Port operation system based on multi-sensor fusion positioning

Abstract

The present application relates to a port operation system based on multi-sensor fusion positioning, comprising a plurality of ground positioning base stations arranged uniformly along one side of the lane in the operation area, a UWB positioning module is used to obtain the position information of the transport equipment carrying a vehicle positioning tag on the lane; according to the position of the transport equipment obtained by the IMU sensor module of the vehicle positioning tag, the displacement offset of the transport equipment relative to the ground positioning base station is obtained as a correction value to correct the position information of the transport equipment obtained by the UWB positioning module, and is sent to the data server; a first monitoring system obtains the container position information during the port transfer to the operation area and the hoisting container information respectively and sends them to the data server; a second monitoring system obtains the transport equipment information and the transported container information and sends them to the data server; the data server guides the transport equipment to travel to the specified area to realize loading and unloading operation according to the berth position information required by the operation and the position information of the transport equipment on the lane.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of smart port, in particular to a port operation system based on multi-sensor fusion positioning. BACKGROUND

[0002] The statements in this section merely provide background information related to the present application and do not necessarily constitute the prior art.

[0003] The port undertakes a large number of container loading and unloading and handling, and the traditional manual allocation of trailers into the port and the command of the trailer to stop at the designated location and the scheduling of the rail-mounted gantry crane to carry out container loading and unloading operation mode has the problems of high labor cost and low efficiency, and cannot monitor the accurate position of the operation trailer in real time for container loading and unloading operation.

[0004] As for the positioning problem, the traditional Global Navigation Satellite System (GNSS) positioning method often faces the problem of being unable to accurately guide the driver to stop at the specified location in the port application. Due to the low positioning accuracy of the trailer, the positioning signal is easy to be blocked, and the trailer travels in a large number of containers, and the reliability is seriously reduced due to the influence of complex site environment.

[0005] Compared with the GNSS positioning system, the wireless positioning system based on UWB (Ultra Wide Band) technology has higher accuracy and is not easily affected by other wireless signals, but when the base stations are blocked, the positioning accuracy of UWB is greatly affected. In the actual operation process of the port, the UWB positioning method is easily affected by different obstructions in the environment.

[0006] The IMU (Inertial Measurement Unit) sensor positioning module is not affected by the obstructions in the complex environment, and can well make up for the shortcomings of the UWB positioning method. Although the IMU sensor positioning method can accurately give the position of the object in a short time, the error will gradually accumulate and increase with time, and the accurate position of the trailer in the port cannot be obtained.

[0007] Therefore, in the complex environment of the port, it is difficult to achieve accurate positioning of the trailer by a single positioning method, and it is also difficult to realize automatic operation in the port. SUMMARY

[0008] In order to solve the technical problems in the above background art, the present application provides a port operation system based on multi-sensor fusion positioning, which fuses UWB positioning and IMU sensor positioning, uses transportation equipment information identification and container identification as technical support, can change the mode of traditional complex and tedious manual registration and coordination to command port tractor for container loading and unloading operation, realizes functions such as online autonomous reservation registration or on-site information input of incoming vehicle information, guiding of incoming operation, real-time return of vehicle position information, greatly improves the operation efficiency and automation degree of the port, and realizes the goal of automatic positioning parking for container loading and unloading operation.

[0009] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0010] The first aspect of the present application provides a port operation system based on multi-sensor fusion positioning, comprising:

[0011] The ground positioning base station is uniformly arranged along one side of the lane in the operation field area, and the time difference of the vehicle-mounted positioning tag reaching the ground positioning base station and the distance between the adjacent two base stations are obtained by using the UWB positioning module to obtain the position information of the transportation equipment carrying the vehicle-mounted positioning tag on the lane; the displacement offset of the transportation equipment relative to the ground positioning base station is obtained according to the position of the transportation equipment obtained by the IMU sensor module of the vehicle-mounted positioning tag, which is used as a correction value to correct the position information of the transportation equipment obtained by the UWB positioning module, and is sent to the data server;

[0012] The monitoring system has at least two groups, the first monitoring system is located in the container area, and respectively obtains the position information of the container during the port transfer to the operation field area and the information of the container in the hoisting and sends them to the data server; the second monitoring system is located at the end of the lane in the operation field area, and obtains the transportation equipment information and the container information transported and sends them to the data server;

[0013] The data server guides the transportation equipment carrying the vehicle-mounted positioning tag to run to the specified position to realize the loading and unloading operation according to the berth position information required by the operation and the position information of the transportation equipment on the lane, and realizes the operation monitoring through the information obtained by the monitoring system during the operation.

[0014] The vehicle-mounted positioning tag comprises a UWB positioning module, an IMU sensor module, a communication module and a power module connected together.

[0015] The ground positioning base station comprises a UWB positioning module, a communication module, a laser calibration system and a power module connected together.

[0016] The time between the ground positioning base stations is kept synchronous.

[0017] The vehicle-mounted positioning tag UWB positioning module communicates with the UWB positioning module of each ground positioning base station to obtain the time difference between the arrival of the vehicle-mounted positioning tag at each ground positioning base station, and obtains the location information of the transportation equipment carrying the vehicle-mounted positioning tag on the lane based on the distance between two adjacent ground positioning base stations.

[0018] The IMU sensor module has an accelerometer and a gyroscope, which acquire the acceleration and angular velocity of the transportation equipment, convert them into position, velocity and attitude, and then send them to the data server.

[0019] The locations of the transport equipment obtained by the UWB positioning module and the IMU sensor module are x1 and x2, respectively. After multiple measurements at the same location within the work area, let the estimated x-axis position of the vehicle positioning tag within the work lane be denoted as x1. Satisfy the following formula:

[0020]

[0021] k is the Kalman gain, ranging from 0 to 1; by taking the derivative of the Kalman gain, we obtain the minimum value of the variance of the estimated value, which is the position offset of the vehicle positioning tag relative to the ground positioning base station. The position offset is used to update the real-time position of the transportation equipment at the corresponding ground positioning base station.

[0022] Kalman gain k makes the estimated value Standard deviation Minimum, estimated variance Satisfy the following formula:

[0023]

[0024] By taking the derivative with respect to k and setting the derivative value to 0, we obtain the Kalman gain k when the extreme value is reached.

[0025] The monitoring system sends the acquired container location and information to the data server, specifically:

[0026] The location information of containers in the work area is represented by a distributed grid formed by a four-dimensional array (X, Y, H, N). X is the horizontal position coordinate, Y is the vertical position coordinate, H is the height of the container, and N is the number of the work area. Among them, the horizontal and vertical positions of the first container in the first row and first column are (1, 1), the H coordinate of the container closest to the ground is 1, and N = 1, 2, 3, 4, 5.

[0027] The monitoring system identifies container information and location information, stores the four-dimensional array of container information and corresponding location information in the data server, and when the hoisting equipment is used to load the container, it finds the corresponding location information based on the information of the container being hoisted, clears it, forms operation information, and saves it to the data server.

[0028] It also has a driver terminal, which can receive guidance instructions from the data server via a mobile APP, mini-program or vehicle location information prompt device, so that the transportation equipment can run to the designated location to carry out loading and unloading operations.

[0029] Compared with existing technologies, one or more of the above technical solutions have the following beneficial effects:

[0030] 1. After the transport equipment is equipped with vehicle-mounted positioning tags, the UWB positioning module and the IMU sensor positioning module are used to perform sensor fusion at the decision-making end to achieve accurate positioning of the port transport equipment. By comparing data between different sensors, the interference caused by system noise is reduced, and the reliability of the UWB positioning algorithm is improved in the case of signal obstruction and the IMU sensor positioning algorithm in the case of long time.

[0031] 2. By utilizing the location of the acquired transportation equipment, the data server can guide the port's container loading and unloading operations based on the location of the transportation equipment.

[0032] 3. For vehicle-mounted positioning tags and ground positioning base stations, the TDOA estimation method based on UWB positioning modules is used, and the measured data is processed using the corresponding algorithm to effectively improve the accuracy of ranging.

[0033] 4. By utilizing the transportation equipment and container information obtained from the monitoring system, an intelligent record of the transportation equipment entering and leaving the port operation area can be formed, and the location information and transportation status of containers can be identified and recorded.

[0034] 5. Using the driver's terminal to register the transportation equipment entering the port and guide the transportation equipment into the container loading and unloading queue helps the port achieve automated operations. Attached Figure Description

[0035] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0036] Figure 1 This is a schematic diagram illustrating the principle of tag positioning using the time of arrival (TDOA) of a UWB positioning module provided in one or more embodiments of the present invention.

[0037] Figure 2 This is a schematic diagram of the structure of a UWB ultra-wideband wireless positioning system provided in one or more embodiments of the present invention;

[0038] Figure 3 This is a schematic diagram of the IMU sensor localization algorithm structure provided in one or more embodiments of the present invention;

[0039] Figure 4 This is a schematic diagram of the system signal transmitter composition of an ultra-wideband positioning system provided in one or more embodiments of the present invention;

[0040] Figure 5 This is a schematic diagram of the signal receiver composition of an ultra-wideband positioning system provided in one or more embodiments of the present invention;

[0041] Figure 6 This is a schematic diagram of the Chan-Taylor hybrid weighting algorithm process provided in one or more embodiments of the present invention;

[0042] Figure 7 This is a schematic diagram illustrating the factors affecting the accuracy of a UWB positioning system provided in one or more embodiments of the present invention;

[0043] Figure 8 This is a schematic diagram of an application architecture for base station time synchronization provided by one or more embodiments of the present invention;

[0044] Figure 9 This is a schematic diagram of the architecture of a smart port trailer positioning system provided in one or more embodiments of the present invention;

[0045] Figure 10 This is a schematic diagram of a network topology provided in one or more embodiments of the present invention;

[0046] Figure 11 This is a schematic diagram of the workflow of a trailer positioning system provided in one or more embodiments of the present invention;

[0047] Figure 12 This is a schematic diagram of the work area provided in one or more embodiments of the present invention;

[0048] Figure 13 This is a schematic diagram of the vehicle tag location provided in one or more embodiments of the present invention;

[0049] Figure 14 This is a schematic diagram of multi-sensor fusion provided by one or more embodiments of the present invention;

[0050] Figure 15 This is a schematic diagram of the vehicle positioning tag structure provided in one or more embodiments of the present invention;

[0051] Figure 16 This is a schematic diagram of the structure of a ground positioning base station provided in one or more embodiments of the present invention. Detailed Implementation

[0052] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0053] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0054] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0055] As described in the background section, in the complex environment of a port, it is difficult to achieve accurate positioning of a trailer using a single positioning method, thus making it difficult to achieve automated operations in the port.

[0056] Therefore, the following embodiments present a port operation system based on multi-sensor fusion positioning. This system utilizes a multi-sensor fusion positioning method based on UWB positioning technology and IMU sensor positioning technology, and achieves positioning through laser calibration. It employs deep learning-based license plate recognition and container number recognition technologies to provide technical support for the intelligent port operation system. This system can change the traditional, complex, and cumbersome manual registration and coordination mode for port trucks to perform container loading and unloading operations. It enables functions such as online autonomous registration or on-site information entry for vehicles entering the port, guided truck entry into the port, and high-frequency, high-precision real-time return of vehicle location information from sensor data. This greatly improves the port's operational efficiency and automation level, achieving the goal of automated intelligent trucks stopping at designated points for container loading and unloading operations.

[0057] The transport equipment (e.g., a trailer) in the following embodiments is a device or vehicle for transporting containers. It requires a driver to drive and operate within the working area of ​​the port. When it reaches a designated area, it uses lifting equipment (e.g., a rail-mounted crane) to unload or load containers.

[0058] The berth location information in the following examples refers to the ship's berth number, which is information that can accurately describe the position of the container on the ship and is a digital code written according to certain rules.

[0059] Example 1:

[0060] like Figures 1-16 As shown, the port operation system based on multi-sensor fusion positioning includes:

[0061] Multiple ground positioning base stations are evenly arranged along one side of the work area lane. The UWB positioning module is used to obtain the time difference between the arrival of the vehicle positioning tag at the ground positioning base station and the distance between two adjacent base stations to obtain the position information of the transportation equipment carrying the vehicle positioning tag on the lane. Based on the position of the transportation equipment obtained by the IMU sensor module of the vehicle positioning tag, the displacement offset of the transportation equipment relative to the ground positioning base station is obtained, which is used as a correction value to correct the position information of the transportation equipment obtained by the UWB positioning module and sent to the data server.

[0062] The monitoring system has at least two sets. The first monitoring system is located in the container area and acquires the container location information during the transfer from the port to the work area, as well as the container information during hoisting, and sends it to the data server. The second monitoring system is located at the end of the driveway in the work area and acquires the transportation equipment information and the information of the transported containers and sends it to the data server.

[0063] The data server guides the transport equipment carrying vehicle positioning tags to the designated location to carry out loading and unloading operations based on the location information of the bay required for the operation and the location information of the transport equipment on the lane. During the operation, the information obtained by the monitoring system is used to monitor the operation.

[0064] Specifically:

[0065] Taking a port's automated container yard as an example, the port's automated container yard is divided into five operational areas, level with the wharf's operational shoreline. Each area has 34 container bays and is 200 meters long. Each area is equipped with one rail-mounted gantry crane. The port has a total of 14 electric trailers used for loading and unloading ships and for merging and transferring operations within the port. The trailers are all the same model, specifications, and platform height. The automated operational area lanes are configured as two lanes in one direction, each lane being 3 meters wide. The two lanes are separated by a rounded curb 20 cm above the ground. This method is used to isolate container areas from lanes and lanes from equipment to prevent vehicles from crossing between lanes during operations, thus avoiding operational efficiency and safety hazards.

[0066] The main problems currently existing in this work area are:

[0067] (1) The positioning time for trailers is too long, resulting in low efficiency; no more than 25 trailers per hour.

[0068] (2) Trailer positioning requires the assistance of employees, which increases labor costs and poses safety hazards.

[0069] (3) Traditional trailer positioning methods have a low level of intelligence.

[0070] To address the aforementioned issues, a port operation system based on multi-sensor fusion positioning is proposed, including:

[0071] Trailer positioning systems based on the Time Difference of Arrival (TDOA) estimation method between ground positioning base stations and vehicle-mounted positioning tags, trailer positioning systems based on IMU sensors, and laser calibration systems. Specifically, these include:

[0072] UWB positioning base stations, arranged in a straight line along one side of the automated operation area's driveway, serve as data transmission lines connecting to the control center. They communicate with each base station to obtain trailer tags (using UWB positioning modules) indicating the specific distance to each station. Based on data transmitted from the positioning modules and the trailer driver's appointment information, the system guides drivers entering the port to complete their tasks according to the correct procedures via a smart port app (or mini-program). When the smart port app (or mini-program) malfunctions, an onboard location information display screen can be used as a substitute (obtained from the gatehouse upon entry into the operation area).

[0073] like Figure 15 and 16 As shown, the vehicle-mounted positioning tag includes a UWB positioning module, an IMU sensor module, a wireless transmission module, and a power module. The ground positioning base station includes a UWB positioning module, a wireless transmission module, a wired transmission module, a laser calibration system, and a power module.

[0074] The ground positioning base stations installed on one side of the automated site's lanes are primarily used for communication with vehicle-mounted positioning tags. In the UWB positioning system, the distance between the tag and two neighboring base stations is calculated using the Time of Arrival (TDOA), thus allowing the UWB positioning system to determine the trailer's precise location within the site's operating lanes.

[0075] The vehicle-mounted IMU sensor is located inside the vehicle-mounted UWB base station and works with the UWB positioning module to acquire the truck's location information. Each UWB positioning base station on one side of the lane is equipped with a laser positioning calibration system, which can calibrate the IMU data that positions the trailer as it passes the base station, reducing positioning errors caused by time and distance factors.

[0076] Two 5M high-definition video surveillance systems are installed in the work area. The first system, located in the container area, is primarily responsible for monitoring the specific locations of containers transferred from the port to the work area and recording information about containers already loaded onto rail-mounted cranes. The system establishes a container distribution grid with the first row and first column as (1,1), using a four-dimensional array (X,Y,H,N) to represent the container's location within the work area. Here, X represents the lateral coordinate, Y represents the longitudinal coordinate, H represents the container's height (with the H coordinate of a container touching the ground as 1), and N represents the location within the work area (N=1, 2, 3, 4, 5). When a container is transferred into the work area, the monitoring system identifies the container number and records its specific storage location, storing the container number and the corresponding four-dimensional array representing its location information in the data server. When the rail-mounted crane loads a container onto a truck, the system automatically locates and clears the corresponding data, and records and stores the relevant operation information (time, area number, container number, etc.) in the data server.

[0077] The second monitoring system is located at the end of the work lane and can identify specific license plate numbers and container numbers. It is responsible for recording information on vehicles entering and leaving the work area, and outputting relevant information such as the container number and work time to the control center and saving it to the data server.

[0078] The mobile software in the positioning system uses the location information of designated work bays provided by the management center. The data server performs data calculations and location comparisons, issuing instructions to guide drivers to stop and load / unload containers. Simultaneously, the smart port app has functions such as port entry information registration and parking fee payment, greatly simplifying the traditional registration process. While reducing labor costs, it improves the efficiency of the work site, enabling a significant increase in container throughput per unit time for the same size area.

[0079] To address potential operational difficulties with the smart port app and mini-program, and for drivers with specific needs, a port vehicle-mounted location information display screen is provided. Drivers simply need to mount the electronic screen inside their vehicle to follow the prompts during port operations. This feature is designed for drivers who forget to bring their phones or, for various reasons, cannot conveniently use them, providing a backup solution for tow truck drivers without mobile phones.

[0080] The port control and management center is equipped with data switches, management computers, data servers for storing data and managing driver mobile guidance programs, as well as the control software for the management center. The data switches are divided into two parts: the central switch and the operational data switch.

[0081] The central switch connects to the central control computer, data server, and work data switch, and is responsible for data exchange among the three. After receiving the work information submitted by the vehicles entering the port, the main control program of the central control computer can modify or confirm the vehicle work information through the connection with the data server via the central switch, and complete operations such as sorting, retrieving, ranking, and storing the data in the data server.

[0082] The operation switch is primarily responsible for data transmission from the base station modules in the automated operation area and connects to the parking management computer. It inputs data transmitted from the front end into the data server via the central switch for vehicle location calculations, guiding drivers to park precisely at designated locations. The parking management area is equipped with a parking management computer and a deep learning-based license plate recognition camera. After recognizing the license plate number, the system controls and guides staff to process tow truck departure payments, or the tow truck driver can scan a code to pay and leave the parking area. Vehicle departure information is registered by the parking management computer and stored in the data server via the switch, or directly stored in the data server via the internet after the driver pays online via QR code.

[0083] The data server in the management center is primarily responsible for storing various types of information and providing computing and storage services for the smart port app (mini-program). Data such as vehicle entry registration information, departure information, and container location information are all stored on the server.

[0084] Finally, company trailers that have completed their work in the automated operation area can return the electronic tag and vehicle location information display screen (if used) at the parking lot exit, and leave the port after paying the fee.

[0085] For example:

[0086] The operating lanes within the site are divided into two roads; this embodiment only applies to the operating lane open to public vehicles. If the number of vehicles making reservations exceeds the port's maximum loading and unloading capacity threshold within a half-hour period, the system will lock reservation privileges for that time slot, recommending that tow truck drivers reserve other time slots.

[0087] Truck drivers arrive at the port at their scheduled appointment time or the time indicated on the Smart Port App and wait to enter the work area. Drivers who have made appointments can pick up a portable vehicle tag at the entrance booth and enter the port directly. The port entrance is equipped with license plate recognition cameras; vehicles needing to enter the port can be identified, and the entrance gate will automatically rise to allow entry. Drivers without appointments can register their information on-site and pick up a portable vehicle location tag before queuing to load containers. Drivers who cannot use the Smart Port App or mini-program normally due to personal reasons or other reasons can register to receive a vehicle location information screen instead. The vehicle location information screen can be attached to the windshield and guides the driver to the designated area by displaying a route map. The vehicle location information screen is connected to a data server via the network and can guide the driver to a relatively precise location on the work lane through voice prompts, facilitating container loading and unloading operations by the rail-mounted crane.

[0088] If the truck driver fails to arrive at the port on time and the preceding vehicle has completed its work, the system will assign an electric trailer within the port to perform the work, transporting the container to the designated location within the port and uploading the information. Upon entering the port, the truck driver only needs to follow the prompts to the designated location to install the container trailer with the assistance of staff.

[0089] like Figure 11 As shown, after registering to enter the port, the driver can follow the prompts to operate. If the preceding vehicle has completed its work, the trailer will drive into the target work area according to the instructions. At this time, the vehicle's entry data is stored in the central data server. If the preceding vehicle has not completed its work, the trailer driver needs to wait in the port rest area for the preceding vehicle to complete its container loading and unloading task before driving into the area. The Smart Port App will recommend the most suitable rest area for the driver (based on factors such as route distance).

[0090] like Figure 12 As shown, once the vehicle enters the work area, it can be identified and monitored by the positioning base stations within the area. After passing the first laser positioning base station, the UWB positioning module and IMU sensor in the vehicle-mounted positioning tag are activated to begin collecting location information. The system then performs algorithmic analysis on the data collected by the sensors to calculate the trailer's precise location within the work area. Based on the real-time location information provided by the control center, the system guides the driver to stop at the designated location and wait for the rail-mounted crane operation through voice announcements combined with route map guidance. If the vehicle-mounted positioning tag and the ground positioning base station detect that the driver has not entered the designated work area or has entered the wrong work area, the system will provide a voice prompt to the driver to correct the route and leave the current location as soon as possible. In this embodiment, UWB positioning modules and IMU sensors are used for positioning within the work area. The UWB positioning principle is as follows: Figure 2As shown, the coordinates of the node to be tested are the location information of tag x. The UWB control center can be regarded as the brain of the entire UWB positioning system. It is the center of data processing and integration, deploying various positioning algorithms and processing mechanisms, and receiving information such as time and time difference collected from the tag to be tested from the positioning base station. It realizes the transformation of the measured data into the specific coordinates of the node to be tested and information about its location, thereby achieving positioning. In order to minimize obstruction and increase positioning accuracy, this embodiment chooses to fix the vehicle-mounted portable tag in the middle of the trailer and on the same side of the trailer as the base station. Figure 12 and Figure 13 As shown in the diagram, the upper track base station is located on the right side of the trailer. Therefore, the vehicle-mounted tag should also be located on the right side near the midpoint of the trailer, with few obstructions between it and the base station.

[0091] like Figure 4 As shown, the basic components of the UWB positioning module's ultra-wideband signal transmitter include: a data acquisition module, a pseudo-random (PN) code generation module, a time base generation module, a programmable delay module, a pulse generator, and an amplification module.

[0092] like Figure 5 As shown, the ultra-wideband signal receiver in the UWB positioning module mainly consists of a PN code generation module, a baseband signal processor, a programmable delay module, a time base generation module, and a correlator module. Unlike the transmitter, the receiver requires different modules depending on the positioning technology. In this embodiment, the TDOA estimation method is used for positioning, requiring the addition of a clock synchronization module.

[0093] The TDOA estimation method used for localization is based on the following principle: Figure 1 As shown, this is a time difference-based positioning method that does not require time synchronization between the reference base station and the positioning point; it only requires strict time synchronization between the reference base stations. Compared to TOA positioning technology, TDOA positioning technology is easier to implement. In the implementation process, the three base stations closest to the tag are used as reference base stations by default, with the closest base station being the baseline base station. The dashed lines in the illustration are all hyperbolas, and the intersection of the two sets of hyperbolas represents the true location of the point to be measured.

[0094] Based on the TDOA estimation method for localization, this embodiment uses an improved Chan-Taylor algorithm to reduce the error of UWB localization. The algorithm framework diagram is shown below. Figure 6 As shown. The classic Chan algorithm can utilize all measured TDOA values ​​to form a definite expression solution; however, its positioning accuracy is affected when the Fresnel zone is blocked by more than 50%. The Taylor series expansion method is a recursive algorithm, but if the initial value is not chosen appropriately, it may lead to non-convergence of the algorithm.

[0095] The three ground positioning base stations that are closest to the vehicle positioning tag are reference base stations, or reference nodes. Among them, the base station that is closest to the vehicle positioning tag is the reference base station, or reference node. The position of the transportation equipment carrying the vehicle positioning tag on the lane is an unknown node.

[0096] Obtain the TDOA value based on the reference node and the unknown node;

[0097] Input the reference node coordinates and TDOA value;

[0098] The initial coordinates of the unknown nodes are calculated using the Chan algorithm, and the node positions are estimated again using the Taylor series expansion method.

[0099] Calculate the weighting coefficients, and then use these coefficients to calculate the final coordinates of the unknown nodes.

[0100] In this embodiment, [x(k), y(k)] is defined as the coordinates of the unknown target node calculated using the k-th method. In the Chan algorithm, the obtainable value is the distance difference, so defining the difference is more convenient. Therefore, r is defined as... i 1(k) represents the difference between the distance from the unknown node's measured coordinates to anchor node i and the distance to anchor node 1 when using the k-th method, i.e.

[0101]

[0102] Define Δr as the square of the difference between the true value and the measured value:

[0103]

[0104] Define the weighting coefficient as η(k):

[0105]

[0106] Where n is the number of reference base stations.

[0107] The final estimated coordinates of the unknown nodes can be expressed as:

[0108]

[0109]

[0110] Errors in UWB positioning systems are unavoidable, and the main influencing factors are represented by a fishbone diagram model. Figure 7 Provided.

[0111] To minimize the error of the TDOA estimation method, time synchronization must be achieved among all base stations within a high-precision range. There are several methods to achieve base station time synchronization, such as... Figure 8The diagram illustrates two main synchronization methods. In this invention, a time synchronization controller-base station wired power supply network architecture was chosen for application. Compared to other wireless communication architectures (such as peer-to-peer positioning base station-AP network architecture), this architecture offers higher system capacity, stability, and lower latency. The advantage of wireless networks lies in their ability to effectively reduce construction costs. Time and time difference data measured by the base station are transmitted back to the server via data cable for processing and storage, guiding the trailer driver to operate correctly.

[0112] like Figure 14 As shown, to reduce the unavoidable error impact of the UWB positioning module in complex environments, this embodiment also incorporates an IMU sensor into the vehicle-mounted positioning tag. The vehicle position information acquired by the IMU sensor and the vehicle position information acquired by the UWB positioning algorithm are fused at the decision-making end. If the two deviate significantly, the driver will be prompted to perform position calibration at any ground positioning base station. This embodiment uses a Kalman filter for data fusion. The vehicle positions x1 and x2 acquired by the UWB positioning algorithm and the IMU sensor both follow a normal distribution with standard deviations σ1 and σ2, and an average value equal to the true value x. After multiple measurements at the same location within the work area, the standard deviations of the normal distributions for the two positioning methods in the port operation environment can be obtained. Using the Kalman algorithm, let the estimated x-axis position of the vehicle positioning tag within the work lane be... but:

[0113]

[0114] Where k is the Kalman gain, ranging from 0 to 1. To obtain vehicle position information with a smaller standard deviation and estimates closer to the true values, we need to find the Kalman gain k such that the estimated values... Standard deviation Minimum, estimated variance:

[0115]

[0116] To find the minimum variance of the estimated value, we need to differentiate with respect to k. Setting the derivative to zero, we can obtain the Kalman gain at the extreme value, i.e.:

[0117]

[0118] right Taking the derivative, we get

[0119]

[0120] If the above equation is set to 0, then...

[0121]

[0122] The positioning method uniformly uses calibrated relative displacement for vehicle positioning. For example... Figure 12 and 13 As shown, laser positioning calibration base stations (e.g., laser calibration poles) are set up on both sides of the road in the work area. Vehicle-mounted positioning tags have reflectors on the outside of the vehicle, at the same height as the laser emitter on the calibration pole. When a vehicle passes a laser calibration pole, the laser beam from the emitter on the pole is blocked by the reflector on the positioning tag. The positioning system detects this blocking and can then accurately pinpoint the vehicle's location within the work area. Simultaneously, as the vehicle passes the laser positioning calibration base station, its real-time position is updated at the corresponding ground positioning base station. Subsequently, the position information measured by the UWB positioning algorithm and the IMU sensor positioning algorithm is calculated using the offset from the base station. For example, if the UWB positioning algorithm measures the vehicle's position as changing from 125m to 130m after passing the ground positioning base station, the overall offset is 5m forward. The final UWB positioning algorithm-determined vehicle position is 5m forward of the base station position. The calculation method for the IMU sensor's position information is the same as the UWB positioning algorithm, both calculating the position offset after passing the laser-calibrated ground positioning base station.

[0123] The structural block diagram of the IMU sensor localization algorithm is as follows: Figure 3 As shown, this embodiment primarily utilizes the accelerometer within the IMU sensor to calculate the vehicle's translational motion in a single dimension. The acceleration information (AccX) collected by the sensor is used to calculate the trailer's X-axis position on the work area road, thereby obtaining high-precision trailer position information. This overcomes the shortcomings of UWB positioning, which is prone to significant measurement errors when encountering physical obstructions. Furthermore, the use of laser positioning at fixed intervals for accuracy correction reduces the problem of IMU sensor errors gradually increasing over time.

[0124] After the trailer enters the work area, its position is monitored in real time by a multi-sensor fusion positioning system. The system can guide the driver to stop at a designated location and wait for the rail crane to load and unload containers. Container identification and monitoring within the area can identify container numbers through image recognition, record the location of specific containers within the area, and record the number of containers in the area.

[0125] Once the UWB positioning system identifies the trailer as having stopped and come to a stable stop at the designated location, the rail-mounted gantry crane begins loading and unloading operations. During the gantry crane's operation, if the vehicle's position deviates, the system will automatically stop the operation and alert the trailer driver, requiring immediate correction. Vehicle identification monitoring at the end of the lane will verify the license plate number against the container number; the vehicle can only leave the lane after the container information matches the vehicle information. After the vehicle leaves the lane, the system stores the data on the completed container operation in the central data server.

[0126] The driver can then proceed to the parking lot exit to prepare for departure from the port. Figure 10 and 11 As shown, drivers must pay and return their vehicle tag via the Smart Port App or the parking lot exit booth before leaving the port. If a driver received a vehicle location information display screen upon entering the port, they must return it along with the tag to the port at the parking lot booth. At this point, the vehicle departure data is stored in the central data server.

[0127] The aforementioned system networks the port's operations, allowing for the processing of procedures and data registration at each stage via a mobile app. This enables more efficient management of yard operations and truck queues, representing a highly intelligent management approach.

[0128] A TDOA estimation method based on a UWB positioning module was used, and the Chan-Taylor algorithm was employed to process the measured data, effectively improving the ranging accuracy and ultimately determining the trailer's precise location within the work lane. The proposed method involves placing the positioning tag in the middle of the trailer and installing it on the side of the road where a base station is located. In practical applications, setting the base station at a height close to the tag ensures that environmental factors such as occlusion do not negatively impact measurement accuracy.

[0129] A low-cost, high-precision positioning method based on multi-sensor fusion is proposed. This method utilizes a UWB positioning module and an IMU sensor positioning module to perform sensor fusion at the decision-making stage, achieving accurate positioning of port trailers. By comparing data from different sensors, interference from system noise is reduced, and the reliability of the UWB positioning algorithm is improved under conditions of signal obstruction and the IMU sensor positioning algorithm under long-term conditions.

[0130] The method involves adding a laser positioning system to a ground-based UWB positioning base station to determine the trailer's location. Even when there are significant errors between the UWB positioning algorithm and the IMU sensor positioning algorithm, the system can promptly calibrate the vehicle's position, further improving the reliability of the entire positioning system.

[0131] The system intelligently records the specific location and entry / exit information of each container in the container storage area, and a high-definition monitoring system is installed next to the container loading and storage area in the work area. It can also use deep learning to identify the number of the container entering the storage area and the target container being operated by the rail-mounted crane, and identify the final (entry into the storage area) or initial (departure from the storage area) position of the container through the monitoring video footage, thus completing the identification and recording of container location information and transportation status.

[0132] A complete management system for truck entry into the port is proposed, from self-registration and appointment via mobile app, to waiting for work upon arrival, to loading and unloading containers, and finally to payment upon departure. This achieves intelligent management of external trucks entering the port.

[0133] After the UWB positioning system provides specific location information, it prompts the truck driver to stop at the designated location, changing the traditional method of port personnel assisting with parking and container loading / unloading. It can also automatically stop the rail-mounted gantry crane operation upon detecting a vehicle position deviation, maximizing safety during operations.

[0134] All data related to trailers entering and leaving the port can be recorded on the data server, including information on vehicles about to enter, currently in operation, and already departed, enabling visualized management of the port trailer management system data. Through data integration and analysis, different types of reports can be viewed as needed, including but not limited to daily, monthly, and annual reports, as well as statistics on the number of vehicles entering the port from different companies.

[0135] In this embodiment, the data server in the control center is responsible for processing and storing various port data. Different levels of software have different management permissions. For example, the central control center has the highest level and can view and modify all subordinate devices. The parking management system, however, only has permissions to manage and view the towing vehicle payment process and cannot view or edit information from higher-level management systems or towing vehicle drivers. The system as a whole has good compatibility and data protection.

[0136] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A port operation system based on multi-sensor fusion positioning, characterized in that: include: Multiple ground positioning base stations are evenly arranged along one side of the work area lane. The UWB positioning module is used to obtain the time difference between the arrival of the vehicle positioning tag at the ground positioning base station and the distance between two adjacent base stations to obtain the position information of the transportation equipment carrying the vehicle positioning tag on the lane. Based on the position of the transportation equipment obtained by the IMU sensor module of the vehicle positioning tag, the displacement offset of the transportation equipment relative to the ground positioning base station is obtained, which is used as a correction value to correct the position information of the transportation equipment obtained by the UWB positioning module and sent to the data server. The monitoring system has at least two sets. The first monitoring system is located in the container area and acquires the container location information during the transfer from the port to the work area, as well as the container information during hoisting, and sends it to the data server. The second monitoring system is located at the end of the driveway in the work area and acquires the transportation equipment information and the information of the transported containers and sends it to the data server. The data server guides the transport equipment carrying the vehicle positioning tag to the designated location to carry out loading and unloading operations based on the location information of the bay required for the operation and the location information of the transport equipment on the lane. During the operation, the information obtained by the monitoring system is used to monitor the operation. The ground positioning base station includes a UWB positioning module, a communication module, a laser calibration system, and a power module connected together; each UWB positioning base station on one side of the lane is equipped with a laser positioning calibration system to calibrate the IMU data of the trailer's position when the trailer passes the base station, reducing positioning errors caused by time and distance factors. The monitoring system identifies container information and location information, stores a four-dimensional array of container information and corresponding location information in the data server, and when the hoisting equipment is used to load the container, it finds the corresponding location information based on the information of the hoisted container, clears it, forms operation information, and saves it to the data server.

2. The port operation system based on multi-sensor fusion positioning as described in claim 1, characterized in that: The vehicle-mounted positioning tag includes a UWB positioning module, an IMU sensor module, a communication module, and a power module connected together.

3. The port operation system based on multi-sensor fusion positioning as described in claim 1, characterized in that: The time between the ground positioning base stations is kept synchronized.

4. The port operation system based on multi-sensor fusion positioning as described in claim 2, characterized in that: The UWB positioning module of the vehicle-mounted positioning tag communicates with the UWB positioning module of each ground positioning base station to obtain the time difference between the arrival of the vehicle-mounted positioning tag at each ground positioning base station, and obtains the location information of the transportation equipment carrying the vehicle-mounted positioning tag on the lane based on the distance between two adjacent ground positioning base stations.

5. The port operation system based on multi-sensor fusion positioning as described in claim 2, characterized in that: The IMU sensor module has an accelerometer and a gyroscope, which acquire the acceleration and angular velocity of the transportation equipment, convert them into position, velocity and attitude, and then send them to the data server.

6. The port operation system based on multi-sensor fusion positioning as described in claim 5, characterized in that: The vehicle positions acquired by the UWB positioning module and the IMU sensor module are respectively and After multiple measurements at the same location within the work area, let the estimated x-axis position of the vehicle positioning tag within the work lane be denoted as . , Satisfy the following formula: ； k is the Kalman gain, ranging from 0 to 1; by taking the derivative of the Kalman gain, we obtain the minimum value of the variance of the estimated value, which is the position offset of the vehicle positioning tag relative to the ground positioning base station. The position offset is used to update the real-time position of the transportation equipment at the corresponding ground positioning base station.

7. The port operation system based on multi-sensor fusion positioning as described in claim 6, characterized in that: The Kalman gain k makes the estimated value Standard deviation Minimum, estimated variance Satisfy the following formula: ； By taking the derivative with respect to k and setting the derivative value to 0, we obtain the Kalman gain k when the extreme value is reached.

8. The port operation system based on multi-sensor fusion positioning as described in claim 1, characterized in that: The monitoring system sends the acquired container location information and container information to the data server, specifically: The location information of containers in the work area is represented by a distributed grid formed by a four-dimensional array (X, Y, H, N). X is the horizontal position coordinate, Y is the vertical position coordinate, H is the height of the container, and N is the number of the work area. Among them, the horizontal and vertical positions of the first container in the first row and first column are (1, 1), the H coordinate of the container closest to the ground is 1, and N=1, 2, 3, 4, 5.

9. The port operation system based on multi-sensor fusion positioning as described in claim 1, characterized in that: It also has a driver terminal that receives guidance instructions from the data server, enabling the transport equipment to move to the designated location to perform loading and unloading operations.

Images