Full / empty detection system and determination device

Abstract

To suppress false detections in parking lot management and improve detection accuracy of a vehicle.SOLUTION: A full / empty detection system includes: a first communication device that is installed corresponding to a first parking space; a second communication device that is arranged in a first direction when viewed from the first parking space; a third communication device that is arranged in a second direction being the direction different from the first direction when viewed from the first parking space; and a determination device that determines whether or not a vehicle is parked in the first parking space on the basis of a first received electric field strength of a signal communicated between the first communication device and the second communication device and a second received electric field strength of a signal communicated between the first communication device and the third communication device.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a technology for detecting vehicles parked in a parking lot. [Background technology]

[0002] Conventionally, as the number of non-metallic parts in vehicles increases, it has become difficult to detect vehicles using metal sensors such as loop coils.

[0003] Therefore, a technology has been proposed that uses radio waves to detect vehicles in parking lots (see, for example, Patent Document 1). This technology detects vehicles in parking lots by utilizing the fact that received signal strength indication (in other words, RSSI) changes when radio waves are blocked, and then compares the RSSI measured in a specific parking stall (a unit parking space for vehicles in a parking lot) with a pre-stored threshold value to determine whether the parking lot is full or empty. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6624773 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional methods, the presence of a vehicle parked in a parking space is detected as a change in the RSSI of radio waves due to the presence of the vehicle in the communication path between the slave unit and the master unit, and this is used to detect whether the parking space is full or empty.

[0006] However, radio waves may be blocked by factors other than the vehicle parked in the parking space being judged (for example, the influence of a vehicle temporarily parked near the parking space being judged), causing changes in the radio wave RSSI. In such cases, false detection may occur in the parking space availability detection.

[0007] The technology disclosed in this specification has been made in consideration of the problems described above, and is a technology for suppressing false detections and improving vehicle detection accuracy. [Means for solving the problem]

[0008] The parking space detection system, which is a first aspect of the technology disclosed in the present specification, is an parking space detection system that detects a vehicle parked in a first parking space, and includes: a first communication device installed corresponding to the first parking space; a second communication device arranged in a first direction as viewed from the first parking space; a third communication device arranged in a second direction as viewed from the first parking space that is different from the first direction; and a determinator for determining whether the vehicle is parked in the first parking space using a first received field strength of a signal communicated between the first communication device and the second communication device and a second received field strength of a signal communicated between the first communication device and the third communication device. [Effects of the Invention]

[0009] According to at least the first aspect of the technology disclosed in the present specification, by using the received electric field strength in multiple directions relative to the parking stall, false detections can be suppressed and vehicle detection accuracy can be improved even when there is a decrease in the received electric field strength due to vehicles other than the parking stall.

[0010] Furthermore, objects, features, aspects, and advantages associated with the technology disclosed herein will become more apparent from the detailed description and accompanying drawings set forth below. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a plan view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 2] 1 is a side view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 3] FIG. 1 is a diagram conceptually illustrating an example of the configuration of a main part of an occupancy detection system. [Figure 4] FIG. 2 is a diagram conceptually illustrating an example of the configuration of a main part of a parent device according to an embodiment. [Figure 5] FIG. 2 is a diagram conceptually illustrating an example of the configuration of a main part of a slave unit according to an embodiment. [Figure 6] 1 is a diagram conceptually illustrating an example of the configuration of a main part of a determination machine according to an embodiment. [Figure 7] 10 is a flowchart illustrating an example of a threshold value setting operation of the vacancy detection system according to the embodiment. [Figure 8] 10 is a flowchart illustrating an example of a determination operation of the occupancy detection system according to the embodiment. [Figure 9] FIG. 10 is a diagram showing an example of patterns for determining whether a parking space is full or empty. [Figure 10] 10 is a diagram showing a comparison of RSSI data and a threshold value α according to an embodiment, and showing which pattern the data corresponds to. FIG. [Figure 11] 10 is a flowchart illustrating an example of a threshold value setting operation of the vacancy detection system according to the embodiment. [Figure 12] 10 is a flowchart illustrating an example of a determination operation of the occupancy detection system according to the embodiment. [Figure 13] 10 is a diagram showing a comparison of RSSI data according to an embodiment with thresholds α and β in terms of magnitude, and which pattern applies. FIG. [Figure 14] 1 is a plan view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 15] 1 is a side view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 16] 10 is a flowchart illustrating an example of a threshold value setting operation of the vacancy detection system according to the embodiment. [Figure 17] 10 is a flowchart illustrating an example of a determination operation of the occupancy detection system according to the embodiment. [Figure 18]10 is a diagram showing a comparison of RSSI data and a threshold value α according to an embodiment, and showing which pattern the data corresponds to. FIG. [Figure 19] 10 is a flowchart illustrating an example of a threshold value setting operation of the vacancy detection system according to the embodiment. [Figure 20] 10 is a flowchart illustrating an example of a determination operation of the occupancy detection system according to the embodiment. [Figure 21] 10 is a diagram showing a comparison of RSSI data according to an embodiment with thresholds α and β in terms of magnitude, and which pattern applies. FIG. [Figure 22] 1 is a plan view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 23] 1 is a side view showing a schematic configuration of an occupancy detection system according to an embodiment. [Figure 24] 10 is a flowchart illustrating an example of a threshold value setting operation of the vacancy detection system according to the embodiment. [Figure 25] 10 is a flowchart illustrating an example of a determination operation of the occupancy detection system according to the embodiment. [Figure 26] FIG. 10 is a diagram showing an example of patterns for determining whether a parking space is full or empty. [Figure 27] 10 is a diagram showing a comparison of RSSI data according to an embodiment with thresholds α and β in terms of magnitude, and which pattern applies. FIG. [Figure 28] FIG. 7 is a diagram illustrating a schematic example of a hardware configuration when the vacancy detection system shown in FIGS. 4, 5, and 6 is actually operated. [Figure 29] FIG. 7 is a diagram illustrating a schematic example of a hardware configuration when the vacancy detection system shown in FIGS. 4, 5, and 6 is actually operated. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments will be described with reference to the accompanying drawings. In the following embodiments, detailed features are shown for the purpose of explaining the technology, but these are merely examples and are not necessarily essential features for enabling the embodiments to be implemented.

[0013] The drawings are schematic, and for the sake of convenience, components may be omitted or simplified as appropriate. The relative sizes and positions of components shown in different drawings are not necessarily accurately depicted and may be changed as appropriate. Hatching may also be used in drawings such as plan views that are not cross-sectional views to facilitate understanding of the embodiments.

[0014] In the following description, the same components are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed descriptions of them may be omitted to avoid duplication.

[0015] Furthermore, in the description given in this specification, when a certain component is described as "comprising," "including," or "having," unless otherwise specified, this is not an exclusive expression that excludes the presence of other components.

[0016] Furthermore, although ordinal numbers such as "first" or "second" may be used in the descriptions in this specification, these terms are used for convenience to facilitate understanding of the contents of the embodiments, and the contents of the embodiments are not limited to the order that may result from these ordinal numbers.

[0017] Furthermore, in the description provided in this specification, terms that indicate specific positions or directions, such as "top," "bottom," "left," "right," "side," "bottom," "front," or "back," may be used, but these terms are used for convenience to facilitate understanding of the contents of the embodiments and have no relation to the positions or directions when the embodiments are actually implemented.

[0018] First Embodiment The occupancy detection system and the determination device according to this embodiment will be described below.

[0019] In the following, parent units are installed at two locations, one in front of the other in back of the parking stall (a unit parking space for a vehicle in a parking lot), at a height higher than the vehicle (for example, 2 m above ground), and one child unit is placed in each parking stall. Communication is then carried out between the two parent units and the two child units placed in front of and behind the parent units.

[0020] The accuracy of vacant / empty parking detection is improved based on four patterns of RSSI fluctuations, which are combinations of the parking status of the parking space being judged and the parking status of the adjacent parking space behind it.

[0021] <Configuration of the occupancy detection system> Fig. 1 is a plan view schematically showing the configuration of an occupancy detection system according to this embodiment, and Fig. 2 is a side view schematically showing the configuration of the occupancy detection system according to this embodiment.

[0022] As shown in the example of FIGS. 1 and 2, the vacancy detection system includes a master unit 1a, a master unit 1b, a slave unit 2a, a slave unit 2b, and a determination unit 3.

[0023] The main unit 1a is installed on the entrance / exit side of the parking stall 100 (the side where parked vehicles enter and exit) so as to face the parking stall 100. The main unit 1a is installed, for example, at a height of 2 m from the ground on the side wall of a pillar 104. The pillar 104 is installed at a position away from the parking stall 100 on the entrance / exit side of the parking stall 100. In addition, in FIG. 2, a vehicle 10a is parked in the parking stall 100 so that the front of the vehicle 10a is positioned on the entrance / exit side of the parking stall 100.

[0024] Master unit 1b is installed on the entrance / exit side of parking stall 102 (the side where parked vehicles enter and exit) so as to face parking stall 102. Master unit 1b is installed, for example, at a height of 2 m from the ground on the side wall of pillar 106. Pillar 106 is installed at a position away from parking stall 102 on the entrance / exit side of parking stall 102. In addition, in FIG. 2, vehicle 10b is parked in parking stall 102 so that the front of vehicle 10b is positioned on the entrance / exit side of parking stall 102.

[0025] Here, parking stall 100 and parking stall 102 are parking stalls arranged adjacent to each other with their rear portions facing opposite entrances and exits.

[0026] The slave unit 2a is installed in the parking stall 100 in a plan view. The slave unit 2a is installed, for example, on the ground within the parking stall 100, at a position vertically lower than the master units 1a and 1b. Note that the parking stall 100 also includes the white lines that separate the parking stalls 100.

[0027] The slave unit 2b is installed in the parking stall 102 in a plan view. The slave unit 2b is installed, for example, on the ground in the parking stall 100, and is installed at a position vertically lower than the master units 1a and 1b. Note that the parking stall 102 also includes the white lines that separate the parking stalls 102.

[0028] The determinator 3 can communicate with the parent device 1a wirelessly or via a wire. Here, communication between the parent device 1a and the determinator 3 is referred to as communication 60a. The determinator 3 can also communicate with the parent device 1b wirelessly or via a wire. Here, communication between the parent device 1b and the determinator 3 is referred to as communication 60b.

[0029] The RSSI data measured in communication from the slave device 2a to the master device 1a (uplink communication 20a), the RSSI data measured in communication from the slave device 2a to the master device 1b (uplink communication 20b), the RSSI data measured in communication from the slave device 2b to the master device 1a (uplink communication 21a), and the RSSI data measured in communication from the slave device 2b to the master device 1b (uplink communication 21b) are transmitted to the determinator 3 via communication 60a or communication 60b.

[0030] The determinator 3 compares the above four RSSI data with thresholds, and detects whether the parking stalls are full or empty based on four combinations of the presence of a parked vehicle (hereinafter also referred to as "full") and the absence of a parked vehicle (hereinafter also referred to as "empty") in each of the parking stalls 100 and 102.

[0031] 3 is a conceptual diagram illustrating an example of the configuration of the main components of the vacancy detection system. Here, the master unit 1 corresponds to at least one of the master units 1a and 1b. The slave unit 2 corresponds to at least one of the slave units 2a and 2b.

[0032] 3, the master unit 1 measures the RSSI based on the signal received from the slave unit 2. The master unit 1 then transmits the measured RSSI to the determination unit 3, which then performs an occupancy / full detection.

[0033] 4 is a diagram conceptually illustrating an example of the configuration of the main parts of the master device 1 according to this embodiment. As illustrated in the example of FIG. 4, the master device 1 includes a control device 112 and a communication device 111 that communicates with the slave device 2 or the determinator 3. The control device 112 includes a storage device 11 and an RSSI detection unit 12.

[0034] 5 is a diagram conceptually illustrating an example of the configuration of the main parts of the slave device 2 according to this embodiment. As illustrated in the example of FIG. 5, the slave device 2 includes a control device 122 and a communication device 121 that communicates with the master device 1. The control device 122 includes a storage device 21 and an RSSI detection unit 22.

[0035] Fig. 6 is a diagram conceptually illustrating an example of the configuration of the main parts of the determinator 3 according to this embodiment. As shown in Fig. 6, the determinator 3 includes a control device 133, a display device 131, and a communication device 132 that communicates with the parent device 1. The control device 133 includes a storage device 31 and a determination device 32. The display device 131 lights up in red when the battery is full and in blue when the battery is empty, for example.

[0036] <Operation of the occupancy detection system> Next, the operation of the vacancy detection system will be described with reference to Fig. 7. Fig. 7 is a flowchart showing an example of the threshold value setting operation of the vacancy detection system according to this embodiment.

[0037] First, in step ST1, when there are no parked vehicles (parked vehicles), the RSSI detection unit 12 of the master unit 1a measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is then set as RSSI data D1, and the measurement result of the signal received from the slave unit 2b is set as RSSI data D2. Furthermore, when there are no parked vehicles, the RSSI detection unit 12 of the master unit 1b measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is then set as RSSI data D3, and the measurement result of the signal received from the slave unit 2b is set as RSSI data D4.

[0038] Next, in step ST2, master device 1a stores RSSI data D1 and RSSI data D2 in storage device 11, and master device 1b stores RSSI data D3 and RSSI data D4 in storage device 11. Alternatively, master device 1a may store RSSI data D3 and RSSI data D4 in storage device 11, and master device 1b may store RSSI data D1 and RSSI data D2 in storage device 11.

[0039] Next, in step ST3, the master unit 1a and the master unit 1b each transmit the RSSI data stored in the storage device 11 to the determination device 3, and the determination device 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 in the storage device 31.

[0040] Next, in step ST4, the determination device 32 of the determination machine 3 selects the smallest value from among the values ​​of the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4, and calculates the value obtained by subtracting a set value X (for example, 10 dB) from that value as the threshold value α.

[0041] Next, in step ST5, the threshold value α calculated in step ST4 is stored in the storage device 31, and the operation ends.

[0042] FIG. 8 is a flowchart showing an example of the determination operation of the vacancy detection system according to this embodiment.

[0043] First, in step ST11, the RSSI detection unit 12 of the master unit 1a measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is defined as RSSI data D1, and the measurement result of the signal received from the slave unit 2b is defined as RSSI data D2. The RSSI detection unit 12 of the master unit 1b also measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is defined as RSSI data D3, and the measurement result of the signal received from the slave unit 2b is defined as RSSI data D4. Here, if there is a vehicle in a parking stall between the master unit 1 and the slave unit 2, the RSSI of the signal received by the master unit 1 will be attenuated because part of the signal will be blocked by the vehicle.

[0044] Next, in step ST12, each of the master devices 1a and 1b transmits RSSI data to the determinator 3, and the storage device 31 in the determinator 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4.

[0045] Next, in step ST13, the decision device 32 of the decision machine 3 compares the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 stored in the storage device 31 with the threshold value α.

[0046] 9 is a diagram showing an example of patterns of whether the parking lot is full or empty for parking stalls 100 and 102. As shown in the example in FIG. 9, four patterns exist by combining whether parking stall 100 on the slave device 2a side is full or empty with whether parking stall 102 on the slave device 2b side is full or empty.

[0047] 10 is a diagram showing a comparison of the magnitude of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 according to this embodiment with threshold value α to determine which pattern they fall into. In FIG. 10, RSSI data D1 is shown by a solid line, RSSI data D2 by a dashed-dotted line, RSSI data D3 by a dotted line, and RSSI data D4 by a dashed line.

[0048] The determination device 32 determines which pattern classification the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 fall into based on FIGS.

[0049] In step ST14, the determination device 32 determines whether or not the situation corresponds to pattern 1. Specifically, if all of the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 are greater than the threshold value α, it determines that the situation corresponds to pattern 1, in which the parking stalls 100 and 102 are empty. If the situation corresponds to pattern 1 (corresponding to YES branching from step ST14 in FIG. 8), the process proceeds to step ST17, where both the parking stalls 100 and 102 are illuminated in blue on the display device 131. On the other hand, if the situation does not correspond to pattern 1 (corresponding to NO branching from step ST14 in FIG. 8), the process proceeds to step ST15.

[0050] In step ST15, the determination device 32 determines whether or not the situation corresponds to pattern 2. Specifically, if only the RSSI data D4 is greater than the threshold value α, it determines that the situation corresponds to pattern 2, in which the parking stall 100 is full and the parking stall 102 is empty. If the situation corresponds to pattern 2 (corresponding to YES branching from step ST15 in FIG. 8), the process proceeds to step ST18, where the display device 131 lights up the parking stall 100 in red and the parking stall 102 in blue. On the other hand, if the situation does not correspond to pattern 2 (corresponding to NO branching from step ST15 in FIG. 8), the process proceeds to step ST16.

[0051] In step ST16, the determination device 32 determines whether or not the situation corresponds to pattern 3. Specifically, if only the RSSI data D1 is greater than the threshold value α, it determines that the situation corresponds to pattern 3, in which the parking stall 100 is empty and the parking stall 102 is full. If the situation corresponds to pattern 3 (corresponding to YES branching from step ST16 in FIG. 8), the process proceeds to step ST19, where the display device 131 lights up the parking stall 100 in blue and the parking stall 102 in red. On the other hand, if the situation does not correspond to pattern 3 (corresponding to NO branching from step ST16 in FIG. 8), the process proceeds to step ST20.

[0052] In step ST20, the determination device 32 determines that the situation corresponds to pattern 4, in which the parking stall 100 is full and the parking stall 102 is full. Then, on the display device 131, both the parking stall 100 and the parking stall 102 are illuminated in red.

[0053] In this embodiment, the installation positions of the sub-units 2a and 2b are set within the corresponding parking stalls, but they are not limited to being set within the parking stalls as long as they are capable of detecting whether the corresponding parking stalls are full or empty.

[0054] Furthermore, the threshold value α may be changed not only when the master unit and slave unit are installed, but also at any timing and any number of times.

[0055] As explained above, even if radio waves are blocked by vehicles parked in adjacent parking spaces, the presence or absence of parked vehicles in the parking space can be determined using RSSI data measured via multiple communication paths, thereby reducing false positives and improving the accuracy of vacant / unoccupied parking space detection.

[0056] <Second embodiment> The following describes the vacancy detection system and the determination device according to this embodiment. In the following description, components similar to those described in the above embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0057] <Configuration of the occupancy detection system> In the first embodiment, an occupancy detection system that uses one threshold value to make a determination was shown, but in this embodiment, an occupancy detection system that uses two threshold values ​​from RSSI data to make a determination will be described. Note that the operation of the master unit 1 and the slave unit 2 is the same as that shown in the first embodiment.

[0058] The overall configuration of the vacancy detection system is the same as that shown in Figures 1, 2, and 3, and therefore a description thereof will be omitted. Also, the configuration diagrams of the master unit 1, slave unit 2, and determination unit 3 are the same as those shown in Figures 4, 5, and 6, and therefore a description thereof will be omitted.

[0059] <Operation of the occupancy detection system> Next, the operation of the vacancy detection system will be described with reference to Fig. 11. Fig. 11 is a flowchart showing an example of the threshold value setting operation of the vacancy detection system according to this embodiment.

[0060] First, in step ST21, when there are no parked vehicles (parked vehicles), the RSSI detection unit 12 of the master unit 1a measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is then set as RSSI data D1, and the measurement result of the signal received from the slave unit 2b is set as RSSI data D2. Furthermore, when there are no parked vehicles, the RSSI detection unit 12 of the master unit 1b measures the RSSI based on the signals received from the slave units 2a and 2b. The measurement result of the signal received from the slave unit 2a is then set as RSSI data D3, and the measurement result of the signal received from the slave unit 2b is set as RSSI data D4.

[0061] Next, in step ST22, master device 1a stores RSSI data D1 and RSSI data D2 in storage device 11, and master device 1b stores RSSI data D3 and RSSI data D4 in storage device 11. Alternatively, master device 1a may store RSSI data D3 and RSSI data D4 in storage device 11, and master device 1b may store RSSI data D1 and RSSI data D2 in storage device 11.

[0062] Next, in step ST23, the master unit 1a and the master unit 1b each transmit the RSSI data stored in the storage device 11 to the decision device 3, and the decision device 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 in the storage device 31.

[0063] Next, in step ST24, the determination device 32 of the determination machine 3 selects the smallest value from among the values ​​of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4, calculates the value obtained by subtracting a set value X (for example, X=10 dB) from that value as a threshold value α, and calculates the value obtained by subtracting a set value Y (for example, Y=15 dB) from that value as a threshold value β.

[0064] Next, in step ST25, the threshold value α and the threshold value β calculated in step ST24 are stored in the storage device 31, and the operation is terminated.

[0065] FIG. 12 is a flowchart showing an example of the determination operation of the vacancy detection system according to this embodiment.

[0066] First, in step ST31, the RSSI detector 12 of the master device 1a measures the RSSI based on the signals received from the slave devices 2a and 2b. The measurement result of the signal received from the slave device 2a is defined as RSSI data D1, and the measurement result of the signal received from the slave device 2b is defined as RSSI data D2. The RSSI detector 12 of the master device 1b also measures the RSSI based on the signals received from the slave devices 2a and 2b. The measurement result of the signal received from the slave device 2a is defined as RSSI data D3, and the measurement result of the signal received from the slave device 2b is defined as RSSI data D4.

[0067] Next, in step ST32, each of the master devices 1a and 1b transmits RSSI data to the determinator 3, and the storage device 31 in the determinator 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4.

[0068] Next, in step ST33, the decision device 32 of the decision machine 3 compares the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 stored in the storage device 31 with the threshold value α and threshold value β.

[0069] 13 is a diagram showing a comparison of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 according to this embodiment with thresholds α and β in terms of magnitude, and showing which pattern they fit into. In FIG. 13, RSSI data D1 is shown by a solid line, RSSI data D2 is shown by a dashed-dotted line, RSSI data D3 is shown by a dotted line, and RSSI data D4 is shown by a dashed line.

[0070] The determination device 32 determines which pattern classification the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 fall into based on FIGS.

[0071] In step ST34, the determination device 32 determines whether or not pattern 4 applies. Specifically, when both the RSSI data D2 and the RSSI data D3 are smaller than the threshold value β, this is the condition in which attenuation due to vehicle obstruction is greatest, and therefore it is determined that pattern 4 applies, in which the parking stalls 100 and 102 are full. If pattern 4 applies (corresponding to YES branching from step ST34 in FIG. 12), the process proceeds to step ST37, where both the parking stalls 100 and 102 are illuminated in red on the display device 131. On the other hand, if pattern 4 does not apply (corresponding to NO branching from step ST34 in FIG. 12), the process proceeds to step ST35.

[0072] In step ST35, the determination device 32 determines whether or not the situation corresponds to pattern 1. Specifically, if all of the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 are greater than the threshold value α, it determines that the situation corresponds to pattern 1, in which the parking stalls 100 and 102 are empty. If the situation corresponds to pattern 1 (corresponding to YES branching from step ST35 in FIG. 12), the process proceeds to step ST38, where both the parking stalls 100 and 102 are illuminated in blue on the display device 131. On the other hand, if the situation does not correspond to pattern 1 (corresponding to NO branching from step ST35 in FIG. 12), the process proceeds to step ST36.

[0073] In step ST36, the determination device 32 determines whether or not the situation corresponds to pattern 2. Specifically, if only the RSSI data D4 is greater than the threshold value α, it determines that the situation corresponds to pattern 2, in which the parking stall 100 is full and the parking stall 102 is empty. If the situation corresponds to pattern 2 (corresponding to YES branching from step ST36 in FIG. 12), the process proceeds to step ST39, where the display device 131 lights up the parking stall 100 in red and the parking stall 102 in blue. On the other hand, if the situation does not correspond to pattern 2 (corresponding to NO branching from step ST36 in FIG. 12), the process proceeds to step ST40.

[0074] In step ST40, the determination device 32 determines that the parking space 100 is empty and the parking space 102 is full, which corresponds to pattern 3. Then, on the display device 131, the parking space 100 is illuminated in blue and the parking space 102 is illuminated in red.

[0075] In this embodiment, the installation positions of the sub-units 2a and 2b are set within the corresponding parking stalls, but they are not limited to being set within the parking stalls as long as they are capable of detecting whether the corresponding parking stalls are full or empty.

[0076] Furthermore, the threshold values ​​α and β may be changed not only when the master unit and the slave unit are installed, but also at any timing and any number of times.

[0077] As described above, by making a detailed determination using two threshold values, it is possible to suppress erroneous detection due to the influence of obstructions, and improve the accuracy of occupancy detection.

[0078] <Third embodiment> The following describes the vacancy detection system and the determination device according to this embodiment. In the following description, components similar to those described in the above embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0079] <Configuration of the occupancy detection system> In the first embodiment, a form of uplink communication was shown, but in this embodiment, the communication direction between the parent device 1 and the child device 2 is changed, and a form of communication from the parent device 1 to the child device 2 (hereinafter also referred to as downlink communication) is described.

[0080] The slave device 2 measures the RSSI based on the signal received from the master device 1 and stores the measured RSSI data in the storage device 21. The stored RSSI data is then transmitted from the slave device 2 to the master device 1 and further aggregated in the determinator 3. The operation of the determinator 3 is the same as that described in the first embodiment.

[0081] Fig. 14 is a plan view schematically showing the configuration of an occupancy detection system according to this embodiment, and Fig. 15 is a side view schematically showing the configuration of an occupancy detection system according to this embodiment.

[0082] As shown in the examples of FIGS. 14 and 15, the vacancy detection system includes a master unit 1a, a master unit 1b, a slave unit 2a, a slave unit 2b, and a determination unit 3.

[0083] The main unit 1a is installed on the entrance / exit side of the parking stall 100 (the side where parked vehicles enter and exit) so as to face the parking stall 100. The main unit 1a is installed, for example, at a height of 2 m from the ground on the side wall of a pillar 104. The pillar 104 is installed at a position away from the parking stall 100 on the entrance / exit side of the parking stall 100. In addition, in FIG. 15, a vehicle 10a is parked in the parking stall 100 so that the front of the vehicle 10a is positioned on the entrance / exit side of the parking stall 100.

[0084] Master unit 1b is installed on the entrance / exit side of parking stall 102 (the side where parked vehicles enter and exit) so as to face parking stall 102. Master unit 1b is installed, for example, at a height of 2 m from the ground on the side wall of pillar 106. Pillar 106 is installed at a position away from parking stall 102 on the entrance / exit side of parking stall 102. In addition, in FIG. 15, vehicle 10b is parked in parking stall 102 so that the front of vehicle 10b is positioned on the entrance / exit side of parking stall 102.

[0085] Here, parking stall 100 and parking stall 102 are parking stalls arranged adjacent to each other with their rear portions facing opposite entrances and exits.

[0086] The slave unit 2a is installed in the parking stall 100 in a plan view. The slave unit 2a is installed, for example, on the ground within the parking stall 100, at a position vertically lower than the master units 1a and 1b. Note that the parking stall 100 also includes the white lines that separate the parking stalls 100.

[0087] The slave unit 2b is installed in the parking stall 102 in a plan view. The slave unit 2b is installed, for example, on the ground in the parking stall 100, and is installed at a position vertically lower than the master units 1a and 1b. Note that the parking stall 102 also includes the white lines that separate the parking stalls 102.

[0088] The determinator 3 can communicate with the parent device 1a wirelessly or via a wire. Here, communication between the parent device 1a and the determinator 3 is referred to as communication 60a. The determinator 3 can also communicate with the parent device 1b wirelessly or via a wire. Here, communication between the parent device 1b and the determinator 3 is referred to as communication 60b.

[0089] The RSSI data measured in communication from the parent device 1a to the child device 2a (downlink communication 30a), the RSSI data measured in communication from the parent device 1b to the child device 2a (downlink communication 30b), the RSSI data measured in communication from the parent device 1a to the child device 2b (downlink communication 31a), and the RSSI data measured in communication from the parent device 1b to the child device 2b (downlink communication 31b) are transmitted to the determinator 3 via communication 60a or communication 60b.

[0090] The operation of the determinator 3 is the same as that shown in the first embodiment, and therefore a description thereof will be omitted. Also, the configuration diagrams of the master unit 1, slave unit 2, and determinator 3 are the same as those shown in Figures 4, 5, and 6, and therefore a description thereof will be omitted.

[0091] <Operation of the occupancy detection system> Next, the operation of the vacancy detection system will be described with reference to Fig. 16. Fig. 16 is a flowchart showing an example of the threshold value setting operation of the vacancy detection system according to this embodiment.

[0092] First, in step ST41, when there are no parked vehicles (parked vehicles), the RSSI detection unit 22 of the slave 2a measures the RSSI based on the signals received from the master 1a and the master 1b. The measurement result of the signal received from the master 1a is then set as RSSI data D1, and the measurement result of the signal received from the master 1b is set as RSSI data D2. Furthermore, when there are no parked vehicles, the RSSI detection unit 22 of the slave 2b measures the RSSI based on the signals received from the master 1a and the master 1b. The measurement result of the signal received from the master 1a is then set as RSSI data D3, and the measurement result of the signal received from the master 1b is set as RSSI data D4.

[0093] Next, in step ST42, the slave device 2a stores the RSSI data D1 and the RSSI data D2 in the storage device 21, and the slave device 2b stores the RSSI data D3 and the RSSI data D4 in the storage device 21. Alternatively, the slave device 2a may store the RSSI data D3 and the RSSI data D4 in the storage device 21, and the slave device 2b may store the RSSI data D1 and the RSSI data D2 in the storage device 21.

[0094] Next, in step ST43, the RSSI data D1 and RSSI data D2 stored in the memory device 21 of the slave device 2a are transmitted to the master device 1a and stored in the memory device 11, and the RSSI data D3 and RSSI data D4 stored in the memory device 21 of the slave device 2b are transmitted to the master device 1b and stored in the memory device 11.

[0095] Next, in step ST44, the master unit 1a and the master unit 1b each transmit the RSSI data stored in the storage device 11 to the decision device 3, and the decision device 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 in the storage device 31.

[0096] Next, in step ST45, the determination device 32 of the determination machine 3 selects the smallest value from among the values ​​of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4, and calculates the value obtained by subtracting a set value X (for example, 10 dB) from that value as the threshold value α.

[0097] Next, in step ST46, the threshold value α calculated in step ST45 is stored in the storage device 31, and the operation is terminated.

[0098] FIG. 17 is a flowchart showing an example of the determination operation of the vacancy detection system according to this embodiment.

[0099] First, in step ST51, the RSSI detection unit 22 of the slave unit 2a measures the RSSI based on the signals received from the master unit 1a and the master unit 1b. The measurement result of the signal received from the master unit 1a is defined as RSSI data D1, and the measurement result of the signal received from the master unit 1b is defined as RSSI data D2. The RSSI detection unit 22 of the slave unit 2b also measures the RSSI based on the signals received from the master unit 1a and the master unit 1b. The measurement result of the signal received from the master unit 1a is defined as RSSI data D3, and the measurement result of the signal received from the master unit 1b is defined as RSSI data D4. Here, if there is a vehicle in a parking stall between the master unit 1 and the slave unit 2, the RSSI of the signal received by the slave unit 2 will be attenuated because part of the signal will be blocked by the vehicle.

[0100] Next, in step ST52, the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 stored in storage device 21 of slave device 2 are transmitted to master device 1 and stored in storage device 11. Here, the RSSI data D1 and RSSI data D2 stored in storage device 21 of slave device 2a may be transmitted to master device 1a, which is located closer than master device 1b, and stored in storage device 11, and the RSSI data D3 and RSSI data D4 stored in storage device 21 of slave device 2b may be transmitted to master device 1b, which is located closer than master device 1a, and stored in storage device 11.

[0101] Next, in step ST53, each of the master devices 1a and 1b transmits RSSI data to the determinator 3, and the storage device 31 in the determinator 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4.

[0102] Next, in step ST54, the decision device 32 of the decision machine 3 compares the RSSI data D1, RSSI data D2, RSSI data D3 and RSSI data D4 stored in the storage device 31 with the threshold value α.

[0103] 18 is a diagram showing a comparison of the magnitude of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 according to this embodiment with threshold value α, and showing which pattern they fall into. In FIG. 18, RSSI data D1 is shown by a solid line, RSSI data D2 is shown by a dashed-dotted line, RSSI data D3 is shown by a dotted line, and RSSI data D4 is shown by a dashed line.

[0104] The determination device 32 determines which pattern classification the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 fall into based on FIGS.

[0105] In step ST55, the determination device 32 determines whether or not the situation corresponds to pattern 1. Specifically, if all of the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 are greater than the threshold value α, it determines that the situation corresponds to pattern 1, in which the parking stalls 100 and 102 are empty. If the situation corresponds to pattern 1 (corresponding to YES branching from step ST55 in FIG. 17), the process proceeds to step ST58, where both the parking stalls 100 and 102 are illuminated in blue on the display device 131. On the other hand, if the situation does not correspond to pattern 1 (corresponding to NO branching from step ST55 in FIG. 17), the process proceeds to step ST56.

[0106] In step ST56, the determination device 32 determines whether or not the situation corresponds to pattern 2. Specifically, if only the RSSI data D4 is greater than the threshold value α, it determines that the situation corresponds to pattern 2, in which the parking stall 100 is full and the parking stall 102 is empty. If the situation corresponds to pattern 2 (corresponding to YES branching from step ST56 in FIG. 17), the process proceeds to step ST59, where the display device 131 lights up the parking stall 100 in red and the parking stall 102 in blue. On the other hand, if the situation does not correspond to pattern 2 (corresponding to NO branching from step ST56 in FIG. 17), the process proceeds to step ST57.

[0107] In step ST57, the determination device 32 determines whether or not the situation corresponds to pattern 3. Specifically, if only the RSSI data D1 is greater than the threshold value α, it determines that the situation corresponds to pattern 3, in which the parking stall 100 is empty and the parking stall 102 is full. If the situation corresponds to pattern 3 (corresponding to YES branching from step ST57 in FIG. 17), the process proceeds to step ST60, where the display device 131 lights up the parking stall 100 in blue and the parking stall 102 in red. On the other hand, if the situation does not correspond to pattern 3 (corresponding to NO branching from step ST57 in FIG. 17), the process proceeds to step ST61.

[0108] In step ST61, the determination device 32 determines that the situation corresponds to pattern 4, in which the parking stall 100 is full and the parking stall 102 is full. Then, on the display device 131, both the parking stall 100 and the parking stall 102 are illuminated in red.

[0109] In this embodiment, the installation positions of the sub-units 2a and 2b are set within the corresponding parking stalls, but they are not limited to being set within the parking stalls as long as they are capable of detecting whether the corresponding parking stalls are full or empty.

[0110] Furthermore, the threshold value α may be changed not only when the master unit and slave unit are installed, but also at any timing and any number of times.

[0111] As explained above, even when using RSSI data in downlink communication from the parent unit 1, even if radio waves are blocked by a vehicle parked in an adjacent parking space, the presence or absence of a parked vehicle in the parking space can be determined using RSSI data measured via multiple communication paths, thereby reducing false positives and improving the accuracy of vacancy detection.

[0112] <Fourth embodiment> The following describes the vacancy detection system and the determination device according to this embodiment. In the following description, components similar to those described in the above embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0113] <Configuration of the occupancy detection system> In the third embodiment, an occupancy detection system that uses one threshold value to make a determination was shown, but in this embodiment, an occupancy detection system that uses two threshold values ​​from RSSI data to make a determination will be described. Note that the operation of the master unit 1 and the slave unit 2 is the same as that shown in the third embodiment.

[0114] The overall configuration of the vacancy detection system is the same as that shown in Figures 14, 15, and 3, and therefore a description thereof will be omitted. Also, the configuration diagrams of the master unit 1, slave unit 2, and determination unit 3 are the same as those shown in Figures 4, 5, and 6, and therefore a description thereof will be omitted.

[0115] <Operation of the occupancy detection system> Next, the operation of the vacancy detection system will be described with reference to Fig. 19. Fig. 19 is a flowchart showing an example of the threshold value setting operation of the vacancy detection system according to this embodiment.

[0116] First, in step ST71, when there are no parked vehicles (parked vehicles), the RSSI detection unit 22 of the slave 2a measures the RSSI based on the signals received from the master 1a and the master 1b. The measurement result of the signal received from the master 1a is then set as RSSI data D1, and the measurement result of the signal received from the master 1b is set as RSSI data D2. Furthermore, when there are no parked vehicles, the RSSI detection unit 22 of the slave 2b measures the RSSI based on the signals received from the master 1a and the master 1b. The measurement result of the signal received from the master 1a is then set as RSSI data D3, and the measurement result of the signal received from the master 1b is set as RSSI data D4.

[0117] Next, in step ST72, the slave device 2a stores the RSSI data D1 and the RSSI data D2 in the storage device 21, and the slave device 2b stores the RSSI data D3 and the RSSI data D4 in the storage device 21. Alternatively, the slave device 2a may store the RSSI data D3 and the RSSI data D4 in the storage device 21, and the slave device 2b may store the RSSI data D1 and the RSSI data D2 in the storage device 21.

[0118] Next, in step ST73, the RSSI data D1 and RSSI data D2 stored in the memory device 21 of the slave device 2a are transmitted to the master device 1a and stored in the memory device 11, and the RSSI data D3 and RSSI data D4 stored in the memory device 21 of the slave device 2b are transmitted to the master device 1b and stored in the memory device 11.

[0119] Next, in step ST74, the master unit 1a and the master unit 1b each transmit the RSSI data stored in the memory device 11 to the decision device 3, and the memory device 31 in the decision device 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4.

[0120] Next, in step ST75, the determination device 32 of the determination machine 3 selects the smallest value from among the values ​​of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4, calculates the value obtained by subtracting a set value X (for example, X=10 dB) from that value as a threshold value α, and calculates the value obtained by subtracting a set value Y (for example, Y=15 dB) from that value as a threshold value β.

[0121] Next, in step ST76, the threshold value α and the threshold value β calculated in step ST75 are stored in the storage device 31, and the operation is terminated.

[0122] FIG. 20 is a flowchart showing an example of the determination operation of the vacancy detection system according to this embodiment.

[0123] First, in step ST81, the RSSI detection unit 22 of the slave device 2a measures the RSSI based on the signals received from the master device 1a and the master device 1b. The measurement result of the signal received from the master device 1a is defined as RSSI data D1, and the measurement result of the signal received from the master device 1b is defined as RSSI data D2. The RSSI detection unit 22 of the slave device 2b also measures the RSSI based on the signals received from the master device 1a and the master device 1b. The measurement result of the signal received from the master device 1a is defined as RSSI data D3, and the measurement result of the signal received from the master device 1b is defined as RSSI data D4.

[0124] Next, in step ST82, the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 stored in storage device 21 of slave device 2 are transmitted to master device 1 and stored in storage device 11. Here, the RSSI data D1 and RSSI data D2 stored in storage device 21 of slave device 2a may be transmitted to master device 1a, which is located closer than master device 1b, and stored in storage device 11, and the RSSI data D3 and RSSI data D4 stored in storage device 21 of slave device 2b may be transmitted to master device 1b, which is located closer than master device 1a, and stored in storage device 11.

[0125] Next, in step ST83, the master devices 1a and 1b each transmit RSSI data to the determinator 3, and the storage device 31 in the determinator 3 stores the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4.

[0126] Next, in step ST84, the decision device 32 of the decision machine 3 compares the RSSI data D1, RSSI data D2, RSSI data D3 and RSSI data D4 stored in the storage device 31 with the threshold value α and threshold value β.

[0127] 21 is a diagram showing a comparison of RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 according to this embodiment with thresholds α and β in terms of magnitude, and showing which pattern each corresponds to. In FIG. 21, RSSI data D1 is shown by a solid line, RSSI data D2 is shown by a dashed-dotted line, RSSI data D3 is shown by a dotted line, and RSSI data D4 is shown by a dashed line.

[0128] The determination device 32 determines which pattern classification the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 fall into based on FIGS.

[0129] In step ST85, the determination device 32 determines whether or not pattern 4 applies. Specifically, when both the RSSI data D2 and the RSSI data D3 are smaller than the threshold value β, this is the condition in which attenuation due to vehicle obstruction is greatest, and therefore it is determined that pattern 4 applies, in which the parking stalls 100 and 102 are full. If pattern 4 applies (corresponding to YES branching from step ST85 in FIG. 20), the process proceeds to step ST88, where both the parking stalls 100 and 102 are illuminated in red on the display device 131. On the other hand, if pattern 4 does not apply (corresponding to NO branching from step ST85 in FIG. 20), the process proceeds to step ST86.

[0130] In step ST86, the determination device 32 determines whether or not the situation corresponds to pattern 1. Specifically, if all of the RSSI data D1, RSSI data D2, RSSI data D3, and RSSI data D4 are greater than the threshold value α, it determines that the situation corresponds to pattern 1, in which the parking stalls 100 and 102 are empty. If the situation corresponds to pattern 1 (corresponding to YES branching from step ST86 in FIG. 20), the process proceeds to step ST89, where both the parking stalls 100 and 102 are illuminated in blue on the display device 131. On the other hand, if the situation does not correspond to pattern 1 (corresponding to NO branching from step ST86 in FIG. 20), the process proceeds to step ST87.

[0131] In step ST87, the determination device 32 determines whether or not the situation corresponds to pattern 2. Specifically, if only the RSSI data D4 is greater than the threshold value α, it determines that the situation corresponds to pattern 2, in which the parking stall 100 is full and the parking stall 102 is empty. If the situation corresponds to pattern 2 (corresponding to YES branching from step ST87 in FIG. 20), the process proceeds to step ST90, where the display device 131 lights up the parking stall 100 in red and the parking stall 102 in blue. On the other hand, if the situation does not correspond to pattern 2 (corresponding to NO branching from step ST87 in FIG. 20), the process proceeds to step ST91.

[0132] In step ST91, the determination device 32 determines that the parking space 100 is empty and the parking space 102 is full, which corresponds to pattern 3. Then, on the display device 131, the parking space 100 is illuminated in blue and the parking space 102 is illuminated in red.

[0133] In this embodiment, the installation positions of the sub-units 2a and 2b are set within the corresponding parking stalls, but they are not limited to being set within the parking stalls as long as they are capable of detecting whether the corresponding parking stalls are full or empty.

[0134] Furthermore, the threshold values ​​α and β may be changed not only when the master unit and the slave unit are installed, but also at any timing and any number of times.

[0135] As described above, by making a detailed determination using two threshold values, it is possible to suppress erroneous detection due to the influence of obstructions, and improve the accuracy of occupancy detection.

[0136] <Fifth embodiment> The following describes the vacancy detection system and the determination device according to this embodiment. In the following description, components similar to those described in the above embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0137] <Configuration of the occupancy detection system> In the first embodiment, the judgment was made based on the parking status of the parking space being judged and the parking status of the parking space adjacent to the rear of the parking space being judged, but in this embodiment, the parking space being judged is detected based on three factors: the parking space being judged, the parking space adjacent to the rear of the parking space, and a parking space that is not adjacent to the parking space being judged and is located between the parking space being judged and the parent unit.

[0138] Fig. 22 is a plan view schematically showing the configuration of an occupancy detection system according to this embodiment. Fig. 23 is a side view schematically showing the configuration of an occupancy detection system according to this embodiment.

[0139] As shown in the examples of FIGS. 22 and 23, the vacancy detection system includes a master unit 1a, a master unit 1b, a slave unit 2a, a slave unit 2b, a slave unit 2c, and a determination unit 3.

[0140] Master unit 1a is installed on the entrance / exit side of parking stall 100 (the side where parked vehicles enter and exit) and behind parking stall 101. Master unit 1a is installed, for example, at a height of 2 m from the ground on the side wall of pillar 104. Pillar 104 is installed on the entrance / exit side of parking stall 100 and behind parking stall 101, away from parking stall 101. In addition, in FIG. 23 , vehicle 10a is parked in parking stall 100 with the front of vehicle 10a positioned on the entrance / exit side of parking stall 100. In addition, vehicle 10c is parked in parking stall 101 with the front of vehicle 10c positioned on the entrance / exit side of parking stall 101.

[0141] Master unit 1b is installed on the entrance / exit side of parking stall 102 (the side where parked vehicles enter and exit) so as to face parking stall 102. Master unit 1b is installed, for example, at a height of 2 m from the ground on the side wall of pillar 106. Pillar 106 is installed at a position away from parking stall 102 on the entrance / exit side of parking stall 102. In addition, in FIG. 23, vehicle 10b is parked in parking stall 102 so that the front of vehicle 10b is positioned on the entrance / exit side of parking stall 102.

[0142] Here, parking stalls 100 and 102 are adjacent to each other with their rear portions positioned adjacent to each other so that their entrances and exits are on opposite sides. Parking stalls 100 and 101 are adjacent to each other with their entrances and exits facing each other.

[0143] The slave unit 2a is installed in the parking stall 100 in a plan view. The slave unit 2a is installed, for example, on the ground within the parking stall 100, at a position vertically lower than the master units 1a and 1b. Note that the parking stall 100 also includes the white lines that separate the parking stalls 100.

[0144] The slave unit 2b is installed in the parking stall 102 in a plan view. The slave unit 2b is installed, for example, on the ground in the parking stall 100, and is installed at a position vertically lower than the master units 1a and 1b. Note that the parking stall 102 also includes the white lines that separate the parking stalls 102.

[0145] The slave unit 2c is installed in the parking stall 101 in a plan view. The slave unit 2c is installed, for example, on the ground in the parking stall 100, and is installed at a position vertically lower than the master units 1a and 1b. The parking stall 101 also includes the white lines that separate the parking stalls 101.

[0146] The determinator 3 can communicate with the parent device 1a wirelessly or via a wire. Here, communication between the parent device 1a and the determinator 3 is referred to as communication 60a. The determinator 3 can also communicate with the parent device 1b wirelessly or via a wire. Here, communication between the parent device 1b and the determinator 3 is referred to as communication 60b.

[0147] The RSSI data measured in the communication from the slave device 2a to the master device 1a (uplink communication 20a), the RSSI data measured in the communication from the slave device 2a to the master device 1b (uplink communication 20b), the RSSI data measured in the communication from the slave device 2b to the master device 1a (uplink communication 21a), the RSSI data measured in the communication from the slave device 2b to the master device 1b (uplink communication 21b), the RSSI data measured in the communication from the slave device 2c to the master device 1a (uplink communication 22a), and the RSSI data measured in the communication from the slave device 2c to the master device 1b (uplink communication 22b) are transmitted to the determinator 3 via communication 60a or communication 60b.

[0148] The determinator 3 compares the six RSSI data with thresholds and detects whether the parking stalls are full or empty based on eight combinations of the presence of a parked vehicle (full) and absence of a parked vehicle (empty) for each of the parking stalls 100, 102, and 101.

[0149] The configuration diagrams of the master unit 1, slave unit 2 and determinator 3 are the same as those shown in FIGS. 4, 5 and 6, and therefore the description thereof will be omitted.

[0150] <Operation of the occupancy detection system> Next, the operation of the vacancy detection system will be described with reference to Fig. 24. Fig. 24 is a flowchart showing an example of the threshold value setting operation of the vacancy detection system according to this embodiment.

[0151] First, in step ST101, when there are no parked vehicles (parked vehicles), the RSSI detection unit 12 of the master unit 1a measures the RSSI based on the signals received from the slave units 2a, 2b, and 2c. The measurement result of the signal received from the slave unit 2a is set as RSSI data D1, the measurement result of the signal received from the slave unit 2b is set as RSSI data D2, and the measurement result of the signal received from the slave unit 2c is set as RSSI data D5. Furthermore, when there are no parked vehicles, the RSSI detection unit 12 of the master unit 1b measures the RSSI based on the signals received from the slave units 2a, 2b, and 2c. The measurement result of the signal received from the slave unit 2a is set as RSSI data D3, the measurement result of the signal received from the slave unit 2b is set as RSSI data D4, and the measurement result of the signal received from the slave unit 2c is set as RSSI data D6.

[0152] Next, in step ST102, master device 1a stores RSSI data D1, RSSI data D2, and RSSI data D5 in storage device 11, and master device 1b stores RSSI data D3, RSSI data D4, and RSSI data D6 in storage device 11. Alternatively, master device 1a may store RSSI data D3, RSSI data D4, and RSSI data D6 in storage device 11, and master device 1b may store RSSI data D1, RSSI data D2, and RSSI data D5 in storage device 11.

[0153] Next, in step ST103, the master unit 1a and the master unit 1b each transmit the RSSI data stored in the storage device 11 to the determination device 3, and the storage device 31 within the determination device 3 stores RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6.

[0154] Next, in step ST104, the determination device 32 of the determination machine 3 selects the smallest value from among the values ​​of RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6, calculates the value obtained by subtracting a set value X (for example, X=10 dB) from that value as a threshold value α, and calculates the value obtained by subtracting a set value Y (for example, Y=15 dB) from that value as a threshold value β.

[0155] Next, in step ST105, the threshold value α and the threshold value β calculated in step ST104 are stored in the storage device 31, and the operation is terminated.

[0156] FIG. 25 is a flowchart showing an example of the determination operation of the vacancy detection system according to this embodiment.

[0157] First, in step ST111, the RSSI detection unit 12 of the master device 1a measures the RSSI based on signals received from the slave devices 2a, 2b, and 2c. The measurement result of the signal received from the slave device 2a is defined as RSSI data D1, the measurement result of the signal received from the slave device 2b is defined as RSSI data D2, and the measurement result of the signal received from the slave device 2c is defined as RSSI data D5. The RSSI detection unit 12 of the master device 1b also measures the RSSI based on signals received from the slave devices 2a, 2b, and 2c. The measurement result of the signal received from the slave device 2a is defined as RSSI data D3, the measurement result of the signal received from the slave device 2b is defined as RSSI data D4, and the measurement result of the signal received from the slave device 2c is defined as RSSI data D6.

[0158] Next, in step ST112, each of the master units 1a and 1b transmits RSSI data to the decision device 3, and the storage device 31 in the decision device 3 stores RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6.

[0159] Next, in step ST113, the decision device 32 of the decision machine 3 compares the RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5 and RSSI data D6 stored in the storage device 31 with the threshold values ​​α and β.

[0160] Here, Fig. 26 is a diagram showing an example of patterns of whether the parking lot is full or empty for parking stalls 100, 102, and 101. As shown in the example in Fig. 26, eight patterns exist by combining whether parking stall 100 on the side of slave device 2a is full or empty, whether parking stall 102 on the side of slave device 2b is full or empty, and whether parking stall 101 on the side of slave device 2c is full or empty.

[0161] Fig. 27 is a diagram showing a comparison of RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6 according to this embodiment with thresholds α and β in terms of magnitude, and showing which pattern they fit into. In Fig. 27, RSSI data D1 is shown by a solid line, RSSI data D2 is shown by a dashed line, RSSI data D3 is shown by a dotted line, RSSI data D4 is shown by a broken line, RSSI data D5 is shown by a double line, and RSSI data D6 is shown by a chain double-dot line.

[0162] The determining device 32 determines which pattern classification the RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6 belong to, based on FIGS.

[0163] In step ST114, the determination device 32 determines whether or not the situation corresponds to pattern 1. Specifically, if all of the RSSI data D1, RSSI data D2, RSSI data D3, RSSI data D4, RSSI data D5, and RSSI data D6 are greater than the threshold value α, the determination device 32 determines that the situation corresponds to pattern 1, in which the parking stalls 100, 102, and 101 are empty. If the situation corresponds to pattern 1 (corresponding to YES branching from step ST114 in FIG. 25), the process proceeds to step ST121, where the parking stalls 100, 102, and 101 are illuminated in blue on the display device 131. On the other hand, if the situation does not correspond to pattern 1 (corresponding to NO branching from step ST114 in FIG. 25), the process proceeds to step ST115.

[0164] In step ST115, the determination device 32 determines whether or not the situation corresponds to pattern 2. Specifically, if the RSSI data D4 and the RSSI data D5 are greater than the threshold value α, it determines that the situation corresponds to pattern 2, in which parking stall 100 is full, parking stall 102 is empty, and parking stall 101 is empty. If the situation corresponds to pattern 2 (corresponding to YES branching from step ST115 in FIG. 25), the process proceeds to step ST122, where the display device 131 lights up the parking stall 100 in red, the parking stall 102 in blue, and the parking stall 101 in blue. On the other hand, if the situation does not correspond to pattern 2 (corresponding to NO branching from step ST115 in FIG. 25), the process proceeds to step ST116.

[0165] In step ST116, the determination device 32 determines whether or not the situation corresponds to pattern 3. Specifically, if the RSSI data D1 and the RSSI data D5 are greater than the threshold value α, it determines that the situation corresponds to pattern 3, in which parking stall 100 is empty, parking stall 102 is full, and parking stall 101 is empty. If the situation corresponds to pattern 3 (corresponding to YES branching from step ST116 in FIG. 25), the process proceeds to step ST123, where the display device 131 lights up the parking stall 100 in blue, the parking stall 102 in red, and the parking stall 101 in blue. On the other hand, if the situation does not correspond to pattern 3 (corresponding to NO branching from step ST116 in FIG. 25), the process proceeds to step ST117.

[0166] In step ST117, the determination device 32 determines whether or not pattern 4 applies. Specifically, when only the RSSI data D5 is greater than the threshold value α, it determines that pattern 4 applies, in which parking stall 100 is full, parking stall 102 is full, and parking stall 101 is empty. If pattern 4 applies (corresponding to YES branching from step ST117 in FIG. 25), the process proceeds to step ST124, where the display device 131 lights up the parking stall 100 in red, the parking stall 102 in red, and the parking stall 101 in blue. On the other hand, if pattern 4 does not apply (corresponding to NO branching from step ST117 in FIG. 25), the process proceeds to step ST118.

[0167] In step ST118, the determination device 32 determines whether or not pattern 5 applies. Specifically, if the RSSI data D2 and the RSSI data D4 are greater than the threshold value α, it determines that pattern 5 applies, in which parking stall 100 is empty, parking stall 102 is empty, and parking stall 101 is full. If pattern 5 applies (corresponding to YES branching from step ST118 in FIG. 25), the process proceeds to step ST125, where the display device 131 lights up the parking stall 100 in blue, the parking stall 102 in blue, and the parking stall 101 in red. On the other hand, if pattern 5 does not apply (corresponding to NO branching from step ST118 in FIG. 25), the process proceeds to step ST119.

[0168] In step ST119, the determination device 32 determines whether or not pattern 6 applies. Specifically, when only the RSSI data D4 is greater than the threshold value α, it determines that pattern 6 applies, in which parking stall 100 is full, parking stall 102 is empty, and parking stall 101 is full. If pattern 6 applies (corresponding to YES branching from step ST119 in FIG. 25), the process proceeds to step ST126, where the display device 131 lights up the parking stall 100 in red, the parking stall 102 in blue, and the parking stall 101 in red. On the other hand, if pattern 6 does not apply (corresponding to NO branching from step ST119 in FIG. 25), the process proceeds to step ST120.

[0169] In step ST120, the determination device 32 determines whether or not the situation corresponds to pattern 7. Specifically, if the RSSI data D1, RSSI data D2, RSSI data D4, and RSSI data D5 are greater than the threshold value β, it is determined that the situation corresponds to pattern 7, in which parking stall 100 is empty, parking stall 102 is full, and parking stall 101 is full. If the situation corresponds to pattern 7 (corresponding to YES branching from step ST120 in FIG. 25), the process proceeds to step ST127, where the display device 131 lights up the parking stall 100 in blue, the parking stall 102 in red, and the parking stall 101 in red. On the other hand, if the situation does not correspond to pattern 7 (corresponding to NO branching from step ST120 in FIG. 25), the process proceeds to step ST128.

[0170] In step ST128, the determination device 32 determines that the situation corresponds to pattern 8, in which parking stalls 100, 102, and 101 are full. Then, on the display device 131, parking stalls 100, 102, and 101 are illuminated in red.

[0171] In this embodiment, the installation positions of the sub-units 2a and 2b are set within the corresponding parking stalls, but they are not limited to being set within the parking stalls as long as they are capable of detecting whether the corresponding parking stalls are full or empty.

[0172] Furthermore, the threshold values ​​α and β may be changed not only when the master unit and the slave unit are installed, but also at any timing and any number of times.

[0173] Furthermore, as shown in the first embodiment, the determination may be made only with the threshold value α without using the threshold value β.

[0174] Furthermore, as shown in the third embodiment, when the parent device 1 transmits a signal and the child device 2 receives the signal, RSSI information (RSSI information of downlink communication) may be transmitted from the child device 2 to the parent device 1, and further transmitted to the determination device 3.

[0175] As explained above, even if the number of parking spaces to be judged is increased, by using RSSI data measured via multiple communication paths to determine whether or not there is a parked vehicle in the parking space, false positives can be suppressed and the accuracy of vacant / unoccupied detection can be improved.

[0176] Furthermore, even if the slave 2c is installed not in a parking stall where a vehicle is to be parked but on the road in front of the parking stall to be judged, it can judge the eight patterns shown in Fig. 26 and correctly judge the vacant / occupied status of the parking stalls 100, 102, and 101. In this case, the display device 131 may light up the vacant / occupied status of the parking stalls 100 and 102, but may not light up the vacant / occupied status of the parking stall 101.

[0177] <Hardware configuration of the occupancy detection system> 28 and 29 are diagrams illustrating a schematic example of a hardware configuration when the vacancy detection system shown in FIGS. 4, 5, and 6 is actually operated.

[0178] Note that the hardware configurations illustrated in Figures 28 and 29 may not match the numbers, etc., of the configurations illustrated in Figures 4, 5, and 6, but this is because the configurations illustrated in Figures 4, 5, and 6 represent conceptual units.

[0179] Therefore, at least the following cases can be envisaged: a configuration illustrated in Figures 4, 5, and 6 is made up of multiple hardware configurations illustrated in Figures 28 and 29; a configuration illustrated in Figures 4, 5, and 6 corresponds to a part of the hardware configuration illustrated in Figures 28 and 29; and further, multiple configurations illustrated in Figures 4, 5, and 6 are provided in a single hardware configuration illustrated in Figures 28 and 29.

[0180] 28 shows a processing circuit 1102A that performs calculations, a storage device 1103 that can store information, an output device 1105A that can output information such as a display, a liquid crystal display device, or a lamp, and a measuring device 1106A that can measure physical quantities, as hardware configurations for realizing the storage device 11, RSSI detection unit 12, storage device 21, RSSI detection unit 22, storage device 31, determination device 32, display device 131, etc. in Figures 4, 5, and 6. This configuration is the same in all of the above embodiments.

[0181] 29 shows a processing circuit 1102B that performs calculations, an output device 1105B that can output information such as a display, a liquid crystal display device, or a lamp, and a measuring device 1106B that can measure physical quantities, etc., as a hardware configuration for realizing the storage device 11, RSSI detection unit 12, storage device 21, RSSI detection unit 22, storage device 31, determination device 32, display device 131, etc. in Figures 4, 5, and 6. This configuration is the same in all of the above embodiments.

[0182] The storage device 11, the storage device 21, and the storage device 31 are realized by the storage device 1103 or another storage device (not shown here).

[0183] The storage device 1103 may be, for example, a memory (recording medium) including a volatile or non-volatile semiconductor memory such as a hard disk drive (i.e., HDD), random access memory (i.e., RAM), read only memory (i.e., ROM), flash memory, erasable programmable read only memory (EPROM), and electrically erasable programmable read-only memory (EEPROM), a magnetic disk, a flexible disk, an optical disk, a compact disk, a mini disk, or a DVD, or any recording medium that will be used in the future.

[0184] The processing circuit 1102A may execute a program stored in the storage device 1103, an external CD-ROM, an external DVD-ROM, an external flash memory, etc. That is, it may be, for example, a central processing unit (CPU), a microprocessor, a microcomputer, or a digital signal processor (DSP).

[0185] When the processing circuit 1102A executes a program stored in the storage device 1103, an external CD-ROM, an external DVD-ROM, an external flash memory, or the like, the determination device 32 is realized by software, firmware, or a combination of software and firmware that causes the processing circuit 1102A to execute a program stored in the storage device 1103. Note that the function of the determination device 32 may be realized, for example, by a plurality of processing circuits working together.

[0186] The software and firmware may be written as a program and stored in the storage device 1103. In this case, the processing circuit 1102A realizes the above functions by reading and executing the program stored in the storage device 1103. In other words, the storage device 1103 may store a program that, when executed by the processing circuit 1102A, results in the above functions being realized.

[0187] The processing circuit 1102B may also be dedicated hardware, i.e., for example, a single circuit, multiple circuits, a programmed processor, a parallel programmed processor, an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or a combination thereof.

[0188] When the processing circuit 1102B is a dedicated hardware, the determination device 32 is realized by the operation of the processing circuit 1102B. Note that the functions of the determination device 32 may be realized by separate circuits or by a single circuit.

[0189] The functions of the determination device 32 may be partially realized by a processing circuit 1102A that executes a program stored in the storage device 1103, and partially realized by a processing circuit 1102B that is dedicated hardware.

[0190] Furthermore, the display device 131 is realized by the output device 1105A or the output device 1105B.

[0191] Moreover, the RSSI detector 12 and the RSSI detector 22 are realized by the measuring device 1106A or the measuring device 1106B.

[0192] <Effects Produced by the Multiple Embodiments Described Above> Next, examples of effects obtained by the above-described embodiments will be described. Note that in the following description, the effects will be described based on the specific configurations exemplified in the above-described embodiments, but these may be replaced with other specific configurations exemplified in the present specification as long as the same effects are obtained. In other words, for convenience, only one of the associated specific configurations may be described as a representative below, but the representatively described specific configuration may be replaced with another associated specific configuration.

[0193] Furthermore, the replacement may be made across multiple embodiments, i.e., configurations illustrated in different embodiments may be combined to produce the same effect.

[0194] According to the embodiment described above, the parking space availability detection system includes a first communication device, a second communication device, a third communication device, and a determinator 3. Here, the first communication device corresponds to, for example, the slave unit 2a. The second communication device corresponds to, for example, the master unit 1a. The third communication device corresponds to, for example, the master unit 1b. The slave unit 2a is installed corresponding to a first parking stall. Here, the first parking stall corresponds to, for example, the parking stall 100. The master unit 1a is disposed in a first direction as viewed from the parking stall 100. The master unit 1b is disposed in a second direction as viewed from the parking stall 100, which is different from the first direction. The determinator 3 determines whether a vehicle is parked in the parking stall 100 using a first reception field strength of a signal communicated between the slave unit 2a and the master unit 1a and a second reception field strength of a signal communicated between the slave unit 2a and the master unit 1b. Here, the first reception field strength corresponds to, for example, RSSI data D1, etc. The second reception field strength corresponds to, for example, RSSI data D3, etc.

[0195] With this configuration, by using the received electric field strength in multiple directions relative to the parking space, even if there is a decrease in the received electric field strength due to a vehicle other than the parking space (for example, a vehicle temporarily parked near the parking space being judged), false detections can be suppressed and the vehicle detection accuracy can be improved.

[0196] Furthermore, even if other configurations shown as examples in this specification are appropriately added to the above configuration, that is, even if other configurations in this specification that were not mentioned as the above configuration are appropriately added, the same effect can be achieved.

[0197] Furthermore, according to the embodiment described above, RSSI data D1 is the received field strength at master unit 1a when a signal is transmitted from slave unit 2a to master unit 1a. RSSI data D3 is the received field strength at master unit 1b when a signal is transmitted from slave unit 2a to master unit 1b. With this configuration, the presence or absence of a vehicle in a parking stall can be determined with high accuracy using the RSSI data measured by RSSI detectors 12 of master units 1a and 1b.

[0198] Furthermore, according to the embodiment described above, the RSSI data D1 is the received field strength at the slave unit 2a when a signal is transmitted from the master unit 1a to the slave unit 2a. The RSSI data D3 is the received field strength at the slave unit 2a when a signal is transmitted from the master unit 1b to the slave unit 2a. With this configuration, the presence or absence of a vehicle in a parking stall can be determined with high accuracy using the RSSI data measured by the RSSI detectors 22 of the slave units 2a and 2b.

[0199] Furthermore, according to the embodiment described above, the second direction is the direction opposite to the first direction. In other words, master unit 1a and master unit 1b are installed so as to sandwich parking stall 100 in a plan view. With this configuration, by using the received electric field strengths in multiple directions relative to the parking stall, even if the received electric field strength of one signal is reduced due to an obstacle other than the parking stall, false detection can be suppressed and vehicle detection accuracy can be improved by referring to the received electric field strengths of other signals.

[0200] Furthermore, according to the embodiment described above, the parking stall adjacent to parking stall 100 is defined as the second parking stall. Here, the second parking stall corresponds to, for example, parking stall 102. The parking space availability detection system includes a fourth communication device installed corresponding to parking stall 102. Here, the fourth communication device corresponds to, for example, slave unit 2b. The determinator 3 determines whether vehicles are parked in each of parking stalls 100 and 102 based on four combinations of the RSSI data D1, the RSSI data D3, the third reception field strength of the signal communicated between slave unit 2b and master unit 1a, and the fourth reception field strength of the signal communicated between slave unit 2b and master unit 1b. Here, the third reception field strength corresponds to, for example, RSSI data D2. The fourth reception field strength corresponds to, for example, RSSI data D4. With this configuration, the presence or absence of vehicles in the two parking stalls can be efficiently determined based on the combinations of the reception field strengths of the four pieces of RSSI data.

[0201] According to the embodiment described above, the parking stall opposite parking stall 100 is defined as the third parking stall. Here, the third parking stall corresponds to parking stall 101, for example. The parking space availability detection system includes a fifth communication device installed corresponding to parking stall 101. Here, the fifth communication device corresponds to slave unit 2c, for example. The determinator 3 determines whether vehicles are parked in each of parking stalls 100, 102, and 101 based on eight combinations of the RSSI data D1, D3, D2, D4, a fifth reception field strength of the signal communicated between slave unit 2c and master unit 1a, and a sixth reception field strength of the signal communicated between slave unit 2c and master unit 1b. Here, the fifth reception field strength corresponds to RSSI data D5, for example. The sixth reception field strength corresponds to RSSI data D6, for example. With this configuration, it is possible to efficiently determine whether or not there are vehicles in the three parking stalls based on the combination of the received electric field strengths of the eight pieces of RSSI data.

[0202] According to the embodiment described above, the determination device 3 determines whether a vehicle is parked in the parking stall 100 by using RSSI data D1 of the signal communicated between the slave unit 2a installed corresponding to the parking stall 100 and the master unit 1a arranged in a first direction as viewed from the parking stall 100, and RSSI data D3 of the signal communicated between the slave unit 2a and the master unit 1b arranged in a second direction that is different from the first direction as viewed from the parking stall 100.

[0203] With this configuration, by using the received electric field strength in multiple directions relative to the parking stall, false detections can be suppressed and vehicle detection accuracy can be improved even if there is a decrease in the received electric field strength due to vehicles other than the parking stall.

[0204] Furthermore, even if other configurations shown as examples in this specification are appropriately added to the above configuration, that is, even if other configurations in this specification that were not mentioned as the above configuration are appropriately added, the same effect can be achieved.

[0205] <Modifications of the above-described embodiments> In the multiple embodiments described above, the slave units 2 are installed in both the parking stalls 100 and 102, but when the target of determination is the parking stall 100, only the slave unit 2a may be installed in the parking stall 100, and the slave unit 2b may not be installed in the parking stall 102. In that case, the RSSI data D1 between the slave unit 2a and the master unit 1a and the RSSI data D3 between the slave unit 2a and the master unit 1b may be used to determine whether the parking stall 100 is full (when both the RSSI data D1 and the RSSI data D3 are smaller than the threshold value α, the parking stall 100 is determined to be full, and when at least one of the RSSI data D1 and the RSSI data D3 is larger than the threshold value α, the parking stall 100 is determined to be empty).

[0206] Furthermore, in the multiple embodiments described above, parent unit 1a and parent unit 1b are installed so that they sandwich a parking stall when viewed from above, but the relative positions of parent unit 1a and parent unit 1b are not limited to this case, and they may be arranged in different directions when viewed from the parking stall.

[0207] Furthermore, in the multiple embodiments described above, the dimensions, shapes, relative positional relationships, and implementation conditions of each component may also be described, but these are merely examples in all aspects and are not limiting.

[0208] Therefore, countless modifications and equivalents not shown as examples are contemplated within the scope of the technology disclosed in the present specification, including, for example, modifying, adding, or omitting at least one component, and further, extracting at least one component in at least one embodiment and combining it with a component in another embodiment.

[0209] Furthermore, unless a contradiction arises, when it is stated in the above-described embodiments that "one" component is provided, "one or more" of that component may also be provided.

[0210] Furthermore, the descriptions in this specification are incorporated by reference for all purposes related to the present technology, and none of them are admitted to be prior art.

[0211] Various aspects of the present disclosure are summarized below as appendices.

[0212] (Appendix 1) an occupancy detection system that detects a vehicle parked in a first parking space; a first communication device installed corresponding to the first parking stall; a second communication device disposed in a first direction as viewed from the first parking stall; a third communication device disposed in a second direction, which is a direction different from the first direction as viewed from the first parking stall; a determiner for determining whether the vehicle is parked in the first parking stall by using a first reception field strength of a signal communicated between the first communication device and the second communication device and a second reception field strength of a signal communicated between the first communication device and the third communication device; Vacancy detection system.

[0213] (Appendix 2) An occupancy detection system as described in Appendix 1, the first reception field strength is a reception field strength at the second communication device when a signal is transmitted from the first communication device to the second communication device; The second reception field strength is a reception field strength at the third communication device when a signal is transmitted from the first communication device to the third communication device. Vacancy detection system.

[0214] (Appendix 3) An occupancy detection system as described in Appendix 1, the first reception field strength is a reception field strength at the first communication device when a signal is transmitted from the second communication device to the first communication device; The second reception field strength is a reception field strength at the first communication device when a signal is transmitted from the third communication device to the first communication device. Vacancy detection system.

[0215] (Appendix 4) An occupancy detection system according to any one of appendices 1 to 3, The second direction is opposite to the first direction. Vacancy detection system.

[0216] (Appendix 5) An occupancy detection system according to any one of appendices 1 to 4, A parking space adjacent to the first parking space is defined as a second parking space; Further, a fourth communication device is provided corresponding to the second parking stall, the determinator determines whether the vehicle is parked in each of the first parking stall and the second parking stall based on four combination patterns of magnitudes of the first reception electric field strength, the second reception electric field strength, the third reception electric field strength of the signal communicated between the fourth communication device and the second communication device, and the fourth reception electric field strength of the signal communicated between the fourth communication device and the third communication device. Vacancy detection system.

[0217] (Appendix 6) An occupancy detection system as described in Appendix 5, The parking stall opposite to the first parking stall is a third parking stall, a fifth communication device installed corresponding to the third parking stall; the determinator determines whether the vehicle is parked in each of the first parking stall, the second parking stall, and the third parking stall based on eight combination patterns of magnitudes of the first reception electric field strength, the second reception electric field strength, the third reception electric field strength, the fourth reception electric field strength, a fifth reception electric field strength of a signal communicated between the fifth communication device and the second communication device, and a sixth reception electric field strength of a signal communicated between the fifth communication device and the third communication device; Vacancy detection system.

[0218] (Appendix 7) a determination device for determining whether or not a vehicle is parked in a first parking space, The determination machine determining whether the vehicle is parked in the first parking stall by using a first reception field strength of a signal communicated between a first communication device installed corresponding to the first parking stall and a second communication device arranged in a first direction as seen from the first parking stall, and a second reception field strength of a signal communicated between the first communication device and a third communication device arranged in a second direction as seen from the first parking stall, the second direction being different from the first direction; Judgment machine.

[0219] (Appendix 8) 7. A determination machine according to claim 7, the first reception field strength is a reception field strength at the second communication device when a signal is transmitted from the first communication device to the second communication device; The second reception field strength is a reception field strength at the third communication device when a signal is transmitted from the first communication device to the third communication device. Judgment machine.

[0220] (Appendix 9) 7. A determination machine according to claim 7, the first reception field strength is a reception field strength at the first communication device when a signal is transmitted from the second communication device to the first communication device; The second reception field strength is a reception field strength at the first communication device when a signal is transmitted from the third communication device to the first communication device. Judgment machine. [Explanation of symbols]

[0221] 1 parent unit, 1a parent unit, 1b parent unit, 2 child unit, 2a child unit, 2b child unit, 2c child unit, 3 determination unit, 10a vehicle, 10b vehicle, 10c vehicle, 11 storage device, 12 RSSI detection unit, 20a uplink communication, 20b uplink communication, 21 storage device, 21a uplink communication, 21b uplink communication, 22 RSSI detection unit, 22a uplink communication, 22b uplink communication, 30a downlink communication, 30b downlink communication, 31 storage device, 31a downlink communication, 31b downlink communication, 32 determination device, 60a communication, 60b communication, 100 parking stall, 101 parking stall, 102 parking stall, 104 pole, 106 pole, 111 communication device, 112 control device, 121 communication device, 122 Control device, 131 display device, 132 communication device, 133 control device, 1102A processing circuit, 1102B processing circuit, 1103 storage device, 1105A output device, 1105B output device, 1106A measuring device, 1106B measuring device.

Claims

1. an occupancy detection system that detects a vehicle parked in a first parking stall, a first communication device installed corresponding to the first parking stall; a second communication device disposed in a first direction as viewed from the first parking stall; a third communication device disposed in a second direction, which is a direction different from the first direction as viewed from the first parking stall; a determiner for determining whether the vehicle is parked in the first parking stall using a first reception field strength of a signal communicated between the first communication device and the second communication device and a second reception field strength of a signal communicated between the first communication device and the third communication device; Vacancy detection system.

2. The occupancy detection system according to claim 1, the first reception field strength is a reception field strength at the second communication device when a signal is transmitted from the first communication device to the second communication device; the second reception field strength is a reception field strength at the third communication device when a signal is transmitted from the first communication device to the third communication device; Vacancy detection system.

3. The occupancy detection system according to claim 1, the first reception field strength is a reception field strength at the first communication device when a signal is transmitted from the second communication device to the first communication device; the second reception field strength is a reception field strength at the first communication device when a signal is transmitted from the third communication device to the first communication device; Vacancy detection system.

4. The occupancy detection system according to any one of claims 1 to 3, The second direction is opposite to the first direction. Vacancy detection system.

5. The occupancy detection system according to any one of claims 1 to 3, A parking stall adjacent to the first parking stall is defined as a second parking stall; a fourth communication device installed corresponding to the second parking stall; the determinator determines whether the vehicle is parked in each of the first parking stall and the second parking stall based on four combination patterns of magnitudes of the first reception electric field strength, the second reception electric field strength, the third reception electric field strength of the signal communicated between the fourth communication device and the second communication device, and the fourth reception electric field strength of the signal communicated between the fourth communication device and the third communication device. Vacancy detection system.

6. The occupancy detection system according to claim 5, The parking stall opposite to the first parking stall is a third parking stall, a fifth communication device installed corresponding to the third parking stall; the determinator determines whether the vehicle is parked in each of the first parking stall, the second parking stall, and the third parking stall based on eight combination patterns of magnitudes of the first reception field strength, the second reception field strength, the third reception field strength, the fourth reception field strength, a fifth reception field strength of a signal communicated between the fifth communication device and the second communication device, and a sixth reception field strength of a signal communicated between the fifth communication device and the third communication device. Vacancy detection system.

7. a determination device for determining whether or not a vehicle is parked in a first parking stall, The determination machine determining whether the vehicle is parked in the first parking stall by using a first reception field strength of a signal communicated between a first communication device installed corresponding to the first parking stall and a second communication device arranged in a first direction as seen from the first parking stall, and a second reception field strength of a signal communicated between the first communication device and a third communication device arranged in a second direction as seen from the first parking stall, the second direction being different from the first direction; Judgment machine.

8. The determination device according to claim 7, the first reception field strength is a reception field strength at the second communication device when a signal is transmitted from the first communication device to the second communication device; the second reception field strength is a reception field strength at the third communication device when a signal is transmitted from the first communication device to the third communication device; Judgment machine.

9. The determination device according to claim 7, the first reception field strength is a reception field strength at the first communication device when a signal is transmitted from the second communication device to the first communication device; the second reception field strength is a reception field strength at the first communication device when a signal is transmitted from the third communication device to the first communication device; Judgment machine.

Images