Ultrahigh-frequency passive RFID tag space attitude tracking and sensing method and related system

Abstract

The invention belongs to the technical field of ultrahigh-frequency passive RFID, and discloses an ultrahigh-frequency passive RFID tag space attitude tracking and sensing method and a related system, which can realize real-time tracking and sensing of space attitude of a moving object by continuously calculating coordinate information and attitude angle of the moving object relative to a physical antenna. The method is suitable for application scenes of dynamic tracking, can significantly improve the robustness and accuracy of attitude tracking through the reconstruction of the double-tag array and the phase characteristics in a complex environment (such as a place with a multipath effect and a large environmental noise influence), can flexibly adapt to different object shapes and moving modes, and has a wide application prospect. And different tracking requirements can be met only by adjusting the configuration of the tag array. In conclusion, the method not only can improve the measurement precision, but also has the advantages of low cost, strong real-time performance, good environmental adaptability, high flexibility and the like, so that the method has wide application potential in various scenes needing attitude tracking.

Description

Technical Field

[0001] The present invention belongs to the technical field of ultra-high frequency passive RFID, and in particular relates to an ultra-high frequency passive RFID tag space posture tracking and sensing method and a related system. Background Art

[0002] Ultra-high frequency passive RFID tag spatial posture tracking perception uses the reader to transmit radio frequency signals to activate the electronic tag. The activated electronic tag sends the data stored in it back to the reader through the antenna in the form of radio frequency signals. The phase characteristic value in the reflected signal is a key parameter related to the transmission distance and the carrier wavelength of the signal.

[0003] At present, RFID mobile tag estimation mainly focuses on positioning and trajectory tracking, that is, the position change of tags in static or continuous time. However, when the spatial direction of the tag needs to be known in the scene, the result will not meet the application scenario. In addition, the tag array positioning is used in the posture perception process. The phase information of the mobile tag is accompanied by some inherent problems, such as ambiguity and phase changes caused by hardware physical characteristics and coupling effects between tag arrays. Considering the above factors, the phase eigenvalue model is reconstructed to improve the accuracy of phase information, which can improve the accuracy of positioning and posture angle.

[0004] In the prior art, the invention patent application "An RFID positioning method based on an improved hyperbolic model" (application number 202110544161.7) proposes a positioning method that uses a linear approximation method to solve a hyperbolic model to obtain the tag position. In the process, the Taylor series method is used to correct the error of the linear approximation to improve the positioning accuracy. However, linear approximation may introduce large errors, and the calculation complexity of using Taylor series correction is high. In addition, the tag position in the scene is fixed, and the flexibility to changes in application scenarios is not high.

[0005] The invention patent application "A multi-antenna RFID tag positioning method and system based on phase difference" (application number: 202310854029.5) proposes a method of obtaining phase difference through multiple antennas, generating a complete number of wavelengths, and then constructing a cost function to obtain the optimal position of the tag. It must use three antennas for positioning, and has high requirements for the layout and calibration accuracy of the antenna array, which increases the deployment and maintenance costs and the workload.

[0006] The invention patent application "An RFID positioning method and device based on phase difference correction" (application number: 201910263830.6) proposes a method to reduce phase interference between tags based on a phase difference correction model of the interference angle in the claims. It requires at least two readers to obtain data for correction, which greatly increases the cost of hardware configuration compared to a single reader system. At the same time, in order to ensure synchronization and coordination between multiple readers, additional software or hardware support may be required, which increases the complexity and cost of the system.

[0007] The invention patent application "An RFID indoor positioning algorithm based on dual-tag array phase difference" (application number: 201810966075.3) proposes a method of using a dual-tag array to obtain phase difference, and after processing to eliminate ambiguity, using the phase-distance relationship to calculate the distance difference to construct a hyperbola for positioning. It does not consider the coupling interference between tag arrays, and the results only focus on static target positioning, which cannot meet the needs of dynamically changing scenarios and has low application scenario flexibility.

[0008] In summary, RFID tag spatial posture tracking perception is necessary to perceive moving objects and reduce system complexity and cost. Summary of the invention

[0009] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a method and related system for ultra-high frequency passive RFID tag spatial posture tracking and perception, which realizes the posture tracking and perception of moving objects by reading the phase characteristics of the tag array through a single reader / writer dual antenna system, and significantly improves the tag measurement phase accuracy by combining the reconstructed tag phase characteristic value, thereby improving the system accuracy and scenario applicability.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] In a first aspect, the present invention provides a method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag, comprising the following steps:

[0012] Obtain two phase eigenvalues ​​returned by a dual-tag array attached to a moving object under a fixed frequency for a single physical antenna, and make a difference between the two phase eigenvalues ​​to obtain the phase difference;

[0013] A virtual antenna is constructed according to the phase difference, and a hyperbola equation is constructed according to the physical antenna and the virtual antenna;

[0014] Obtain hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and obtain the coordinates of the moving object in the two-dimensional plane;

[0015] According to the coordinates of the moving object in the two-dimensional plane and the phase change law of the tag array, the attitude angle of the moving object relative to the physical antenna is calculated;

[0016] Repeat the above steps to continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

[0017] A further improvement of the present invention is that the specific method for obtaining two phase characteristic values ​​returned by a dual tag array attached to a moving object at a fixed frequency by a single physical antenna is as follows:

[0018] A single physical antenna transmits a radio frequency signal within a predetermined UHF frequency band to a dual tag array attached to a moving object;

[0019] After each tag in the dual-tag array receives the RF signal, each tag will reflect a different phase signal characteristic value according to the relative distance and relative angle between each tag and the physical antenna.

[0020] A further improvement of the present invention is that the specific method of constructing a hyperbolic equation based on a physical antenna and a virtual antenna is as follows:

[0021] The geometric layout of the dual-tag array relative to the antenna is adopted, a virtual antenna is constructed through a mathematical model, and a hyperbolic equation is constructed using the physical antenna and the virtual antenna.

[0022] A further improvement of the present invention is that the specific method of obtaining the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna and obtaining the coordinates of the moving object in the two-dimensional plane is as follows:

[0023] Obtain a hyperbola equation corresponding to another physical antenna parallel to the physical antenna;

[0024] An optimization algorithm is used to calculate the intersection of two hyperbolic equations, and the intersection is used as the coordinate of the label array in the two-dimensional plane;

[0025] According to the coordinates of the tag array in the two-dimensional plane, a weighted average algorithm is used to obtain the coordinates of the moving object in the two-dimensional plane.

[0026] A further improvement of the present invention is that, based on the coordinates of the mobile object in the two-dimensional plane and in combination with the phase change law of the tag array, the specific method for calculating the attitude angle of the mobile object relative to the physical antenna is as follows:

[0027] Obtaining phase information of each tag in the tag array;

[0028] According to the phase information of the tag, a mapping relationship between the phase change of the tag and the rotation angle is established;

[0029] According to the mapping relationship between the tag phase change and the rotation angle, the tag phase data is converted into a rotation angle value to obtain the rotation angle value of the tag array;

[0030] According to the rotation angle value of the tag array, the optimization algorithm is used to obtain the attitude angle of the moving object.

[0031] A further improvement of the present invention is that the coordinate information and attitude angle of the moving object relative to the physical antenna are continuously calculated, and the specific method for completing the real-time tracking perception of the spatial attitude of the moving object is as follows:

[0032] Obtain the coordinates of the moving object in the two-dimensional plane at the next moment, and combine the phase change law of the tag array to obtain the attitude angle of the moving object relative to the physical antenna at the next moment;

[0033] The coordinate information and attitude angle of the moving object relative to the physical antenna at the next moment are compared with the coordinate information and attitude angle of the moving object relative to the physical antenna at the previous moment. If there is a change, the spatial attitude information of the moving object is updated; otherwise, the spatial attitude information is not updated.

[0034] In a second aspect, the present invention provides an ultra-high frequency passive RFID tag spatial posture tracking and perception system, comprising:

[0035] The phase difference acquisition module is used to obtain two phase characteristic values ​​returned by a dual-tag array attached to a moving object under a fixed frequency by a single physical antenna, and to obtain the phase difference by subtracting the two phase characteristic values.

[0036] A hyperbolic equation building module is used to build a virtual antenna according to the phase difference and to build a hyperbolic equation according to the physical antenna and the virtual antenna;

[0037] A coordinate acquisition module is used to obtain the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and use an optimization algorithm to find the intersection of multiple hyperbolas to obtain the coordinates of the moving object in the two-dimensional plane;

[0038] The attitude angle acquisition module is used to calculate the attitude angle of the mobile object relative to the physical antenna based on the coordinates of the mobile object in the two-dimensional plane and the phase change law of the tag array;

[0039] The attitude tracking and perception module is used to repeat the above steps, continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

[0040] A further improvement of the present invention is that the physical antenna uses a reader to send a radio frequency signal to a dual tag array attached to a mobile object within a predetermined UHF frequency band, and receives two phase characteristic values ​​returned by the dual tag array on the mobile object.

[0041] In a third aspect, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of a method for spatial posture tracking and perception of an ultra-high frequency passive RFID tag when executing the computer program.

[0042] In a fourth aspect, the present invention provides a storage medium having a computer program stored thereon, wherein when the computer program is executed by a processor, the steps of a method for spatial posture tracking and perception of an ultra-high frequency passive RFID tag are implemented.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] The present invention uses the phase eigenvalue of the mobile tag array to estimate the two-dimensional posture of the mobile object. First, the phase signal information is reconstructed according to the relative distance and relative angle between the tag and the reader antenna, the coupling effect between the tags and the physical characteristics of the tag itself. Then, based on the reconstructed phase eigenvalue, a hyperbola is constructed through the phase difference characteristics of the tag array collected by the dual antennas, and the intersection of the hyperbola equation group constructed by the dual antennas is calculated to estimate the tag position. Combined with the phase change mode of the tag array, the rotation angle is calculated to achieve the posture tracking of the mobile object in the two-dimensional plane. The present invention continuously calculates the coordinate information and attitude angle of the mobile object relative to the physical antenna to achieve real-time tracking and perception of the spatial posture of the mobile object. It is suitable for dynamic tracking application scenarios. In complex environments (such as places with large multipath effects and environmental noise), through the reconstruction of the dual tag array and phase characteristics, the method can significantly improve the robustness and accuracy of posture tracking. The present invention can flexibly adapt to different object shapes and movement modes. It only needs to adjust the configuration of the tag array to be applied to different tracking needs. In summary, the present invention can not only improve the measurement accuracy, but also has the advantages of low cost, strong real-time performance, good environmental adaptability, and high flexibility, which makes it have wide application potential in various scenarios that require posture tracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 is a flow chart of Example 1;

[0046] Figure 2 is a system diagram of Example 2;

[0047] Figure 3 It is a schematic diagram of the process of Example 3;

[0048] Figure 4 A schematic diagram of a label rotation scenario provided in Example 4;

[0049] Figure 5 A diagram showing the relationship between the phase of a received signal and the rotation angle of a tag provided in Example 4;

[0050] Figure 6 A graph showing the relationship between the phase offset of the received signal and the spacing between the tag arrays provided in Example 4;

[0051] Figure 7 A graph showing the relationship between the phase offset of the received signal and the distance between the tag array and the antenna provided in Example 4;

[0052] Figure 8 A schematic diagram of a tag array movement scenario provided in Example 5;

[0053] Fig. 9 A schematic diagram of the iterative process of the particle swarm optimization algorithm provided in Example 5;

[0054] Fig.10 A comparison chart of the cumulative distribution function of position estimation after adding or not adding the tag coupling term provided in Example 5;

[0055] Fig.11 This is a system diagram provided for Example 8. DETAILED DESCRIPTION

[0056] In order to further understand the content of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the embodiments are only for explaining the present invention and are not intended to limit it.

[0057] Embodiment 1:

[0058] See also Figure 1 , a method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag, comprising the following steps:

[0059] Step 1: obtain two phase eigenvalues ​​returned by a dual-tag array attached to a moving object at a fixed frequency from a single physical antenna, and make a difference between the two phase eigenvalues ​​to obtain a phase difference.

[0060] Step 2: construct a virtual antenna according to the phase difference, and construct a hyperbola equation according to the physical antenna and the virtual antenna.

[0061] Step three, obtain the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and obtain the coordinates of the moving object in the two-dimensional plane.

[0062] Step 4: According to the coordinates of the moving object in the two-dimensional plane and the phase change law of the tag array, the coordinate information and attitude angle of the moving object relative to the physical antenna are calculated.

[0063] Step 5: Repeat steps 1 to 4 to continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

[0064] Embodiment 2:

[0065] An ultra-high frequency passive RFID tag spatial posture tracking and perception system, comprising:

[0066] The phase difference acquisition module is used to obtain two phase characteristic values ​​returned by a dual-tag array attached to a moving object under a fixed frequency by a single physical antenna, and to obtain the phase difference by subtracting the two phase characteristic values.

[0067] A hyperbolic equation building module is used to build a virtual antenna according to the phase difference and to build a hyperbolic equation according to the physical antenna and the virtual antenna;

[0068] A coordinate acquisition module is used to obtain the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and use an optimization algorithm to find the intersection of multiple hyperbolas to obtain the coordinates of the moving object in the two-dimensional plane;

[0069] The attitude angle acquisition module is used to calculate the attitude angle of the mobile object relative to the physical antenna based on the coordinates of the mobile object in the two-dimensional plane and the phase change law of the tag array;

[0070] The attitude tracking and perception module is used to repeat the above steps, continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

[0071] Embodiment 3:

[0072] like Figure 3 As shown, a flow chart of a method for ultra-high frequency passive RFID tag spatial posture tracking and sensing provided in this embodiment specifically includes the following steps S100 to S105.

[0073] Step S100: the reader sends a radio frequency signal to the tag array at a fixed frequency through a physical antenna and receives a returned response, thereby collecting a measured phase characteristic value of the tag array.

[0074] Step S101 , based on the relative distance and relative angle between the tag array and the reader antenna, the phase propagation signal characteristic value is reconstructed by jointly considering the coupling effect between tags and the physical characteristics of the tags themselves.

[0075] Step S102: construct a virtual antenna according to the geometric layout relationship between the tag array and the physical antenna to complete the hyperbolic construction.

[0076] Step S103, using two parallel antennas to obtain two hyperbolic equations, and using an optimization algorithm to calculate and obtain the two-dimensional plane coordinate information of the mobile tag array.

[0077] Step S104, according to the two-dimensional plane coordinate information of the mobile tag array, combined with the relationship between tag rotation and phase change, an algorithm is used to obtain the rotation angle of the tag array relative to the antenna.

[0078] Step S105 , dynamically obtaining the position and attitude angle of the moving object changing with time through a weighted average algorithm according to the tag coordinate information and the rotation angle information.

[0079] Embodiment 4:

[0080] Based on Example 3, according to steps S100 to S101, the reader reads the tag array at a fixed frequency through the physical antenna and obtains the phase characteristic value. Exemplarily, according to step S101, the phase characteristic value returned by the tag array is related to the relative distance of the physical antenna, the rotation angle of the tag relative to the physical antenna, the physical characteristics of the tag itself, and the coupling effect between the tag arrays. Figure 4 As shown in the figure, the x-axis is defined as the axis perpendicular to the antenna plane, the y-axis is defined as the axis parallel to the antenna plane, the xoy plane is parallel to the ground, and the z-axis is perpendicular to the xoy plane, so that the tag rotates around the x-axis. The relationship between the phase and the tag rotation angle is as follows: Figure 5 As shown, it can be seen that the change of the tag around the x-axis presents a linear characteristic, and the slope of the phase fitting curve is approximately ±2. According to the analysis of the distance between the two tags and the antenna and the label array interval The relationship between the phase offset caused by the phase information and the phase offset of the received signal and the spacing between the tag arrays is as follows: Figure 6 As shown, the relationship between the received signal phase offset and the distance between the tag array and the antenna is as follows: Figure 7 As shown, a mathematical model of tag coupling and phase information is constructed:

[0081]

[0082] Combined with the label rotation angle, the change and law of phase information are affected, and the phase propagation signal model is reconstructed:

[0083]

[0084] According to S102 to S103, a virtual antenna is constructed using the geometric layout of the dual-tag array relative to the antenna. The virtual antenna is not a real physical antenna, but is used to simulate the phase difference characteristic value generated by the dual-tag array in space for subsequent positioning. According to the definition of a hyperbola, the distance difference Δd between two fixed foci is a constant point trajectory. As long as the distance difference is known, the position of the antenna can be used as the two foci to construct a hyperbola. For example, assuming φ j,i (j,i=1,2) represents antenna Aj Get Tag T i The phase eigenvalue of the antenna is (x j ,y j ), the coordinates of the label are (x i ,y i ), if the angle between the tag array and the antenna is θ, the distance vector difference between the two tag coordinates and the antenna coordinates is calculated as

[0085]

[0086] Antenna A j The phase difference characteristic of the received tag array can be expressed as Δφ j =φ j,1 -φ j,2 |, Δd can be calculated from the phase difference j

[0087]

[0088] According to Δd j Multiple hyperbolas are constructed. The ambiguity of the phase will cause the value of the distance difference to be non-unique. The label spacing is set to be less than λ / 4, and the phase ambiguity is eliminated according to the changing trend of the distance difference and the phase difference. When Δd j and Δφ j When there is the same trend, k = 0; when Δd j <0 and Δφ j >0, k=-1; when Δd j >0 and Δφ j When <0, k = 1. After eliminating the phase ambiguity, another antenna is used to construct another hyperbola equation. In this way, each antenna can construct a unique hyperbola to solve the system of equations.

[0089] Embodiment 5:

[0090] Based on Example 3: According to S103 to S104, illustratively, the present invention sets the tag movement scene as follows Figure 8 As shown, the phase eigenvalue of the mobile tag received by the antenna at time t is φj,i,t, and the coordinates are expressed as (x j,t ,y j,t ), since the antennas are placed in parallel in the scene, each tag in the tag array has the same rotation angle relative to any antenna, that is, θ t =θ j,1,t =θ j,2,tWhen the tag moves, the position and rotation angle relative to the antenna change with time t. The changes in these parameters will be reflected in the changes in the phase eigenvalue. According to the coordinate information of the tag at different times t in S103, the position change of the tag at this moment minus the position change of the previous moment Δt, the total phase change minus the phase change of the tag rotation is the actual phase change caused by the movement of the tag.

[0091]

[0092] According to S105, after establishing multiple hyperbolas, the phase change equations of the tags at different times t are combined and solved. Since the solution of the hyperbolic equations is relatively complicated, the hyperbolic equations are transformed and the optimization algorithm is further used to solve the objective function. The objective function finally optimized is:

[0093]

[0094] For example, the position and rotation angle change information (x j,t ,y j,t ,Δθ t ), the iterative process diagram of the particle swarm optimization algorithm is as follows Fig. 9 This process can obtain the two-dimensional coordinates and rotation angles of each tag in the tag array, and further consider the single tag position and rotation angle information of multiple tags, and use weighted average to obtain the two-dimensional plane coordinates and attitude angles of the moving object.

[0095]

[0096] In summary, the position and angle information of the moving object in the two-dimensional plane under the dual antenna system is calculated to achieve the position and attitude tracking of the moving object. By introducing the coupling term to correct the phase error, the positioning accuracy is improved, such as Fig.10 The following is a comparison chart of the cumulative distribution function of position estimation after adding or not adding the tag coupling term. At the same time, the influence of tag rotation on the phase is used to calculate the rotation angle in combination with the mathematical model, and then the single tag parameters are taken into account in the multi-tag to obtain the information in the two-dimensional plane of the moving object by weighted average, thereby determining the complete posture of the object. This solution achieves high-precision position and posture tracking.

[0097] Embodiment 6:

[0098] A method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag comprises the following steps:

[0099] Step S100, the reader sends a radio frequency signal to the tag array at a fixed frequency through a physical antenna and receives a returned response, and collects a measured phase characteristic value of the tag array;

[0100] Assume two labels T i After the received RF signal (i=1,2) is processed by its internal circuit, it will be based on the relative position (distance) d between it and the reader antenna. i , relative angle θ i and the coupling effect between tag arrays The difference in hardware physical characteristics μ produces different phase shifts. By analyzing the phase changes caused by these factors in detail, the phase characteristic value φ of each tag is reconstructed. i , and this phase eigenvalue will serve as the basis for subsequent calculations.

[0101] Step S101, based on the relative distance and relative angle between the tag array and the reader antenna, the phase propagation signal characteristic value is reconstructed by considering the coupling effect between tags and the physical characteristics of the tags themselves;

[0102] Assume φ j,i Represented as antenna A j Get Tag T i Phase, in step A), the two target labels are T i , calculate the phase difference Δφ of the antenna at a certain moment j =φ j,1 -φ j,2 |, let d(A j ,T i ) is the physical antenna A j To label T i The distance between the two tags and the antenna is

[0103]

[0104] Step S102, constructing a virtual antenna according to the geometric layout relationship between the tag array and the physical antenna to complete the hyperbolic construction;

[0105] Selecting two tags as foci to construct a hyperbola is equivalent to setting the physical antenna and the virtual antenna as the two foci of the hyperbola. Since the two physical antennas are parallel, the tag array maintains the same angle θ = θ1 = θ2 relative to any antenna. Assume that the antenna coordinates are (x j ,y j )j=1,2, the label coordinates are (x i ,y i )i=1,2, the distance between two labels in the label array is By calculating the distance vector difference between the two tags relative to the antenna coordinates

[0106]

[0107] Step S103, using two parallel antennas to obtain two hyperbolic equations, and using an optimization algorithm to calculate and obtain the two-dimensional plane coordinate information of the mobile tag array;

[0108] After constructing the hyperbolic equation, it is necessary to solve it to obtain the coordinates of the label array. In order to simplify the solution process, the hyperbolic equation system is converted into an optimization problem and further solved using the optimization algorithm. That is, the optimization objective function is: The optimization solution is obtained to obtain the coordinates of the moving object in the two-dimensional plane.

[0109] Step S104, according to the two-dimensional plane coordinate information of the mobile tag array, combined with the relationship between tag rotation and phase change, an algorithm is used to obtain the rotation angle of the tag array relative to the antenna; the specific method is as follows:

[0110] S1041, obtain the phase information of each tag in the tag array; since the rotation of the tag array will cause the relative angle between each tag and the reader antenna to change, this change will be reflected in the phase information, read and record the phase information of each tag in the tag array, as the tag array rotates, the phase characteristic value of each tag will change continuously, and in the test, the tag rotates periodically, and the phase characteristic value will also show periodic changes.

[0111] S1042, based on the phase information of each tag, establish a mapping relationship between the phase change of a single tag and the rotation angle; establish a mapping relationship between the phase change of a single tag and the rotation angle through experiments, convert the single tag phase data obtained by analysis into a rotation angle value, and based on the reconstructed phase eigenvalue φ i , which includes the effect of tag rotation on phase change. The rotation angle of the tag relative to the antenna can be derived through the tag coordinate information and the law of tag rotation phase change.

[0112] S1043, according to the mapping relationship between the phase change of a single tag and the rotation angle, the phase data of the single tag is converted into the rotation angle value data to obtain the rotation angle value data of the tag array; according to the rotation angle value data of the tag array, the attitude angle of the moving object is obtained by using an optimization algorithm. The attitude angle of the moving object is obtained by using the optimization algorithm, and the calculation process uses weighted average or other optimization algorithms to improve the calculation accuracy. It is further characterized in that each tag in the tag array produces a different phase change at the same rotation angle, and the rotation state of the moving object is accurately inferred by analyzing the differences in the phase change values ​​of different tags.

[0113] Step S105: dynamically obtain the position and attitude angle of the moving object changing with time through a weighted average algorithm based on the tag coordinate information and the rotation angle information. The specific method is as follows:

[0114] S1051, obtaining the coordinates of the moving object in the two-dimensional plane at the next moment, and combining the phase change law of the tag array to obtain the attitude angle of the moving object relative to the physical antenna at the next moment;

[0115] In the above steps, the time parameter t is introduced. In each repeated experiment, the reader antenna A at time t j To label T i Send a signal and receive a returned response, collecting the tag's phase characteristic value φ in real time j,i,t , based on the collected phase data and calculate the phase difference Δφ j,t =φ j,1,t -φ j,2,t , construct a virtual antenna to complete the tag dynamic positioning effect, according to the two-dimensional coordinates of the tag array at different times t, combined with the phase change pattern of the tag array, by subtracting the phase change caused by the moving distance from the total phase change, the pure rotational phase shift is obtained. The phase change pattern is expressed as

[0116]

[0117] The optimization algorithm is combined to optimize the objective function to be optimized and calculate the coordinates and attitude angle of the moving object in the two-dimensional plane.

[0118]

[0119] S1052, compare the coordinate information and attitude angle of the mobile object relative to the physical antenna at the next moment with the coordinate information and attitude angle of the mobile object relative to the physical antenna at the previous moment. If there is a change, update the spatial attitude information of the mobile object; otherwise, do not update the spatial attitude information.

[0120] Embodiment 7:

[0121] The present invention uses double tag T i The relative position (distance) between (i=1,2) and the reader antenna d i , relative angle θ i and the coupling effect between tag arrays The phase changes caused by the hardware physical feature differences μ are analyzed in detail to reconstruct the phase feature value φ of each tag i . Further, the difference Δφ between the two phase eigenvalues ​​is calculated j =φ j,1 -φ j,2 |, get the distance difference between the two tags and the antenna

[0122]

[0123] After the distance difference is known, two tags are selected as the focus to construct the hyperbola. By obtaining the distance vector difference between the two tags and the antenna With Δd j To simplify the solution process, the system of equations is converted into an optimization problem, and the optimization algorithm is used to solve the coordinates of the label array. It contains the position and angle information of the tag, and uses a weighted average algorithm to obtain the coordinates of the moving object in the two-dimensional plane.

[0124] As the tag array rotates, the phase of each tag changes continuously, and in the test, the tag rotates periodically, and the phase eigenvalue also shows periodic changes. i , which includes the effect of the tag rotation term on the phase change. The tag coordinate information is obtained by using the tag rotation phase change law and the hyperbolic equation group, and the rotation angle of the tag relative to the antenna can be derived. Each tag in the tag array produces a different amount of phase change at the same rotation angle. By analyzing the differences in the phase change values ​​of different tags, the rotation state of the moving object can be accurately inferred. Considering the rotation angle value of the tag array, the weighted average optimization algorithm is used to obtain the attitude angle of the moving object.

[0125] In repeated experiments, the calculated coordinate information and attitude angles are compared with the previous judgment results. If there is a change, the spatial attitude information of the moving object is updated.

[0126] Embodiment 8:

[0127] See also Fig.11 As shown, the present invention also provides an electronic device 100 for an ultra-high frequency passive RFID tag spatial posture tracking and sensing method; the electronic device 100 includes a memory 101, at least one processor 102, a computer program 103 stored in the memory 101 and executable on the at least one processor 102, and at least one communication bus 104.

[0128] The memory 101 can be used to store the computer program 103. The processor 102 implements the steps of the ultra-high frequency passive RFID tag spatial posture tracking and sensing method described in Example 1 by running or executing the computer program stored in the memory 101 and calling the data stored in the memory 101. The memory 101 can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data (such as audio data) created according to the use of the electronic device 100, etc. In addition, the memory 101 can include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other non-volatile solid-state storage devices.

[0129] The at least one processor 102 may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The processor 102 may be a microprocessor or any conventional processor, etc. The processor 102 is the control center of the electronic device 100, and uses various interfaces and lines to connect various parts of the entire electronic device 100.

[0130] The memory 101 in the electronic device 100 stores a plurality of instructions to implement a method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag, and the processor 102 can execute the plurality of instructions to implement:

[0131] Obtain two phase eigenvalues ​​returned by a dual-tag array attached to a moving object under a fixed frequency for a single physical antenna, and make a difference between the two phase eigenvalues ​​to obtain the phase difference;

[0132] A virtual antenna is constructed according to the phase difference, and a hyperbola equation is constructed according to the physical antenna and the virtual antenna;

[0133] Obtain hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and obtain the coordinates of the moving object in the two-dimensional plane;

[0134] According to the coordinates of the moving object in the two-dimensional plane and the phase change law of the tag array, the attitude angle of the moving object relative to the physical antenna is calculated;

[0135] Repeat the above steps to continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

[0136] Embodiment 9:

[0137] If the module / unit integrated in the electronic device 100 is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device that can carry the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory and read-only memory (ROM, Read-Only Memory).

[0138] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may 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.

[0139] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0140] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0141] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0142] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag, characterized in that: The following steps are involved: Obtain two phase eigenvalues ​​returned by a dual-tag array attached to a moving object under a fixed frequency for a single physical antenna, and make a difference between the two phase eigenvalues ​​to obtain the phase difference; A virtual antenna is constructed according to the phase difference, and a hyperbola equation is constructed according to the physical antenna and the virtual antenna; Obtain hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and obtain the coordinates of the moving object in the two-dimensional plane; According to the coordinates of the moving object in the two-dimensional plane and the phase change law of the tag array, the attitude angle of the moving object relative to the physical antenna is calculated; Repeat the above steps to continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

2. The method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag according to claim 1 is characterized in that: The specific method to obtain the two phase eigenvalues ​​returned by a dual tag array attached to a moving object at a fixed frequency for a single physical antenna is as follows: A single physical antenna transmits a radio frequency signal within a predetermined UHF frequency band to a dual tag array attached to a moving object; After each tag in the dual-tag array receives the RF signal, each tag will reflect a different phase signal characteristic value according to the relative distance and relative angle between each tag and the physical antenna.

3. The method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag according to claim 1 is characterized in that: The specific method of constructing the hyperbolic equation based on the physical antenna and the virtual antenna is as follows: The geometric layout of the dual-tag array relative to the antenna is adopted, a virtual antenna is constructed through a mathematical model, and a hyperbolic equation is constructed using the physical antenna and the virtual antenna.

4. The method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag according to claim 1 is characterized in that: The specific method of obtaining the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna and obtaining the coordinates of the moving object in the two-dimensional plane is as follows: Obtain a hyperbola equation corresponding to another physical antenna parallel to the physical antenna; An optimization algorithm is used to calculate the intersection of two hyperbolic equations, and the intersection is used as the coordinate of the label array in the two-dimensional plane; According to the coordinates of the tag array in the two-dimensional plane, a weighted average algorithm is used to obtain the coordinates of the moving object in the two-dimensional plane.

5. The method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag according to claim 1 is characterized in that: According to the coordinates of the moving object in the two-dimensional plane and the phase change law of the tag array, the specific method for calculating the attitude angle of the moving object relative to the physical antenna is as follows: Obtaining phase information of each tag in the tag array; According to the phase information of the tag, a mapping relationship between the phase change of the tag and the rotation angle is established; According to the mapping relationship between the tag phase change and the rotation angle, the tag phase data is converted into a rotation angle value to obtain the rotation angle value of the tag array; According to the rotation angle value of the tag array, the optimization algorithm is used to obtain the attitude angle of the moving object.

6. The method for tracking and sensing spatial posture of an ultra-high frequency passive RFID tag according to claim 1 is characterized in that: The specific method of continuously calculating the coordinate information and attitude angle of the moving object relative to the physical antenna and completing the real-time tracking and perception of the spatial attitude of the moving object is as follows: Obtain the coordinates of the moving object in the two-dimensional plane at the next moment, and combine the phase change law of the tag array to obtain the attitude angle of the moving object relative to the physical antenna at the next moment; Compare the coordinate information and attitude angle of the moving object relative to the physical antenna at the next moment with the coordinate information and attitude angle of the moving object relative to the physical antenna at the previous moment, and if there is a change, update the spatial attitude information of the moving object; Otherwise, the spatial attitude information is not updated.

7. An ultra-high frequency passive RFID tag spatial posture tracking and perception system, characterized in that: include: The phase difference acquisition module is used to obtain two phase characteristic values ​​returned by a dual-tag array attached to a moving object under a fixed frequency by a single physical antenna, and to obtain the phase difference by subtracting the two phase characteristic values. A hyperbolic equation building module is used to build a virtual antenna according to the phase difference and to build a hyperbolic equation according to the physical antenna and the virtual antenna; A coordinate acquisition module is used to obtain the hyperbolic equations corresponding to other physical antennas parallel to the physical antenna, and use an optimization algorithm to find the intersection of multiple hyperbolas to obtain the coordinates of the moving object in the two-dimensional plane; The attitude angle acquisition module is used to calculate the attitude angle of the mobile object relative to the physical antenna based on the coordinates of the mobile object in the two-dimensional plane and the phase change law of the tag array; The attitude tracking and perception module is used to repeat the above steps, continuously calculate the coordinate information and attitude angle of the moving object relative to the physical antenna, and complete the real-time tracking and perception of the spatial attitude of the moving object.

8. The ultra-high frequency passive RFID tag spatial posture tracking and sensing system according to claim 7 is characterized in that: The physical antenna uses a reader to send radio frequency signals to a dual-tag array attached to a moving object within a predetermined UHF frequency band, and receives two phase characteristic values ​​returned by the dual-tag array on the moving object.

9. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of a method for spatial posture tracking and perception of an ultra-high frequency passive RFID tag according to any one of claims 1 to 6 are implemented.

10. A storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of a method for spatial posture tracking and perception of an ultra-high frequency passive RFID tag according to any one of claims 1 to 7 are implemented.

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