to a threshold in either the negative or positive direction.

[0040] The threshold value used in the determination processing unit 12b may be the default value, or it may be appropriately changed based on the strength of the magnetic field measured by the magnetic sensor 11a when the car 6 is not in the parking space 7.

[0041] <Summary of Embodiment 2> The change in the magnetic field in the second region 7b due to the presence or absence of a car 6 in the parking space 7 is smaller than the change in the magnetic field in the first region 7a due to the presence or absence of a car 6 in the parking space 7. However, since the size of the body and frame made of soft magnetic material is larger than that of a hard magnetic material engine, the body and frame made of soft magnetic material can change the magnetic field over a wider range and more stably than a hard magnetic material engine. For this reason, the sensing system according to this embodiment 2 can accurately determine the presence or absence of a car 6 in the parking space 7 based on the magnetic field measured by the magnetic sensor 11a in the second region 7b.

[0042] Furthermore, multiple magnetic sensors 11a at different distances from the center of the parking space 7 may be provided in the second region 7b. In this case, if the second region 7b includes areas where small cars and areas where large cars are present, the presence or absence of a car 6 within the parking space 7 can be accurately determined regardless of whether the car 6 is a small car or a large car.

[0043] <Modified form of Embodiment 1> In Embodiment 1, if the sensing device 11 is installed on the magnetic north side of the parking space 7 as shown in Figure 5, and a car 6 is present in the parking space 7, then, as described above, the magnetic sensor 11a in the first region 7a will measure a magnetic field stronger than the strength of the Earth's magnetic field 2. On the other hand, when the car 6 is located on the magnetic north side of the sensing device 11 in Figure 5, the positional relationship between these two devices is the same as the positional relationship between the sensing device 11 and the car 6 in Figure 9, and the magnetic sensor 11a in the first region 7a will measure a magnetic field weaker than the strength of the Earth's magnetic field 2.

[0044] Therefore, the first threshold may be set to a value smaller than the intensity of the geomagnetic field 2, the second threshold may be set to a value larger than the intensity of the geomagnetic field 2, and the third threshold may be set to a value even larger than the second threshold.

[0045] Furthermore, if the electric field strength indicated by the magnetic data is less than the first threshold, the determination processing unit 12b according to Embodiment 1 may determine that the automobile 6 is not located within the parking space 7, but is located on the magnetic north side of the sensing device 11 in Figure 5. Alternatively, if the electric field strength indicated by the magnetic data is between the first threshold and the second threshold, the determination processing unit 12b may determine that the automobile 6 is not located on the magnetic north side of the sensing device 11 in Figure 5, nor within the parking space 7. Alternatively, if the electric field strength indicated by the magnetic data is between the second threshold and the third threshold, the determination processing unit 12b may determine that the automobile 6 is located on the magnetic north side of the sensing device 11 in Figure 5, nor within the parking space 7. Alternatively, if the electric field strength indicated by the magnetic data is above the third threshold, the determination processing unit 12b may determine that the automobile 6 is not located on the magnetic north side of the sensing device 11 in Figure 5, but is located within the parking space 7.

[0046] <Modified form of Embodiment 2> In Embodiment 2, if the sensing device 11 is installed on the magnetically south side of the parking space 7 as shown in Figure 9, and a car 6 is present in the parking space 7, then, as described above, the magnetic sensor 11a in the second region 7b will measure a magnetic field weaker than the strength of the Earth's magnetic field 2. On the other hand, when the car 6 is located on the magnetically south side of the sensing device 11 in Figure 9, the positional relationship between the sensing device 11 and the car 6 becomes the same as the positional relationship between the sensing device 11 and the car 6 in Figure 5, and the magnetic sensor 11a in the second region 7b will measure a magnetic field stronger than the strength of the Earth's magnetic field 2.

[0047] Therefore, the first threshold may be set to a value smaller than the intensity of the geomagnetic field 2, the second threshold may be set to a value larger than the intensity of the geomagnetic field 2, and the third threshold may be set to a value even larger than the second threshold.

[0048] Furthermore, if the electric field strength indicated by the magnetic data is less than the first threshold, the determination processing unit 12b according to Embodiment 2 may determine that the car 6 is not located on the magnetic south side of the sensing device 11 in Figure 9, but is located within the parking space 7. Alternatively, if the electric field strength indicated by the magnetic data is between the first threshold and the second threshold, the determination processing unit 12b may determine that the car 6 is not located on the magnetic south side of the sensing device 11 in Figure 9, nor within the parking space 7. Alternatively, if the electric field strength indicated by the magnetic data is between the second threshold and the third threshold, the determination processing unit 12b according to Embodiment 2 may determine that the car 6 is located on the magnetic south side of the sensing device 11 in Figure 9, nor within the parking space 7. Alternatively, if the electric field strength indicated by the magnetic data is at or above the third threshold, the determination processing unit 12b may determine that the car 6 is not located within the parking space 7, but is located on the magnetic south side of the sensing device 11 in Figure 9.

[0049] <Embodiment 3> Figure 10 is a schematic diagram showing the configuration of the sensing system according to this third embodiment. Hereinafter, among the components of this third embodiment, components that are the same as or similar to the components described above will be denoted by the same or similar reference numerals, and the different components will be mainly described.

[0050] In this third embodiment, the sensing device 11 includes a first sensing device 11-1 and a second sensing device 11-2.

[0051] The first sensing device 11-1 is located in the first region 7a, similar to the sensing device 11 according to Embodiment 1, and includes a magnetic sensor 11a-1, which is a first magnetic sensor, and a first communication device 11b-1. The magnetic sensor 11a-1 and the first communication device 11b-1 are the same as the magnetic sensor 11a and the first communication device 11b according to Embodiment 1, respectively.

[0052] The second sensing device 11-2 is located in the second region 7b, similar to the sensing device 11 according to Embodiment 2, and includes a magnetic sensor 11a-2, which is a second magnetic sensor, and a first communication device 11b-2. The magnetic sensor 11a-2 and the first communication device 11b-2 are the same as the magnetic sensor 11a and the first communication device 11b according to Embodiment 2, respectively.

[0053] The determination processing unit 12b determines the presence or absence of a car 6 in the parking space 7 based on the magnetic data (first magnetic field) obtained from the magnetic sensor 11a-1 and the magnetic data (second magnetic field) obtained from the magnetic sensor 11a-2. For example, the determination processing unit 12b determines that a car 6 is present in the parking space 7 if the difference (absolute value) between the electric field strength indicated by the magnetic data obtained from the magnetic sensor 11a-1 and the electric field strength indicated by the magnetic data obtained from the magnetic sensor 11a-2 is greater than or equal to a predetermined threshold. On the other hand, the determination processing unit 12b determines that a car 6 is not present in the parking space 7 if the difference is less than the threshold.

[0054] With this configuration, the difference becomes more pronounced than the difference between the electric field strength indicated by the magnetic data obtained from magnetic sensor 11a-1 or magnetic data obtained from magnetic sensor 11a-2 and the strength of the Earth's magnetic field 2, thus enabling more accurate determination of the presence or absence of a car 6 within the parking space 7. Furthermore, even in the event of widespread changes in the Earth's magnetic field 2, the determination is based on the difference between the electric field strength indicated by the magnetic data obtained from magnetic sensor 11a-1 and magnetic data obtained from magnetic sensor 11a-2 after the change in the Earth's magnetic field 2, thus preventing misdetermination due to changes in the Earth's magnetic field 2.

[0055] The determination processing unit 12b may perform determinations other than those described above to determine the presence or absence of an automobile 6 in the parking space 7. For example, the determination processing unit 12b may perform a first determination similar to that in Embodiment 1 based on magnetic data obtained from magnetic sensor 11a-1, and a second determination similar to that in Embodiment 2 based on magnetic data obtained from magnetic sensor 11a-2. With such a configuration, if only one of the first or second determinations determines that an automobile 6 is present in the parking space 7, it can be determined that an automobile 6 is parked even if the automobile 6 is parked in a position closer to the magnetic north or magnetic south side of the parking space 7. Also, for example, if the parking space 7 is a parking space for large vehicles, if only one of the first or second determinations determines that an automobile 6 is present in the parking space 7, it can be determined that a vehicle other than a large vehicle, such as a small car, is parked in the parking space 7.

[0056] <Modified examples of Embodiments 1-3> In the above description, the sensing device 11 transmits magnetic data, and the determination device 12 determines the presence or absence of a car 6 in the parking space 7 based on the magnetic data. However, this is not the only possible configuration. For example, as shown in Figure 11, the determination device 12 may include a magnetic sensor 11a and a determination processing unit 12b. The determination processing unit 12b determines the presence or absence of a car 6 in the parking space 7 based on the magnetic field measured by the magnetic sensor 11a, transmits the determination result to a management device (not shown), and the management device outputs the presence or absence of a car 6 for each parking space 7 to an output unit such as a display unit. Even in this case, the same effects as in Embodiment 1 can be obtained. Although Figure 11 shows an example where this modified version is applied to Embodiment 1, this modified version may also be applied to Embodiments 2 and 3.

[0057] In this disclosure in English, 'a' and 'an' mean one or more. Therefore, 'a', 'an', 'one or more', and 'at least one' can be used interchangeably.

[0058] Furthermore, it is possible to freely combine each embodiment and each variation, or to modify or omit each embodiment and each variation as appropriate.

[0059] The various aspects of this disclosure are summarized below as an appendix.

[0060] (Note 1) A magnetic sensor placement method comprising placing a magnetic sensor to measure a magnetic field in at least one of the following: a first region on the ground surface or underground corresponding to a first frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped; and a second region on the ground surface or underground corresponding to a second frame portion on the magnetic south side of the object stopping frame, which is in the opposite direction to the magnetic north side of the object stopping frame, or the area around the second frame portion.

[0061] (Note 2) The magnetic sensor arrangement method described in Appendix 1, A method for arranging a magnetic sensor, comprising arranging a communication device that transmits magnetic data indicating the magnetic field measured by the magnetic sensor to an external source together with the magnetic sensor.

[0062] (Note 3) A sensing device including a magnetic sensor arranged in the magnetic sensor arrangement method described in Appendix 1, and a first communication device that transmits magnetic data indicating the magnetic field measured by the magnetic sensor, A determination device including a second communication device that receives the magnetic data transmitted from the first communication device, and a determination processing unit that determines the presence or absence of the object within the object stopping frame based on the magnetic data received by the second communication device. A sensing system equipped with [the following features].

[0063] (Note 4) A receiving unit that receives the magnetic field measured by a magnetic sensor placed on the frame portion or around the frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should stop, A determination processing unit determines the presence or absence of the object within the object stopping frame based on the magnetic field received by the receiving unit. Equipped with, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is greater than the magnetic field when the object is absent.

[0064] (Note 5) The determination device described in Appendix 4, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is greater than a threshold value set to be greater than the magnetic field when the object is absent.

[0065] (Note 6) A receiving unit that receives magnetic fields measured by magnetic sensors placed on the magnetic north side and the magnetic south side of the object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should stop, or around the frame, A determination processing unit determines the presence or absence of the object within the object stopping frame based on the magnetic field received by the receiving unit. Equipped with, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is smaller than the magnetic field when the object is absent.

[0066] (Note 7) The determination device described in Appendix 6, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is less than a threshold value set to be less than the magnetic field when the object is absent.

[0067] (Note 8) A receiving unit that receives a first magnetic field measured by a first magnetic sensor located in or around the first frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped, and a second magnetic field measured by a second magnetic sensor located in or around the second frame portion on the magnetic south side of the object stopping frame, in the opposite direction to the magnetic north side. A determination processing unit determines the presence or absence of the object within the object stopping frame based on the first magnetic field and the second magnetic field received by the receiving unit. A determination device equipped with the following features.

[0068] (Note 9) The determination device described in Appendix 8, The determination processing unit determines that the object is present within the object stopping frame when the difference between the first magnetic field and the second magnetic field is greater than a predetermined threshold.

[0069] (Note 10) The determination device described in Appendix 8, The determination processing unit is a determination device that determines, for each of the first magnetic field and the second magnetic field, whether or not the object is within the object stopping frame. [Explanation of symbols]

[0070] 1 Object, 2 Geomagnetic field, 6 Automobile, 7 Parking space, 7a First area, 7b Second area, 11 Sensing device, 11a, 11a-1, 11a-2 Magnetic sensor, 11b First communication device, 12 Judgment device, 12a Second communication device, 11c, 12b Judgment processing unit.

Claims

1. A magnetic sensor placement method comprising: placing a magnetic sensor to measure a magnetic field in at least one of the following: a first region on the ground surface or underground corresponding to a first frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped; and a second region on the ground surface or underground corresponding to a second frame portion on the magnetic south side of the object stopping frame, which is in the opposite direction to the magnetic north side.

2. A method for arranging magnetic sensors according to claim 1, A method for arranging a magnetic sensor, comprising arranging a communication device that transmits magnetic data indicating the magnetic field measured by the magnetic sensor to an external source together with the magnetic sensor.

3. A sensing device comprising a magnetic sensor arranged in the magnetic sensor arrangement method described in claim 1, and a first communication device that transmits magnetic data indicating the magnetic field measured by the magnetic sensor, A determination device including a second communication device that receives the magnetic data transmitted from the first communication device, and a determination processing unit that determines the presence or absence of the object within the object stopping frame based on the magnetic data received by the second communication device. A sensing system equipped with [the following features].

4. A receiving unit that receives the magnetic field measured by a magnetic sensor placed on the frame portion or around the frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should stop, A determination processing unit determines the presence or absence of the object within the object stopping frame based on the magnetic field received by the receiving unit. Equipped with, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is greater than the magnetic field when the object is absent.

5. A determination device according to claim 4, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is greater than a threshold value set to be greater than the magnetic field when the object is absent.

6. A receiving unit that receives magnetic fields measured by magnetic sensors placed on the magnetic north side and the magnetic south side of the object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should stop, or around the frame, A determination processing unit determines the presence or absence of the object within the object stopping frame based on the magnetic field received by the receiving unit. Equipped with, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is smaller than the magnetic field when the object is absent.

7. A determination device according to claim 6, The determination processing unit determines that the object is present within the object stopping frame when the magnetic field received by the receiving unit is less than a threshold value set to be smaller than the magnetic field when the object is absent.

8. A receiving unit that receives a first magnetic field measured by a first magnetic sensor located in or around the first frame portion on the magnetic north side of an object stopping frame, which is a frame-shaped marker indicating the position where an object containing a soft magnetic material should be stopped, and a second magnetic field measured by a second magnetic sensor located in or around the second frame portion on the magnetic south side of the object stopping frame, in the opposite direction to the magnetic north side. A determination processing unit determines the presence or absence of the object within the object stopping frame based on the first magnetic field and the second magnetic field received by the receiving unit. A determination device equipped with the following features.

9. A determination device according to claim 8, The determination processing unit determines that the object is within the object stopping frame when the difference between the first magnetic field and the second magnetic field is greater than a predetermined threshold.

10. A determination device according to claim 8, The determination processing unit is a determination device that determines, for each of the first magnetic field and the second magnetic field, whether or not the object is within the object stopping frame.

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