Calibration method and device of radio frequency identification equipment, equipment and medium

Abstract

The invention discloses a calibration method and device for radio frequency identification equipment, the equipment and a medium, and the method comprises the steps: obtaining internal and external power values of the radio frequency identification equipment according to a plurality of power setting items in response to a calibration request; performing secondary fitting by adopting the internal and external power values, and performing power calibration on the radio frequency identification equipment according to a secondary fitting result to obtain intermediate radio frequency identification equipment; initializing intermediate radio frequency identification equipment according to preset radio frequency signal characteristics, and respectively measuring signal receiving intensity under multiple groups of attenuation; and performing difference value fitting according to the signal receiving strength and the attenuation amount, and performing receiving calibration on the intermediate radio frequency identification equipment according to a difference value fitting result to obtain target radio frequency identification equipment. Therefore, dynamic calibration of the radio frequency identification equipment is realized through forward / reverse power calibration and receiving calibration of the received signal strength, and the positioning precision of the radio frequency identification equipment in a complex environment is further improved.

Description

Technical Field

[0001] The present invention relates to the field of RFID technology, and in particular to a calibration method, device, equipment and medium for a radio frequency identification device. Background Art

[0002] With the rapid development of Internet of Things technology, RFID (Radio Frequency Identification) technology, as a contactless automatic identification technology, is widely used in logistics management, warehouse management, intelligent manufacturing and other fields. RFID handheld devices can easily read and identify electronic tags on items due to their portability and flexibility.

[0003] In the existing RFID handheld device search and location solutions, the solution based on RSSI (Received Signal Strength Indication) is widely used due to its advantages of simple implementation and low cost. Specifically, the distance between the RFID handheld device and the tag is measured, and the distance is estimated by the attenuation of the RSSI signal strength.

[0004] However, in the process of searching for objects in complex environments, the above-mentioned solution is easily affected by factors such as hardware differences between RFID modules of different devices, differences in tag performance, and environmental multipath reflection, resulting in unstable positioning results and reduced positioning accuracy. Summary of the invention

[0005] The present invention provides a calibration method, device, equipment and medium for radio frequency identification equipment, which solves the technical problem that the existing solutions are easily affected by factors such as hardware differences between RFID modules of different devices, tag performance differences and environmental multipath reflections during the process of searching for objects in complex environments, resulting in unstable positioning results and reduced positioning accuracy.

[0006] The present invention provides a calibration method for a radio frequency identification device, comprising:

[0007] In response to the calibration request, respectively obtaining internal and external power values ​​of the radio frequency identification device according to a plurality of power setting items;

[0008] Performing quadratic fitting using the internal and external power values, and performing power calibration on the radio frequency identification device according to the quadratic fitting result to obtain an intermediate radio frequency identification device;

[0009] Initializing the intermediate RFID device according to the preset RF signal characteristics, and measuring the signal reception strength under multiple groups of attenuation amounts respectively;

[0010] A difference fitting is performed according to the signal reception strength and the attenuation, and a receiving calibration is performed on the intermediate radio frequency identification device according to the difference fitting result to obtain a target radio frequency identification device.

[0011] Optionally, in response to the calibration request, obtaining internal and external power values ​​of the radio frequency identification device respectively according to a plurality of power setting items includes:

[0012] When the radio frequency identification device is connected to the spectrum analyzer and a calibration request is received, the radio frequency signal is outputted respectively according to a plurality of power setting items by the radio frequency identification device;

[0013] A power meter is used to detect the internal and external power values ​​corresponding to each of the radio frequency signals.

[0014] Optionally, the internal and external power values ​​include an internal power value and an external power value; and the performing of quadratic fitting using the internal and external power values, and performing power calibration on the radio frequency identification device according to the quadratic fitting result to obtain the intermediate radio frequency identification device, comprises:

[0015] A second fitting is performed using the internal power value of each group as an independent variable and the corresponding external power value as a dependent variable to obtain a first fitting relationship;

[0016] Extracting a first fitting coefficient in the first fitting relationship and writing the first fitting coefficient into a register in the radio frequency identification device to obtain a calibration device;

[0017] The calibration device is used to output the radio frequency signal again according to the plurality of power setting items and measure the calibration power to construct a power calibration table;

[0018] The radio frequency identification device is power calibrated according to the power calibration table to obtain an intermediate radio frequency identification device.

[0019] Optionally, the radio frequency signal characteristics include output power and output frequency; and initializing the intermediate radio frequency identification device according to the preset radio frequency signal characteristics and measuring the signal reception strength under multiple groups of attenuation amounts respectively includes:

[0020] connecting the intermediate radio frequency identification device to a programmable attenuator;

[0021] Initialize the intermediate RFID device according to a preset output power and output frequency;

[0022] Setting multiple groups of attenuation amounts by means of the program-controllable attenuator;

[0023] The intermediate radio frequency identification device outputs radio frequency signals respectively under the attenuation of each group, and measures the signal reception strength respectively.

[0024] Optionally, performing difference fitting according to the signal reception strength and the attenuation, and performing reception calibration on the intermediate radio frequency identification device according to the difference fitting result to obtain the target radio frequency identification device includes:

[0025] Calculating the actual attenuation value corresponding to each group of signal reception strengths;

[0026] Calculating the attenuation difference between each of the actual attenuation values ​​and the corresponding attenuation amount;

[0027] Performing quadratic fitting with the signal reception strength as an independent variable and the attenuation difference as a dependent variable to obtain a second fitting relationship;

[0028] A second fitting parameter in the second fitting relational expression is extracted and written into a register in the intermediate radio frequency identification device to obtain a target radio frequency identification device.

[0029] Optionally, the radio frequency identification device further includes a plurality of radio frequency tags for matching use, and the method further includes:

[0030] When a target RFID device is obtained and a power instruction is received, initializing the transmission power of the target RFID device according to the power instruction;

[0031] The target RFID device is used to detect the RFID tag at the first preset position in real time, and the target RFID device is moved backward according to a preset distance gradient;

[0032] When the target RFID device cannot detect the RFID tag, obtaining first detection data at the current moment;

[0033] Acquire second detection data corresponding to the radio frequency tag at a second preset position using the target radio frequency identification device;

[0034] The antenna gain of the radio frequency tag is calibrated according to the first detection data and the second detection data to obtain a target radio frequency tag.

[0035] Optionally, calibrating the antenna gain of the radio frequency tag according to the first detection data and the second detection data to obtain a target radio frequency tag includes:

[0036] Substituting the first detection data and the second detection data into a preset distance calculation formula and a received signal strength calculation formula to calculate a tag antenna transmission gain and a tag antenna receiving gain;

[0037] The tag antenna transmission gain and the tag antenna reception gain are used to replace the antenna gain of the radio frequency tag to obtain a target radio frequency tag.

[0038] A second aspect of the present invention provides a calibration device for a radio frequency identification device, comprising:

[0039] A power value acquisition module, used to respond to a calibration request and obtain internal and external power values ​​of the radio frequency identification device according to a plurality of power setting items;

[0040] A power calibration module, used to perform a quadratic fit using the internal and external power values, and perform power calibration on the radio frequency identification device according to the quadratic fitting result to obtain an intermediate radio frequency identification device;

[0041] A signal receiving strength measurement module, used to initialize the intermediate RFID device according to preset RF signal characteristics, and respectively measure the signal receiving strength under multiple groups of attenuation amounts;

[0042] The receiving calibration module is used to perform difference fitting according to the signal receiving strength and the attenuation, and perform receiving calibration on the intermediate radio frequency identification device according to the difference fitting result to obtain the target radio frequency identification device.

[0043] A third aspect of the present invention provides an electronic device, comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the calibration method of the radio frequency identification device as described in any one of the first aspect of the present invention.

[0044] A fourth aspect of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed, implements the calibration method for a radio frequency identification device as described in any one of the first aspects of the present invention.

[0045] It can be seen from the above technical solutions that the present invention has the following advantages:

[0046] The present invention obtains the internal and external power values ​​of the radio frequency identification device according to multiple power setting items respectively by responding to the calibration request; uses each internal and external power value to perform quadratic fitting, performs power calibration on the radio frequency identification device according to the quadratic fitting result, and obtains the intermediate radio frequency identification device; initializes the intermediate radio frequency identification device according to the preset radio frequency signal characteristics, and measures the signal receiving strength under multiple groups of attenuation respectively; performs difference fitting according to the signal receiving strength and the attenuation, performs receiving calibration on the intermediate radio frequency identification device according to the difference fitting result, and obtains the target radio frequency identification device. Thus, the dynamic calibration of the radio frequency identification device is realized by forward / reverse power calibration and receiving calibration of the received signal strength, thereby improving the positioning accuracy of the radio frequency identification device in a complex environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0048] Figure 1 A flowchart of a calibration method for a radio frequency identification device provided by an embodiment of the present invention;

[0049] Figure 2 A flowchart of the detailed steps of a calibration method for a radio frequency identification device provided by an embodiment of the present invention;

[0050] Figure 3 A structural block diagram of a calibration device for a radio frequency identification device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0051] The embodiments of the present invention provide a calibration method, apparatus, device and medium for a radio frequency identification device, which are used to solve the technical problem that in the process of searching for objects in a complex environment, the existing solutions are easily affected by factors such as hardware differences between RFID modules of different devices, tag performance differences and environmental multipath reflections, resulting in unstable positioning results and reduced positioning accuracy.

[0052] Radio frequency identification device, referred to as RFID device, is a technical device that uses radio frequency signals to achieve contactless information transmission through spatial coupling and achieves identification purposes through the transmitted information. Radio frequency identification devices are composed of electronic tags, readers and antennas. Electronic tags store relevant information about items. When entering the radio frequency field of the reader, the tag receives the radio frequency signal emitted by the reader and sends out the product information stored in the chip with the energy obtained by the induced current. After the reader reads and decodes the information, it is sent to the central information system for relevant data processing. The antenna transmits radio frequency signals between the tag and the reader. In the embodiment of the present application, the radio frequency identification device is an RFID handheld device or an RFID fixed device.

[0053] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] See also Figure 1 , Figure 1A flowchart of a calibration method for a radio frequency identification device provided by an embodiment of the present invention.

[0055] The present invention provides a calibration method for a radio frequency identification device, comprising:

[0056] Step 101, in response to a calibration request, obtaining internal and external power values ​​of the RFID device respectively according to a plurality of power setting items;

[0057] The power setting item refers to the pre-set power value point in the RFID device, which is used to set the expected output power value of the RF module in the RFID device.

[0058] In this embodiment, after receiving the calibration request, it indicates that the factory-produced RFID device needs to be calibrated at this time. After the RFID device is connected to a device required for calibration, such as a spectrum analyzer, the RFID device is controlled to output RF signals respectively according to multiple power setting items, and the RF signals are detected to obtain the internal and external power values ​​corresponding to the RFID device.

[0059] Among them, the internal and external power values ​​include internal power values ​​and external power values. The value of the power setting item is equal to the internal power value. The power value is detected by power meters respectively set inside and outside the radio frequency identification device. The specific detection means are not limited in the embodiments of this application.

[0060] Step 102, performing a quadratic fit using each internal and external power value, and performing power calibration on the RFID device according to the quadratic fit result to obtain an intermediate RFID device;

[0061] In this embodiment, after the internal and external power values ​​of the RFID device are detected and obtained, a quadratic fitting is performed with the internal power value as the independent variable and the external power value as the dependent variable. The first fitting coefficient is calculated with the result of the quadratic fitting and written into the register of the RFID device to perform power calibration on the RFID device and obtain an intermediate RFID device that has undergone power calibration.

[0062] Among them, power calibration includes forward power calibration and reverse power calibration. The forward power calibration uses the internal power value as the independent variable and the output external power value as the dependent variable for quadratic fitting. The reverse power calibration uses the internal power value as the independent variable and the received external power value as the dependent variable for quadratic fitting to perform bidirectional calibration of the intermediate RF device.

[0063] In addition to the quadratic fitting, the relationship between the internal and external power values ​​can also be fitted by other fitting means, such as difference fitting.

[0064] Step 103, initializing the intermediate RFID device according to the preset RF signal characteristics, and measuring the signal reception strength under multiple groups of attenuation amounts respectively;

[0065] Received Signal Strength Indication (RSSI) is an indicator used to measure the strength of wireless signals. By measuring the signal strength at different locations, the approximate location of the signal source can be determined.

[0066] Attenuation refers to the degree of reduction in energy or intensity of a signal during transmission due to various factors. In this embodiment, the programmable attenuator can be set by controlling parameters such as signal, operating frequency, and temperature. It is usually expressed in decibels (dB). For example, an attenuation of 30 dB means that the power of the input signal is reduced to 1 / 1000 of the original after passing through the attenuator.

[0067] RF signal characteristics refer to the power and frequency that need to be set when using RFID equipment.

[0068] Since the accuracy of the signal reception strength has a great influence on the positioning accuracy, after completing the power calibration of the RFID device, the signal reception strength thereof can be further calibrated so that the positioning accuracy can be further improved.

[0069] Specifically, the intermediate RFID device is initialized according to a fixed RF signal characteristic, the intermediate RFID device is connected to a program-controlled attenuator or a sensitivity tester, different attenuation amounts are set to output the RF signal, and the signal reception strength of the return signal is measured as the calibration data basis for the subsequent signal reception strength.

[0070] Step 104 , performing difference fitting according to the signal reception strength and the attenuation, and performing receiving calibration on the intermediate RFID device according to the difference fitting result to obtain the target RFID device.

[0071] After measuring the signal reception strength corresponding to multiple groups of attenuation values, in order to realize the RSSI calibration of the RF module in the RFID device, difference fitting is performed according to each group of signal reception strength and the corresponding attenuation value, and the corresponding register parameters are calculated based on the difference fitting results to perform reception calibration on the intermediate RFID device, so that the RSSI reception is more accurate and the target RFID device is obtained.

[0072] In this embodiment, by responding to the calibration request, the internal and external power values ​​of the RFID device are obtained according to multiple power setting items; the internal and external power values ​​are used for quadratic fitting, and the power of the RFID device is calibrated according to the quadratic fitting results to obtain the intermediate RFID device; the intermediate RFID device is initialized according to the preset RF signal characteristics, and the signal receiving strength under multiple groups of attenuation is measured respectively; the difference fitting is performed according to the signal receiving strength and the attenuation, and the intermediate RFID device is calibrated according to the difference fitting results to obtain the target RFID device. Thus, the dynamic calibration of the RFID device is achieved by forward / reverse power calibration and receiving calibration of the received signal strength, thereby improving the positioning accuracy of the RFID device in complex environments.

[0073] See also Figure 2 , Figure 2 A flowchart of a calibration method for a radio frequency identification device provided by an embodiment of the present invention.

[0074] The present invention provides a calibration method for a radio frequency identification device, wherein the radio frequency identification device also includes a plurality of radio frequency tags for matching use, including:

[0075] Step 201, in response to a calibration request, obtaining internal and external power values ​​of the RFID device respectively according to a plurality of power setting items;

[0076] In an example of the present application, step 201 may include the following sub-steps:

[0077] When the RFID device is connected to the spectrum analyzer and a calibration request is received, the RFID device outputs RF signals respectively according to the multiple power setting items;

[0078] A power meter is used to detect the internal and external power values ​​corresponding to each RF signal.

[0079] In an embodiment of the present application, after the RF output port of the RFID device is connected to the spectrum analyzer, if a calibration request is received, the RFID device outputs RF signals according to multiple preset power setting items, that is, the RF module inside the RFID device outputs RF signals according to multiple power value points.

[0080] At the same time, a power meter is used to measure the power of the RF signal generated inside the RF module and the RF signal output to the outside, respectively, to obtain the internal and external power values ​​corresponding to each power point, which serve as the data basis for subsequent power calibration.

[0081] Step 202, performing a quadratic fit using each internal and external power value, and performing power calibration on the RFID device according to the quadratic fit result to obtain an intermediate RFID device;

[0082] In an example of the present application, the internal and external power values ​​include an internal power value and an external power value; step 202 may include the following sub-steps:

[0083] The first fitting relationship is obtained by performing quadratic fitting using the internal power value of each group as the independent variable and the corresponding external power value as the dependent variable;

[0084] Extracting a first fitting coefficient in a first fitting relational expression and writing the coefficient into a register in a radio frequency identification device to obtain a calibration device;

[0085] The calibration equipment is used to output the radio frequency signal again according to multiple power setting items and measure the calibration power to construct a power calibration table;

[0086] The power of the radio frequency identification device is calibrated according to the power calibration table to obtain an intermediate radio frequency identification device.

[0087] After measuring and obtaining multiple groups of internal power values ​​and external power values, a quadratic fitting is performed using each group of internal power values ​​as an independent variable and the corresponding external power values ​​as a dependent variable to generate the first fitting relationship, as shown below:

[0088]

[0089] Wherein, x is the internal power value, y is the external power value, and A, B and C are the first fitting coefficients.

[0090] After solving the first fitting relationship according to multiple sets of internal power values ​​and external power values, the first fitting coefficient is obtained, which is extracted and written into the register in the RF identification device to obtain the calibration device. The calibration device is used to output the RF signal again according to multiple power setting items and measure the calibration power, build a power calibration table, and convert it into a digital ADC power table. All power calibration tables are traversed, and the calibration power of each power point in all power tables is calculated. When the carriers of different powers are turned on later, the power is adjusted by comparing with the calibration power y value in the ADC power table to obtain the intermediate RFID device.

[0091] The reverse power calibration process is the same as the forward power calibration process described above, and will not be described in detail here.

[0092] Step 203, initializing the intermediate RFID device according to the preset RF signal characteristics, and measuring the signal reception strength under multiple groups of attenuation amounts respectively;

[0093] In an example of the present application, the radio frequency signal characteristics include output power and output frequency; step 203 may include the following sub-steps:

[0094] Connecting the intermediate RFID device to the programmable attenuator;

[0095] Initialize the intermediate RFID device according to the preset output power and output frequency;

[0096] Set multiple groups of attenuation through programmable attenuators;

[0097] The intermediate radio frequency identification device outputs radio frequency signals respectively under each group of attenuation amounts, and measures the signal reception strength respectively.

[0098] After obtaining the intermediate RFID device, connect its transmitting port to a programmable attenuator or sensitivity tester, and initialize the intermediate RFID device according to a single preset output power and output frequency. Since its transmitting power has been calibrated, in order to improve the accuracy of the signal receiving strength, multiple groups of attenuation are set through the programmable attenuator to simulate the environment. The intermediate RFID device outputs RF signals under each group of attenuation, and measures the signal receiving strength of the return signal.

[0099] In a specific implementation, the parameters in the program-controllable attenuator are adjusted to represent different attenuation amounts, and the intermediate RFID device outputs RF signals at each set of attenuation amounts. The signal reception strength of the return signal is measured by the measurement component in the intermediate RFID device to serve as the data basis for subsequent RSSI reception calibration.

[0100] Step 204, performing difference fitting according to the signal reception strength and the attenuation, and performing receiving calibration on the intermediate RFID device according to the difference fitting result to obtain the target RFID device;

[0101] In an example of the present application, step 204 may include the following sub-steps:

[0102] Calculate the actual attenuation value corresponding to each group of signal reception strength;

[0103] Calculate the attenuation difference between each actual attenuation value and the corresponding attenuation amount;

[0104] The signal receiving strength is used as the independent variable and the attenuation difference is used as the dependent variable to perform quadratic fitting to obtain the second fitting relationship;

[0105] A second fitting parameter in the second fitting relational expression is extracted and written into a register in the intermediate radio frequency identification device to obtain a target radio frequency identification device.

[0106] In this embodiment, the actual attenuation value corresponding to each group of signal receiving strength is calculated. For example, the signal strength sent by the transmitter is 100mW, and after a certain distance of transmission, the signal strength received by the receiver is 1mW. Its actual attenuation value is:

[0107]

[0108] At the same time, the attenuation amount is a preset value, and the attenuation difference between each group of actual attenuation values ​​and the corresponding attenuation amount is calculated.

[0109] A quadratic fitting is performed with each group of signal reception strength as the independent variable and the corresponding attenuation difference as the dependent variable, and the second fitting parameter in the second fitting relationship is extracted. The quadratic fitting parameter is written into the register in the intermediate RFID device to obtain the target RFID device. The quadratic fitting process is similar to the quadratic fitting process of the first fitting relationship mentioned above, which will not be repeated here.

[0110] In a specific implementation, the transmitting port can be connected to a sensitivity tester (programmable attenuator), and the sensitivity tester can be adjusted to have different attenuations to measure multiple groups of module RSSI receiving data. The RSSI values ​​received in the multiple groups of data can be compared with the reverse attenuation set by the sensitivity tester, and then corrected by difference fitting to make RSSI reception more accurate.

[0111] Step 205, when the target RFID device is obtained and the power instruction is received, the transmission power of the target RFID device is initialized according to the power instruction;

[0112] In this embodiment, after the intermediate RFID device is calibrated to obtain the target RFID device, if a power instruction is received, the transmission power of the target RFID device is initialized according to the power instruction to complete the calibration data basis of the RFID tag.

[0113] Step 206, using a target radio frequency identification device to detect the radio frequency tag at the first preset position in real time, and moving the target radio frequency device backward according to a preset distance gradient;

[0114] Step 207, when the target RFID device cannot detect the RFID tag, obtain the first detection data at the current moment;

[0115] Taking a handheld target RFID device as an example, after placing the RFID tag matching the target RFID device at a first preset position, the target RFID device is moved backward according to a preset distance gradient until the RFID tag can no longer be detected, and the first detection data last detected by the target RFID device is obtained.

[0116] It should be noted that the first detection data includes but is not limited to the distance between the target RFID device and the RFID tag, the transmission power, the receiving power and the received signal strength of the target RFID device.

[0117] Step 208, using a target radio frequency identification device to obtain second detection data corresponding to the radio frequency tag at a second preset position;

[0118] The second preset position refers to a position at a certain distance from the RFID tag and where the RFID tag can be detected, such as a position with a spacing of 1 meter. After the target RFID device moves to the second preset position, the RFID signal is sent again to detect the position of the RFID tag to obtain the second detection data at this time.

[0119] The second detection data has the same content type as the first detection data.

[0120] Step 209: Calibrate the antenna gain of the radio frequency tag according to the first detection data and the second detection data to obtain the target radio frequency tag.

[0121] In an example of the present application, step 209 may include the following sub-steps:

[0122] Substituting the first detection data and the second detection data into a preset distance calculation formula and a received signal strength calculation formula to calculate the tag antenna transmission gain and the tag antenna receiving gain;

[0123] The tag antenna transmitting gain and the tag antenna receiving gain are used to replace the antenna gain of the RF tag to obtain the target RF tag.

[0124] In this embodiment, after obtaining the first detection data and the second detection data, the preset distance calculation formula and the received signal strength calculation formula are substituted, and the distance calculation formula is as follows:

[0125]

[0126] in, is the tag antenna transmission gain, is the tag antenna receiving gain, is the received signal strength, and λ is the wavelength in meters.

[0127] The formula for calculating the received signal strength is:

[0128]

[0129] in, is the transmission power of the target RFID device, is the received power of the target RFID device.

[0130] After substituting the above formula into the solution, the tag antenna transmission gain and the tag antenna receiving gain are obtained and replaced with the original antenna gain of the RFID tag to obtain the target RFID tag, thus completing the overall calibration of the RFID device and the RFID tag.

[0131] In addition, the new antenna gain of the RFID tag can be directly obtained by subtracting the original antenna gain of the RFID tag from the tag antenna transmission gain and the tag antenna reception gain.

[0132] Take a handheld RFID device as an example. After power calibration, reception calibration, and antenna gain calibration of the corresponding RFID tag, the target RFID tag is attached or placed on multiple objects to be found. When it is necessary to find the object to be found in a complex environment, the free space path loss formula is used:

[0133]

[0134] Among them, P t is the transmit power (in dB), P r is the received power (in dB), G t is the transmit antenna gain, G r is the receiving antenna gain, λ is the wavelength (in meters), and d is the distance between the transmitter and the receiver (in meters).

[0135] The distance d is obtained by transforming the above formula:

[0136]

[0137] In this embodiment, the handheld RFID device is divided into two systems: a RFID tag and a handheld RFID device. Therefore, the actual distance D is:

[0138]

[0139] in, The distance calculated by the above spatial path loss formula is obtained by using the tag as the transmitter and the handheld RFID device as the receiver; The distance is calculated using the above spatial path loss formula with a handheld RFID device as the transmitter and the RFID tag as the receiver.

[0140] It should be noted that for handheld RFID devices, the transmitting antenna gain and the receiving antenna gain It has been calibrated after leaving the factory and is a known parameter. λ is the wavelength of the electromagnetic wave, which is derived by λ=c / f, where c is the speed of light, which is 3.0×10 8 m / s, f is the frequency set by the user, generally 915.25Mhz, which is also a fixed value, that is, λ is also a known parameter. It can be calculated by the following formula:

[0141]

[0142] in, is the transmission power of the handheld RFID device, is the receiving power of the handheld radio frequency identification device, which is obtained after the forward and reverse power calibration is performed in the above step 202.

[0143] For RFID tags, the tag transmitting antenna gain is and the receiving antenna gain The above steps 205-209 are used to calibrate the obtained value. λ is the wavelength of the electromagnetic wave, which is derived from λ=c / f, where c is the speed of light, which is 3.0×10 8 m / s, f is the frequency set by the user, generally 915.25Mhz, which is also a fixed value, that is, λ is also a known parameter. The RSSI value returned by the RFID tag received by the handheld RFID device is obtained by calibration in the above steps 203-204.

[0144] In this embodiment, by responding to the calibration request, the internal and external power values ​​of the RFID device are obtained according to multiple power setting items; the internal and external power values ​​are used for quadratic fitting, and the power of the RFID device is calibrated according to the quadratic fitting results to obtain the intermediate RFID device; the intermediate RFID device is initialized according to the preset RF signal characteristics, and the signal receiving strength under multiple groups of attenuation is measured respectively; the difference fitting is performed according to the signal receiving strength and the attenuation, and the intermediate RFID device is calibrated according to the difference fitting results to obtain the target RFID device. Thus, the dynamic calibration of the RFID device is achieved by forward / reverse power calibration and receiving calibration of the received signal strength, thereby improving the positioning accuracy of the RFID device in complex environments.

[0145] See also Figure 3 , Figure 3 A structural block diagram of a calibration device for a radio frequency identification device according to an embodiment of the present application is shown.

[0146] An embodiment of the present invention provides a calibration device for a radio frequency identification device, comprising:

[0147] The power value acquisition module 301 is used to respond to the calibration request and acquire the internal and external power values ​​of the RFID device according to multiple power setting items;

[0148] A power calibration module 302 is used to perform a quadratic fit using each internal and external power value, and perform power calibration on the RFID device according to the quadratic fit result to obtain an intermediate RFID device;

[0149] The signal receiving strength measurement module 303 is used to initialize the intermediate RFID device according to the preset RF signal characteristics and respectively measure the signal receiving strength under multiple groups of attenuation amounts;

[0150] The receiving calibration module 304 is used to perform difference fitting according to the signal receiving strength and the attenuation, and perform receiving calibration on the intermediate RFID device according to the difference fitting result to obtain the target RFID device.

[0151] Optionally, the power value acquisition module 301 is specifically used for:

[0152] When the RFID device is connected to the spectrum analyzer and a calibration request is received, the RFID device outputs RF signals respectively according to the multiple power setting items;

[0153] A power meter is used to detect the internal and external power values ​​corresponding to each RF signal.

[0154] Optionally, the internal and external power values ​​include an internal power value and an external power value; the power calibration module 302 is specifically used for:

[0155] The first fitting relationship is obtained by performing quadratic fitting using the internal power value of each group as the independent variable and the corresponding external power value as the dependent variable;

[0156] Extracting a first fitting coefficient in a first fitting relational expression and writing the coefficient into a register in a radio frequency identification device to obtain a calibration device;

[0157] The calibration equipment is used to output the radio frequency signal again according to multiple power setting items and measure the calibration power to construct a power calibration table;

[0158] The power of the radio frequency identification device is calibrated according to the power calibration table to obtain an intermediate radio frequency identification device.

[0159] Optionally, the radio frequency signal characteristics include output power and output frequency; the signal reception strength measurement module 303 is specifically used for:

[0160] Connecting the intermediate RFID device to the programmable attenuator;

[0161] Initialize the intermediate RFID device according to the preset output power and output frequency;

[0162] Set multiple groups of attenuation through programmable attenuators;

[0163] The intermediate radio frequency identification device outputs radio frequency signals respectively under each group of attenuation amounts, and measures the signal reception strength respectively.

[0164] Optionally, the receiving calibration module 304 is specifically configured to:

[0165] Calculate the actual attenuation value corresponding to each group of signal reception strength;

[0166] Calculate the attenuation difference between each actual attenuation value and the corresponding attenuation amount;

[0167] The signal receiving strength is used as the independent variable and the attenuation difference is used as the dependent variable to perform quadratic fitting to obtain the second fitting relationship;

[0168] A second fitting parameter in the second fitting relational expression is extracted and written into a register in the intermediate radio frequency identification device to obtain a target radio frequency identification device.

[0169] Optionally, the radio frequency identification device further includes a plurality of radio frequency tags for matching use, and the apparatus further includes:

[0170] A power initialization module, for initializing the transmission power of the target RFID device according to the power instruction when the target RFID device is obtained and the power instruction is received;

[0171] The device backward movement module is used to use the target radio frequency identification device to detect the radio frequency tag at the first preset position in real time, and move the target radio frequency device backward according to the preset distance gradient;

[0172] A first detection data acquisition module, used to acquire first detection data at the current moment when the target RFID device cannot detect the RFID tag;

[0173] A second detection data acquisition module, used to acquire second detection data corresponding to the radio frequency tag at a second preset position using a target radio frequency identification device;

[0174] The gain calibration module is used to calibrate the antenna gain of the radio frequency tag according to the first detection data and the second detection data to obtain a target radio frequency tag.

[0175] Optionally, the gain calibration module is specifically used for:

[0176] Substituting the first detection data and the second detection data into a preset distance calculation formula and a received signal strength calculation formula to calculate the tag antenna transmission gain and the tag antenna receiving gain;

[0177] The tag antenna transmitting gain and the tag antenna receiving gain are used to replace the antenna gain of the RF tag to obtain the target RF tag.

[0178] An embodiment of the present invention provides an electronic device, including a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the calibration method of the radio frequency identification device as described in any embodiment of the present invention.

[0179] An embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon. When the computer program is executed, the calibration method of a radio frequency identification device as described in any embodiment of the present invention is implemented.

[0180] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described devices and modules can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0181] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0182] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0183] In addition, each functional module in each embodiment of the present invention may be integrated into one processing module, or each module may exist physically separately, or two or more modules may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of software functional modules.

[0184] If the integrated module is implemented in the form of a software function module and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for an electronic device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0185] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A calibration method for a radio frequency identification device, characterized in that: include: In response to the calibration request, respectively obtaining internal and external power values ​​of the radio frequency identification device according to a plurality of power setting items; Performing quadratic fitting using the internal and external power values, and performing power calibration on the radio frequency identification device according to the quadratic fitting result to obtain an intermediate radio frequency identification device; Initializing the intermediate RFID device according to the preset RF signal characteristics, and measuring the signal reception strength under multiple groups of attenuation amounts respectively; A difference fitting is performed according to the signal reception strength and the attenuation, and a receiving calibration is performed on the intermediate radio frequency identification device according to the difference fitting result to obtain a target radio frequency identification device.

2. The method according to claim 1, characterized in that The step of responding to the calibration request and obtaining internal and external power values ​​of the radio frequency identification device according to a plurality of power setting items includes: When the radio frequency identification device is connected to the spectrum analyzer and a calibration request is received, the radio frequency signal is outputted respectively according to a plurality of power setting items by the radio frequency identification device; A power meter is used to detect the internal and external power values ​​corresponding to each of the radio frequency signals.

3. The method according to claim 1, characterized in that The internal and external power values ​​include internal power values ​​and external power values; the method of performing quadratic fitting using the internal and external power values, and performing power calibration on the radio frequency identification device according to the quadratic fitting result to obtain an intermediate radio frequency identification device includes: A second fitting is performed using the internal power value of each group as an independent variable and the corresponding external power value as a dependent variable to obtain a first fitting relationship; Extracting a first fitting coefficient in the first fitting relationship and writing the first fitting coefficient into a register in the radio frequency identification device to obtain a calibration device; The calibration device is used to output the radio frequency signal again according to the plurality of power setting items and measure the calibration power to construct a power calibration table; The radio frequency identification device is power calibrated according to the power calibration table to obtain an intermediate radio frequency identification device.

4. The method according to claim 1, characterized in that: The radio frequency signal characteristics include output power and output frequency; the initializing the intermediate radio frequency identification device according to the preset radio frequency signal characteristics and measuring the signal receiving strength under multiple groups of attenuation amounts respectively include: connecting the intermediate radio frequency identification device to a programmable attenuator; Initialize the intermediate RFID device according to a preset output power and output frequency; Setting multiple groups of attenuation amounts by means of the program-controllable attenuator; The intermediate radio frequency identification device outputs radio frequency signals respectively under the attenuation of each group, and measures the signal reception strength respectively.

5. The method according to claim 1, characterized in that The performing difference fitting according to the signal reception strength and the attenuation, and performing reception calibration on the intermediate radio frequency identification device according to the difference fitting result to obtain the target radio frequency identification device, comprises: Calculating the actual attenuation value corresponding to each group of signal reception strengths; Calculating the attenuation difference between each of the actual attenuation values ​​and the corresponding attenuation amount; Performing quadratic fitting with the signal reception strength as an independent variable and the attenuation difference as a dependent variable to obtain a second fitting relationship; A second fitting parameter in the second fitting relational expression is extracted and written into a register in the intermediate radio frequency identification device to obtain a target radio frequency identification device.

6. The method according to any one of claims 1 to 5, characterized in that: The radio frequency identification device also includes a plurality of radio frequency tags for matching, and the method further includes: When a target RFID device is obtained and a power instruction is received, initializing the transmission power of the target RFID device according to the power instruction; The target RFID device is used to detect the RFID tag at the first preset position in real time, and the target RFID device is moved backward according to a preset distance gradient; When the target RFID device cannot detect the RFID tag, obtaining first detection data at the current moment; Acquire second detection data corresponding to the radio frequency tag at a second preset position using the target radio frequency identification device; The antenna gain of the radio frequency tag is calibrated according to the first detection data and the second detection data to obtain a target radio frequency tag.

7. The method according to claim 6, characterized in that The step of calibrating the antenna gain of the radio frequency tag according to the first detection data and the second detection data to obtain a target radio frequency tag includes: Substituting the first detection data and the second detection data into a preset distance calculation formula and a received signal strength calculation formula to calculate a tag antenna transmission gain and a tag antenna receiving gain; The tag antenna transmission gain and the tag antenna reception gain are used to replace the antenna gain of the radio frequency tag to obtain a target radio frequency tag.

8. A calibration device for a radio frequency identification device, characterized in that: include: A power value acquisition module, used to respond to a calibration request and obtain internal and external power values ​​of the radio frequency identification device according to a plurality of power setting items; A power calibration module, used to perform a quadratic fit using the internal and external power values, and perform power calibration on the radio frequency identification device according to the quadratic fitting result to obtain an intermediate radio frequency identification device; A signal receiving strength measurement module, used to initialize the intermediate RFID device according to preset RF signal characteristics, and respectively measure the signal receiving strength under multiple groups of attenuation amounts; The receiving calibration module is used to perform difference fitting according to the signal receiving strength and the attenuation, and perform receiving calibration on the intermediate radio frequency identification device according to the difference fitting result to obtain the target radio frequency identification device.

9. An electronic device, characterized in that: The method comprises a memory and a processor, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the processor executes the steps of the calibration method of the radio frequency identification device according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed, the calibration method of the radio frequency identification device according to any one of claims 1 to 7 is implemented.

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