Vehicle positioning system for vehicle carriers, vehicle positioning method for vehicle carriers, and vehicle positioning program for vehicle carriers

Abstract

This technology can improve the accuracy of assistance during vehicle loading and unloading operations on vehicle carriers, as well as the accuracy of vehicle guidance during autonomous driving, thereby enabling more efficient and time-saving vehicle loading and unloading operations. [Solution] The system comprises a plurality of first devices 1 installed at intervals inside a ship, a second device 2 installed on a vehicle loaded onto a vehicle carrier, distance calculation means for calculating the distance between each of the plurality of first devices and the second device based on the bidirectional transmission and reception times of information or signals between each of the plurality of first devices and the second device, and position identification means for identifying the position of the second device 2 based on the distance between each of the first devices and the second device, and the position information of each of the first devices. The first devices periodically transmit beacon signals, and auxiliary means for identifying the position of the second device is provided based on the time from receiving the beacon signal from the second device to receiving a probe request from the second device, or based on the strength of the beacon signal received by the second device.

Description

Technical Field

[0001] The present invention relates to a vehicle positioning system for a vehicle carrier, a vehicle positioning method for a vehicle carrier, and a vehicle positioning program for a vehicle carrier, which can capture the position of a vehicle in real time when loading and unloading the vehicle onto the vehicle carrier.

Background Art

[0002] The work of loading and unloading vehicles onto a vehicle carrier needs to accommodate all vehicle types. Moreover, the alignment and parking of vehicles inside the ship require accuracy in the order of several centimeters and are carried out by workers with excellent driving skills (see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, since the current loading and unloading operations are performed by workers, they largely depend on human judgment errors and the technical ability of the workers, and the accuracy and speed of loading and unloading are not guaranteed. In order to cope with the future shortage of skilled drivers, automation of driving and accurate assistance in driving are required. However, inside the ship, the GPS signal is difficult to reach, and the accuracy cannot be guaranteed when using the conventional position identification method using the GPS signal. Moreover, if the vehicle is damaged due to loading, unloading, or a deviation in the parking position, it will be treated as a total loss, leading to an increase in insurance premiums.

[0005] The present invention has been made in view of the above circumstances, and its main objective is to provide a vehicle positioning system for vehicle carriers, a vehicle positioning method for vehicle carriers, and a vehicle positioning program for vehicle carriers that can improve the assistance accuracy for loading and unloading vehicles onto and off vehicle carriers, as well as the vehicle guidance accuracy during autonomous driving, thereby enabling more efficient and time-saving vehicle loading and unloading operations, and reducing the risk of collisions between vehicles, thereby enabling safe loading and unloading operations. [Means for solving the problem]

[0006] To achieve the above objectives, the vehicle positioning system for vehicle carriers according to the present invention is A vehicle positioning system for a vehicle carrier that uses a plurality of first devices installed inside the vehicle carrier and whose positions within the vehicle are identified, and a second device installed on a vehicle loaded onto the vehicle carrier to determine the position of the vehicle, Distance calculation means for calculating the distance between each of the multiple first devices and the second device based on the bidirectional transmission and reception times of information or signals between each of the multiple first devices and the second device, A position identification means that identifies the position of the second device based on the distance between each of the first and second devices calculated by the distance calculation means, and the position information of each of the first devices. It is characterized by having [this feature].

[0007] Here, the first device whose location within the ship is identified includes not only cases where the location of the first device within the ship is identified in advance, but also cases where it is identified retrospectively by some means. Furthermore, the identified location information of the first device may be stored in a readable format in its own memory, or it may be stored in a database in another storage device. The positional information of the first device within the ship is three-dimensional positional information, and may be determined using a geocentric Cartesian coordinate system, a geodetic coordinate system, or a coordinate system independently established within the transport ship. Furthermore, the installation method of the first device within the ship is not particularly limited; it may be installed on the surface of pillars, walls, ceilings, etc. within the ship, or it may be embedded in pillars, walls, ceilings, etc. It may also be fixed to other installations within the ship (such as lighting fixtures, piping, or structures like signs).

[0008] Installing the second device on a vehicle includes not only cases where the second device is directly installed on the vehicle (by attaching the second device using appropriate means such as adhesive or brackets), but also cases where it is housed in a compartment provided on the vehicle and attached to it. Furthermore, the second device may be substituted for an electronic device mounted on the vehicle by installing the application of this system on that electronic device.

[0009] Here, it is desirable to intentionally make the height positions on which the first device is installed different, and by managing the height position of the first device, it becomes possible to more accurately determine the three-dimensional position information of the second device.

[0010] Therefore, the distance calculation means calculates the distance between each of the multiple first devices and the second device installed on the vehicle, and the position identification means makes it possible to identify the position of the second device, i.e., the position of the vehicle, based on the distance between each of the multiple first devices and the second device, and the position information of the first devices.

[0011] Here, the distance calculation means is: The difference between the time on the first device's clock when it transmits information or signals and the time on the second device's clock when it receives the information or signals transmitted from the first device. The difference between the time on the second device's clock when it transmits information or signals and the time on the first device's clock when it receives the information or signals transmitted from the second device. Based on this, the propagation time of information or signals between the first device and the second device may be calculated, and the distance between the first device and the second device may be calculated based on this propagation time. In this way, by calculating the distance between the first and second devices based on the transmission and reception times of information or signals in both directions between the first and second devices, it becomes possible to accurately calculate the propagation time of information or signals between the first and second devices, even if time synchronization is not maintained between the first and second devices.

[0012] In the above system, it is assumed that each of the multiple first devices and the second device are in a state where they can communicate with each other. In order to grasp the vehicle's position information during the transient state until such a state is formed, it is desirable to provide an auxiliary positioning means that periodically transmits a beacon signal from the first device and determines the position of the second device based on the time until the first device receives a probe request transmitted from the second device in response to the beacon signal, or based on the strength of the beacon signal received by the second device. By providing such auxiliary positioning means, it becomes possible to determine the position of a vehicle even when a communication state cannot be established between each of the multiple first devices and the second device when loading and unloading a vehicle onto a vehicle carrier (especially when moving a vehicle from the outside to the inside of the carrier or from the inside to the outside of the carrier), thereby enabling safe loading and unloading and improving work efficiency. Using the vehicle positions obtained from the above system, the following system can be constructed. In other words, it includes a shipboard information database that stores shipboard information including a deck layout diagram, and a target position setting means that sets a target position on the ship by referring to the shipboard information database, starting from the position of the second device identified by the position identification means. A route generation means generates a route from the starting point to the target position set by the target position determination means by referring to the onboard information database, Route guidance means that guides the route to the target location generated by the route generation means via a second device, and A system with even more features may be constructed.

[0013] By using such a system, for each vehicle where the second device is installed, the route from the current position to the target position set by the target position setting means is guided via the second device, so it becomes possible to guide a suitable route from the current position for each vehicle.

Advantages of the Invention

[0014] As described above, according to the vehicle positioning system for a vehicle carrier, the vehicle positioning method for a vehicle carrier, and the vehicle positioning program for a vehicle carrier according to the present invention, based on the transmission and reception times of information or signals in both directions between each of the plurality of first devices and the second device, the distance between each of the plurality of first devices and the second device is calculated. From the calculated distances between each of the plurality of first devices and the second device and the position information of the first device, the position of the vehicle in which the second device is installed is specified. Therefore, even inside a ship with poor reception sensitivity of satellite signals, it becomes possible to obtain the position information of the vehicles inside the ship with high accuracy using a simple device.

Brief Description of the Drawings

[0015] [Figure 1] It is a diagram showing an installation example of the first device and the second device used in the vehicle positioning system for a vehicle carrier according to the present invention, and is a diagram showing an example of loading a vehicle from a rampway provided at the vehicle loading / unloading entrance at the stern of the vehicle carrier. (a) is a perspective view of the vicinity of the stern, and (b) is a perspective view of the side of the vehicle carrier seen obliquely from above. [Figure 2] It is a diagram showing an installation example of the first device and the second device used in the vehicle positioning system for a vehicle carrier according to the present invention. (a) is a side view showing the schematic configuration inside the vehicle carrier, and (b) is a plan view showing an example of the loading state of the vehicles in the hold. [Figure 3] It is a diagram showing a configuration example of the vehicle positioning system for a vehicle carrier according to the present invention. [Figure 4] It is a block diagram showing a configuration example of the first device. [Figure 5] It is a block diagram showing a configuration example of the second device. [Figure 6] It is a block diagram showing the configuration of the server device. [Figure 7] It is a flowchart showing distance calculation processing. [Figure 8] It is a flowchart showing position identification processing. [Figure 9] It is a flowchart showing an example of a process for setting a route during vehicle loading and unloading using the vehicle positioning system for a vehicle carrier according to the present invention. [Figure 10] It is a flowchart showing an example of a process until a vehicle is moved to a predetermined parking position in a vehicle carrier and fixed using the vehicle positioning system for a vehicle carrier according to the present invention.

Mode for Carrying Out the Invention

[0016] Hereinafter, embodiments according to the present invention will be described with reference to the accompanying drawings.

[0017] In FIGS. 1 and 2, a schematic configuration example of a vehicle carrier B in which a vehicle positioning system S for a vehicle carrier is used is shown. Loading and unloading of vehicles between the vehicle carrier B and the outside of the ship are performed, for example, from a vehicle loading / unloading port E provided at the stern. Inside the vehicle carrier B, a boarding deck D1 is provided that allows a vehicle boarding through a rampway R installed at the vehicle loading / unloading port E from the outside of the ship to move horizontally from the stern to the bow. A plurality of vehicle decks D2, D3, D4, D5, D6 for storing the vehicle C are provided on the lower layer side and the upper layer side of this boarding deck D1. The movement of the vehicle C between the decks is performed via a ramp S (internal ramp) arranged obliquely between the upper and lower decks, and the vehicles are aligned and parked at a predetermined interval in a predetermined hold H based on a pre-established stowage plan.

[0018] As shown in FIG. 3, the vehicle positioning system S for a vehicle carrier according to the present invention includes a plurality of first devices 1, a second device 2 installed (mounted or attached) to the vehicle C, and a server device 3. The first device 1 is preferably installed in the inter-deck space between each deck, and may be installed at any mounting location on the ship that is at a suitable height for transmitting and receiving radio waves inside the ship (inter-deck space), such as on a wall, pillar, ceiling (the underside of the upper deck of the inter-deck space), or on the side of a ramp, or it may be installed on an object fixed inside the ship (light fixture, bulletin board, dedicated mounting pole, etc.). The first device 1 may be fixed to the surface of the ship location or object by appropriate means such as screws, adhesive, or brackets, or it may be installed by embedding it in the ship location or object.

[0019] Furthermore, each first device 1 has its own three-dimensional position information measured and identified. This three-dimensional position information of the first device 1 may be identified in advance and stored in a readable format inside the first device, or it may be identified retrospectively by some means after the system has been started. In addition, the three-dimensional position information of the first device 1 may be compiled into a database and stored in the storage unit (storage unit 33 described later) of the server device 3. Here, the three-dimensional position information may be represented, for example, by latitude, longitude, and ellipsoidal height in the WGS84 coordinate system, or by a unique three-dimensional coordinate system set up in each area of ​​the ship. Furthermore, the first device 1 is capable of transmitting beacon signals.

[0020] The first device 1 and the second device 2 can communicate directly with each other. Furthermore, the first device 1 can be connected to the server device 3 via the communication network 4, and the second device 2 can also be connected to the server device 3 via the communication network 4.

[0021] Each of the first device 1 and second device 2 has a built-in clock, and these built-in clocks can be synchronized to a reference time by a method described later. By synchronizing them, it is possible to obtain accurate positional information of multiple second devices 2 at the same time.

[0022] Furthermore, the first device 1 can also function as the first device 1 for multiple second devices 2, and when multiple second devices 2 exist, each of these second devices 2 may be configured to function as the first device for multiple other second devices. In other words, if the precise location of a second device can be determined, the distance between that second device and other second devices can be calculated and used to determine the location of the other second devices. In this embodiment, we will describe a case where only the first device is used to locate the second device.

[0023] (Regarding the first device) As shown in Figure 4, the first device 1 comprises a control unit 11, an RF chip 12, and an oscillator 13, each connected by a bus. It also includes a RAM 14 and a storage unit 15, each connected to the control unit 11 by a bus. Furthermore, the first device 1 has a beacon signal transmission unit 17.

[0024] The control unit 11 consists of a CPU and ROM, and executes programs stored in ROM to control the first device 1. The RF chip 12 is equipped with at least a clock 16, but may also be equipped with a phase detector. The RF chip 12 also has the function of processing the transmission and reception of wireless signals, and the data received by the RF chip 12 is subject to calculation processing by the control unit 11. The RAM 14 is the work area of ​​the control unit 11, and the storage unit 15 is a storage area for saving programs, data, etc.

[0025] The oscillator 13 oscillates at a predetermined frequency and outputs a signal to provide the operating timing for each part of the device. A crystal oscillator or an atomic oscillator can be used as the oscillator 13. The clock 16 keeps time using the output signal of the oscillator 13 as the source oscillation and outputs the time. The time kept by the clock 16 is controlled by the control unit 11 to be transmitted to the second device 2 via the RF chip 12. If a phase detector is also provided, it detects the phase of the carrier wave that constitutes the information received from the second device 2, and also detects the phase of the signal transmitted by the oscillator 13 of the first device 1.

[0026] The RF chip 12 is capable of sending and receiving data with other computer devices. Data received by the RF chip 12 is stored in the RAM 14 or storage unit 15 and is subject to calculation processing by the control unit 11. When the 3D position information of the first device 1 is received via the RF chip 12, it is stored in the RAM 14 or storage unit 15 and controlled by the control unit 11 to be transmitted to the second device 2 via the RF chip 12.

[0027] The beacon signal transmission unit 17 generates a beacon signal, and the RF chip 12 converts the generated beacon signal into a wireless signal and transmits it. When the control unit 11 receives a probe request in response to the transmission of this beacon signal, it measures the time from when the beacon signal is transmitted until when the probe request is received.

[0028] In this shipboard positioning system S, the installation location of the first device 1 is not particularly limited, but since it is used to determine the current position of vehicles on board, it is preferable to install it in a location where there are no obstacles between it and as many vehicles as possible, and the location should be appropriately selected according to the infrastructure conditions inside the transport ship using this positioning system S.

[0029] To obtain three-dimensional positional information of vehicles on board, the first device 1 does not need to be installed on the same plane; rather, it is preferable that adjacent first devices 1 be installed at different heights. For example, even when the first device 1 is attached to a wall inside the ship, it is preferable to make the mounting height of the first device 1 different for each wall and to manage the mounting height of the first device 1 for each deck (each space between decks). Furthermore, it is desirable that the first device 1 be installed comprehensively throughout the ship, and in order to cover the entire interior of the ship, it is advisable to place it appropriately in areas where GPS signals can be easily received.

[0030] Furthermore, the location information of the installation site of the first device 1 may be stored in its own storage unit 15, associated with identification information that can identify the first device 1, or stored in the storage unit 33 of the server device 3, or it may be made available via the communication network 4 from another management server that manages location information.

[0031] (Regarding the second device) Next, the second device 2 will be described. This second device 2 is installed (attached or attached to) a vehicle parked inside the ship. Installation (attachment or attachment) to the vehicle may be done in advance before the vehicle is driven, or it may be attached or attached to the vehicle only when it is desired to obtain the vehicle's location information using this vehicle location identification system S. In other words, if the second device 2 is operated and stopped by turning its own power on and off, it may be operated (functioned) by turning on the power only when it is desired to obtain the vehicle's location information.

[0032] Here, vehicle 5 is not particularly limited and includes automobiles, trucks, buses, towed vehicles, military vehicles, etc., and can be anything that can be accommodated on board the ship. The installation of the second device 2 is not limited to cases where the second device 2 is directly attached to the vehicle by some means of attachment, but also includes cases where it is fixed to something that houses the vehicle (e.g., a container) or an accessory (e.g., a luggage rack attached to the roof of the vehicle). Furthermore, the second device 2 is not limited to cases where it is fixed to the outside of the vehicle 5 with strings, bands, wires, chains, magnets, adhesives, etc., but also includes cases where it is embedded in the vehicle body.

[0033] Furthermore, "attached to the second device 2" means that even if the second device 2 is not mounted on the vehicle, it is in a state where it is moved together with the vehicle. For example, if there is a bag or storage case in the passenger compartment, this includes the state in which the second device 2 is placed inside that bag or storage case.

[0034] As shown in Figure 5, the second device 2 comprises a control unit 21, an RF chip 22, and an oscillator 23, each connected by a bus. It also includes a RAM 24, a storage unit 25, and a display unit 27, each connected to the control unit 21 by a bus. The RF chip 22 includes at least a clock 26, but may also include a phase detector if necessary.

[0035] The control unit 21 is configured with a CPU and ROM, and executes programs stored in the storage unit 25 to control the second device 2. The RAM 24 is the work area of ​​the control unit 21, and the storage unit 25 is a memory area for saving programs and data. The display unit 27 displays vehicle location information and route information to a target location, etc., which will be described later, in a visually recognizable manner. The control unit 21 performs calculation processing based on programs and data read from the RAM 24 and storage unit 25, as well as data input from an input unit (not shown).

[0036] The RF chip 22 is capable of sending and receiving data with other computer devices. The data received by the RF chip 22 is loaded into the RAM 24 and subjected to calculation processing by the control unit 21. The RF chip 22 is also capable of receiving beacon signals transmitted from the first device 1, and upon receiving this beacon signal, the control unit 21 sends back a probe request via the RF chip 22.

[0037] The oscillator 23 oscillates at a predetermined frequency and outputs a signal to provide the operating timing for each part of the device. A crystal oscillator or an atomic oscillator can be used as the oscillator 23. The clock 26 keeps time using the output signal of the oscillator 23 as the source oscillation and outputs the time. The time kept by the clock is controlled by the control unit 21 to be transmitted to the first device 1 via the RF chip 22. If a phase detector is also present, it detects the phase of the carrier wave that constitutes the information received from the first device 1, and also detects the phase of the signal oscillated by the oscillator 23 of the second device 2.

[0038] (About the server) Next, the server device 3 of the present invention will be described. The server device 3 can acquire location information from the second device 2.

[0039] The acquired location information is stored in server device 3 as location information for the vehicle (second device 2) on board the ship. The location information of the vehicle (second device 2) is transmitted from second device 2 to server device 3, for example, associating identification information that can identify second device 2 with the time the location information was determined. Server device 3 may also be able to communicate with first device 1 and second device 2 via a smart meter installed on vehicle carrier B.

[0040] Figure 6 is a block diagram showing the configuration of a server device 3 according to an embodiment of the present invention. The server device 3 comprises at least a control unit 31, a RAM 32, a storage unit 33, and a communication interface 34, each connected by an internal bus. It also includes a database 35 for storing information received from the first device 1 and the second device 2. The location information of the first device 1 may also be stored in this database 35 after being compiled into the database.

[0041] The control unit 31 consists of a CPU, ROM, etc., and executes programs stored in the storage unit 33 to control the server device 3. The control unit 31 also has an internal timer for measuring time. The RAM 32 is the work area of ​​the control unit 31. The storage unit 33 is a storage area for saving programs and data. The control unit 31 reads programs and data from the storage unit 33 and RAM 32, and, based on information received from the first device 1 or the second device 2, executes various control processes in the control unit according to the program.

[0042] Using the above configuration, the process of determining the position of the second device (vehicle) will now be explained. Two methods are used to determine the position of this second device (vehicle). • Location determination method using beacon signals transmitted from the first device • A location determination method that utilizes wireless bidirectional time comparison between the first and second devices.

[0043] (Regarding location determination methods using beacon signals transmitted from the first device: Method A) There are two methods A for determining the location of the second device 2 using beacon signals transmitted from the first device 1. (1) Location determination using the arrival time of the probe request When the second device 2 receives a beacon signal transmitted from the first device 1, the second device 2 sends back a probe request. When the first device 1 receives this probe request, the control unit 11 measures the time from when it transmitted the beacon signal until it received the probe request. Based on the above time measured by each first device (the time from when it transmitted the beacon signal until it received the probe request) and the position information of each first device, the server device uses the principle of triangulation to determine the position coordinates of the second device (vehicle) on board the ship. (2) Location determination using the strength of the beacon signal received by the second device After the first device 1 transmits a beacon signal, when the second device 2 receives the beacon signal from the first device 1, the second device 2 transmits the strength of the beacon signal along with the beacon ID. Once the strengths of the beacon signals from multiple first devices are known, the server device 3, knowing the position of the first device 1, uses the strengths of the beacon signals received by the second device 2 to determine the position coordinates of the second device (vehicle) on board the ship using the principle of triangulation. These beacon-based location determination processes supplement location determination in cases where location determination using the wireless bidirectional time comparison between the first and second devices described below is not possible or difficult.

[0044] (Regarding a method utilizing wireless bidirectional time comparison between the first and second devices: Method B) [Distance calculation process] In this method B, first, a process is performed to calculate the distance between device 1 and device 2. This distance calculation process calculates the distance between each of the first devices 1 and the second device 2, based on the propagation time Tp of the information or signal between each of the first devices 1 and the second device 2, provided that the first devices 1 and the second device 2 are within a distance range that allows them to mutually send and receive information or signals.

[0045] The distance calculation process is performed at predetermined time intervals (for example, every minute) or whenever predetermined conditions are met, and the process is carried out in steps S1 to S16 as shown in Figure 7. For convenience, here we will explain the case of calculating the distance between one first device 1 and one second device 2.

[0046] First, information or a signal is transmitted from the first device 1 to the second device 2 (step S1). The information or signal transmitted from the first device 1 to the second device 2 is not particularly limited.

[0047] In the first device 1, the time (T11) when information or a signal is transmitted in step S1 is recorded (step S2), and this recorded time is stored in the memory or storage unit 15 within the control unit 11 (step S3).

[0048] Subsequently, the second device 2 receives the information or signal from the first device 1 (step S4). The second device 2 records the time (T21) when the information or signal was received in step S4 (step S5). The recorded time (including the measured phase, if one is measured) is then stored in the memory or storage unit 25 of the control unit 21 (step S6).

[0049] Next, the second device 2 transmits information or a signal to the first device 1 (step S7). The information or signal transmitted from the second device 2 to the first device 1 is not particularly limited. The second device 2 records the time (T22) when the information or signal was transmitted in step S7 (step S8). Then, the recorded time is stored in the memory or storage unit 25 of the control unit 21 (step S9).

[0050] The first device 1 receives the information or signal transmitted in step S7 (step S10). The first device 1 records the time (T12) when it received the information or signal in step S10 (step S11). The recorded time (including the measured phase if the phase is measured) is then stored in the memory or storage unit 15 of the control unit 11 (step S12).

[0051] Subsequently, the first device 1 transmits to the second device 2 via its RF chip 12 the information stored in step S3 regarding the time (T11) when the signal was transmitted in step S1, and the information stored in step S12 regarding the time (T12) when the signal was received in step S10 (step S13). At this time, the position information of the first device 1 is also transmitted to the second device 2.

[0052] Then, in step S1, the second device 2 receives information regarding the time (T11) when the first device 1 transmitted information or a signal, and information regarding the time (T12) when the first device received information or a signal in step S10 (step S14).

[0053] Next, the distance between the first device 1 and the second device 2 is calculated using the second device 2 (step S15). This distance is calculated in the following manner.

[0054] Information regarding the time of the first device's clock (T11) is transmitted to the second device 2 via radio waves. The difference between this time and the time of the second device 2's clock (T21) when the second device 2 receives this information is recorded as ΔTa on the second device 2 side. In other words, if we define the time of the first device's clock when it transmits information or a signal from the first device 1 to the second device 2 as T11, and the time of the second device's clock when it receives the information or signal transmitted from the first device 1 and sets time as T21, and the difference between them as ΔTa, then this ΔTa (the difference in transmission and reception times when information or a signal is transmitted from the first device 1 to the second device 2) is the difference between the time of the first device 1's clock and the second device 2's clock (time difference: T20-T10) plus the propagation time (propagation delay) Tp, resulting in the relationship shown in Equation 1. This time difference (T20-T10) would be zero if the clocks of the first device 1 and the second device 2 were synchronized, but here we assume that a time difference (T20-T10) exists (they are not synchronized). [Formula 1] ΔTa=T21-T11=(T20-T10)+Tp

[0055] To determine this propagation time Tp, the second device 2 also sends information about the time of this clock (T22) to the first device 1, and the difference between this time and the time of the first device 1's clock (T12) when the first device 1 receives it is recorded as ΔTb on the first device side. That is, if we define the time of the second device's clock when the second device 2 transmits information or a signal to the first device 1 as T22, and the time of the first device 1's clock when it receives the information or signal transmitted from the second device 2 as T12, and the difference between them as ΔTb, then this ΔTb (the difference in transmission and reception times when the second device 2 transmits information or a signal to the first device 1) is the difference between the time of the first device 1's clock and the second device 2's clock (time difference: T10-T20) plus the propagation time (propagation delay) Tp, resulting in the relationship shown in Equation 2. Here, the time difference (T10-T20) would be zero if the clocks of the first device 1 and the second device 2 were synchronized, but here we assume that a time difference (T10-T20) exists (they are not synchronized). [Formula 2] ΔTb=T12−T22=(T10−T20)+Tp

[0056] The time differences between the two clocks, (T20-T10) and (T10-T20), are added when transmitting from the first device to the second device, and the same amount of time difference is subtracted when transmitting from the second device to the first device. Therefore, to find the propagation time Tp, we add equations 1 and 2, which cancels out the terms for the time differences (T20-T10) and (T10-T20), resulting in the relationship in equation 3. [Formula 3] Tp=(ΔTa+ΔTb) / 2 =((T21-T11)+(T12-T22)) / 2

[0057] Therefore, the propagation time Tp can be calculated based only on the time read by the clock of the first device 1 and the time read by the clock of the second device 2.

[0058] Incidentally, the time difference (T10-T20) between the clock of the first device 1 and the clock of the second device 2 is given by the relationship in Equation 4, obtained by [Equation 1] - [Equation 2]. [Formula 4] (T10-T20)=(ΔTa−ΔTb) / 2

[0059] Subsequently, the distance between the first device 1 and the second device 2 is calculated by multiplying the propagation time calculated using Equation 3 by the propagation speed of the information or signal (e.g., high speed) (step S15).

[0060] Then, the distance between the first device 1 and the second device 2 calculated in step S15 is stored in the memory or storage unit 25 of the control unit 21, and if subsequent processing is to be performed by the server device 3, it is transmitted to the server device 3 along with information such as the ID information of the first device 1 and the second device 2 and the time of calculation of the distance (step S16). By executing step S16, the distance calculation process is completed.

[0061] Therefore, since equation (3) for calculating the propagation time Tp does not include a term for the time difference (time difference: T20-T10) between the clocks of the first device 1 and the second device 2, the propagation time for information or signals to propagate between the first device 1 and the second device 2 can be calculated regardless of whether there is a time difference between the clocks of the first device 1 and the second device 2 (independent of the time difference (time difference: T10-T20) between the clocks of the first device 1 and the second device 2).

[0062] [Location identification process] Next, we will explain the process for determining the location of the vehicle to which the second device 2 is installed. This location determination process determines the location of the second device 2 based on the distances between each of the multiple first devices 1 and the second device 2, which were calculated in the distance calculation process. Since the second device 2 is installed on a vehicle inside the ship, this can be described as a process for determining the location of the vehicle inside the ship.

[0063] This positioning process should preferably be performed immediately after the distance calculation process is completed. Furthermore, in order to determine the position of the second device 2, it is assumed that the distance calculation device has calculated the distance to each of the multiple first devices 1 for each of the second devices 2.

[0064] In other words, when obtaining three-dimensional positional information of vehicles on board a ship (to obtain x, y, and z coordinates), the position of the second device 2 can be determined by a well-known multi-point surveying calculation method based on the distance between one second device 2 and at least four first devices 1, and the positional information of each of the four first devices 1 used to calculate this distance. Therefore, since this system can determine the three-dimensional position of the second device 2 if four or more distance data points are available between the first device 1 and the second device 2, it is advisable to appropriately distribute the first devices so that the second device 2 can send and receive information or signals with at least four first devices 1 even if the second device 2 moves. In particular, in locations where positional accuracy is required, it is necessary to pre-adjust the number of first devices 1 and their three-dimensional mounting positions to achieve the required accuracy.

[0065] Figure 8 shows a flowchart of the location identification process according to an embodiment of the present invention. This location identification process can be performed on any of the first device 1, the second device 2, or the server device 3. When the location identification process is performed on the first device 1 or the server device 3, the distance between each of the multiple first devices 1 and the second device 2, as well as the location information of the first device 1, can be associated with the identification information of the second device 2, transmitted to the first device 1 or the server device 3, and used (see step S16 above).

[0066] First, the position determination process requires that distance information for at least four different first devices 1 and second devices 2 be obtained at the same time or close together. Here, "close together" means that the time at which the distances for the four first devices 1 and second devices 2 used to determine the position of second device 2 are calculated is within a range that does not hinder the capture of the movement of the second device. If the distances are not calculated at the same time or close together (for example, if the time at which the propagation time of information or signals between each of the multiple first devices 1 and second device 2 is measured is the same time or close together), it becomes difficult to accurately determine the position of second device 2 (a vehicle on board the ship) if it is assumed to be moving.

[0067] Therefore, first, it is determined whether four or more data points of the distance between the first device 1 and the second device 2 have been acquired within a predetermined time range (step S21).

[0068] If four or more distance data points between the first device 1 and the second device 2 are not obtained within a predetermined time range, accurate three-dimensional position information cannot be obtained even using this positioning method. Therefore, positioning processing using the beacon signal (positioning processing by method A) is performed until four or more distance data points are obtained within a predetermined time range (step S22). Then, display processing is performed such as displaying the current position of the second device 2 (vehicle position on the ship) obtained using the beacon signal on a display screen (not shown) of the server device 3 (step 23).

[0069] In contrast, if four or more distance data points between the first device 1 and the second device 2 can be acquired within a predetermined time range, the position determination method using wireless bidirectional time comparison (position determination processing by method B) can be used to obtain accurate three-dimensional position information. Then, the current position of the second device 2 is determined using the multi-point surveying calculation method described above (step S24), and display processing is performed on the display screen of the server device 3, such as displaying the current position of the vehicle (second device 2) on the ship (step 23). At the same time, the position information of the second device 2 is stored in the storage unit 33 of the server device 3 along with the time it was calculated and used for subsequent processing.

[0070] Therefore, if there are four or more first devices 1 capable of transmitting and receiving between the second device 2 installed on a vehicle on board the ship within a predetermined time range, the three-dimensional position of the second device 2 is determined by a position determination process based on the distance between each first device 1 and the second device 2 calculated by the distance calculation process, and the position information of each first device 1 used in this distance calculation. As the vehicle on which the second device 2 is installed moves, the four first devices 1 from which distance calculation is possible switch sequentially, making it possible to continuously capture the position of the second device 2. Thus, if there are four or more first devices 1 capable of calculating distance, it becomes possible to determine the three-dimensional position of the second device 2. By adjusting the mounting locations and heights of the first devices to appropriately scatter them, it becomes possible to capture the position of the displaced second device in real time.

[0071] By performing the above process on all vehicles on board (vehicles equipped with the second device), accurate three-dimensional positional information for all vehicles on board can be obtained. By visualizing this information and performing 3D mapping, it becomes possible to understand the three-dimensional positions of the vehicles on board.

[0072] Incidentally, if the second device 2 installed in each vehicle is not time-synchronized, the location information of all vehicles on board at a given time recorded on the server will become inaccurate (a discrepancy will occur between the location recorded on the server at a given time and the actual location at that time), which could lead to incorrect guidance or information being sent to the workers. Furthermore, when the vehicles are operated automatically, incorrect instructions may be sent. In particular, when controlling multiple vehicles simultaneously, all devices (first device 1 and second device 2) must be time-synchronized in order to properly issue response instructions from the server device at the appropriate time. Therefore, by synchronizing the time of the second device 2 with the time of the first device based on the time difference in equation (4), it becomes possible to synchronize the time of the second device as well by synchronizing the server device 3 and multiple first devices 1 at predetermined timings. This makes it possible to collect accurate location information of all vehicles on board at the same time in real time, enabling smooth, accurate, and safe loading and unloading of vehicles.

[0073] Furthermore, as mentioned above, the method (Method B) that utilizes wireless bidirectional time comparison between the first device 1 and the second device 2 is premised on the second device installed on the vehicle being within an area where it can communicate with at least four first devices. Therefore, there is a risk that location information cannot be obtained outside the ship or near the vehicle entrance / exit where vehicles are entering the ship. Also, even inside the ship, signal propagation between the first and second devices may be hindered by the presence of physical obstacles between them or interference from other radio waves. However, even in such cases, the location identification method (Method A) using beacons transmitted from the first device is used supplementarily in step S22, making it possible to ensure redundancy in vehicle location identification and improve the reliability and safety of the system.

[0074] In the above configuration, a method for capturing the location information of vehicles on board the ship in real time has been described. However, in vehicle loading and unloading operations, vehicles are loaded onto the ship from a vehicle yard located within port facilities near the vehicle carrier, and unloaded vehicles are lined up in the vehicle yard. Therefore, understanding and controlling the location of vehicles outside the ship is also important. To capture the location information of vehicles in real time, including the vehicle yard near the vehicle carrier, the first device may be installed on the outside of the vehicle carrier, that is, on the upper side of the carrier or on mooring posts, lighting equipment, and other facilities on the pier, and the location of vehicles including the vehicle yard may be managed.

[0075] (Example of using this system 1) Using the vehicle positioning system for vehicle carriers described above, the following system can be constructed. First, I will explain the system that uses this system to suggest the optimal route from your current location to your destination on the ship (for example, the vehicle parking location on the ship or the vehicle loading / unloading entrance). In this system, in addition to the configuration shown in Figure 3, an onboard information database 40 is further provided (shown by the dashed line in Figure 6). The shipboard information database 40 stores shipboard information such as the deck layout, information on various facilities, the width and length of each passageway, and areas that are accessible and inaccessible.

[0076] First, the location information of all vehicles on board is calculated in real time using the method described above, with the first device 1 installed on board the ship and the second device 2 installed on the vehicles (step S31), and the target position of each vehicle is set by referring to the onboard information database 40 (step S32). Next, the system checks for the presence of other vehicles nearby (step S33). If no other vehicles are nearby, it refers to the onboard information stored in the onboard information database 40 to calculate the shortest route from the current location to the target location. In this process, the system generates the shortest possible route from the onboard information database 40, taking into account factors such as aisle width and equipment layout (step S34).

[0077] Then, the generated route information is transmitted to the second device 2, and the route is displayed on the display unit 27 of the second device 2 in a visually identifiable manner, or the device 2 provides voice guidance on which direction to move from the current location, thereby guiding the user along the calculated route (step S35). Furthermore, if the vehicle is equipped with an autonomous driving system, a command is sent to the autonomous driving system to drive according to the route calculated in step 34 (step S36).

[0078] In response to this, if it is determined that another vehicle is nearby, the ship's information database 40 is consulted to generate the optimal route from the current position to the target position, that is, a safe and shortest route that avoids contact with the other vehicle, taking into account conditions such as the width of the passageway, the arrangement of equipment, and other vehicles on the same deck (step S37). Subsequently, information regarding the generated route is transmitted to the second device 2, and the generated route is guided by displaying the route visually on the display unit 27 of the second device 2, or by announcing the direction in which to move from the current location via voice (step S35). Furthermore, if the vehicle is equipped with an autonomous driving system, a command is sent to the autonomous driving system to drive according to the route generated in step 37 (step S36).

[0079] Therefore, with the system described above, it becomes possible to collect accurate location information of each vehicle on board in real time and then provide appropriate guidance and information to each vehicle individually according to its current location.

[0080] Furthermore, since this system enables control based on the precise location information of the vehicles, it is also effective in accurately moving and securing the vehicles to be loaded to the intended stopping points. Because the server device 3 grasps the precise location of each vehicle on board in real time, as shown in Figure 10, after the position of the second device 2 (vehicle C) is calculated (step S41), a route to the set stopping position on the board is generated (step S42). Then, a command is sent to the automatic driving system to drive according to the generated route, causing the vehicle to automatically drive to the stopping position (step S43). After vehicle C reaches the stopping position, the orientation of the vehicle and the distance from adjacent vehicles and equipment are adjusted (step S44), and then the vehicle is automatically secured (step S45).

[0081] Therefore, with the above system, vehicle operation by skilled drivers becomes unnecessary, and only the movement and stopping position of the vehicle need to be confirmed. This eliminates human judgment errors and reliance on the skills of workers, and also ensures the accuracy and speed of loading and unloading.

[0082] (Example of using this system 2) Furthermore, in a system that loads vehicles onto a vehicle carrier and uses information about the port of unloading to guide the vehicles into the ship in an order that facilitates loading and unloading, this system can capture the precise location of each vehicle in real time, making it possible to accurately guide each vehicle to its designated location on the ship in the set order. [Explanation of Symbols]

[0083] 1 1st device 2 Second device 3 Server equipment S Shipboard positioning system C Vehicle B Vehicle carrier

Claims

1. A vehicle positioning system for a vehicle carrier that uses a plurality of first devices installed at intervals inside the vehicle carrier and whose positions within the vehicle carrier are specified, and a second device installed on a vehicle loaded onto the vehicle carrier, to determine the position of the vehicle, Distance calculation means for calculating the distance between each of the multiple first devices and the second device based on the bidirectional transmission and reception times of information or signals between each of the multiple first devices and the second device, A position determination means that determines the position of the second device based on the distance between each of the first and second devices calculated by the distance calculation means, and the position information of each of the first devices, A vehicle positioning system for vehicle carriers, characterized by having the following features.

2. The vehicle positioning system for a vehicle carrier ship according to claim 1, characterized in that the first device periodically transmits a beacon signal, and an auxiliary positioning means is provided to determine the position of the second device based on the time from when the first device receives the beacon signal and a probe request transmitted from the second device, or based on the intensity of the beacon signal received by the second device.

3. The vehicle positioning system for a vehicle carrier according to claim 1 or 2, characterized in that the first device is further arranged at a distance from the outside of the vehicle carrier.

4. The ship includes an onboard information database that stores onboard information, including a deck layout diagram of the ship, A target position setting means sets a target position within the ship by referring to the shipboard information database, using the position of the second device identified by the position identification means as the starting point. Route generation means for generating a route from the starting point to the target position by referring to the onboard information database, Route guidance means that guides the vehicle through the second device along the route to the target location generated by the route generation means, or transmits a command to the vehicle's automatic driving system to drive along the route. The vehicle positioning system for vehicle carriers according to claim 1 or 2, further comprising the above.

5. The distance calculation means is The difference between the time on the first device's clock when it transmits information or a signal and the time on the second device's clock when it receives the information or signal transmitted from the first device, The difference between the time on the second device's clock when it transmits information or a signal and the time on the first device's clock when it receives the information or signal transmitted from the second device. The vehicle positioning system for a vehicle carrier ship according to claim 1 or 2, characterized in that it calculates the propagation time of the information or signal between the first device and the second device based on this propagation time, and calculates the distance between the first device and the second device based on this propagation time.

6. A vehicle positioning method for a vehicle carrier, comprising: a plurality of first devices installed at intervals inside the vehicle carrier and whose positions within the vehicle carrier are specified; and a second device installed on a vehicle loaded onto the vehicle carrier, wherein the position of the vehicle is determined using the above, A distance calculation step that calculates the distance between each of the multiple first devices and the second device based on the bidirectional transmission and reception times of information or signals between each of the multiple first devices and the second device, A position determination step in which the position of the second device is determined based on the distance between each of the first and second devices calculated in the distance calculation step, and the position information of each of the first devices, A vehicle positioning method for vehicle carriers, characterized by having the following features.

7. The vehicle positioning method for a vehicle carrier ship according to claim 6, further comprising an auxiliary positioning step of determining the position of the second device based on the time from when the first device periodically transmits a beacon signal and the first device receives a probe request transmitted from the second device in response to the beacon signal, or based on the intensity of the beacon signal received by the second device.

8. The vehicle positioning method for a vehicle carrier according to claim 6 or 7, characterized in that the first device is further arranged at an interval outside the vehicle carrier.

9. The ship includes an onboard information database that stores onboard information, including a deck layout diagram of the ship, A target position setting step in which the position of the second device identified in the position identification step is used as the starting point, and the target position within the ship is set by referring to the shipboard information database, A route generation step that generates a route from the starting point to the target position set by the target position setting step by referring to the onboard information database, A route guidance step which involves guiding the vehicle through the second device along the route to the target location generated in the route generation step, or transmitting a command to the vehicle's automatic driving system to drive along the route. The vehicle positioning method for a vehicle carrier according to claim 6 or 7, further comprising the above.

10. A vehicle positioning program for a vehicle carrier, for causing a computer to perform each step of the vehicle positioning method for a vehicle carrier described in any one of claims 6 to 7.

11. A vehicle positioning program for a vehicle carrier, for causing a computer to perform each step of the vehicle positioning method for a vehicle carrier described in claim 9.

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