Precise positioning method for outdoor steel coil warehouse travelling crane based on Beidou differential positioning

Abstract

The invention relates to a Beidou differential positioning-based accurate positioning method for an outdoor steel coil warehouse crane, and the method comprises the following steps: a Beidou differential base station continuously receives Beidou satellite signals, calculates differential correction data in real time, and broadcasts the differential correction data to a Beidou differential mobile station through a data link; wherein the Beidou differential mobile station is installed on a trolley of the travelling crane, the travelling crane further comprises a cart, the cart is a bridge frame of the travelling crane and moves along a main track of an outdoor steel coil warehouse, and the trolley moves along a transverse track of the bridge frame; the Beidou differential mobile station dynamically solves the relative coordinates of the trolley relative to the Beidou differential base station by adopting a real-time dynamic differential positioning method according to the received differential correction data; and based on the relative coordinates of the trolley relative to the Beidou differential base station, calculating the positions of the cart and the trolley by adopting a coordinate conversion algorithm coupled with a traveling structure, and completing the positioning process. Compared with the prior art, the method has the advantages of improving the positioning precision and the like.

Description

Technical Field

[0001] This invention relates to the field of vehicle positioning, and in particular to a precise positioning method for outdoor steel coil warehouse vehicles based on BeiDou differential positioning. Background Technology

[0002] Currently, in large outdoor steel coil warehouses, precise positioning of overhead cranes is crucial for achieving automated and intelligent management. The overhead crane consists of a main trolley moving along the length of the warehouse and a secondary trolley moving along the main trolley's crossbeam. Precise positioning means simultaneously acquiring the high-precision positions of both the main trolley and the secondary trolley. Existing positioning technologies mainly include: 1. GPS / BeiDou Standard Positioning: This method uses a single GPS or BeiDou receiver for positioning. While low-cost, its accuracy is typically in the meter range and is susceptible to various error sources. It cannot meet the centimeter-level accuracy requirements for precise stacking and retrieval of steel coils, nor can it accurately distinguish the independent coordinates of the large and small vehicles.

[0003] 2. Laser Positioning: This method involves installing laser devices on fixed structures such as vehicles and warehouses for distance measurement and positioning. While this technology can achieve high precision, it typically only measures one dimension (e.g., the position of the main vehicle). To simultaneously measure the position of smaller vehicles, additional equipment is required, leading to high costs, system complexity, and poor reliability in harsh outdoor weather conditions.

[0004] 3. RFID and Ultra-Wideband (UWB) Positioning: This involves pre-burying or installing a large number of tags or base stations within the warehouse. In large outdoor steel coil warehouses, this solution requires a massive number of base stations or tags, resulting in high costs. More importantly, metal steel coils strongly shield and reflect radio frequency signals, severely impacting positioning accuracy and stability. Furthermore, in outdoor steel coil warehouses, severe weather conditions may affect the circuitry and installation stability of the UWB positioning equipment, leading to decreased positioning accuracy or equipment malfunction.

[0005] 4. Encoders and Mechanical Switches: The vehicle position is calculated by measuring the number of wheel rotations (encoder). This method produces cumulative errors, requires frequent calibration, and is difficult to decouple the motion of the main vehicle and auxiliary vehicle, thus failing to provide absolute position in a unified coordinate system.

[0006] In summary, existing technologies, when applied to precise positioning scenarios for overhead cranes in outdoor steel coil warehouses, generally suffer from problems such as insufficient accuracy, high cost, poor environmental adaptability, or inability to provide two-dimensional coordinates that precisely correspond to the physical structure of the crane (large trolley / small trolley). Summary of the Invention

[0007] The purpose of this invention is to provide a precise positioning method for outdoor steel coil warehouse cranes based on BeiDou differential positioning, achieving centimeter-level positioning.

[0008] The objective of this invention can be achieved through the following technical solutions: A precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning includes the following steps: The Beidou differential reference station continuously receives Beidou satellite signals, calculates differential correction data in real time, and broadcasts it to the Beidou differential mobile station via data link. The Beidou differential mobile station is installed on the trolley of the traveling crane, which also includes a main trolley, which is the bridge of the traveling crane. The main trolley moves along the main track of the outdoor steel coil warehouse, and the trolley moves along the transverse track of the bridge. Based on the received differential correction data, the BeiDou differential mobile station dynamically calculates the relative coordinates of the vehicle with respect to the BeiDou differential reference station using a real-time dynamic differential positioning method. Based on the relative coordinates of the vehicle with respect to the BeiDou differential reference station, a coordinate transformation algorithm coupled with the vehicle structure is used to calculate the positions of the vehicle and the trolley, thus completing the positioning process.

[0009] Furthermore, the calculation steps for the differential correction data include: The BeiDou differential reference station calculates the apparent pseudorange between itself and all visible BeiDou satellites at the current moment based on the received BeiDou satellite signals. Based on the geographical location of the BeiDou differential reference station in the outdoor steel coil warehouse, the true geometric distance between the BeiDou differential reference station and each visible BeiDou satellite was calculated. The apparent pseudorange of the satellite is compared with the actual geometric distance to obtain the differential correction amount of the BeiDou satellite signal, wherein the differential correction amount = actual geometric distance - apparent pseudorange of the satellite; The calculated differential correction value for each visible BeiDou satellite is encoded into a specific format to form a differential correction data packet.

[0010] Furthermore, the data link is a BeiDou differential radio station.

[0011] Furthermore, the steps for calculating the relative coordinates of the vehicle with respect to the BeiDou differential reference station include: The BeiDou differential mobile station and the BeiDou differential reference station synchronously receive the BeiDou satellite signals; The BeiDou differential mobile station calculates its own apparent pseudorange using the received BeiDou satellite signals and corrects it using the differential correction data to obtain the corrected pseudorange. The BeiDou differential mobile station uses the corrected pseudorange corresponding to multiple visible BeiDou satellites and employs a positioning algorithm to calculate the three-dimensional coordinates of the BeiDou differential mobile station, which serve as the relative coordinates of the vehicle relative to the BeiDou differential reference station.

[0012] Furthermore, the step of obtaining the corrected pseudorange includes: The BeiDou differential mobile station decodes the received differential correction data and extracts the differential correction amount corresponding to each visible BeiDou satellite; The apparent pseudorange of the BeiDou differential mobile station is corrected using the differential correction amount to obtain the corrected pseudorange, where the corrected pseudorange = apparent pseudorange of the BeiDou differential mobile station + differential correction amount.

[0013] Furthermore, the step of calculating the positions of the large vehicle and the small vehicle includes: The direction of movement of the large trolley along the main track of the outdoor steel coil warehouse is set as the X-axis, and the direction of movement of the small trolley along the transverse track of the bridge frame is set as the Y-axis. A point is selected in the outdoor steel coil warehouse as the origin (0, 0) to construct a local plane rectangular coordinate system of the warehouse coupled with the movement of the trolley. Obtain the geodetic coordinates of the origin (0, 0) in the local Cartesian coordinate system of the warehouse and at least one known point in the outdoor steel coil warehouse; Based on the geodetic coordinates and the warehouse local coordinates in the warehouse local plane rectangular coordinate system, calculate the transformation parameters between the geodetic coordinate system and the warehouse local plane rectangular coordinate system; The geodetic coordinates of the Beidou differential mobile station are acquired in real time. Using the transformation parameters and Gaussian projection, they are converted into the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse. The X value corresponds to the position of the large vehicle, and the Y value corresponds to the position of the small vehicle.

[0014] Furthermore, the calculation expression for the conversion parameter is as follows: At the end of each of the two tracks of the vehicle, a point is selected as a calibration point. The two tracks are parallel. The end of the first track is taken as the origin of the coordinate system (0, 0), denoted as point A. The end of the other track is taken as the direction reference point, denoted as point B. The direction connecting points A and B is perpendicular to the direction of the track, i.e., the Y-axis direction. The direction of the track is taken as the X-axis direction, which is perpendicular to the direction connecting points A and B. The BeiDou differential mobile stations were placed at points A and B, and the geodetic coordinates of points A and B were recorded respectively, with the geodetic coordinates of point A being used as the longitude. ,latitude The geodetic coordinates of point B are used as longitude. ,latitude ; The orbital direction vector is calculated based on the geodetic coordinates of points A and B, and is expressed as follows: , In the formula, The orbital direction vector; Calculate the azimuth angle of the vertical direction of the orbit. The calculation expression is: , In the formula, It is a two-parameter arctangent function. This represents the difference in longitude between points A and B. Based on the azimuth angle of the vertical direction of the orbit Determine the direction of the track As the rotation angle, it is expressed as: or , The average longitude of the outdoor steel coil warehouse area is calculated as the central meridian, and the expression for calculating the average longitude is as follows: , In the formula, The average longitude.

[0015] Furthermore, the step of obtaining the real-time coordinates (X, Y) includes: The geodetic coordinates obtained in real time by the BeiDou differential mobile station are set as ( The Gauss-Kruger projection transformation method is used to project the coordinates, and the projected coordinates are obtained. Based on the transformation parameters, the projected coordinates are transformed to the local Cartesian coordinate system of the warehouse to obtain the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse.

[0016] Furthermore, the step of obtaining the projected coordinates includes: Obtain basic parameters, including the semi-major axis of the WGS-84 ellipsoid. Flatness The square of the first eccentricity The square of the second eccentricity Central Meridian ; According to coordinates ( Auxiliary parameters, including latitude, are calculated from the central meridian and the central meridian. ,longitude , , radius of curvature of the 5'-5' circle , , ; The calculation of the arc length of the central meridian is expressed as follows: , in: ， ， ， ， In the formula, The arc length of the central meridian; Based on the arc length of the central meridian, the projected coordinates are calculated using the Gauss-Kruger projection formula, wherein the projected coordinates are expressed as: , , In the formula, These are the coordinates after projection.

[0017] Furthermore, the step of obtaining the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse includes: Coordinate translation: Based on the projected coordinates, calculate the coordinates of the origin (0, 0) in the projected coordinate system. Then, translate the current point to obtain the translated coordinates. ,in , ; Coordinate rotation: Calculating orbital direction Angle with the north direction of the projected coordinate system Using a rotation matrix to change the coordinates Rotate to the local Cartesian coordinate system of the warehouse to obtain: , , In the formula, These are the coordinates corresponding to the local Cartesian coordinate system of the warehouse. Scale adjustment: Adjust the scale according to the distances in the actual scene. and Multiply by a certain scaling factor to obtain the actual time coordinates (X, Y).

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention calculates the relative coordinates of the vehicle to the Beidou differential mobile station in real time by installing the Beidou differential reference station on the vehicle, and performs coordinate conversion using a set of coordinate transformation algorithms coupled with the physical motion of the vehicle, which can directly solve the precise position of the vehicle and the vehicle in the local coordinate system of the warehouse.

[0019] (2) The Beidou differential positioning technology in this invention can effectively eliminate the main sources of error. Even in the environment of a steel coil warehouse with a large metal structure, it can maintain stable and reliable positioning performance and improve the positioning accuracy from the meter level to the 1-3 cm level, meeting the stringent requirements of automated management of steel coils.

[0020] (3) The Beidou differential reference station of the present invention can serve all vehicles in the scene. Compared with laser or UWB solutions, it has lower long-term ownership cost and better scalability.

[0021] (4) This invention is not affected by severe weather such as dust, rain, snow, and fog, and can work continuously around the clock.

[0022] (5) By providing accurate (X, Y) coordinates, the present invention can effectively eliminate the fuzzy judgment of distance and position in manual operation, reduce the dependence on operator experience, and improve the accuracy of operation.

[0023] (6) The implementation cycle of this invention is short and has little impact on existing operations.

[0024] (7) The precise coordinates of the large and small vehicles calculated by this invention can reach the centimeter level. Instructions can be directly issued by the automated system to realize the automatic grabbing, transportation and stacking of steel coils, greatly improving the work efficiency and realizing true work automation. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the method flow of the present invention. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0027] This embodiment provides a precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning. The core of this method is to install a BeiDou differential mobile station on the crane's trolley and directly calculate the precise positions of the crane and trolley in the local Cartesian coordinate system of the warehouse through a coordinate transformation algorithm coupled with the physical motion of the crane.

[0028] In this embodiment, the traveling crane includes a trolley and a main trolley. The main trolley is the bridge of the traveling crane, which moves along the main track of the warehouse. The trolley is a transverse trolley on the bridge, which moves along the transverse track of the bridge. This method is implemented through the following hardware structure, which comprises: BeiDou differential reference station: Serving as a fixed reference point, it is installed at a known precise coordinate location inside an outdoor steel coil warehouse. Its core function is to continuously receive BeiDou satellite signals and calculate and generate differential correction data in real time.

[0029] Beidou Differential Radio: Responsible for establishing a stable and reliable wireless data link between the Beidou differential reference station and the Beidou differential mobile station, and broadcasting differential correction data to the Beidou differential mobile station on the vehicle in real time.

[0030] BeiDou Differential Rover Station: Uniquely installed on the vehicle's trolley. Its function is to receive BeiDou satellite signals and differential correction data from the BeiDou differential reference station in real time, providing high-precision raw geographic coordinates for subsequent coordinate calculations.

[0031] Central control box: As the core unit for vehicle-mounted data processing and communication, it is responsible for collecting high-precision positioning data output by the Beidou differential mobile station and executing the core coordinate transformation algorithm to convert the vehicle's geographical coordinates into the vehicle's coordinates (X) and vehicle coordinates (Y) in the warehouse's local Cartesian coordinate system. Finally, the results are uploaded to the SaaS platform via industrial Ethernet or wireless network.

[0032] Specifically, in conjunction with the above hardware composition structure, such as Figure 1 As shown, the method includes the following steps: S1. Operation and Data Broadcasting of BeiDou Differential Reference Station: The BeiDou differential reference station continuously receives BeiDou satellite signals, calculates differential correction data, and broadcasts it in real time through the BeiDou differential radio station.

[0033] Specifically, this step includes the following: 1) Synchronous observations from the BeiDou differential reference station: The BeiDou differential reference station is installed at a precisely known geographical location, and its coordinates (X0, Y0, Z0) are obtained in advance through precise measurements. The BeiDou differential reference station continuously receives signals from all visible BeiDou satellites and, like a regular receiver, calculates its current apparent pseudorange. Pseudorange refers to the distance measurement from the satellite to the receiver, but it includes various errors.

[0034] 2) Calculation Error: Since the precise coordinates of the BeiDou differential reference station are known, the true geometric distance from the BeiDou differential reference station to each satellite can be accurately calculated. Comparing the "satellite apparent pseudorange" with the "true geometric distance," the difference between the two represents the comprehensive error of the satellite signal at that moment. This comprehensive error includes satellite orbit error, satellite clock error, ionospheric delay, tropospheric delay, etc. Differential Correction = True Geometric Distance - Satellite Apparent Pseudorange

[0035] 3) Generating and broadcasting differential correction data: The BeiDou differential reference station calculates the pseudorange correction for each visible satellite. These corrections are encoded into a specific format (usually RTCM format) to form differential correction data packets. These differential correction data are broadcast in real time and periodically (e.g., once per second) via a data link (such as a BeiDou differential radio).

[0036] S2. Operation of Beidou Differential Mobile Station: The Beidou differential mobile station installed on the trolley simultaneously receives Beidou satellite signals and differential correction data, and uses a real-time dynamic differential positioning method to dynamically calculate the relative coordinates of the trolley with respect to the Beidou differential reference station.

[0037] Specifically, this step employs Real-Time Kinematic Differential (RTK) technology to perform real-time dynamic solution, including the following: 1) Synchronous signal reception: The BeiDou differential mobile station and the BeiDou differential reference station synchronously observe the same group of BeiDou satellites and calculate their own satellite apparent pseudorange.

[0038] 2) Receiving differential correction data: The BeiDou differential mobile station receives differential correction data packets broadcast from the BeiDou differential reference station via a data link (such as a BeiDou differential radio).

[0039] 3) Pseudorange Correction: The BeiDou differential mobile station decodes data packets and extracts the pseudorange correction for each satellite. The BeiDou differential mobile station applies this correction to the apparent pseudorange of its measured corresponding satellite, resulting in a corrected and more accurate pseudorange. Corrected pseudorange = Apparent pseudorange of the BeiDou differential mobile station + Differential correction. Since the distance between the BeiDou differential reference station and the BeiDou differential mobile station is relatively short (usually within a few kilometers to tens of kilometers), the atmospheric delay errors experienced by both, such as those in the ionosphere and troposphere, as well as satellite orbit and clock errors, can be considered essentially the same. Therefore, the error correction calculated by the BeiDou differential reference station can effectively eliminate most of the errors in the BeiDou differential mobile station's measurements.

[0040] 4) Calculating high-precision coordinates: The BeiDou differential mobile station uses the corrected pseudorange from at least four satellites and calculates its own three-dimensional coordinates (longitude, latitude, and elevation) using a standard positioning algorithm (least squares method). Since most errors have been eliminated, the calculated coordinate accuracy can reach the centimeter level, which is the so-called high-precision positioning data.

[0041] S3. Coordinate Transformation and Output: After the central control box obtains the precise geographical coordinates of the vehicle, it executes a coordinate transformation algorithm coupled with the vehicle structure to convert them into (X, Y) coordinates in the local Cartesian coordinate system of the warehouse. The X value corresponds to the physical position of the main vehicle, and the Y value corresponds to the physical position of the vehicle.

[0042] This step primarily addresses the physical structure of the overhead crane, which consists of a main trolley (X-axis movement) and a secondary trolley (Y-axis movement). An algorithm is proposed to accurately convert the WGS-84 latitude and longitude coordinates obtained from the BeiDou differential mobile station mounted on the secondary trolley into the unique location coordinates of the secondary trolley within the warehouse. This algorithm is implemented within the central control box, and the specific steps are as follows: 1) Establish a local Cartesian coordinate system in the warehouse coupled with the crane's motion: The X-axis is defined as the direction of the main crane's running track, and the Y-axis is defined as the direction of the trolley's running track on the main beam. The main crane is the bridge of the overhead crane, moving along the main track of the warehouse; the trolley is the transverse trolley on the bridge, moving along the transverse track of the bridge. Select the starting point of the track at one end of the warehouse or other fixed feature point as the origin (0, 0), thus constructing a unique local Cartesian coordinate system in the warehouse that completely corresponds to the physical motion of the crane.

[0043] 2) Benchmark point calibration: Using Beidou RTK equipment, accurately measure the WGS-84 geodetic coordinates (longitude and latitude) of the origin (0, 0) of the local plane rectangular coordinate system of the warehouse and at least one other known point (e.g., the endpoint of the other end of the track).

[0044] 3) Coordinate transformation parameter calculation: The latitude and longitude coordinates of the calibration points (the two vertices at one end of the two tracks of the warehouse crane) are converted to geodetic coordinates using Gauss-Kruger projection (or UTM projection). Based on the geodetic coordinates of these points and their corresponding local warehouse coordinates (X, Y), the transformation parameters between the two coordinate systems are accurately calculated, mainly including the rotation angle (i.e., the deflection angle of the warehouse X-axis relative to true north) and the three-dimensional translation (offset in the X, Y, and Z directions).

[0045] The calculation process for the transformation parameters is as follows: ① Calibration: Establish a coordinate origin at the end of one end of the train's track. This coordinate system will serve as the absolute reference for all subsequent calculations. Select a point at the end of each of the two train tracks as a calibration point.

[0046] Point A: The end of the first track, serving as the origin of the coordinate system (0, 0); Point B: The end of the second track, used as a directional reference point; The BeiDou differential mobile station was precisely placed at point A, and its geodetic coordinates (longitude) were collected and recorded. ,latitude ); The BeiDou differential mobile station was precisely placed at point B, and its geodetic coordinates (longitude) were collected and recorded. ,latitude ); ② Since the two tracks are parallel, and points A and B are located at the ends of the two tracks respectively, these two points can be used to determine the track direction and coordinate system. The direction of the line connecting points A and B is the perpendicular direction of the track (Y-axis direction), and the track direction (X-axis direction) is perpendicular to the direction of the line connecting points A and B. The track direction vector can be calculated using the coordinates of points A and B: , ③ Calculate the azimuth angle in the vertical direction of the track. : , in, , and These are the latitudes (in radians) of points A and B, respectively.

[0047] ④ Determine the track direction The orbital direction differs from the vertical direction by 90°, therefore: or , The direction of the track As the rotation angle.

[0048] ⑤ Calculate the average longitude of the warehouse area as the central meridian: , Central Meridian As subsequent projection parameters, the offsets in the X, Y, and Z directions can be calculated.

[0049] 4) Real-time Coordinate Transformation and Output: The BeiDou differential mobile station installed on the trolley obtains its WGS-84 latitude and longitude with centimeter-level accuracy in real time. The algorithm in the central control box immediately performs Gaussian projection on these coordinates and applies pre-calculated rotation and translation parameters to convert them into real-time, high-precision coordinates (X, Y) of the trolley in the local Cartesian coordinate system of the warehouse through affine transformation. These coordinates (X, Y) directly correspond to the position of the main vehicle (X value) and the position of the trolley (Y value) and are then sent to the SaaS platform.

[0050] Specifically, the real-time coordinate transformation step includes the following: When the vehicle is moving, the geodetic coordinates obtained by the Beidou differential mobile station on the trolley are ( Use the following steps to convert it to Cartesian coordinates in the warehouse coordinate system.

[0051] ① Gauss-Kruger projection conversion Basic parameters: (Semi-major axis of the WGS-84 ellipsoid) (flatness) (The square of the first eccentricity) (The square of the second eccentricity) (Central Meridian Longitude, Radius) Parameters for auxiliary calculation: (Latitude, Radius) (Longitude, radians) (Difference in longitude, radians) (Radius of curvature of the Mao-You circle) Meridian arc length calculation: Gauss-Kruger projection formula: , , ② Coordinate translation and rotation Transform the projected coordinates to the local Cartesian coordinate system of the warehouse: Coordinate translation: First, calculate the coordinates (x0, y0) of the origin in the projected coordinate system, and then translate the current point: x' = x - x0, y' = y - y0; Coordinate rotation: Calculate the angle between the orbital direction and the north direction of the projected coordinate system. Apply a rotation matrix to rotate the coordinates to the warehouse coordinate system: , , ③ Scale adjustment Based on the distance in the real-world scenario, and Multiply by a certain proportionality factor.

[0052] After the above steps, multiply by the proportionality factor. and This refers to the precise position of the trolley in the Cartesian coordinate system on the local plane of the warehouse, where the position is multiplied by a scaling factor. The displacement corresponding to the direction of the main vehicle, multiplied by a proportionality factor. The displacement corresponding to the direction of the trolley.

[0053] Furthermore, by obtaining precise positioning of the small and large vehicles through the above methods, the vehicle's (X, Y) coordinates can be directly mapped to the physical storage location in the warehouse, enabling the data in the warehouse management system (WMS) to correspond accurately with the physical inventory in real time, achieving "consistency between accounts and goods," and completely eliminating human errors such as misplacement and misretrieval.

[0054] Furthermore, based on precise (X, Y) coordinates, sophisticated electronic fences and collision avoidance models can be created. This not only prevents collisions between vehicles but also prevents collisions between vehicles and obstacles in specific areas (such as stacked ultra-high steel coils) while moving, significantly improving safety.

[0055] After accumulating high-precision trajectory data of large and small vehicles over a long period of time, it can be used to conduct detailed analysis of the vehicle's operating efficiency, idle time, and operational bottlenecks on the X and Y axes, providing unprecedentedly accurate data support for optimizing path algorithms, improving warehouse layout, and evaluating equipment performance.

[0056] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this invention, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0057] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The solutions in the embodiments of the present invention can be implemented using various computer languages, such as the object-oriented programming language Java and the interpreted scripting language JavaScript.

[0058] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0059] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0060] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0061] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of the invention.

[0062] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning, characterized in that, Includes the following steps: The Beidou differential reference station continuously receives Beidou satellite signals, calculates differential correction data in real time, and broadcasts it to the Beidou differential mobile station via data link. The Beidou differential mobile station is installed on the trolley of the traveling crane, which also includes a main trolley, which is the bridge of the traveling crane. The main trolley moves along the main track of the outdoor steel coil warehouse, and the trolley moves along the transverse track of the bridge. Based on the received differential correction data, the BeiDou differential mobile station dynamically calculates the relative coordinates of the vehicle with respect to the BeiDou differential reference station using a real-time dynamic differential positioning method. Based on the relative coordinates of the vehicle with respect to the BeiDou differential reference station, a coordinate transformation algorithm coupled with the vehicle structure is used to calculate the positions of the vehicle and the trolley, thus completing the positioning process.

2. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 1, characterized in that, The calculation steps for the differential correction data include: The BeiDou differential reference station calculates the apparent pseudorange between itself and all visible BeiDou satellites at the current moment based on the received BeiDou satellite signals. Based on the geographical location of the BeiDou differential reference station in the outdoor steel coil warehouse, the true geometric distance between the BeiDou differential reference station and each visible BeiDou satellite was calculated. The apparent pseudorange of the satellite is compared with the actual geometric distance to obtain the differential correction amount of the BeiDou satellite signal, wherein the differential correction amount = actual geometric distance - apparent pseudorange of the satellite; The calculated differential correction value for each visible BeiDou satellite is encoded into a specific format to form a differential correction data packet.

3. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 1, characterized in that, The data link is a Beidou differential radio station.

4. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 1, characterized in that, The steps for calculating the relative coordinates of the trolley with respect to the BeiDou differential reference station include: The BeiDou differential mobile station and the BeiDou differential reference station synchronously receive the BeiDou satellite signals; The BeiDou differential mobile station calculates its own apparent pseudorange using the received BeiDou satellite signals and corrects it using the differential correction data to obtain the corrected pseudorange. The BeiDou differential mobile station uses the corrected pseudorange corresponding to multiple visible BeiDou satellites and employs a positioning algorithm to calculate the three-dimensional coordinates of the BeiDou differential mobile station, which serve as the relative coordinates of the vehicle relative to the BeiDou differential reference station.

5. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 4, characterized in that, The step of obtaining the corrected pseudorange includes: The BeiDou differential mobile station decodes the received differential correction data and extracts the differential correction amount corresponding to each visible BeiDou satellite; The apparent pseudorange of the BeiDou differential mobile station is corrected using the differential correction amount to obtain the corrected pseudorange, where the corrected pseudorange = apparent pseudorange of the BeiDou differential mobile station + differential correction amount.

6. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 1, characterized in that, The steps for calculating the positions of the large vehicle and the small vehicle include: The direction of movement of the large trolley along the main track of the outdoor steel coil warehouse is set as the X-axis, and the direction of movement of the small trolley along the transverse track of the bridge frame is set as the Y-axis. A point is selected in the outdoor steel coil warehouse as the origin (0, 0) to construct a local plane rectangular coordinate system of the warehouse coupled with the movement of the trolley. Obtain the geodetic coordinates of the origin (0, 0) in the local Cartesian coordinate system of the warehouse and at least one known point in the outdoor steel coil warehouse; Based on the geodetic coordinates and the warehouse local coordinates in the warehouse local plane rectangular coordinate system, calculate the transformation parameters between the geodetic coordinate system and the warehouse local plane rectangular coordinate system; The geodetic coordinates of the Beidou differential mobile station are acquired in real time. Using the transformation parameters and Gaussian projection, they are converted into the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse. The X value corresponds to the position of the main vehicle, and the Y value corresponds to the position of the vehicle.

7. The precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 6, characterized in that, The calculation expression for the conversion parameter is: At the end of each of the two tracks of the vehicle, a point is selected as a calibration point. The two tracks are parallel. The end of the first track is taken as the origin of the coordinate system (0, 0), denoted as point A. The end of the other track is taken as the direction reference point, denoted as point B. The direction connecting points A and B is perpendicular to the direction of the track, i.e., the Y-axis direction. The direction of the track is taken as the X-axis direction, which is perpendicular to the direction connecting points A and B. The BeiDou differential mobile stations were placed at points A and B, and the geodetic coordinates of points A and B were recorded respectively. The geodetic coordinates of point A were used as the longitude. ,latitude The geodetic coordinates of point B are used as longitude. ,latitude ; The orbital direction vector is calculated based on the geodetic coordinates of points A and B, and is expressed as follows: ， In the formula, The orbital direction vector; Calculate the azimuth angle of the vertical direction of the orbit. The calculation expression is: ， In the formula, It is a two-parameter arctangent function. This represents the difference in longitude between points A and B. Based on the azimuth angle of the vertical direction of the orbit Determine the direction of the track As the rotation angle, it is expressed as: or , The average longitude of the outdoor steel coil warehouse area is calculated as the central meridian, and the expression for calculating the average longitude is as follows: ， In the formula, The average longitude.

8. A precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 6, characterized in that, The steps for obtaining the real-time coordinates (X, Y) include: The geodetic coordinates obtained in real time by the BeiDou differential mobile station are set as ( The Gauss-Kruger projection transformation method is used to project the coordinates, and the projected coordinates are obtained. Based on the transformation parameters, the projected coordinates are transformed to the local Cartesian coordinate system of the warehouse to obtain the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse.

9. A precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 8, characterized in that, The steps for obtaining the projected coordinates include: Obtain basic parameters, including the semi-major axis of the WGS-84 ellipsoid. Flatness The square of the first eccentricity The square of the second eccentricity Central Meridian ; According to coordinates ( Auxiliary parameters, including latitude, are calculated from the central meridian and the central meridian. ,longitude , , radius of curvature of the 5'-5' circle , , ; The calculation of the arc length of the central meridian is expressed as follows: ， in: ， ， ， ， In the formula, The arc length of the central meridian; Based on the arc length of the central meridian, the projected coordinates are calculated using the Gauss-Kruger projection formula, wherein the projected coordinates are expressed as: ， ， In the formula, These are the coordinates after projection.

10. A precise positioning method for an outdoor steel coil warehouse crane based on BeiDou differential positioning according to claim 8, characterized in that, The step of obtaining the real-time coordinates (X, Y) of the vehicle in the local Cartesian coordinate system of the warehouse includes: Coordinate translation: Based on the projected coordinates, calculate the coordinates of the origin (0, 0) in the projected coordinate system. Then, translate the current point to obtain the translated coordinates. ,in , ; Coordinate rotation: Calculate orbital direction Angle with the north direction of the projected coordinate system Using a rotation matrix to change the coordinates Rotate to the local Cartesian coordinate system of the warehouse to obtain: ， ， In the formula, These are the coordinates corresponding to the local Cartesian coordinate system of the warehouse. Scale adjustment: Adjust the scale according to the distances in the actual scene. and Multiply by a certain scaling factor to obtain the actual time coordinates (X, Y).

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