A preset height-based BLE Bluetooth AoA positioning method and system

Abstract

The application relates to a BLE Bluetooth AoA positioning method and system based on a preset height, and the positioning method comprises the following steps: 1) receiving label information and phase data generated based on a positioning signal, and acquiring a corresponding received signal strength indicator; 2) judging whether the received signal strength indicator is lower than a preset indicator threshold, if yes, ending, if not, executing step 3); 3) calculating and obtaining an arrival angle based on the phase data; 4) obtaining a preset height value of a pre-stored Bluetooth label based on the label information, and calculating and obtaining the coordinates of the Bluetooth label based on the arrival angle, coordinate parameters of an array antenna and the preset height value of the Bluetooth label. Compared with the prior art, the application has the advantages of high reliability, high calculation efficiency and the like, and the introduction of the preset height parameter of the label reduces the algorithm requirement of an edge gateway and post-maintenance.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of indoor positioning technology, in particular to a BLE Bluetooth AoA positioning method and system based on a preset height. BACKGROUND

[0002] For the asset management of factories, warehouses and the like, since the equipment is relatively dense and the number is large, if relying on manpower to count and count, the efficiency is low, and it is impossible to realize real-time positioning and tracking of various equipment, and the position of the equipment cannot be obtained in time, so as to realize real-time counting and counting. With the development of technology, factories, warehouses and manufacturing facilities increasingly use tags. There are two main purposes for using asset tags: determining whether the asset is online and tracking mobile assets. The positioning function based on Bluetooth tags is a popular low-power asset tracking solution. However, the existing Bluetooth positioning method has various defects, such as the RSSI fingerprint positioning technology requiring multiple positioning base stations, data training for different scenes, and high demand for computing power.

[0003] A reliable, low-cost and low-power Bluetooth positioning method is still of great significance for the asset tracking needs of factories and warehouses. SUMMARY

[0004] The purpose of the present application is to overcome the defects of the prior art and provide a BLE Bluetooth AoA positioning method and system based on a preset height, which has high reliability and high computing efficiency. At the same time, by introducing the preset height parameter of the tag, the computing power requirement of the edge gateway and the later maintenance are reduced.

[0005] The purpose of the present application can be achieved by the following technical solutions:

[0006] A BLE Bluetooth AoA positioning method based on a preset height, which runs in an edge gateway, realizes positioning of a tracking object based on a Bluetooth tag arranged on the tracking object, and the positioning signal sent by the Bluetooth tag is transmitted to the edge gateway through an array antenna and a positioning base station in turn. The positioning method comprises the following steps:

[0007] 1) receiving tag information and phase data generated based on the positioning signal, and obtaining a corresponding received signal strength indicator;

[0008] 2) judging whether the received signal strength indicator is lower than a preset indicator threshold, if yes, ending, if not, executing step 3);

[0009] 3) calculating the arrival angle based on the phase data;

[0010] 4) obtaining a preset height value of the Bluetooth tag pre-stored based on the tag information, and calculating a coordinate of the Bluetooth tag based on the angle of arrival, the coordinate parameter of the array antenna, and the preset height value.

[0011] Further, the preset index threshold is set according to a use place and a positioning base station coverage range.

[0012] Further, the step 3) specifically comprises:

[0013] obtaining a first correction phase difference value between different antennas based on phase data corresponding to each antenna of the array antenna;

[0014] second correcting the first correction phase difference value based on a positioning signal frequency deviation value to obtain a final phase difference value;

[0015] obtaining an angle of arrival of the positioning signal relative to a center point of the two antennas based on the final phase difference value.

[0016] Further, the obtaining of the first correction phase difference value specifically comprises:

[0017] performing circle fitting on the first phase data to obtain a displacement of a circle center position, and correcting other phase data using the displacement;

[0018] numerically averaging phase differences of phase data at fixed intervals to obtain a phase difference estimate value;

[0019] performing multiple calculations based on the Music algorithm in a range of ±5° of the phase difference estimate value through dichotomy to obtain the first correction phase difference value.

[0020] Further, the number of times of performing the calculation based on the Music algorithm is determined based on a preset precision.

[0021] Further, the obtaining of the positioning signal frequency deviation value specifically comprises:

[0022] performing linear fitting on all phase data corresponding to a specified antenna to obtain the frequency deviation value corresponding to the antenna.

[0023] Further, the antenna parameter of the array antenna comprises an antenna arrangement and coordinate information, and two of the following formulas are selected for calculation of the coordinate of the Bluetooth tag according to the antenna arrangement:

[0024] (y0-y1) 2 =(tanθ1*x1) 2 -(z0-z1) 2 (1)

[0025] (tanθ2*(y0-y2)) 2= (x0-x2) 2 +(z0-z2) 2 (2)

[0026] (x0-x3) 2 +(y0-y3) 2 = (tan theta3 * (z0-z3)) 2 (3)

[0027] Wherein, formula (1) is the formula adopted when two antennas are arranged along the x axis, formula (2) is the formula adopted when two antennas are arranged along the y axis, formula (3) is the formula adopted when two antennas are arranged along the z axis, theta1, theta2, theta3 are the angles of arrival calculated corresponding to two antennas, (x1, y1, z1), (x2, y2, z2), (x3, y3, z3) are the center coordinates of the two antennas, (x0, y0, z0) are the coordinates of the Bluetooth tag to be positioned.

[0028] Further, selecting two formulas for Bluetooth tag coordinate calculation is specifically:

[0029] Two corresponding curves are drawn by two formulas, and the difference between the horizontal coordinates or the vertical coordinates of the two curves is judged, and the coordinate calculation result is obtained by bisection method.

[0030] The application also provides an edge gateway, comprising one or more processors, a memory and one or more programs stored in the memory, the one or more programs comprising instructions for performing the preset height-based BLE Bluetooth AoA positioning method as described above.

[0031] The application also provides a preset height-based BLE Bluetooth AoA positioning system, comprising a Bluetooth tag, an array antenna, a positioning base station, an edge gateway and a server connected in sequence, wherein,

[0032] The Bluetooth tag is arranged on a tracking object and periodically sends a positioning signal with a CTE data packet;

[0033] The array antenna receives the positioning information and transmits it to the positioning base station;

[0034] The positioning base receives the positioning signal to obtain tag information and phase data, and uploads the data to the edge gateway;

[0035] The edge gateway pre-stores preset height values corresponding to different Bluetooth tags, obtains the coordinates of the Bluetooth tag by using the positioning method as described above, and uploads them to the server;

[0036] The server stores the received coordinate information and feeds back the corresponding coordinate information when receiving a query request.

[0037] Further, the positioning base station generates a control signal for controlling switching of the array antenna.

[0038] Compared with the prior art, the present application has the following beneficial effects:

[0039] 1、The present application queries the height value recorded during the label registration through the label information, and calculates the coordinate data according to the number of positioning base stations receiving the same positioning signal, the coordinates of the antenna and the angle of arrival, and the preset height value, and corrects the coordinate data, thereby realizing positioning based on the preset height.

[0040] 2、When the received signal strength indicator (RSSI) is too low, it indicates that the label is far away from the gateway, and the signal anti-interference ability is reduced. The present application filters the signal before calculating the coordinates, sets the threshold value of RSSI according to the use place and the measurement range, judges the RSSI of the signal with CTE data packet received by the positioning base station, and skips the coordinate calculation step when the RSSI is lower than the threshold value, thereby reducing the calculation resource consumption and improving the calculation efficiency.

[0041] 3、The phase data is usually affected by electromagnetic interference, which causes the zero point to deviate. The present application determines the position of the zero point after deviation by circular fitting of the phase signal, corrects the phase data, and improves the test accuracy of the phase data.

[0042] 4、The present application obtains the phase difference estimate value through the average difference value of the phase data between the antennas, calculates the accurate value of the phase difference in the phase difference estimate value range through the music algorithm, and then performs frequency correction and angle of arrival conversion on the phase difference. This process can balance the calculation speed and accuracy of the angle of arrival, and realize fast angle of arrival conversion.

[0043] 5、The present application provides a BLE Bluetooth AoA positioning system, which can realize fast deployment and is convenient and reliable to use. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The figure is a flowchart of the positioning method of the present application;

[0045] Figure 2 The figure is a schematic diagram of the IQ data circular fitting of the present application;

[0046] Figure 3 The figure is a schematic diagram of the calculation process of the angle of arrival to the label coordinates of the present application;

[0047] Figure 4 The figure is a schematic diagram of the label coordinate calculation when the array antenna is horizontally arranged, wherein (4a) is a schematic diagram of the horizontal arrangement of the antenna, and (4b) is a schematic diagram of the two curves obtained;

[0048] Figure 5A schematic diagram for calculating a tag coordinate when the array antenna of the application is vertically arranged, wherein (5a) is a schematic diagram of the antenna vertically arranged, and (5b) is a schematic diagram of two curves obtained;

[0049] Figure 6 A structural schematic diagram of a positioning system provided by an embodiment of the application. DETAILED DESCRIPTION

[0050] The application will be described in detail below with reference to the drawings and specific embodiments. The embodiments are implemented on the premise of the technical solution of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following embodiments.

[0051] The Bluetooth 5.1 specification supplements the measurement functions of the angle of departure (AoD) and the angle of arrival (AoA), wherein the positioning method based on the Bluetooth Low Energe (BLE) feature and the AoA measurement makes it possible to meet the needs of reliability, low cost and low power consumption. The assets based on factories and warehouses usually have a stable height, and the positioning base station can be deployed at a higher position. Based on the above thinking, the application provides a BLE Bluetooth AoA positioning method and system based on a preset height.

[0052] Embodiment 1

[0053] The embodiment provides a BLE Bluetooth AoA positioning method based on a preset height, which runs in an edge gateway, and realizes positioning of a tracking object based on a Bluetooth tag arranged on the tracking object. The positioning signal sent by the Bluetooth tag is transmitted to the edge gateway in turn through an array antenna and a positioning base station, as shown in Figure 1 The positioning method comprises the following steps:

[0054] S1, receiving tag information and phase data (IQ data) generated based on a positioning signal, and obtaining a corresponding received signal strength indicator.

[0055] S2, judging whether the received signal strength indicator is lower than a preset indicator threshold, if yes, ending, if not, executing step S3.

[0056] When the signal strength is low, the tag is usually far away from the positioning base station, and the anti-interference ability is weak. Filtering out signals with low strength through the received signal strength indicator (RSSI) can effectively save the gateway computing power. According to the use place and the positioning base station coverage range, the preset indicator threshold of RSSI is set, when the signal RSSI is lower than the threshold, the calculation process is ended, when the signal RSSI is higher than the set threshold, the subsequent calculation step is entered.

[0057] S3, calculating an angle of arrival based on the phase data, specifically comprising:

[0058] Based on the phase data corresponding to each antenna of the array antenna, a first correction phase difference value between different antennas is obtained;

[0059] Based on the positioning signal frequency deviation value, the first correction phase difference value is secondarily corrected to obtain a final phase difference value;

[0060] Based on the final phase difference value, an angle of arrival of the positioning signal relative to the center points of the two antennas is obtained.

[0061] Since the phase data is usually affected by electromagnetic interference, the zero point of the IQ value is slightly offset. When the offset is large, it will significantly affect the accuracy of the phase value. The phase value offset is affected by the phase angle and the offset. When the offset is 2% of the maximum value of the IQ value, the additional phase angle deviation introduced can reach 1.7°. To improve the test accuracy, before the phase calculation, as shown in Figure 2 , the offset of the center position of the circle is obtained by fitting the first 8 IQ data of the phase data, and the offset is used to correct other IQ data.

[0062] The phase difference of the CTE signals received by different antennas in the array antenna is usually estimated by the Music algorithm. Directly using the Music algorithm to estimate the phase difference requires a lot of computing power. To reduce the computing power consumption of the edge gateway, first, the phase difference estimate value is obtained by numerically averaging the phase value difference of the IQ data at a fixed interval. The curve of the Music algorithm in the estimate value is symmetrically distributed, so the phase difference value with an accuracy of 0.01° can be obtained through 10 calculations in the range of ±5° of the phase difference estimate value by using the bisection method. If the Music algorithm is used to perform a 0.01° precision traversal, it needs to be calculated 3.6*10^4 times, which can effectively reduce the computing power requirement.

[0063] Since the positioning base station will cause a certain frequency error in the signal frequency reduction and sampling process, this error will be affected by many factors and cannot be directly corrected by preset parameters. By linearly fitting all the phase data corresponding to the specified antenna, a more accurate frequency deviation value can be obtained, and the phase difference value between the antennas is corrected based on this value, and finally a plurality of values are obtained. The angle of arrival θ of the positioning signal relative to the center points of the two antennas can be calculated by the above obtained values through the following formula:

[0064]

[0065] S4, obtaining a preset height value of the Bluetooth tag pre-stored based on the tag information, and calculating a coordinate of the Bluetooth tag based on the angle of arrival, the coordinate parameter of the array antenna, and the preset height value.

[0066] As shown in Figure 3 The calculation process of the angle of arrival to the tag coordinate is shown in the following formula (5-1) to (5-4).

[0067] First, the preset height value (z0) of the tag is obtained from the server according to the tag information, and the quadrant of the tag relative to the coordinate system of the array antenna is determined according to the arrangement direction of the array antenna and the angle of arrival. According to the arrangement direction of the array antenna, two corresponding formulas are selected from the following three formulas for calculating the tag coordinate.

[0068] (y0-y1) 2 =(tanθ1*x1) 2 -(z0-z1) 2 (5-2)

[0069] (tanθ2*(y0-y2)) 2 =(x0-x2) 2 +(z0-z2) 2 (5-3)

[0070] (x0-x3) 2 +(y0-y3) 2 =(tanθ3*(z0-z3)) 2 (5-4)

[0071] wherein the tag coordinate is (x0, y0, z0). When the antenna is arranged along the x-axis, the corresponding formula is (5-2), wherein θ1 in the formula is the angle of arrival, and (x1, y1, z1) in the formula is the center coordinate of the antenna. When the antenna is arranged along the y-axis, the corresponding formula is (5-3), wherein θ2 in the formula is the angle of arrival, and (x2, y2, z2) in the formula is the center coordinate of the antenna. When the antenna is arranged along the z-axis, the corresponding formula is (5-4), wherein θ3 in the formula is the angle of arrival, and (x3, y3, z3) in the formula is the center coordinate of the antenna.

[0072] When the array antenna is horizontally arranged, the relationship between the tag and the array antenna is shown in (4a) of Figure 4 After substituting the antenna coordinate, the angle of arrival, and the preset height of the tag into the formulas (5-2) and (5-3), the following coordinates of the tag can be obtained. Figure 4The intersection of the two curves shown in Fig. 4b is the calculation result of the tag coordinates. Since it cannot be directly solved by formula, the tag coordinates are determined by the positive and negative of the difference between the horizontal or vertical coordinates of the two curves, and the coordinate calculation result with centimeter level accuracy is quickly obtained by bisection method. When the height difference between the tag and the positioning base station is 2m and the horizontal distance is less than 10m, the single base station positioning error is less than 0.7m.

[0073] When the array antenna is vertically arranged, the relationship between the tag and the array antenna is shown in Fig. 5a. Figure 5 The antenna coordinates, angle of arrival and preset height of the tag are substituted into formula (5-2) and (5-4) to obtain two curves shown in Fig. 5b, and the intersection of the two curves is the calculation result of the tag coordinates. Figure 5 The error order of magnitude of the calculation result is the same as that of the horizontal positioning method. Figure 4 The arrangement is basically the same.

[0074] After the calculation is completed, the edge gateway uploads the calculation result to the server for storage. When the positioning signal of a tag is received by multiple positioning base stations, the coordinates obtained by the multiple positioning base stations are weighted and averaged according to the time information in the server to improve the positioning accuracy.

[0075] If the above method is realized in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on this understanding, the technical solutions of the present application or the part of the prior art that essentially contributes or the part of the technical solutions can be embodied in the form of a software product, which is stored in a storage medium and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the method described in the embodiments of the present application. The aforementioned storage medium includes: a U disk, a mobile hard disk, a read-only memory (ROM, Read-Only Memory), a random access memory (RAM, Random Access Memory), a magnetic disk or an optical disk, and various storage medium that can store program codes.

[0076] Based on the above positioning method, an edge gateway can also be provided, which includes one or more processors, a memory and one or more programs stored in the memory, and the one or more programs include instructions for executing the preset height based BLE Bluetooth AoA positioning method as described above.

[0077] Embodiment 2

[0078] As shown in Fig. 6a, the relationship between the tag and the array antenna is shown in Fig. 6a. Figure 6As shown, the embodiment provides a BLE Bluetooth AoA positioning system based on a preset height, which comprises a Bluetooth tag 1, an array antenna 2, a positioning base station 3, an edge gateway 4 and a server 5 connected in sequence, wherein:

[0079] The Bluetooth tag 1 is installed on the asset to be tracked, supports Bluetooth 5.1, and the installation height is entered in advance into the edge gateway 4. After installation, the positioning signal with CTE data packet is periodically sent;

[0080] The array antenna 2 is deployed at a high position and can switch the antenna under the control signal of the positioning base station;

[0081] The positioning base station 3 can control the switching of the array antenna, receive the positioning signal to obtain the tag information and phase data, and upload the data to the edge gateway 4;

[0082] The edge gateway 4 has a certain computing power and is connected with one or more positioning base stations 3. After receiving the tag information and phase data uploaded by the positioning base station 3, the edge gateway 4 integrates and converts the data into position information and uploads the position information to the server 5. The edge gateway 4 stores a computer program capable of realizing the positioning method as described in embodiment 1;

[0083] The server 5 receives and records the tag position information uploaded by the edge gateway 4 and can be queried by relevant management personnel.

[0084] The working process of the BLE Bluetooth AoA positioning system based on a preset height in the embodiment includes:

[0085] 1) Deploy the positioning base station 3 and the array antenna 2, and record the deployment direction and coordinate parameters of the array antenna 2;

[0086] 2) When the asset is stored, the Bluetooth tag 1 is broadcast configured and the installation height is recorded;

[0087] 3) When the tag enters the positioning range, the tag position information is calculated and obtained by the edge gateway 4 and uploaded to the server 5;

[0088] 4) The user retrieves the positioning record of the specified tag from the server 5.

[0089] The above detailed the preferred embodiment of the application. It should be understood that those skilled in the art can make many modifications and changes without creative labor according to the concept of the application. Therefore, any technical solution obtained by logical analysis, reasoning or limited experiment based on the existing technology according to the concept of the application shall be within the protection scope determined by the claims.

Claims

1. A BLE Bluetooth AoA positioning method based on a preset height, characterized in that, The positioning method is run in the edge gateway, and positioning of a tracking object is achieved based on a Bluetooth tag arranged on the tracking object. A positioning signal transmitted by the Bluetooth tag is transmitted to the edge gateway in sequence through an array antenna and a positioning base station. The positioning method comprises the following steps: 1) receiving tag information and phase data generated based on the positioning signal, and obtaining a corresponding received signal strength indicator; 2) determining whether the received signal strength indicator is lower than a preset indicator threshold, and if so, ending, and if not, executing step 3); 3) calculating an angle of arrival based on the phase data; Step 3) specifically comprises: obtaining a first corrected phase difference value between different antennas based on the phase data corresponding to each antenna of the array antenna; secondarily correcting the first corrected phase difference value based on a frequency deviation value of the positioning signal to obtain a final phase difference value; obtaining an angle of arrival of the positioning signal relative to the center points of the two antennas based on the final phase difference value; The first corrected phase difference value is specifically obtained as follows: performing circular fitting on the first phase data to obtain a displacement of the center of the circle, and correcting other phase data using the displacement; numerically averaging the phase difference of the phase data at a fixed interval to obtain a phase difference estimate value; performing multiple calculations based on the Music algorithm within the range of the phase difference estimate value ± 5° through the bisection method to obtain the first corrected phase difference value; 4) obtaining a preset height value of the Bluetooth tag pre-stored based on the tag information, and calculating the coordinates of the Bluetooth tag based on the angle of arrival, the coordinate parameters of the array antenna, and the preset height value. 2.The preset height based BLE Bluetooth AoA positioning method according to claim 1, wherein, The preset indicator threshold is set according to the use site and the coverage range of the positioning base station. 3.The preset height based BLE Bluetooth AoA positioning method according to claim 1, wherein, The number of times of performing the calculation based on the Music algorithm is determined based on a preset accuracy. 4.The preset height based BLE Bluetooth AoA positioning method according to claim 1, wherein, The frequency deviation value of the positioning signal is specifically obtained as follows: performing linear fitting on all phase data corresponding to a specified antenna to obtain the frequency deviation value corresponding to the antenna. 5.The preset height based BLE Bluetooth AoA positioning method according to claim 1, wherein, The antenna parameters of the array antenna include antenna arrangement and coordinate information. Two formulas are selected for the calculation of the coordinates of the Bluetooth tag according to the antenna arrangement as follows: (y0 - y1) 2 = (tan θ1 * x1) 2 -(z0 - z1) 2 (1) (tan θ2 * (y0- y2)) 2 = (x0- x2) 2 + (z0- z2) 2 (2) (x0 - x3) 2 +(y0 - y3) 2 = (tan θ3 * (z0 - z3)) 2 (3) wherein formula (1) is a formula used when two antennas are arranged along the x-axis, formula (2) is a formula used when two antennas are arranged along the y-axis, and formula (3) is a formula used when two antennas are arranged along the z-axis. θ1, θ2, and θ3 are the angles of arrival calculated for the two antennas. (x1, y1, z1), (x2, y2, z2), and (x3, y3, z3) are the center coordinates of the two antennas. (x0, y0, z0) are the coordinates of the Bluetooth tag to be positioned. 6.The preset height based BLE Bluetooth AoA positioning method according to claim 5, wherein, The selection of two formulas for the calculation of the coordinates of the Bluetooth tag is specifically as follows: Two curves corresponding to the two formulas are drawn, and a judgment is made based on the positive or negative of the difference between the horizontal coordinates or the vertical coordinates of the two curves. The coordinate calculation result is obtained through the bisection method.

7. An edge gateway, characterized by One or more processors, a memory, and one or more programs stored in the memory are included. The one or more programs include instructions for executing the preset height-based BLE Bluetooth AoA positioning method as claimed in any one of claims 1-6. 8.A BLE Bluetooth AoA positioning system based on a preset height, characterized in that, The system comprises a Bluetooth tag, an array antenna, a positioning base station, an edge gateway and a server connected in sequence, wherein, The Bluetooth tag is arranged on a tracking object and periodically transmits a positioning signal with a CTE data packet; The array antenna receives the positioning signal and transmits it to the positioning base station; The positioning base receives the positioning signal, acquires tag information and phase data, and uploads the data to the edge gateway; The edge gateway pre-stores preset height values corresponding to different Bluetooth tags, acquires coordinates of the Bluetooth tag by using the positioning method in any one of claims 1-6, and uploads the coordinates to the server; The server stores the received coordinate information and feeds back corresponding coordinate information upon receiving a query request.

Images