CN112183136B - Method for directionally reading and tracking commercial label in real time, storage medium and equipment - Google Patents

Abstract

The invention discloses a commercial tag directional reading and real-time tracking method, storage medium and equipment. A master-slave distributed antenna array is adopted. The master transmitter and the slave transmitter of the distributed antenna array alternately send synchronization signals, and Measure the phase offset between the transmitting antenna and the receiving antenna, compensate an initial phase for each slave transmitter to synchronize with the master transmitter; perform a quick search, query the reference tag closest to the target tag, and obtain the response of the reference tag information; obtain the energy distribution under different transmission settings and the setting information about the energy supply for the target tag, combine the simulated annealing algorithm and particle filter to dynamically select the transmission parameters to stimulate the tag in the target area and track the movement of the target tag in real time to complete the target position. of commercial tags for directional reading and real-time tracking. The invention greatly reduces the cost of directional reading and tracking of target tags, and has wide application prospects.

Description

A method, storage medium and device for directional reading and real-time tracking of commercial tags

technical field

The invention belongs to the field of Internet of Things sensing technology, and in particular relates to a commercial tag directional reading and real-time tracking method, storage medium and device.

Background technique

Radio frequency identification (RFID) technology is a wireless communication technology that identifies specific targets through radio signals, and reads and writes related data, so as to achieve the purpose of identifying targets and exchanging data. RFID system has the characteristics of long service life and good safety, and has been widely used in logistics, warehousing and other fields.

In current passive RFID systems, improving the read rate of tags in a targeted manner is a challenging problem. Existing selective reading methods are less applicable, mainly due to:

(1) A typical selective read approach is to mask some specific bit strings and allow tags with the same bit string in the ID number to respond. This method needs to assume that the ID information of all target tags is known, which is impossible in many practical applications, and it is impossible to select tags within a specific target area.

(2) The method that can query the unknown tag needs to modify the hardware and communication protocol of the tag, which is difficult to implement on commercial RFID tags.

(3) It is not feasible to use the RFID positioning algorithm to find tags in the target area, because running the RFID positioning algorithm in a complex environment will introduce large errors and have a high delay, which does not help to achieve high reading take rate.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to provide a method, storage medium and equipment for directional reading and real-time tracking of commercial tags, which can significantly improve the reading rate of tags around the target position and track the tags in real time. The movement of these labels is suitable for warehousing, logistics and other situations.

The present invention adopts following technical scheme:

A method for directional reading and real-time tracking of commercial tags, comprising the following steps:

S1. A master-slave distributed antenna array is used. The master transmitter and the slave transmitter of the distributed antenna array transmit synchronization signals alternately, and measure the phase offset between the transmitting antenna and the receiving antenna. For each slave transmitter Compensate an initial phase to synchronize with the main transmitter;

S2, perform a quick search, query the reference tag with the closest distance to the target tag, and obtain the response information E ₀ of the reference tag;

S3, using the response information E ₀ of the reference label in step S2 to obtain the energy distribution under different transmission settings and the setting information about supplying energy for the target label, and dynamically selecting the transmission parameters to stimulate the label in the target area in combination with the simulated annealing algorithm and the particle filter. Track the movement of the target tag in real time, and complete the directional reading and real-time tracking of the commercial tag at the target position.

和频率偏移

后，对每个从发射器补偿一个初始相位使之与主发射器同步。Specifically, in step S1, before the beamforming signal is sent, the frequency and phase synchronization antennas are compensated first; a priori identical distribution scheme is used to let the master transmitter and the slave transmitter alternately send synchronization signals, according to the difference Δθ(t ) to obtain the phase offset between the transmit and receive antennas

and frequency offset

Afterwards, each slave transmitter is compensated for an initial phase to synchronize with the master transmitter.

Further, the received signal on the master and slave antennas is P _M (t), when the slave transmitter alone sends a synchronization signal, the received signal is P _s (t), and Δθ(t) is:

为从主机发射器端到主机接收器端捕获的相位，

为从主机发射器端到从机接收器端捕获的相位，

为从从机发射器端到主机接收器端捕获的相位，

为从从机发射器端到从机接收器端捕获的相位，t为时间。in,

is the phase captured from the host transmitter side to the host receiver side,

is the phase captured from the master transmitter side to the slave receiver side,

is the phase captured from the slave transmitter side to the master receiver side,

is the phase captured from the slave transmitter side to the slave receiver side, and t is the time.

Specifically, in step S2, the selective reading mechanism designed in the commercial EPC C1G2 protocol is adopted, the SELECT command is sent to select the reference tag, the reference tag is read by setting parameters in the Query command, and then the reader selects multiple transmissions. parameter, obtain the response information of the reference tag under different settings of this parameter, keep the master transmitter signal unchanged, change the initial phase of each slave transmitter signal within [0, 2π) with δ as the step size, use the evaluation function f to evaluate The energy of the tag reply, record the value of the evaluation function under all transmission settings, compose the response information E ₀ of the reference tag, and take E ₀ as the initial setting of the simulated annealing algorithm in step S3.

Further, the response information E ₀ of the reference tag is specifically:

E ₀ =[f(1), f(2), ..., f(2π/δ)]

Specifically, in step S3, a simulated annealing algorithm is used to approach the global optimal value of a given evaluation function _{En, and a list of appropriate transmission parameters for target tag tracking is obtained according to the evaluation function En, and the list of E n from high} to Low ordering, get a list of transport parameters Θ _n , traverse the list Θ _n by changing the sending parameters one by one, in the same inventory loop, use the same transport parameters θ _n (k), before starting the next inventory loop, the system will E Compare the values of _n (Θ _n (k)) and E _n (Θ _n (k+1)); according to the probability function P does indeed switch to the next transfer parameter; before starting a new inventory cycle, according to the reference tag's The latest response refreshes the value of _{En (Θ n (} k)), if the elements in _En are not updated, the decay coefficient α causes the elements in _En to decrease over time k; if the current transmission parameter settings, the evaluation function The value of _En is equal to 0, and the transmission of the signal with the transmission parameter setting of maximum _En continues until movement is detected.

Further, the evaluation function _En is:

为发射参数，T_r为参考标签。where n is the number of iterations, μ is the weight coefficient, N _t and N _u are the number of target labels and non-target labels, respectively, β is a constant, α is the decay coefficient over time k, k is time,

is the transmission parameter, and T _r is the reference label.

Further, a particle filter is introduced. If the evaluation function E _{n is} regarded as the probability density of the transmission setting, it is necessary to estimate the probability density under motion or environmental changes, and define the transfer function w to update the function E _n , and all values in E _n are updated. is En ₊₁ , starting from sorting and traversal until a mobility event is detected, where the evaluation function _En depends on the estimation of the number of target tags, in a static scenario, an EPC-based classification method is used, if the received If EPC belongs to a non-target tag, increase the value of Nu _{, otherwise mark the tag as a target tag and increase the value of N t ;} in dynamic scenarios, the dynamic time warping method is used to calculate the similarity between the amplitude curves of the reference tag and the current tag degree, record the amplitude of each tag, and get the distance M(u, υ) between the reference tag and the current tag.

Another technical solution of the present invention is a computer-readable storage medium storing one or more programs, the one or more programs including instructions that, when executed by a computing device, cause the computing device to execute according to any of the methods described.

Another technical solution of the present invention is a computing device, comprising:

One or more processors, a memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including using instructions for performing any of the described methods.

Compared with the prior art, the present invention at least has the following beneficial effects:

The invention is a method for directional reading and real-time tracking of commercial tags, without assuming tag ID information, without changing the hardware or protocol on the commercial tags, so it is compatible with the existing RFID system, and can cooperate with various types of commercial passive tags It can selectively read tags at the target position, which can increase the read rate of target tags by more than 3 times compared with the latest USRP Gen2 readers.

Further, a phase offset of the transmitter can be compensated through antenna synchronization, so as to ensure that subsequent transmitted signals meet the design requirements.

Further, by calculating Δθ(t), the phase offset of the master transmitter and the slave transmitter can be obtained, and the slave can be synchronized with the master by compensating for the phase offset.

Further, by using the SELECT command and the Query command in the commercial EPC C1G2 protocol, it is possible to accurately communicate with the reference tag closest to the target tag, which is conducive to directional acquisition of the response information of the reference tag.

Further, the response information includes the amplitude of the reply signal from the reference tag under different transmission settings, which will be used as the initial setting of the simulated annealing algorithm in step S3.

Further, a simulated annealing algorithm can be used to obtain the most suitable transmission parameter settings for target tag tracking.

Further, the evaluation function reflects a list of appropriate transfer parameters for target label tracking. By optimizing the pair by simulated annealing algorithm, the optimal transmission parameter settings for target tag tracking can be obtained.

Further, the introduction of particle filter can estimate the moving trajectory of the target tag in real time.

To sum up, the present invention does not need to know the target tag ID and does not need to modify the protocol and hardware, is compatible with the existing commercial RFID system, greatly reduces the cost of directional reading and tracking of the target tag, and has broad application prospects.

The technical solutions of the present invention will be further described in detail below through the accompanying drawings and embodiments.

Description of drawings

Fig. 1 is the system flow chart of the present invention;

Fig. 2 is the flow chart of the second generation protocol of the first type of EPC;

Figure 3 is a graph of the dynamic time warping results of different categories of labels, wherein (a) is the amplitude of the reference label and the target label, (b) is the amplitude of the reference label and the non-target label;

Figure 4 is a system hardware deployment diagram;

FIG. 5 is a flow chart of the method of the present invention.

Detailed ways

The invention provides a method, storage medium and equipment for directional reading and real-time tracking of commercial labels. By capturing the response information of reference labels pasted on shelves or mobile containers, energy distribution and related target labels in different transmission settings can be obtained. The power supply setting information, using RF beamforming technology to excite the tag at the target position, and combined with simulated annealing algorithm and particle filter to dynamically select appropriate transmission parameters to track the movement of the target tag in real time. The method of the present invention is different from the previous method of selectively reading through the ID information of the known target tag, and does not require any protocol or hardware modification to the RFID tag. The read rate of tags around the target position and the movement of these tags are tracked in real time; compared with existing methods, the deployment cost is greatly reduced and the application is more extensive.

Referring to FIG. 5, a method for directional reading and real-time tracking of commercial tags of the present invention includes the following steps:

S1. Synchronous distributed transmit antenna;

The master and slave transmitters of the distributed antenna array transmit synchronization signals alternately, measure the phase offset between the transmitting antenna and the receiving antenna, and compensate each slave transmitter with an initial phase to synchronize it with the master transmitter.

A master-slave distributed antenna array is used, and the antennas need to be synchronized by compensating for frequency and phase before transmitting the beamforming signal. Using a priori identical distribution scheme, the master transmitter and the slave transmitter alternately send synchronization signals, and the phase offset between the transmitting antenna and the receiving sky is measured. Compensate an initial phase for each slave transmitter to synchronize with the master transmitter.

The master transmitter transmits the synchronization signal separately in the 'sync' message, and the received signal P _M (t) on the master and slave antennas is expressed as:

表示从主发射器的发射端T_M到主发射器或从发射器的接收端R_x捕获的相位，用下式表示：where H represents the channel parameter matrix between the master transmitter and the slave transmitter,

Represents the phase captured from the transmitting end _TM of the main transmitter to the receiving end Rx of the main transmitter or from the receiving end of the transmitter, expressed _by the following formula:

是主发射器的发送相位，

是主发射器或从发射器的接收相位，

是主发射器的发送频率，

是主发射器或从发射器的接收频率。in,

is the transmit phase of the main transmitter,

is the receive phase of the master or slave transmitter,

is the transmit frequency of the main transmitter,

is the receive frequency of the master or slave transmitter.

When the synchronization signal is sent separately from the transmitter, the received signal is denoted Ps( _t ).

Calculate the difference Δθ(t) between the two, we can get:

和频率偏移

后，对从发射器补偿一个初始相位使之与主发射器同步。get phase offset

and frequency offset

Afterwards, the slave transmitter is compensated for an initial phase to synchronize with the master transmitter.

S2. Perform a quick search, query the reference tag closest to the target tag, and obtain response information about the reference tag;

Please refer to Figure 2, using the selective reading mechanism designed in the current commercial EPC C1G2 protocol, sending appropriate SELECT commands and Query commands to read the reference tag; then the reader selects multiple transmission parameters to obtain different parameter settings. Refer to the label below for response information.

SELECT and Query commands can be simplified to tuples S and Q as follows:

S(b,p,l,m),Q(s,q) (4)

The SELECT command is intended to select a subset of tags with a sub-bit string starting at bit p and ending at bit (p+l-1) in the b-th memory area and equal to m, in In tuple Q, set the element Sel to true to select tags that meet the requirements described in the SELECT command so that they can respond in the current inventory loop.

By setting the EPC of the reference label at the target location to Mask m, the reference label can be accessed efficiently.

In order to collect the information of the reference tag (called a snapshot), the reader selects multiple transmission parameters and obtains the reply of the reference tag under different parameter settings.

First keep the master transmitter signal unchanged, and change the initial phase of each slave transmitter signal in the range of [0, 2π) with δ as the step size. δ is set to 0.1π.

That is, the master transmitter continuously sends the signal P _M (t), and the slave transmitter sends the signal P _S (t), its initial phase is θ′ _TS , and the dynamic settings are:

是从发射器信号最初的初始相位。通过添加相位和频率偏移Δθ(t)使其与主发射器同步。where i represents the index of the inventory loop, i∈[1,2,3,...,2π/δ],

is the initial initial phase of the signal from the transmitter. It is synchronized with the main transmitter by adding a phase and frequency offset Δθ(t).

To evaluate the energy of the reference tag reply when using one send parameter set, define the evaluation function f as follows:

时从参考标签T_r接收的信号的振幅；从阅读器接收的能量越高，标签信号的振幅就越大。Among them, A( ) indicates that when the sending parameter is equal to

is the amplitude of the signal received from the reference tag _Tr ; the higher the energy received from the reader, the greater the amplitude of the tag signal.

The amplitude of the reply from the reference tag _Tr was recorded at all transmission settings, namely:

E ₀ =[f(1), f(2), ..., f(2π/δ)] (7)

Among them, E ₀ is the snapshot of the reference label, and E ₀ is used as the initial setting of the simulated annealing (SA) algorithm in step S3.

S3. Use the response information of the reference tag to obtain the energy distribution in different transmission settings and the setting information about the energy supply for the target tag, and combine the simulated annealing algorithm and particle filter to dynamically select appropriate transmission parameters to stimulate the tags in the target area and real-time Track the movement of the target tag.

The simulated annealing algorithm and particle filter are combined to dynamically select the appropriate transmission parameters to track the movement of the target tag in real time. Once the reader detects possible movement or environmental changes, the reader will update the evaluation function and restart the simulated annealing algorithm. At the same time, the similarity of the motion trajectories between the reference label and the target label is compared through the dynamic time warping algorithm, and the target label is distinguished from the entire label population.

When the target tag is movable, the reader needs to dynamically adjust the launch parameters to track the target tag. Even if the label is static, objects moving around the label can cause the selected parameter settings to be suboptimal. To find a suitable transfer setting, a simulated annealing algorithm is employed, which is a probabilistic technique used to approach the global optimum for a given evaluation function _En .

Define the evaluation function _En as:

where n is the number of iterations, μ is the weight coefficient, which is set to 1.1 according to experiments, and N _t and Nu are the number of target labels and non-target labels _, respectively.

函数E_n给出系统性能的评估。如前所述，将E_n的初始值设置为在步骤S2中获得的快照E₀。In application, there is N _u >> N _t , the parameter β is used to make β · N _t similar to Nu _. The default values are μ=1.1, β=N _u /N _t . α is the decay coefficient with time k, and α=0.9 is set experimentally. When the launch parameters are set to

The function _En gives an estimate of the system performance. As before, the initial value of _{En is set to the snapshot E 0 obtained} in step S2.

Obtain a list of appropriate transfer parameters for target tag tracking according to the evaluation function _En , sort _En from high to low to obtain a list of transfer parameters Θ _n :

Θ _n = arg(d(E _n )) (9)

Among them, d(·) represents the descending sorting function. The order in the list _Θn shows the priority of sending parameters.

Then, traverse the list Θ _n by changing the send parameters one by one, in the same inventory loop, using the same transfer parameters θ _n (k), before starting the next inventory cycle, the system will E _n (Θ _n (k)) Compare with the value of _{En (Θ n (} K+1)).

Whether it does switch to the next transfer parameter according to the value of the probability function P:

where Γ represents the simulated temperature in the annealing algorithm, and ΔΓ is the changing temperature after this switch, defined as:

ΔΓ=E _n (Θ _n (K+1))-E _n (Θ _n (k)) (11)

Lower the temperature Γ by multiplying by the cooling parameter η (ie Γ = η·Γ), repeating this process until Γ is equal to 0 or less than the threshold.

Before starting a new inventory cycle, the system will refresh the value of _En ( _Θn (k)) based on the latest responses of the tags (eg A(T _r , _i ), N _t and Nu ). If the elements in _En are not updated, the decay coefficient α will cause the elements in _En to decrease with time k. If, at the current transmission parameter setting, the value of the evaluation function _En is equal to 0, the transmission of the transmission parameter setting with the largest _En will continue to be signaled until movement is detected.

If the target label continues to move, or if there are moving objects in the current work area, the recorded values in the evaluation function _En will tend to be inaccurate. For example, previous annealing algorithms may result in lost tracking of the target tag if an obstacle obstructs the main propagation path between the target tag and the reader, or if the target tag moves to another location with the reference tag. Therefore, the impact of mobility needs to be considered.

It is observed through experiments that the phase information of the tag is more reliable than the amplitude information when determining the moving state of the tag.

When a snapshot of the reference label is captured in step S2, the phase of the reference label is recorded

In step S3, the corresponding phase is compared with the value in Φ, if there is no movement, the phase will remain stable, otherwise the phase will fluctuate. The phase change is compared with an experimentally determined threshold, and if the change is greater than the threshold, the target tag is considered to be moving.

At present, the system can determine when the target tag starts to move, but still does not know the movement trajectory of the tag. To solve this problem, a particle filter is introduced. If the evaluation function En _is regarded as the probability density of the transmission setting, the probability density under motion (or environmental change) needs to be estimated. To update the function _En , define the transformation function w:

w _n+1 (i)=C·[w _n (i-1),w _n (i),w _n (i+1)] ^T (12)

Among them, C represents the coefficient matrix, which refers to the transition probability from the last state to the next state, and the value in C is set to 1/3.

Then update the evaluation function En by multiplying it with the transformation function w _{n +1} , ie:

E _n+1 (i)=w _n+1 (i)·E _n (i) (13)

At this point, all values in En will be updated to En _{+ 1} , starting with sorting and traversal until a mobility event is detected.

In step S3, the evaluation function _En relies on an accurate estimate of the number of target labels. Two cases are considered here:

(1) In a static scenario (such as a warehouse shelf), the system has no knowledge of the EPC of the target label (the label of a newly incoming package on the shelf), but already knows the non-target label in the environment (the labels of all packages on other shelves) label) EPC.

(2) In dynamic scenarios (such as shopping carts), the system does not know the EPC information of target and non-target tags, but the target tags move together with the reference tags.

In the first case, an EPC-based classification method is adopted: if the received EPC belongs to a non-target label, the value of Nu is increased; otherwise, the label is marked as a target label and the value of N _{t is} increased.

In the second case, a trajectory-based classification method is used: due to the close physical distance, the target label always has an amplitude trajectory similar to the reference label;

Referring to Figure 3, the dynamic time warping (DTW) method is used to calculate the similarity between the amplitude curves of the reference tag and the current tag. Figure 3 details the amplitude values of the reference tag, target tag, and non-target tag after dynamic time warping. Among them, Figure 3(a) shows that the reference label and the target label have similar amplitude distributions, and Figure 3(b) shows that the reference label and the non-target label have different amplitude distributions.

First calculate the difference between the amplitudes using the following formula:

ξ(u,υ)=amp(T _r ,u)-amp(T _c ,υ) (14)

where amp(T _x , y) represents the amplitude of the y-th response of the label T _x , and T _c represents the current label.

The amplitude of each label is recorded, and the distance between the reference label and the current label is further calculated by the following formula:

M(u,υ)=ξ(u,υ)+min(M(u-1,υ-1),M(u-1,υ),M(u,υ-1)) (15)

where M(u, υ) is the distance function.

Next, the distance M in each inventory cycle is calculated for all received tags and reference tags, and only tags whose distance is less than an experimentally chosen threshold are considered as target tags.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments These are some embodiments of the present invention, but not all embodiments. The components of the embodiments of the invention generally described and illustrated in the drawings herein may be arranged and designed in a variety of different configurations. Thus, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Please refer to FIG. 1 , the present invention is divided into three large modules, namely, an antenna synchronization module, a fast search module and a motion tracking module.

1. Antenna synchronization module:

The present invention adopts a master-slave distributed antenna array, and before sending a beamforming signal, the antenna needs to be compensated for frequency and phase to synchronize the antenna. A priori identical distribution scheme is used to let the master and slave alternately send synchronization signals and measure the phase offset between the transmit and receive antennas. Compensate an initial phase for each slave to synchronize with the master transmitter.

2. Quick search module:

(1) Communication with the reference tag: The selective reading mechanism designed in the current commercial EPC C1G2 protocol is adopted. Send the appropriate SELECT command to select the reference tag, and then achieve efficient reading of the reference tag by setting parameters in the Query command.

(2) Select the transmission parameters and collect the response information of the reference tag: keep the master signal unchanged, constantly change the initial phase of the slave signal, and use the evaluation function to evaluate the energy of the tag reply. Record the value of the evaluation function under all transfer settings, making up the snapshot E0 of the reference label.

3. Motion Tracking Module: This module contains three sub-modules, as shown on the right side of Figure 1.

(1) Use the simulated annealing algorithm to optimize the evaluation function to obtain suitable transmission parameters.

(2) Determine whether the target tag is in a moving state according to whether the phase change of the tag exceeds a threshold. Then a particle filter is introduced to estimate the moving trajectory of the target label in real time.

(3) Using the dynamic time warping (DTW) algorithm to calculate the similarity between the amplitude curves of the reference tag and the current tag, the target tag can be distinguished from the entire tag population.

Referring to Figure 4, the hardware deployment of the present invention is shown in Figure 4: the present invention is deployed on a USRP X310 software-defined radio test bench with two SBX daughter boards serving as RFID readers. The reader uses a multiple-input multiple-output (MIMO) model, and each daughter board supports full-duplex communication. The antenna uses four unidirectional antennas VERT900 with a gain of 3dBi.

To demonstrate the improved read rate of this invention for target tags, it was compared with the recently developed USRP Gen2 reader. By experimenting in three different scenarios, the read rates of the two target tags were compared. Read rate is defined as the number of replies received from target tags per second. Through experiments, it is found that the average reading rate of the target tag in the present invention in three scenarios is 10.51/s, 5.74/s and 8.09/s, while the average reading rate of the Gen2 reader in the same scenario is 2.08/s. , 1.44/s and 2.14/s. Compared with the USRP Gen2 reader, the invention can improve the reading rate of the target tag by more than 3 times.

To sum up, the present invention provides a method, storage medium and device for directional reading and real-time tracking of commercial tags, which utilizes the response information of the reference tag closest to the target tag to obtain the energy distribution in different transmission settings and provide energy for the target tag. It uses RF beamforming technology to excite the target tag, and at the same time combines simulated annealing algorithm and particle filter to dynamically select appropriate transmission parameters to realize the reading and real-time tracking of the target tag.

As will be appreciated by those skilled in the art, the embodiments of the present application may be provided as a method, a system, or a computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) having computer-usable program code embodied therein.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the present application. It will be understood that each flow and/or block in the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to the processor of a general purpose computer, special purpose computer, embedded processor or other programmable data processing device to produce a machine such that the instructions executed by the processor of the computer or other programmable data processing device produce Means for implementing the functions specified in a flow or flow of a flowchart and/or a block or blocks of a block diagram.

These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory result in an article of manufacture comprising instruction means, the instructions The apparatus implements the functions specified in the flow or flow of the flowcharts and/or the block or blocks of the block diagrams.

These computer program instructions can also be loaded on a computer or other programmable data processing device to cause a series of operational steps to be performed on the computer or other programmable device to produce a computer-implemented process such that The instructions provide steps for implementing the functions specified in the flow or blocks of the flowcharts and/or the block or blocks of the block diagrams.

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any changes made on the basis of the technical solution according to the technical idea proposed by the present invention all fall within the scope of the claims of the present invention. within the scope of protection.

Claims (8)

1. A commercial label directional reading and real-time tracking method is characterized by comprising the following steps:

s1, adopting a master-slave distributed antenna array, wherein the master transmitter and the slave transmitter of the distributed antenna array alternately transmit synchronous signals, measuring the phase offset between the transmitting antenna and the receiving antenna, and compensating an initial phase for each slave transmitter to synchronize with the master transmitter;

s2, carrying out fast search, inquiring a reference label closest to a target label, adopting a selective reading mechanism designed in a commercial EPC C1G2 protocol, sending a SELECT command to SELECT the reference label, reading the reference label by setting parameters in a Query command, selecting a plurality of transmission parameters by a reader, obtaining response information of the reference label under different parameter settings, keeping a main transmitter signal unchanged, changing the initial phase of each slave transmitter signal within [0,2 pi ] by taking delta as a step length, evaluating the energy replied by the label by using an evaluation function f, and recording the energy replied by the label under all the transmission parametersEvaluating the value of the function, constituting the response information E of the reference tag₀A 1 is mixing E₀As an initial setting of the simulated annealing algorithm in step S3;

s3, response information E of reference label using step S2₀Obtaining energy distribution and related setting information for supplying energy to the target tag when different transmission parameters are obtained, dynamically selecting the transmission parameters to excite the tag of the target area and track the movement of the target tag in real time by combining a simulated annealing algorithm and a particle filter, and finishing the directional reading and real-time tracking of the commercial tag at the target position;

the method specifically comprises the following steps: using simulated annealing algorithm for approximating a given evaluation function E_nAccording to an evaluation function E_nObtain a list of appropriate transmission parameters for target tag tracking, and_nordering from high to low, a transmission parameter list theta is obtained_nTraversing the list Θ by changing the send parameters one by one_nUsing the same transmission parameter theta in the same counting cycle_n(k) Before starting the next inventory cycle, the system will E_n(Θ_n(k) ) and E_n(Θ_n(k +1)) are compared; switching to the next transmission parameter indeed according to the probability function P; refresh E based on the latest response of the reference tag before starting a new inventory cycle_n(Θ_n(k) If E) is equal to_nIf the element in (1) is not updated, the attenuation coefficient alpha is equal to E_nK decreases with time; if under the current transmission parameter setting, the function E is evaluated_nIs equal to 0, continues to transmit with a maximum E_nUntil movement is detected.

2. The method of claim 1, wherein in step S1, before transmitting the beam-forming signal, the frequency and phase synchronization antenna is compensated; the method comprises the steps that a priori same distribution scheme is adopted, a main transmitter and a secondary transmitter are enabled to alternately send synchronous signals, and phase shift between a transmitting antenna and a receiving antenna is obtained according to difference delta theta (t) of the main transmitter and the secondary transmitter

And frequency offset

Thereafter, each slave transmitter is compensated for an initial phase to synchronize with the master transmitter.

3. The method of claim 2, wherein the received signal on the master and slave antennas is P_M(t) when the synchronization signal is transmitted from the transmitter alone, the received signal is P_s(t), Δ θ (t) is:

wherein,

for the phase acquisition from the main transmitter side to the main receiver side,

for the phase acquisition from the master transmitter side to the slave receiver side,

for the phase acquisition from the transmitter side to the main receiver side,

t is the time for the phase from the transmitter side to the acquisition from the receiver side.

4. The method according to claim 1, wherein in step S2, the response information E of the reference label₀The method specifically comprises the following steps:

E₀＝[f(1)，f(2)，...，f(2π/δ)]。

5. the method according to claim 1, wherein in step S3, the function E is evaluated_nComprises the following steps:

where N is the number of iterations, μ is the weight coefficient, N_tAnd N_uRespectively the number of target tags and non-target tags, beta is a constant, alpha is the attenuation coefficient over time k, k is time,

as a transmission parameter, T_rAre reference labels.

6. The method of claim 5, wherein a particle filter is introduced if the evaluation function E is to be evaluated_nConsidering the probability density of the transmission parameters, it is necessary to estimate the probability density under motion or environmental changes, define the update function E of the transfer function w_n，E_nAll values in (1) are updated to E_n+1Starting from sorting and traversing until a mobility event is detected, wherein the function E is evaluated_nDepending on the estimation of the number of target tags, in static scenarios, a classification method based on EPC is employed, increasing N if the received EPC belongs to a non-target tag_uOtherwise the tag is marked as the target tag and N is increased_tA value of (d); in a dynamic scene, the similarity between the amplitude curves of the reference label and the current label is calculated by adopting a dynamic time warping method, the amplitude of each label is recorded, and the distance M (u, upsilon) between the reference label and the current label is obtained.

7. A computer readable storage medium storing one or more programs, the one or more programs comprising instructions, which when executed by a computing device, cause the computing device to perform any of the methods of claims 1-6.

8. A computing device, comprising:

one or more processors, memory, and one or more programs stored in the memory and configured to be executed by the one or more processors, the one or more programs including instructions for performing any of the methods of claims 1-6.

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