Article positioning method based on ultrahigh frequency RFID

Abstract

The invention discloses an article positioning method based on an ultrahigh frequency RFID, and relates to the technical field of bus positioning based on the ultrahigh frequency RFID, and the method comprises the steps: setting and recognizing the positioning data related to a bus at a stop through an Internet communication module, calculating and outputting the recognized signal intensity through a positioning feedback module, and carrying out the positioning of an article. The method comprises the steps that signal intensity, position offset correction and positioning optimization gain values are obtained, loop iteration is carried out on the gain values, new signal intensity, position offset correction and positioning optimization gain values are output until the positioning error of an article is lower than a standard error, and the position of the article is displayed in real time through an internet communication module. According to the invention, through precise signal intensity estimation, adaptive position correction and dynamic feedback loop optimization, precise, intelligent and real-time positioning of the bus at the stop is realized, and the accuracy, intelligence and real-time performance of positioning of the bus at the stop are improved. And powerful technical support is provided for the technical field of article positioning of bus management at the stop.

Description

Technical Field

[0001] The present invention relates to the technical field of bus positioning based on ultra-high frequency RFID, and in particular to an object positioning method based on ultra-high frequency RFID. Background Art

[0002] RFID technology is a contactless automatic identification technology that uses radio frequency signals and their spatial coupling and transmission characteristics to achieve automatic identification of stationary and moving objects. RFID systems usually consist of three parts: RFID tags, readers and data processing systems. Tags are attached to objects, and readers send radio frequency signals of a certain frequency through antennas. After receiving the signal, the tags send the stored information back through backscatter modulation. The readers receive and decode the information, and finally perform data processing and information management through the data processing system. In the construction of the Internet of Things and smart cities, ultra-high frequency RFID technology has shown great potential in the field of bus positioning due to its contactless, long-distance and fast reading characteristics.

[0003] Traditional systems based on ultra-high frequency RFID often rely on signal strength to estimate the distance between the tag and the reader, but the signal is easily affected by the multipath effect during propagation, resulting in inaccurate signal strength estimation, which in turn affects the positioning accuracy. When the RFID tag is at the edge of the reader's recognition range, the signal strength drops sharply, making the positioning result extremely unstable or even invalid. In addition, most RFID systems cannot dynamically adjust the reading parameters according to environmental changes and changes in the tag position, which leads to large differences in positioning performance in different environments and poor adaptability. In addition, traditional systems lack an effective feedback loop mechanism to continuously optimize positioning accuracy, making it difficult for the system to achieve optimal performance in practical applications. Summary of the invention

[0004] The purpose of the present invention is to provide an object positioning method based on ultra-high frequency RFID, which solves the problems raised in the above background technology.

[0005] To achieve the above purpose, the present invention provides the following technical solutions, and the specific implementation steps of bus stop management applied to smart city construction are as follows:

[0006] Step 1: Use the Internet communication module to set and identify the location data related to the item;

[0007] Step 2: Using the positioning feedback module, calculate the signal strength of the output recognition, position offset correction and optimize the positioning gain value;

[0008] Step 3: loop the gain value and output the new signal strength, position offset correction and gain value of optimized positioning until the positioning error of the object is lower than the standard error;

[0009] Step 4: Use the Internet communication module to display the location of the object in real time, and store the positioning data and loop iteration data generated by it;

[0010] The identified object is a bus that identifies the stop. An RFID tag device is installed on the object and is used for identification by the Internet communication module. The identification can also be applied to logistics and supply chain management, intelligent manufacturing and production line management, and medical health fields.

[0011] The positioning feedback module includes an initial signal strength estimation unit, a position offset correction unit and a positioning reading performance optimization unit.

[0012] Optionally, the devices used in the Internet communication module include an ultra-high frequency RFID reader, a laser rangefinder and a mobile application;

[0013] The equipment used by the positioning feedback module includes a cloud server.

[0014] Optionally, the calculation formula for estimating the initial signal strength unit is as follows:

[0015] XQ=(F×T f ×Z×T j ×λ 2 ) / [((4π) 2 d 2 )×a];

[0016] λ = G / f;

[0017] in:

[0018] XQ is the signal strength value;

[0019] F is the transmission power;

[0020] T f is the transmitting antenna gain value, T f Reflects the ability of the transmitting antenna to enhance the radiation intensity in a specific direction;

[0021] Z is the receiving gain factor, which is used to optimize the accuracy of signal strength estimation according to specific environmental conditions and system requirements;

[0022] T j is the receiving antenna gain value, T j Reflects the receiving sensitivity enhancement capability of the receiving antenna in a specific direction;

[0023] d is the distance value between objects, and d reflects the actual distance between the RFID tag device on the object and the UHF RFID reader;

[0024] a is the system loss factor, including environmental attenuation and cable loss;

[0025] λ is the signal wavelength;

[0026] G is the speed of light;

[0027] f is the signal frequency.

[0028] Optionally, the Internet communication module stores the identification range of the UHF RFID reader, wherein the central identification position of the identification range of the stored reader is (x o ,y o ), with (x o ,y o ) is the center point with a radius of R;

[0029] The laser rangefinder identifies the location of the RFID tag device on the current item as (x d ,y d );

[0030] Current item position (x d ,y d ) and the center recognition position (x o ,y o The distance between ) is calculated as follows:

[0031]

[0032] d - To identify the distance between locations.

[0033] Optionally, based on the distance value d between the identified positions - The analysis of the difference with radius R is as follows:

[0034] If the distance between the identified positions is d - If it is less than or equal to the radius R, the object is considered to be within the recognition range;

[0035] If the distance between the identified positions is d - If the radius is greater than R, the item is considered to be still within the recognition range of the UHF RFID reader, that is, the edge area. A weighted method is used to optimize the position correction by combining distance and signal strength.

[0036] Optionally, the position offset correction unit analyzes the calculation formula of the object within the recognition range as follows:

[0037] x t =x o +β×f×XQ×cosθ;

[0038] y t =y o+β×f×XQ×sinθ;

[0039] The calculation formula for analyzing the position offset correction unit in the edge area of ​​the object is as follows:

[0040] x t - =x o +α(d - )×β×f×XQ×cosθ;

[0041] y t - =y o +α(d - )×β×f×XQ×sinθ;

[0042] in:

[0043] x t and x t - All are X-axis offset values;

[0044] y t and t - All are Y-axis offset values;

[0045] (x t ,y t ) reflects the degree of displacement of the object within the recognition range, (x t - ,y t - ) reflects the degree of deviation of the object in the identified edge area;

[0046] β is the correction factor;

[0047] θ is the angle value, which reflects the angle of the object relative to the direction of the UHF RFID reader;

[0048] α(d - ) is the attenuation factor, α(d - ) reflects the weight of reducing the position correction when the object is close to the edge.

[0049] Optionally, the calculation formula of the positioning reading performance optimization unit is as follows:

[0050] Z - =Z base ×(1+γ×e);

[0051]

[0052] in:

[0053] Z -is the optimized receiving gain factor;

[0054] Z base is the receiving gain basic factor;

[0055] γ is the adjustment factor, which is used to control the amplitude of gain adjustment;

[0056] e is the error rate.

[0057] Optionally, before the UHF RFID reader is put into use for positioning items, n groups of test positioning are performed, and the error rates of the n groups are calculated in turn, and the average value is taken to determine the error standard.

[0058] Standard value avg , error standard value e avg The calculation formula is as follows:

[0059] e avg =(e1+e2+e3+......+e n ) / n;

[0060] n is the total number of trials;

[0061] e1+e2+e3+......+e n is the sum of the error rates of n trials;

[0062] Based on the positioning reading performance optimization unit and the error standard value e avg The positioning feedback steps are as follows:

[0063] S1. If the error rate e is higher than the error standard value e avg , it is considered that the accuracy of the UHF RFID reader in reading and identifying items is low;

[0064] S2, the optimized receiving gain factor Z output by the positioning reading performance optimization unit - Substitute it into the unit for estimating the initial signal strength next time, replace the receiving gain factor Z, and perform calculation;

[0065] S3, loop iteration until the error rate e is lower than the error standard value e avg .

[0066] Optionally, based on the calculation formula of the object in the recognition range and in the edge area analyzed and brought in by the offset correction unit, if the object continues to be calculated using the calculation formula in the edge area in m cycles, it is considered that the center recognition position (x o ,y o ) is inaccurate, and the center recognition position (x) is reset based on the recognition position after m cycles. o ,y o ).

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] 1. The present invention introduces an adjustable receiving gain factor Z by estimating the initial signal strength unit, which can dynamically adjust the receiving gain to compensate for signal attenuation and improve the accuracy of signal strength estimation. This improvement directly optimizes the accuracy of distance estimation and provides more reliable basic data for subsequent position correction.

[0069] Second, the position offset correction unit of the present invention dynamically adjusts the position correction parameters according to the actual distance between the tag and the reader. When the bus at the stop is within the recognition range, the calculation formula of the object within the recognition range is adopted. When the bus at the stop is in the edge area, the attenuation factor α (d - ) increases the correction weight to ensure the positioning stability in the edge area. This adaptive position correction strategy significantly improves the adaptability and positioning accuracy of the system in different environments.

[0070] 3. The present invention combines the positioning and reading performance optimization unit to construct a dynamic feedback loop mechanism. By calculating the error between the actual distance and the estimated distance of the X and Y axes, the receiving gain adjustment factor Z is dynamically adjusted, and the new gain value is fed back to the calculation formula of the initial signal strength estimation unit to achieve iterative optimization. This mechanism enables the system to continuously learn and adapt to environmental changes, and continuously improve positioning accuracy and stability.

[0071] 4. The present invention connects the RFID system to the Internet to realize the functions of remote monitoring, data analysis and intelligent scheduling. Combined with the Internet of Things technology, it can collect and analyze RFID tag data in real time, provide real-time and accurate location information for the application in the field of bus positioning technology at the stop, and further improve the intelligent level of bus management. BRIEF DESCRIPTION OF THE DRAWINGS

[0072] Figure 1 This is a method flow chart of the object positioning method based on UHF RFID;

[0073] Figure 2 This is a schematic diagram of the iterative feedback process of the object positioning method based on UHF RFID;

[0074] Figure 3 It is a structural schematic diagram of the positioning feedback module of the present invention;

[0075] Figure 4 Schematic diagram of the identification area of ​​the present invention. DETAILED DESCRIPTION

[0076] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0077] This method of locating objects based on UHF RFID is different from the traditional system based on UHF RFID. The traditional system based on UHF RFID ignores the factors that are easily affected by the multipath effect during the propagation process, resulting in inaccurate signal strength estimation, which in turn affects the positioning accuracy. If the RFID tag is located at the edge of the reader's recognition range, the signal strength drops sharply, resulting in extremely unstable or even invalid positioning results. The positioning performance varies greatly in different environments and has poor adaptability. In addition, the traditional system lacks an effective feedback loop mechanism to continuously optimize the positioning accuracy. This algorithm unit realizes the precision, intelligence and real-time RFID object positioning through accurate signal strength estimation, adaptive position correction and dynamic feedback loop optimization, providing strong technical support for the field of object positioning technology in bus stop management.

[0078] For example, see Figures 1 to 4 This implementation provides an object positioning method based on ultra-high frequency RFID, which is applied to the bus stop management of smart city construction. The specific implementation steps are as follows:

[0079] Step 1: Use the Internet communication module to set and identify the location data related to the item;

[0080] Step 2: Using the positioning feedback module, calculate the signal strength of the output recognition, position offset correction and optimize the positioning gain value;

[0081] Step 3: loop the gain value and output the new signal strength, position offset correction and gain value of optimized positioning until the positioning error of the object is lower than the standard error;

[0082] Step 4: Use the Internet communication module to display the location of the object in real time, and store the positioning data and loop iteration data generated by it;

[0083] Among them, the identified object is a bus that identifies the stop, and an RFID tag device is installed on the object and used for identification by the Internet communication module.

[0084] This recognition can also be applied to logistics and supply chain management, smart manufacturing and production line management, and medical and health fields;

[0085] The positioning feedback module includes an initial signal strength estimation unit, a position offset correction unit and a positioning reading performance optimization unit;

[0086] The equipment used in the Internet communication module includes UHF RFID readers, laser rangefinders and mobile applications;

[0087] The equipment used in the positioning feedback module includes a cloud server.

[0088] In the intelligent transportation system of this embodiment, UHF RFID technology can be used in scenarios of vehicle identification, parking management and traffic flow monitoring. By installing RFID tags on vehicles and using UHF RFID technology for positioning and tracking, accurate management and intelligent scheduling of vehicles can be achieved. In addition, UHF RFID technology can also be applied to logistics and supply chain management, intelligent manufacturing and production line management, and medical and health fields;

[0089] Logistics and supply chain management: In warehouses and logistics centers, by attaching RFID tags to goods and using ultra-high frequency RFID technology for positioning and tracking, real-time management and monitoring of goods can be achieved, improving logistics efficiency and transparency;

[0090] Smart manufacturing and production line management: In the field of smart manufacturing, UHF RFID technology can be used for real-time monitoring and location tracking of production equipment. By embedding RFID tags into production equipment, the operating status and location information of the equipment can be obtained in real time, thereby optimizing the production process and improving production efficiency.

[0091] Medical and health field: In the management of medical equipment and drugs, UHF RFID technology can be used to achieve full tracking and management of medical equipment and drugs. By attaching RFID tags to medical equipment and drugs, their usage and location information can be grasped in real time to ensure the safety and effectiveness of medical services.

[0092] In this embodiment, the system combines XQ, (x t ,y t ) and (x t - ,y t - ) One of the two results and Z - The three calculation results play their respective roles and cooperate with each other in the RFID object positioning system to achieve high-precision and high-stability positioning of the object. XQ is the signal strength value. The system can dynamically optimize the receiving sensitivity to cope with complex and changing environmental conditions, ensuring that the impact of environmental factors on signal strength is reduced, so that the estimation result can truly reflect the actual distance relationship between the RFID tag and the reader. (x t ,yt ) reflects the degree of displacement of the object within the recognition range, (x t - ,y t - ) reflects the degree of deviation of the object in the edge area of ​​the recognition. This position correction method not only improves the positioning accuracy, but also enhances the system's adaptability to targets within different distance ranges, ensuring that no matter where the object is, the system can provide accurate and reliable position information. - This optimization mechanism is based on the error feedback principle and can automatically adjust the reader performance parameters according to the positioning requirements under different environments and conditions, thereby ensuring that the system can maintain high positioning accuracy and stability in different scenarios. - The calculation results can also affect the replacement calculation of the receiving gain factor Z fed back to XQ, so that the three algorithms of this system have a high correlation and entanglement, so that the overall algorithm system can perform automatic feedback and optimization according to actual conditions to be closer to reality.

[0093] See also Figures 1 to 4 , the calculation formula for estimating the initial signal strength unit is as follows:

[0094] XQ=(F×T f ×Z×T j ×λ 2 ) / [((4π) 2 d 2 )×a];

[0095] λ = G / f;

[0096] in:

[0097] XQ is the signal strength value;

[0098] F is the transmission power;

[0099] T f is the transmitting antenna gain value, T f Reflects the ability of the transmitting antenna to enhance the radiation intensity in a specific direction;

[0100] Z is the receiving gain factor, which is used to optimize the accuracy of signal strength estimation according to specific environmental conditions and system requirements;

[0101] T j is the receiving antenna gain value, T j Reflects the receiving sensitivity enhancement capability of the receiving antenna in a specific direction;

[0102] d is the distance value between objects, and d reflects the actual distance between the RFID tag device on the object and the UHF RFID reader;

[0103] a is the system loss factor, including environmental attenuation and cable loss;

[0104] λ is the signal wavelength;

[0105] G is the speed of light;

[0106] f is the signal frequency.

[0107] In this embodiment: First, in this algorithm unit, in the RFID positioning system, accurate estimation of signal strength is crucial to determining the distance between the tag and the reader. The initial signal strength estimation unit introduces an adjustable parameter - the receiving gain adjustment factor Z, which can dynamically compensate for the attenuation of the signal during transmission due to environmental factors, including distance and multipath effects. This dynamic compensation mechanism makes the signal strength value XQ closer to reality, thereby improving the positioning accuracy;

[0108] The adjustment of the receiving gain adjustment factor Z is not limited to specific environmental parameters, but can be adjusted in real time according to the dynamic changes of the entire environment. This means that whether it is the change from indoor to outdoor environment, or the signal difference in different areas of the indoor environment, the system can adapt by adjusting the receiving gain adjustment factor Z to maintain the stability of signal strength estimation. This adaptability is particularly important for RFID applications that need to frequently change the working environment and respond to sudden environmental changes;

[0109] With the popularization of Internet technology, RFID systems can more easily access cloud servers for big data analysis and processing. By real-time monitoring and recording of signal strength data and combining it with Internet of Things technology, the system can upload this data to the cloud for in-depth analysis. Big data analysis can not only help optimize the adjustment strategy of the receiving gain adjustment factor Z, but also discover potential sources of signal interference and positioning errors, providing strong support for further improvement of system performance.

[0110] See also Figures 1 to 4 , the Internet communication module stores the identification range of the UHF RFID reader, wherein the central identification position of the storage reader identification range is (x o ,y o ), with (x o ,y o ) is the center point with a radius of R;

[0111] The laser rangefinder identifies the location of the RFID tag device on the current item as (x d ,y d );

[0112] Current item position (x d ,y d ) and the center recognition position (x o,y o The distance between ) is calculated as follows:

[0113]

[0114] d - To identify the distance value between locations;

[0115] Based on the distance value d between the identified positions - The analysis of the difference with radius R is as follows:

[0116] If the distance between the identified positions is d - If it is less than or equal to the radius R, the object is considered to be within the recognition range;

[0117] If the distance between the identified positions is d - If it is larger than the radius R, the object is considered to be still within the recognition range of the UHF RFID reader, that is, the edge area, when a weighted method is used to optimize the position correction by combining distance and signal strength;

[0118] The position offset correction unit analyzes the calculation formula of the object within the recognition range as follows:

[0119] x t =x o +β×f×XQ×cosθ;

[0120] y t =y o +β×f×XQ×sinθ;

[0121] The position offset correction unit analyzes the calculation formula of the item in the edge area as follows:

[0122] x t - =x o +α(d - )×β×f×XQ×cosθ;

[0123] y t - =y o +α(d - )×β×f×XQ×sinθ;

[0124] in:

[0125] x t and x t - All are X-axis offset values;

[0126] y t and t - All are Y-axis offset values;

[0127] (x t ,y t ) reflects the degree of displacement of the object within the recognition range, (x t - ,y t - ) reflects the degree of deviation of the object in the identified edge area;

[0128] β is the correction factor;

[0129] θ is the angle value, which reflects the angle of the object relative to the direction of the UHF RFID reader;

[0130] α(d - ) is the attenuation factor, α(d - ) reflects the weight of reducing the position correction when the object is close to the edge.

[0131] In this embodiment, first, x in this algorithm t and t The degree of displacement of the object within the recognition range, and x t - and t - The degree of deviation of the object in the edge area;

[0132] Specifically, in the RFID positioning system, the positioning of the edge area is often more difficult because the signal strength drops rapidly in this area. However, the position offset correction unit introduces an attenuation factor α (d - ), and then automatically increase the weight of position correction when the vehicle and the tag are in the edge area. This weight adjustment mechanism effectively reduces the positioning error in the edge area and improves the stability of positioning, especially in complex environments, such as areas with significant multipath effects. The attenuation factor α (d - ) can significantly improve the positioning accuracy;

[0133] β and f play a role in dynamically adjusting the position estimation in the position offset correction unit. β is a coefficient related to the signal strength and tag direction, which is used to adjust the amplitude of the position estimation, while f represents a normalization factor, which is used to convert the signal strength into comparable units. This dynamic adjustment mechanism enables the position estimation to be adaptively adjusted according to different signal conditions and tag states, improving the flexibility and accuracy of positioning.

[0134] The position offset correction unit can also be combined with GIS (Geographic Information System) map data to achieve more accurate position correction. By comparing and correcting the actual measured position with the map data, the system can further reduce positioning errors and improve the spatial accuracy and consistency of positioning results. This is especially important for RFID applications that require high-precision position information, such as logistics tracking and asset management.

[0135] By considering multiple factors such as signal strength, distance, reader receiving sensitivity, and weighting factors such as the attenuation factor α(d) that varies with distance, x t - and t - It can more accurately reflect the actual offset of the vehicle in the x-axis and y-axis directions. This accuracy helps to reduce the error of position estimation, especially in edge areas and scenes with fast signal attenuation, thereby significantly improving the positioning accuracy of the system;

[0136] In this embodiment, it is worth noting that the RFID system often faces various complex environmental factors in actual applications, which will cause fluctuations in signal strength and increase in positioning errors. t - and t - The introduction of x enables the system to better adapt to these complex environments, and dynamically adjusts the offset to compensate for the impact of signal attenuation and other interference factors, thereby enhancing the robustness and stability of the system. t - and t - The calculation of involves the synergy of multiple parameters, including signal space energy, normalization factor, weighting method related to distance and signal strength, and angle. By continuously optimizing and adjusting the calculation method and weighting strategy of these parameters, the performance of the system can be further improved. For example, the response time of the system can be reduced, the frequency of location updates can be increased, and the calculation complexity can be reduced. t - and t - They can more accurately reflect the deviation of vehicles, so they enable RFID systems to support a wider range of application scenarios, whether it is vehicle positioning in large parking lots, cargo tracking in logistics warehouses, or vehicle monitoring in intelligent transportation systems. t - and t - can provide accurate location information support for these applications, thereby promoting further development and application expansion in these fields. t - and t- The introduction and application of not only improves the performance and application scope of RFID systems, but also promotes the innovation and development of related technologies. For example, it can further study how to optimize the calculation method of offset through advanced machine learning and deep learning algorithms, or explore how to use multi-source fusion technology to improve the overall positioning accuracy and reliability of RFID systems. These technological innovations will further promote the application and development of RFID technology in various fields.

[0137] See also Figures 1 to 4 , the calculation formula for positioning read performance optimization unit is as follows:

[0138] Z - =Z base ×(1+γ×e);

[0139]

[0140] in:

[0141] Z - is the optimized receiving gain factor;

[0142] Z base is the receiving gain basic factor;

[0143] γ is the adjustment factor, which is used to control the amplitude of gain adjustment;

[0144] e is the error rate.

[0145] In this embodiment, the algorithm unit calculates the optimized receiving gain factor Z in real time. - And the optimized receiving gain factor Z - , replaces and adjusts the strength estimation of the initial signal strength estimation unit, so that the reader can dynamically adapt to the changing signal conditions. This real-time optimization mechanism ensures that the reader can maintain the best working state in different environments, improving the performance and positioning accuracy of the reader. For example, in areas with weak signal strength, the positioning reading performance optimization unit can automatically increase the optimized receiving gain factor Z - The value of can enhance the strength of the received signal, and in areas where the signal strength is too strong, the optimized receiving gain factor Z can be reduced - The value of to avoid signal saturation distortion;

[0146] The positioning reading performance optimization unit is combined with the initial signal strength estimation unit and the position offset correction unit to construct a closed-loop feedback system, in which the positioning error is used as a feedback signal to adjust the optimized receiving gain factor Z -By continuously iterating and optimizing this feedback loop, the system can gradually approach the optimal receiving gain adjustment strategy and achieve continuous performance optimization. This feedback mechanism not only improves positioning accuracy and stability, but also enables the system to have stronger self-repair and self-optimization capabilities.

[0147] Combining AI and machine learning technologies, the positioning reading performance optimization unit can further intelligently adjust the optimized receiving gain factor Z - By learning the rules and patterns in historical data and real-time data, the system can automatically find the optimal adjustment strategy and apply it to actual scenarios. This intelligent adjustment not only improves the flexibility and adaptability of the system, but also reduces the need and cost of manual intervention.

[0148] For example 2, please refer to Figures 1 to 4 Before the UHF RFID reader is put into use for item positioning, n groups of test positioning are carried out, and the error rates of each group are calculated in turn, and the average value is taken to determine the error standard value e avg , error standard value e avg The calculation formula is as follows:

[0149] e avg =(e1+e2+e3+......+e n ) / n;

[0150] n is the total number of trials;

[0151] e1+e2+e3+......+e n is the sum of the error rates of n trials;

[0152] Based on the positioning reading performance optimization unit and error standard value e avg The positioning feedback steps are as follows:

[0153] S1. If the error rate e is higher than the error standard value e avg , it is considered that the accuracy of the UHF RFID reader in reading and identifying items is low;

[0154] S2, the optimized receiving gain factor Z output by the positioning reading performance optimization unit - Substitute it into the next estimated initial signal strength unit, replace the receiving gain factor Z, and calculate;

[0155] S3, loop iteration until the error rate e is lower than the error standard value e avg ;

[0156] Based on the calculation formula of the object in the recognition range and in the edge area analyzed and brought in by the offset correction unit, if the object continues to be calculated using the calculation formula in the edge area in m cycles, then the center recognition position (xo ,y o ) is inaccurate, and the center recognition position (x) is reset based on the recognition position after m cycles. o ,y o ).

[0157] In this embodiment, since the positioning reading performance optimization unit can optimize the receiving gain adjustment factor in real time, the optimized receiving gain factor Z - This enables the initial signal strength estimation unit to more accurately reflect the actual signal situation during the signal strength estimation process, reducing the occurrence of positioning errors and misjudgments caused by signal attenuation and interference, thereby enhancing the robustness of the entire RFID positioning system. Even in a complex and changing environment, the system can maintain stable positioning performance;

[0158] In the closed-loop feedback system, the calculation results of the positioning reading performance optimization unit can be quickly fed back to the initial signal strength estimation unit to adjust the signal strength estimation. This fast feedback mechanism accelerates the position correction process and shortens the positioning time, which is particularly important for RFID applications that require fast response and high-efficiency positioning.

[0159] As the core part of the performance optimization parameter calculation, the positioning and reading performance optimization unit has been continuously optimized and adjusted to promote the iterative upgrade of RFID positioning technology. By continuously introducing new algorithms and technical means, the system can continuously improve the positioning accuracy, stability and intelligence level. This continuous technological iteration not only meets the ever-changing market needs but also promotes the development and progress of the entire RFID industry.

[0160] In addition, according to the combined analysis of the loop feedback and the position offset correction unit, the center position of the RFID reader recognition can be adjusted by self-checking, so as to avoid obvious recognition problems caused by the setting and recognition position due to environmental and other reasons, but still continue to mislead the calculation formula of the object in the edge area, thereby improving the accuracy of the system's self-checking recognition;

[0161] In summary, the object positioning method based on UHF RFID combines the contents of the initial signal strength estimation unit, the position offset correction unit and the positioning reading performance optimization unit. Through accurate signal strength estimation, efficient position correction, flexible adaptability and intelligent upgrading, as well as the beneficial effects of remote monitoring and data sharing, it provides strong technical support for object tracking, positioning and management in the era of the Internet of Things.

[0162] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations can be made to the embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An object positioning method based on ultra-high frequency RFID, characterized in that: The specific implementation steps of bus stop management applied to smart city construction are as follows: Step 1: Use the Internet communication module to set and identify the location data related to the item; Step 2: Using the positioning feedback module, calculate the signal strength of the output recognition, position offset correction and optimize the positioning gain value; Step 3: loop the gain value and output the new signal strength, position offset correction and gain value of optimized positioning until the positioning error of the object is lower than the standard error; Step 4: Use the Internet communication module to display the location of the object in real time, and store the positioning data and loop iteration data generated by it; The object to be identified is a bus vehicle that identifies a stop, and an RFID tag device is installed on the object and is used for identification by the Internet communication module; The positioning feedback module includes an initial signal strength estimation unit, a position offset correction unit and a positioning reading performance optimization unit.

2. The object positioning method based on UHF RFID according to claim 1, characterized in that: The devices used in the Internet communication module include UHF RFID readers, laser rangefinders and mobile applications; The equipment used by the positioning feedback module includes a cloud server.

3. The object positioning method based on UHF RFID according to claim 2, characterized in that: The calculation formula for estimating the initial signal strength unit is as follows: XQ=(F×T f ×Z×T j ×λ 2 ) / [((4π) 2 d 2 )×a]; λ = G / f; in: XQ is the signal strength value; F is the transmission power; T f is the transmitting antenna gain value, T f Reflects the ability of the transmitting antenna to enhance the radiation intensity in a specific direction; Z is the receiving gain factor, which is used to optimize the accuracy of signal strength estimation according to specific environmental conditions and system requirements; T j is the receiving antenna gain value, T j Reflects the receiving sensitivity enhancement capability of the receiving antenna in a specific direction; d is the distance value between objects, and d reflects the actual distance between the RFID tag device on the object and the UHF RFID reader; a is the system loss factor, including environmental attenuation and cable loss; λ is the signal wavelength; G is the speed of light; f is the signal frequency.

4. The object positioning method based on UHF RFID according to claim 3 is characterized in that: The Internet communication module stores the identification range of the UHF RFID reader, wherein the central identification position of the identification range of the reader is stored as (x o ,y o ), with (x o ,y o ) is the center point with a radius of R; The laser rangefinder identifies the location of the RFID tag device on the current item as (x d ,y d ); Current item position (x d ,y d ) and the center recognition position (x o ,y o The distance between ) is calculated as follows: d - To identify the distance between locations.

5. The object positioning method based on UHF RFID according to claim 4, characterized in that: Based on the distance value d between the identified positions - The analysis of the difference with radius R is as follows: If the distance between the identified positions is d - If it is less than or equal to the radius R, the object is considered to be within the recognition range; If the distance between the identified positions is d - If the radius is greater than R, the item is considered to be still within the recognition range of the UHF RFID reader, that is, the edge area. A weighted method is used to optimize the position correction by combining distance and signal strength.

6. The object positioning method based on UHF RFID according to claim 5, characterized in that: The calculation formula of the position offset correction unit for analyzing the objects within the recognition range is as follows: x t =x o +β×f×XQ×cosθ; and t =and o +β×f×XQ×sinθ; The calculation formula for analyzing the position offset correction unit in the edge area of ​​the object is as follows: x t - =x o +α(d - )×β×f×XQ×cosθ; y t - =y o +α(d - )×β×f×XQ×sinθ; in: x t and x t - All are X-axis offset values; y t and t - All are Y-axis offset values; (x t ,y t ) reflects the degree of displacement of the object within the recognition range, (x t - ,y t - ) reflects the degree of deviation of the object in the identified edge area; β is the correction factor; θ is the angle value, which reflects the angle of the object relative to the direction of the UHF RFID reader; α(d - ) is the attenuation factor, α(d - ) reflects the weight of reducing the position correction when the object is close to the edge.

7. The object positioning method based on UHF RFID according to claim 4, characterized in that: The calculation formula of the positioning reading performance optimization unit is as follows: WITH - =Z base ×(1+γ×e); in: Z - is the optimized receiving gain factor; Z base is the receiving gain basic factor; γ is the adjustment factor, which is used to control the amplitude of gain adjustment; e is the error rate.

8. The object positioning method based on UHF RFID according to claim 7, characterized in that: Before the UHF RFID reader is used for item positioning, n groups of test positioning are performed, and the error rates of each group are calculated in turn, and the average value is taken to determine the error standard value e avg , error standard value e avg The calculation formula is as follows: and avg =(e1+e2+e3+......+e n ) / n; n is the total number of trials; e1+e2+e3+......+e n is the sum of the error rates of n trials; Based on the positioning reading performance optimization unit and the error standard value e avg The positioning feedback steps are as follows: S1. If the error rate e is higher than the error standard value e avg , it is considered that the accuracy of the UHF RFID reader in reading and identifying items is low; S2, the optimized receiving gain factor Z output by the positioning reading performance optimization unit - Substitute it into the next estimated initial signal strength unit, replace the receiving gain factor Z, and perform calculation; S3, loop iteration until the error rate e is lower than the error standard value e avg .

9. The object positioning method based on UHF RFID according to claim 8, characterized in that: Based on the calculation formula of the object in the recognition range and in the edge area analyzed and brought in by the offset correction unit, if the object continues to be calculated using the calculation formula in the edge area in m cycles, then the center recognition position (x o ,y o ) is inaccurate, and the center recognition position (x) is reset based on the recognition position after m cycles. o ,y o ).

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