IGV fusion positioning method and system based on UHF RFID communication

Abstract

The application provides an IGV fusion positioning method based on UHF RFID communication, comprising the following steps: arranging multiple positioning columns, arranging four UHF RFID readers, laser radar scanners, visual cameras and vehicle information processing systems; measuring column positioning coordinate information of each positioning column and arranging RFID tags; scanning and identifying the RFID tags on the positioning columns around the IGV body, and transmitting multiple signal strength indication values and column positioning coordinate information to the vehicle information processing system; performing laser scanning on the positioning columns near the IGV, thereby obtaining laser-recognized column point cloud data, and then transmitting the laser-recognized column point cloud data to the vehicle information processing system; performing shooting on the positioning columns near the IGV, thereby obtaining visual positioning data, and then transmitting the visual positioning data to the vehicle information processing system; and performing matching and fusion, thereby obtaining real-time positioning coordinates of the IGV. The application provides an IGV fusion positioning system based on UHF RFID communication. The application makes the IGV navigation in the port more accurate, reliable and stable.

Description

Technical Field

[0001] This invention relates to the field of communication and positioning technology for unmanned vehicles in ports, specifically to an IGV fusion positioning method and system based on UHF RFID communication. Background Technology

[0002] Automated container terminals primarily utilize three types of loading and unloading equipment: quay cranes for handling at the quayside, rail-mounted gantry cranes for handling in the yard, and horizontal transport equipment for navigating within the terminal. Integral Inlet Vehicles (IGVs) are the main application of horizontal transport equipment. In automated container terminals, operational scenarios include automatic interaction between IGVs and quay cranes, automatic interaction between IGVs and rail-mounted gantry cranes, interaction between IGVs and charging systems, mutual position confirmation between IGVs, and human-machine interaction involving IGV locking and unlocking. To ensure the safe and efficient operation of the equipment, these complex operational scenarios place higher demands on the positioning accuracy of IGVs. Therefore, for autonomous vehicles, the vehicle's own positioning stability is a key technical aspect.

[0003] Current positioning systems for autonomous vehicles are fusion positioning systems based on the Global Positioning System (GPS), which have the following drawbacks:

[0004] 1. The Global Positioning System (GPS) relies on reference stations and complex calculations, resulting in high equipment costs and difficult maintenance;

[0005] 2. The Global Positioning System (GPS) is susceptible to signal blockage and interference due to factors such as the height of quay cranes, rail-mounted gantry cranes, container stacking, or the atmospheric ionosphere at the port.

[0006] 3. Laser positioning systems and visual positioning systems cannot obtain initial positioning when the global positioning system signal fails. Summary of the Invention

[0007] In view of this, it is necessary to propose an IGV fusion positioning method and system based on UHF RFID communication to address the above-mentioned problems, so as to overcome some of the shortcomings in the background technology and solve the technical problem of how to make IGV navigation in ports more accurate and reliable by fusing laser, vision and UHF-RFID.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention proposes an IGV fusion positioning method based on UHF RFID communication, applicable to automated container terminals equipped with several IGVs. The IGV fusion positioning method includes the following steps:

[0010] Step S1: Arrange multiple positioning columns at the automated container terminal, and install four UHF RFID readers, a LiDAR scanner, a vision camera, and an on-board information processing system on the IGV; the four UHF RFID readers are located at the front left, front right, rear left, and rear right corners of the IGV vehicle, respectively.

[0011] Step S2: Measure the positioning coordinate information of each positioning column, and set RFID tags that record the positioning coordinate information on each positioning column.

[0012] Step S3: Two diagonally opposite UHF RFID readers on the IGV scan and identify RFID tags on the positioning pillars around the IGV in real time. This allows the UHF RFID readers to obtain multiple signal strength indicators for different frequencies of the corresponding RFID tags, as well as the positioning coordinates of the pillars. These multiple signal strength indicators and the pillar positioning coordinates are then transmitted to the vehicle information processing system. A laser radar scanner is used to scan the positioning pillars near the IGV, obtaining laser-identified pillar point cloud data, which is then transmitted to the vehicle information processing system. Finally, a visual camera is used to photograph the positioning pillars near the IGV, obtaining visual positioning data, which is then transmitted to the vehicle information processing system.

[0013] In step S4, the vehicle information processing system matches and fuses the column positioning coordinate information, laser recognition column point cloud data, visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

[0014] Furthermore, the IGV fusion localization method also includes the following steps between step S2 and step S3:

[0015] Step S23: Use several total stations to perform coordinate mapping on the automated container terminal to form a two-dimensional electronic map of the automated container terminal, and store the two-dimensional electronic map in the vehicle information processing system.

[0016] Furthermore, in step S4, the real-time positioning coordinates of the IGV are estimated and corrected using a Kalman filter algorithm to obtain the corrected real-time accurate position of the IGV.

[0017] Furthermore, in step S3, when two of the diagonal UHF RFID readers of the IGV fail to scan and identify the RFID tags on the positioning pillars around the IGV body in real time, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of the RFID tags on the positioning pillars near the IGV.

[0018] If the other two diagonally opposite UHF RFID readers fail to scan and identify the RFID tags on the positioning pillars near the IGV in real time, then maintenance personnel will be notified to carry out repairs.

[0019] Further, step S4 includes the following sub-steps;

[0020] Step S41: Match and fuse the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information;

[0021] The column positioning coordinates are then matched and fused with visual positioning data to obtain visual navigation positioning information.

[0022] Step S42 involves matching the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system.

[0023] Furthermore, when the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by identifying at least three RFID tags and based on the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, i.e., they are not collinear.

[0024] Further, in step S3, the reader coordinates (X, Y) are obtained by solving a system of equations based on the distances from the IGV to several RFID tags; the standard form of the system of equations is: (Xn-X)2+(Yn-Y)2=Dn2, where Xn and Yn represent the coordinates of the RFID tags, and Dn represents the distance of the RFID tag identification; the reader coordinates (X, Y) are obtained by solving the system of equations using Python's three-circle intersection code program.

[0025] This invention further proposes an IGV fusion positioning system based on UHF RFID communication, applied to IGVs that operate in automated container terminals with multiple positioning posts, each post being equipped with a corresponding RFID tag. The IGV fusion positioning system includes:

[0026] The vehicle-mounted information processing system includes an onboard computer, a laser scanning and recognition information processor, a vision recognition information processor, and a UHF RFID information processor. The onboard computer is equipped with an IGV navigation correction software module, the laser scanning and recognition information processor with a laser positioning software module, the vision recognition information processor with a vision recognition software module, and the UHF RFID information processor with a UHF RFID information processing software module. The onboard computer communicates with the laser scanning and recognition information processor, the vision recognition information processor, and the UHF RFID information processor. A lidar scanner is used to perform laser scanning on positioning posts near the IGV, thereby obtaining point cloud data of the laser recognition posts, which is then transmitted to the laser scanning and recognition information processor.

[0027] Visual camera; The visual camera is used to photograph the positioning column near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor.

[0028] Four UHF RFID readers are installed at the four corners of the IGV. A UHF RFID information processor communicates with each of the four UHF RFID readers. The UHF RFID readers are used to scan and identify RFID tags on the positioning pillars around the IGV in real time, thereby obtaining multiple signal strength indication values ​​of different frequencies for the corresponding RFID tags and the positioning coordinate information of the pillars. The multiple signal strength indication values ​​and the positioning coordinate information are then transmitted sequentially through the UHF RFID information processor and the vehicle computer to the laser scanning recognition information processor, and the multiple signal strength indication values ​​and the positioning coordinate information are also transmitted sequentially through the UHF RFID information processor and the vehicle computer to the vision recognition information processor.

[0029] The laser positioning software module is used to match and fuse the specified column positioning coordinates with the laser recognition column point cloud data according to the signal strength indication value received by the laser scanning and recognition information processor, thereby obtaining laser navigation and positioning information, and then transmitting the laser navigation and positioning information to the IGV navigation correction software module.

[0030] The visual recognition software module is used to match and fuse the specified column positioning coordinates with the visual positioning data according to the signal strength indication value received by the visual recognition information processor, thereby obtaining visual navigation positioning information, and then transmitting the visual navigation positioning information to the IGV navigation correction software module.

[0031] The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and two-dimensional electronic maps of automated container terminals to obtain the real-time positioning coordinates of the IGV.

[0032] Furthermore, the IGV navigation correction software module is equipped with a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the corrected real-time accurate position of the IGV.

[0033] The two-dimensional electronic map is obtained by measuring the coordinates of the automated container terminal using several total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

[0034] The present invention further proposes a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the IGV fusion positioning method based on UHF RFID communication as described in any of the preceding claims.

[0035] The beneficial effects of this invention are as follows:

[0036] This invention achieves more accurate, reliable, and stable IGV navigation within ports by integrating laser, vision, and UHF-RFID technologies. It solves the problem of GPS signal failure in the IGV self-positioning system during horizontal transport operations, and also addresses the issue of IGVs failing to obtain initial positioning via laser or vision positioning, leading to positioning anomalies. Specifically, it overcomes the shortcomings of both IGV laser and vision positioning systems in obtaining initial positioning when GPS signals fail. Furthermore, it addresses the impact of laser positioning system identification and matching stability on factors such as equipment movement, obstructed reference points, or changes in container positions in the yard, thereby improving the self-positioning stability of IGVs during horizontal transport operations.

[0037] Advantages of this solution:

[0038] I. The adoption of UHF RFID communication technology results in low investment costs, easy deployment of tags and readers, and simple subsequent maintenance;

[0039] Second, by adopting UHF RFID communication technology, the reading distance can be made farther and the range wider through ultra-high frequency electromagnetic waves and phased array antennas, and multiple objects can be identified simultaneously at the same time.

[0040] Third, it is less affected by on-site equipment and environmental factors at automated terminals, and its signal transmission and reception are more reliable and stable.

[0041] Fourth, data is implanted into each positioning column to facilitate the acquisition of initial positioning values ​​during laser positioning and improve the robustness of fusion positioning. Attached Figure Description

[0042] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate exemplary embodiments of the invention and, together with the description, serve to explain the principles of the invention. These drawings are for illustrative purposes only and are not intended to limit the scope of the invention.

[0043] Figure 1 This is a flowchart illustrating the workflow of the IGV fusion positioning method based on UHF RFID communication according to the present invention.

[0044] Figure 2 This is a block diagram illustrating the principle structure of the IGV fusion positioning system based on UHF RFID communication according to the present invention.

[0045] Figure 3 This is a three-dimensional structural diagram of the positioning column equipped with RFID tags according to the present invention;

[0046] Figure 4 This is a top view schematic diagram of the IGV structure with four UHF RFID readers installed, as per the present invention.

[0047] Figure 5 This is a top view of the working principle diagram of the IGV with four UHF RFID readers installed in conjunction with the positioning column, which is involved in this invention.

[0048] Figure 6 This invention relates to a schematic diagram of coordinate positioning when an IGV equipped with four UHF RFID readers detects multiple positioning columns.

[0049] Figure 7 This is a schematic diagram of the IGV fusion positioning output process based on UHF RFID communication in Embodiment 4 of the present invention;

[0050] Figure 8 This is a schematic diagram of the automatic switching process of four UHF RFID readers in Embodiment 4 of the present invention. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be further described clearly and completely below in conjunction with the embodiments of this invention. It should be noted that the described embodiments are merely some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0052] The terms “first,” “second,” “third,” and “fourth” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, the use of “first,” “second,” “third,” and “fourth” to designate a feature may explicitly or implicitly include one or more of that feature.

[0053] The following is a detailed description of embodiments of the invention depicted in the accompanying drawings. The embodiments are detailed in order to clearly convey the invention. However, the amount of detail provided is not intended to limit the contemplative variations of the embodiments; rather, it is intended to cover all modifications, equivalents, and substitutions falling within the spirit and scope of the invention as defined by the appended claims.

[0054] In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. It will be apparent to those skilled in the art that embodiments of the invention may be practiced without some of these specific details.

[0055] Embodiments of the present invention include various steps, which will be described below. These steps may be performed by hardware components or may be contained in machine-executable instructions that can be used by a general-purpose or special-purpose processor programmed with those instructions to perform these steps. Alternatively, the steps may be performed by a combination of hardware, software, and firmware and / or by a human operator.

[0056] The various methods described herein can be practiced by combining one or more machine-readable storage media containing code according to the invention with suitable standard computer hardware to execute the code contained therein. Apparatus for implementing the various embodiments of the invention may include one or more computers (or one or more processors within a single computer) and a storage system containing or having network access to computer programs encoded according to the various methods described herein, and the method steps of the invention may be performed by modules, routines, subroutines, or sub-parts of a computer program product.

[0057] If the specification states that a component or feature "may", "can", "may" include or have the feature, then it is not necessary to include that particular component or feature or have that feature.

[0058] As used in this specification and the following claims, the words “a,” “an,” and “the” have the meaning of plural reference unless the context clearly indicates otherwise. Furthermore, as used in the description herein, unless the context clearly indicates otherwise, “in” has the meaning of both “in…” and “on…”.

[0059] Exemplary embodiments will now be described more fully below with reference to the accompanying drawings, which illustrate exemplary embodiments. These exemplary embodiments are provided for illustrative purposes only and to make the invention thorough and complete, and to fully convey the scope of the invention to those skilled in the art. However, the disclosed invention can be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Various modifications will be apparent to those skilled in the art. The general principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the invention. Furthermore, all statements regarding embodiments of the invention and specific examples thereof described herein are intended to cover their structural and functional equivalents. Additionally, these equivalents are intended to include currently known equivalents as well as those developed in the future (i.e., any element developed that performs the same function, regardless of its structure). Moreover, the terminology and wording used are for the purpose of describing exemplary embodiments and should not be considered limiting. Therefore, the invention is to be endowed with the broadest scope, including various substitutions, modifications, and equivalents consistent with the disclosed principles and features. For clarity, details of technical materials known in the art related to this invention have not been described in detail so as not to unnecessarily obscure the invention.

[0060] Therefore, for example, those skilled in the art will understand that schematic diagrams, schematics, illustrations, etc., represent conceptual views or processes embodying the systems and methods of the present invention. The functionality of the various elements shown in the figures can be provided using dedicated hardware and hardware capable of executing the relevant software. Similarly, any switches shown in the figures are merely conceptual. Their functionality can be performed through the operation of program logic, through dedicated logic, through interaction between program control and dedicated logic, or even manually; specific techniques may be chosen by the entity implementing the invention. Those skilled in the art should further understand that the exemplary hardware, software, processes, methods, and / or operating systems described herein are for illustrative purposes and are therefore not intended to be limited to any particular named element.

[0061] Embodiments of the present invention may provide a computer program product that may include a machine-readable storage medium on which instructions are tangibly implemented, which may be used to program a computer (or other electronic device) to perform processing. The terms "machine-readable storage medium" or "computer-readable storage medium" include, but are not limited to, fixed (hardware) drives, magnetic tape, floppy disks, optical discs, optical disc read-only memory (CD-ROM) and magneto-optical discs, semiconductor memories such as ROMs, PROMs, random access memories (RAM), programmable read-only memories (PROMs), erasable PROMs (EPROMs), electrically erasable PROMs (EEPROMs), flash memory, magnetic or optical cards, or other types of media / machine-readable media suitable for storing electronic instructions (e.g., computer programming code, such as software or firmware). Machine-readable media may include non-transitory media in which data can be stored and does not include carrier waves and / or transient electronic signals propagated via wireless or wired connections. Examples of non-transitory media may include, but are not limited to, magnetic disks or magnetic tapes, optical storage media such as compact discs (CDs) or digital universal discs (DVDs), flash memory, memory, or memory devices. Computer program products may include code and / or machine-executable instructions, which may represent any combination of procedures, functions, subroutines, programs, routines, subroutines, modules, software packages, classes, or instructions, data structures, or program statements. Code segments may be coupled to other code segments or hardware circuitry by passing and / or receiving information, data, variables, parameters, or memory contents. Information, variables, parameters, data, etc., may be passed, forwarded, or transmitted by any suitable means, including memory sharing, message passing, token passing, network transmission, etc.

[0062] Furthermore, embodiments can be implemented using hardware, software, firmware, middleware, microcode, hardware description languages, or any combination thereof. When implemented in software, firmware, middleware, or microcode, program code or code segments (e.g., a computer program product) that perform the necessary tasks can be stored on a machine-readable medium. The processor can then perform the necessary tasks.

[0063] The systems depicted in the figures can be provided in various configurations. In some embodiments, the system can be configured as a distributed system, wherein one or more components of the system are distributed across one or more networks of a cloud computing system.

[0064] Each of the appended claims defines a separate invention, which, for infringement purposes, is considered to include the various elements or limited equivalents specified in the claims. Depending on the context, all references to "invention" below may refer only to certain specific embodiments in some cases. In other cases, it should be recognized that references to "invention" will refer to one or more, but not necessarily all, the subject matter described in the claims.

[0065] Unless otherwise stated herein or the context clearly contradicts it, all methods described herein may be performed in any suitable order. The use of any and all examples or exemplary language (e.g., “such as”) provided with respect to certain embodiments herein is intended only to better illustrate the invention and not to limit the scope of the claimed invention. No language in the specification should be construed as indicating any unclaimed element essential to the implementation of the invention.

[0066] The various terms used herein are as follows. Where no term is defined below as used in the claims, the broadest definition should be given, and those skilled in the art have provided the term as reflected in printed publications and granted patents at the time of filing.

[0067] Example 1

[0068] like Figure 1 , Figures 3-6 As shown:

[0069] This embodiment proposes an IGV fusion positioning method based on UHF RFID communication, applied to an automated container terminal equipped with several IGVs. The IGV fusion positioning method includes the following steps:

[0070] Step S1: Arrange multiple positioning columns at the automated container terminal, and install four UHF RFID readers, a LiDAR scanner, a vision camera, and an on-board information processing system on the IGV; the four UHF RFID readers are located at the front left, front right, rear left, and rear right corners of the IGV vehicle, respectively.

[0071] Step S2: Measure the column positioning coordinates of each positioning column, and set up RFID tags on each positioning column to record the column positioning coordinates. Specifically, the column positioning coordinates refer to the column positioning coordinates measured using a total station (a high-precision measuring instrument used in various engineering and surveying projects). Since the column and the RFID tag are installed in the same location, the column positioning coordinates are also the column positioning coordinates of the RFID tag. Then, the information is manually entered into the RFID tag.

[0072] Step S3: Two diagonally opposite UHF RFID readers on the IGV scan and identify RFID tags on the positioning pillars around the IGV in real time. This allows the UHF RFID readers to obtain multiple RSSI (Signal Strength Indicator) values ​​for different frequencies corresponding to the RFID tags, as well as the pillar positioning coordinates. These RSSI values ​​and pillar positioning coordinates are then transmitted to the vehicle information processing system. A laser radar scanner is used to scan the positioning pillars near the IGV, obtaining laser-identified pillar point cloud data, which is then transmitted to the vehicle information processing system. Finally, a visual camera is used to photograph the positioning pillars near the IGV, obtaining visual positioning data, which is also transmitted to the vehicle information processing system.

[0073] In step S4, the vehicle information processing system matches and fuses the column positioning coordinate information, laser recognition column point cloud data, visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

[0074] Optimally, the IGV fusion localization method further includes a step between step S2 and step S3:

[0075] Step S23 (executed after step S2) involves using several total stations to perform coordinate mapping on the automated container terminal, thereby creating a two-dimensional electronic map of the automated container terminal, and storing the two-dimensional electronic map in the vehicle information processing system; then step S3 is executed.

[0076] Ideally, in step S4, the real-time positioning coordinates of the IGV are estimated and corrected using a Kalman filter algorithm to obtain the corrected real-time accurate position of the IGV.

[0077] Optimally, in step S3, when two of the diagonal UHF RFID readers of the IGV fail to scan and identify the RFID tags on the positioning pillars around the IGV body in real time, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of the RFID tags on the positioning pillars near the IGV.

[0078] If the other two diagonally opposite UHF RFID readers fail to scan and identify the RFID tags on the positioning pillars near the IGV in real time, then maintenance personnel will be notified to carry out repairs.

[0079] Optimally, step S4 includes the following sub-steps;

[0080] Step S41: Match and fuse the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information;

[0081] The column positioning coordinates are then matched and fused with the visual positioning data to obtain visual navigation positioning information; then step S42 is executed.

[0082] Step S42 involves matching the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system.

[0083] Specifically, the antenna of the UHF RFID reader is a phase array antenna.

[0084] Ideally, when the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by identifying at least three RFID tags and based on the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, i.e., they are not collinear.

[0085] In step S3, the reader coordinates (X, Y) are obtained by solving a system of equations based on the distances from the IGV to several RFID tags. The standard form of the system of equations is: (Xn-X)² + (Yn-Y)² = Dn², where Xn and Yn represent the coordinates of the RFID tags, and Dn represents the distance at which the RFID tags are identified. The reader coordinates (X, Y) are then solved using the standard form of the system of equations and the Python code program for finding the intersection of three circles.

[0086] Example 2

[0087] like Figures 2-6 As shown:

[0088] An IGV fusion positioning system based on UHF RFID communication is applied to IGVs that move in automated container terminals with multiple positioning posts, each post being equipped with a corresponding RFID tag. The IGV fusion positioning system includes:

[0089] The vehicle-mounted information processing system includes an onboard computer, a laser scanning and recognition information processor, a vision recognition information processor, and a UHF RFID information processor. The onboard computer is equipped with an IGV navigation correction software module, the laser scanning and recognition information processor with a laser positioning software module, the vision recognition information processor with a vision recognition software module, and the UHF RFID information processor with a UHF RFID information processing software module. The onboard computer communicates with the laser scanning and recognition information processor, the vision recognition information processor, and the UHF RFID information processor.

[0090] LiDAR scanner; The LiDAR scanner is used to perform laser scanning on the positioning posts near the IGV to obtain laser recognition post point cloud data, and then transmit the laser recognition post point cloud data to the laser scanning recognition information processor.

[0091] Visual camera; The visual camera is used to photograph the positioning column near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor.

[0092] Four UHF RFID readers are installed at the four corners of the IGV. A UHF RFID information processor communicates with each of the four UHF RFID readers. The UHF RFID readers scan and identify RFID tags on the positioning pillars around the IGV in real time, thereby obtaining multiple signal strength indicators (RSSI) of different frequencies for the corresponding RFID tags and the positioning coordinates of the pillars. The multiple RSSI and the positioning coordinates are then transmitted sequentially to the laser scanning and identification information processor via the UHF RFID information processor and the onboard computer, and finally to the vision recognition information processor via the UHF RFID information processor and the onboard computer.

[0093] The laser positioning software module is used to match and fuse the specified column positioning coordinates with the laser recognition column point cloud data according to the signal strength indication value RSSI received by the laser scanning and recognition information processor, thereby obtaining laser navigation and positioning information, and then transmitting the laser navigation and positioning information to the IGV navigation correction software module.

[0094] The visual recognition software module is used to match and fuse the specified column positioning coordinates with the visual positioning data based on the signal strength indication value RSSI received by the visual recognition information processor, thereby obtaining visual navigation positioning information, and then transmitting the visual navigation positioning information to the IGV navigation correction software module.

[0095] The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and two-dimensional electronic maps of automated container terminals to obtain the real-time positioning coordinates of the IGV.

[0096] Ideally, the IGV navigation correction software module includes a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the corrected real-time accurate position of the IGV.

[0097] The two-dimensional electronic map is obtained by measuring the coordinates of the automated container terminal using several total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

[0098] In a further optimized manner, the IGV fusion positioning system based on UHF RFID communication in this embodiment performs the IGV fusion positioning method based on UHF RFID communication as described in any of the technical solutions in Embodiment 1.

[0099] Example 3

[0100] This embodiment proposes a computer-readable storage medium storing a computer program, characterized in that: when the computer program is executed by a processor, it implements the steps of the IGV fusion positioning method based on UHF RFID communication as described in any of the technical solutions of Embodiment 1.

[0101] Example 4

[0102] Example 4 is a further optimization and improvement based on Example 2;

[0103] like Figures 1-8 As shown:

[0104] Ideally, the laser positioning software module is specifically a laser navigation system, which identifies the coordinates (X, Y) of the positioning posts, such as the positioning posts at the boundary of the storage yard or the positioning posts of the perimeter fence.

[0105] Ideally, RFID tags are installed on all positioning columns of the automated terminal, and the coordinates (X, Y) of the corresponding positioning column are written into the RFID tags.

[0106] Ideally, UHF RFID readers are installed at the four corners of the IGV and connected to the onboard computer via data cables to enable data communication. Normally, only the R1 and R3 (diagonal) UHF RFID readers are enabled. Installing four readers is a redundant design, which ensures that in case of failure, another pair of UHF RFID readers can be switched to locate the device in a timely manner.

[0107] Ideally, when the IGV is started up in the automated terminal yard, the UHF RFID reader will scan and identify the RFID tags on the positioning posts around the IGV in real time. Since the UHF RFID reader transmits multi-frequency signals, the UHF RFID reader can obtain multiple RSSI (signal strength indication) values ​​corresponding to different frequencies of each tag.

[0108] Ideally, the UHF RFID reader uploads the RSSI value information of the RFID tag and the stored coordinate information to the vehicle computer. The vehicle computer converts the RSSI value difference into a distance difference and, together with the coordinate information, calculates the distance from the antenna to each RFID tag, thereby determining the positioning coordinates in the UHF RFID positioning system (i.e., the UHF RFID information processing software module).

[0109] Ideally, the onboard computer sends the positioning coordinates from the IGV's UHF RFID positioning system to the laser positioning system. The laser positioning system then combines the received positioning coordinates, laser identification column point cloud data, and built-in location data. Figure 3 The system matches the data and calculates the positioning coordinates of the laser positioning system.

[0110] Ideally, the onboard computer sends the IGV's UHF RFID positioning system coordinates to the visual positioning system (i.e., the visual recognition software module). The visual positioning system then uses the received coordinates, ground marker data identified by the visual camera, and built-in location data to determine the location. Figure 3 The system matches the data and calculates the real-time positioning coordinates of the IGV.

[0111] Ideally, the onboard computer fuses the column positioning coordinates (i.e., RFID positioning data), laser identification column point cloud data (i.e., laser positioning data), and visual positioning data, and uses a Kalman filter algorithm to estimate and correct the position, outputting high-precision position information.

[0112] The specific algorithm is as follows: The UHF RFID reader transmits a signal, and the distance D between the tag and the UHF RFID reader is obtained based on the signal strength reflected back by each RFID tag. The UHF RFID reader mounted on the IGV needs to determine its own coordinates by identifying at least three tags (which must form a triangle, i.e., not collinear). The more tags identified, the more accurate the coordinates. Figure 5 As shown, given the distances from a point on a plane to tags A, B, and C, to determine the location of that point, simply draw circles and find their intersections. The coordinates (X, Y) of the IGV reader can be calculated by solving a system of equations based on the distances from the IGV to several tags. The standard form of the system of equations is:

[0113] (X n -X)2 +(Y n -Y) 2 =D n 2

[0114] Where X n and Y n D represents the coordinates of the RFID tag. n This indicates the distance at which the RFID tag can be identified.

[0115] Then, we used Python to solve for the coordinates (X,Y) of the UHF RFID reader based on the standard model. The code for finding the intersection of the three circles is as follows: the center coordinates of the first circle are (x0,y0) and the radius is R; the center coordinates of the second circle are (e,f) and the radius is N; and the radius of the third circle is P.

[0116] Specifically, the coordinates of the UHF RFID reader can be obtained by analogy from the coordinates of the other UHF RFID reader diagonally. Let the coordinates of any pair of diagonal UHF RFID readers be (X1,Y1) and (X2,Y2), then the algorithm for the vehicle center position is: X=(X1+X2) / 2, Y=(Y1+Y2) / 2, and finally the IGV coordinates (X,Y) are obtained.

[0117] Specifically, UHF RFID readers use phase array antennas. Phase array antennas, also known as phased array antennas, work by controlling the feed phase of the radiating elements to change the radiation pattern shape. Phase array antennas are generally divided into linear phase arrays and planar phase arrays, both based on phase control technology. A planar phase array antenna consists of multiple antenna elements arranged in a specific pattern on a plane, each with independent phase and amplitude control functions. When a planar phase array antenna is working, precise adjustment of the phase and amplitude of each antenna element via a computer or other control system allows for beam direction control. Specifically, by adjusting the phase difference between different antenna elements, the radiated signal can be directed in a specific direction in space. When the phase difference changes, the direction of the beam will also deflect accordingly, thus realizing the scanning of the beam on a two-dimensional plane. In addition, the planar phased array antenna can also control the beam shape by adjusting the amplitude distribution of different antenna elements, such as changing parameters such as beam width and gain. When the planar phased array antenna is working, it can be regarded as a single-port reader becoming a multi-port reader (the number of ports corresponds to the number of phase combinations). The original single-port reader can only connect to one antenna and the radiation range is fixed, while the multi-port reader can connect to many antennas, and each antenna has a different radiation range. This multi-port reader can select the area to be scanned according to the requirements and start the corresponding port to transmit signals, so as to cover the specified area through the corresponding antenna.

[0118] Specifically, UHF RFID readers involve UHF RFID multi-point positioning technology. The coverage area of ​​a UHF RFID reader is a circle with n sectors and N radiation areas. It can be simply understood as an N-port reader connected to antennas in N different radiation areas. In practical applications, radiation areas with adjacent numbers overlap. When the same RFID tag is identified in multiple radiation areas with different numbers, the specific location of the RFID tag can be calculated by the RSSI value.

[0119] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A UHF RFID-based IGV fusion positioning method, applied to an automated container terminal equipped with several IGVs, characterized in that... The IGV fusion localization method includes the following steps: Step S1: Arrange multiple positioning columns at the automated container terminal, and install four UHF RFID readers, a LiDAR scanner, a vision camera, and an on-board information processing system on the IGV; the four UHF RFID readers are located at the front left, front right, rear left, and rear right corners of the IGV vehicle, respectively. Step S2: Measure the positioning coordinate information of each positioning column, and set RFID tags that record the positioning coordinate information on each positioning column. Step S3: Two diagonally opposite UHF RFID readers on the IGV scan and identify RFID tags on the positioning pillars around the IGV in real time. This allows the UHF RFID readers to obtain multiple Signal Strength Indication (RSSI) values ​​for different frequencies corresponding to the RFID tags, as well as the pillar positioning coordinates. These RSSI values ​​and pillar positioning coordinates are then transmitted to the vehicle information processing system. A LiDAR scanner is used to perform a laser scan on the positioning pillars near the IGV, obtaining laser-identified pillar point cloud data, which is then transmitted to the vehicle information processing system. Finally, a visual camera is used to photograph the positioning pillars near the IGV, obtaining visual positioning data, which is also transmitted to the vehicle information processing system. In step S4, the vehicle information processing system matches and fuses the column positioning coordinate information, laser recognition column point cloud data, visual positioning data, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system to obtain the real-time positioning coordinates of the IGV.

2. The IGV fusion positioning method based on UHF RFID communication according to claim 1, characterized in that, The IGV fusion localization method also includes a step between step S2 and step S3: Step S23: Use several total stations to perform coordinate mapping on the automated container terminal to form a two-dimensional electronic map of the automated container terminal, and store the two-dimensional electronic map in the vehicle information processing system.

3. The IGV fusion positioning method based on UHF RFID communication according to claim 1, characterized in that, In step S4, the real-time positioning coordinates of the IGV are estimated and corrected using a Kalman filter algorithm to obtain the corrected real-time accurate position of the IGV.

4. The IGV fusion positioning method based on UHF RFID communication according to claim 1, characterized in that, In step S3, when two of the diagonal UHF RFID readers of the IGV fail to scan and identify the RFID tags on the positioning pillars around the IGV vehicle body in real time, the other two diagonal UHF RFID readers of the IGV replace the two diagonal UHF RFID readers that failed to perform identification, and then the other two diagonal UHF RFID readers of the IGV continue to perform real-time scanning and identification of the RFID tags on the positioning pillars near the IGV. If the other two diagonally opposite UHF RFID readers fail to scan and identify the RFID tags on the positioning pillars near the IGV in real time, then maintenance personnel will be notified to carry out repairs.

5. The IGV fusion positioning method based on UHF RFID communication according to claim 1, characterized in that, Step S4 includes the following sub-steps; Step S41: Match and fuse the column positioning coordinate information with the laser recognition column point cloud data to obtain laser navigation positioning information; The column positioning coordinates are then matched and fused with visual positioning data to obtain visual navigation positioning information. Step S42 involves matching the laser navigation positioning information obtained in step S41, the visual navigation positioning information obtained in step S41, and the two-dimensional electronic map of the automated container terminal stored in the vehicle information processing system.

6. The IGV fusion positioning method based on UHF RFID communication according to any one of claims 1-5, characterized in that, When the UHF RFID reader transmits a signal, the distance D between the RFID tag and the UHF RFID reader is obtained by identifying at least three RFID tags and based on the signal strength reflected back by each RFID tag; wherein the three RFID tags identified by the UHF RFID reader form a triangle, that is, they are not collinear.

7. The IGV fusion positioning method based on UHF RFID communication according to any one of claims 1-5, characterized in that, In step S3, the system of equations is solved using the distances from the IGV to several RFID tags to obtain the reader coordinates (X, Y); the standard form of the system of equations is: (Xn-X). 2 +(Yn-Y) 2 =Dn 2 Where Xn and Yn represent the coordinates of the RFID tag, and Dn represents the distance at which the RFID tag is identified; the coordinates (X, Y) of the reader are obtained by solving the standard form of the system of equations and using Python's code program for finding the intersection of three circles.

8. An IGV fusion positioning system based on UHF RFID communication, characterized in that, Applied to IGVs, which operate in automated container terminals with multiple positioning posts, each post is equipped with a corresponding RFID tag. This IGV integrated positioning system includes: The vehicle-mounted information processing system includes an onboard computer, a laser scanning and recognition information processor, a vision recognition information processor, and a UHF RFID information processor. The onboard computer is equipped with an IGV navigation correction software module, the laser scanning and recognition information processor with a laser positioning software module, the vision recognition information processor with a vision recognition software module, and the UHF RFID information processor with a UHF RFID information processing software module. The onboard computer communicates with the laser scanning and recognition information processor, the vision recognition information processor, and the UHF RFID information processor. LiDAR scanner; The LiDAR scanner is used to perform laser scanning on the positioning posts near the IGV to obtain laser recognition post point cloud data, and then transmit the laser recognition post point cloud data to the laser scanning recognition information processor. Visual camera; The visual camera is used to photograph the positioning column near the IGV to obtain visual positioning data, and then transmit the visual positioning data to the visual recognition information processor. Four UHF RFID readers are installed at the four corners of the IGV. A UHF RFID information processor communicates with each of the four UHF RFID readers. The UHF RFID readers are used to scan and identify RFID tags on the positioning pillars around the IGV in real time, thereby obtaining multiple signal strength indicators (RSSI) of different frequencies for the corresponding RFID tags and the positioning coordinates of the pillars. The multiple RSSI and the positioning coordinates are then transmitted sequentially to the laser scanning and identification information processor via the UHF RFID information processor and the on-board computer, and finally to the vision recognition information processor via the UHF RFID information processor and the on-board computer. The laser positioning software module is used to match and fuse the specified column positioning coordinates with the laser recognition column point cloud data according to the signal strength indication value (RSSI) received by the laser scanning and recognition information processor, thereby obtaining laser navigation and positioning information, and then transmitting the laser navigation and positioning information to the IGV navigation correction software module. The visual recognition software module is used to match and fuse the specified column positioning coordinates with the visual positioning data based on the signal strength indication value (RSSI) received by the visual recognition information processor, thereby obtaining visual navigation positioning information, and then transmitting the visual navigation positioning information to the IGV navigation correction software module. The IGV navigation correction software module is used to match the received laser navigation positioning information, visual navigation positioning information, and two-dimensional electronic maps of automated container terminals to obtain the real-time positioning coordinates of the IGV.

9. The IGV fusion positioning system based on UHF RFID communication according to claim 8, characterized in that, The IGV navigation correction software module is equipped with a Kalman filter algorithm, which is used to estimate and correct the real-time positioning coordinates of the IGV, thereby obtaining the corrected real-time accurate position of the IGV. The two-dimensional electronic map is obtained by measuring the coordinates of the automated container terminal using several total stations, and the two-dimensional electronic map is stored in the IGV navigation correction software module.

10. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the steps of the IGV fusion positioning method based on UHF RFID communication as described in any one of claims 1 to 7.

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