CN105572413B - A kind of method and application measuring passive UHF RFID tag movement speed and direction - Google Patents
A kind of method and application measuring passive UHF RFID tag movement speed and direction Download PDFInfo
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- CN105572413B CN105572413B CN201511028758.7A CN201511028758A CN105572413B CN 105572413 B CN105572413 B CN 105572413B CN 201511028758 A CN201511028758 A CN 201511028758A CN 105572413 B CN105572413 B CN 105572413B
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P3/00—Measuring linear or angular speed; Measuring differences of linear or angular speeds
- G01P3/64—Devices characterised by the determination of the time taken to traverse a fixed distance
- G01P3/66—Devices characterised by the determination of the time taken to traverse a fixed distance using electric or magnetic means
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P13/00—Indicating or recording presence, absence, or direction, of movement
- G01P13/02—Indicating direction only, e.g. by weather vane
- G01P13/04—Indicating positive or negative direction of a linear movement or clockwise or anti-clockwise direction of a rotational movement
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Abstract
The invention discloses a kind of systems for measuring passive UHF RFID tag movement speed and direction, it includes radio frequency receiving and transmitting front end, digital baseband transmission system and microcontroller.The invention also discloses method of the system when measuring passive UHF RFID tag movement speed and direction.The measurement method includes a UHF RFID reader and a set of special algorithm.Compared with prior art, the present invention can solve the problems, such as that existing UHF RFID reader does not have method to go to measure the speed of passive label and moving direction.And the method for the present invention precise and high efficiency, it is simple and easy, it is suitable for large-scale promotion.
Description
Technical field
The invention belongs to electronic technology fields, and in particular to a kind of to measure passive UHF RFID tag movement speed and direction
Method and application.
Background technique
Internet of Things (Internet of things) is the important trend of current information networking development, is referred to as calculated
The third wave of world information industry after machine, internet, wherein radio RF recognition technology RFID has become Internet of Things
One of key technology.RFID technique is a kind of contactless automatic identification technology, it passes through radiofrequency signal automatic identification target
Object simultaneously obtains related data, with its identification can radio read-write, signal penetration capacity is strong, distance is remote, long service life, environment are suitable
Answering property is good, can multi-tag and meanwhile identify, information storage is easy the advantages that big and data are rewritable, be used widely in recent years.
In passive UHF RFID system, passive label towards reading and writing device antenna or leaves reader day with some speed
Line direction is mobile, and traditional UHF RFID reader does not have method to go to measure the speed of passive label and moving direction.Especially
In the application of vehicle electron identifying, each automobile has pasted passive electronic label, and the speed and directional information of its movement are with regard to non-
It is often important, if the reader equipment at crossing can measure the movement speed and directional information by electronic tag, so that it may
Fully known traffic flow information, if get congestion or traffic accident, if more some into or out road of vehicle
Mouthful, if it needs to adjust anti-collision algorithm and removes the electronic mark etc. for accurately reading each automobile, to realize intelligent transportation
Management.
Summary of the invention
The technical problem to be solved in the present invention is to provide a kind of passive UHF RFID tag movement speed and directions of measuring
Method does not have method to go asking for the speed for measuring passive label and moving direction to solve existing UHF RFID reader
Topic.
The present invention also technical problems to be solved are to provide the measurement method of above system.
The last technical problems to be solved of the present invention are to provide the application of above system.
In order to solve the above technical problems, The technical solution adopted by the invention is as follows:
A method of measuring passive UHF RFID tag movement speed and direction, including a passive UHFRFID of measurement
The system of label movement speed and direction, the system include two transmitting baseband Data Profile filters, the road I signal and the road Q letter
Number respectively after different transmitting baseband Data Profile filter output through D/A conversion circuit become analog signal and by
First filter filters off the noise outside image frequency ingredient and band, then analog signal is modulated to required load through upper frequency mixer
On wave, after power output required for being guaranteed after the synthesis of the road I and Q by driving amplifier and power amplifier, by coupler
It is issued with antenna；Antenna receives the label signal returned and is received through coupler by down-conversion mixer, and same with phaselocked loop generation is believed
Number and orthogonal signalling mixing after generate base band the road I signal and the road Q signal；The road the I signal and the road Q signal of base band are handed over by capacitor
Stream coupling after, successively through amplifier amplification, second filter filtering and Analog-digital Converter, become digital baseband I road signal and
The road digital baseband Q signal；After digital baseband I road signal and the road digital baseband Q signal channel filter filter out interference and noise,
Label return signal is found by frame head decision circuitry, is completed by energy detection circuit to digital baseband I road signal and digital base
Energy measuring with the road Q signal, and tell microcontroller currently collected digital baseband I road signal and the road digital baseband Q letter
Number the energy corresponding time；
The measurement method includes the following steps:
(1) when system receives label in the return signal of position 1, energy detection circuit calculates the road digital baseband I signal
With the energy of the road digital baseband Q signal, it is recorded as S respectivelyV_iAnd SV_q, and current time t is reported to microcontroller1；
(2) microcontroller calculates amplitude A when label is in current location1And angle, θ1；Wherein, A1=sqrt (SV_i 2+
SV_q 2), θ1=arctan (SV_q/SV_i)；
(3) return signal of the label to be received such as system in position 2 enters step (2) if receiving return signal；
If do not received return signal, then continue waiting for；
(4) label is recorded in the return signal of position 2 and calculates energy, is recorded as S respectivelyV_iAnd SV_q, and microcontroller
Device reports current time t2；Microcontroller calculates amplitude A when label is in current location2And angle, θ2, A2=sqrt (SV_i 2+
SV_q 2), θ2=arctan (SV_q/SV_i)；
(5) if A2Greater than A1, then label is mobile towards reading and writing device antenna direction；If A2Less than A1, then label deviates from reader
Antenna direction is mobile；Label movement speed ν=(θ2-θ1)*(λ/(2*π))/(t2-t1), λ is the wavelength of carrier wave.
Signal of the label return signal in reader receiving end at position 1 can indicate are as follows: A1(1+cos(ωtagt))cos(ωct+θ1), by orthogonal lower mixing frequency, direct current and high fdrequency component are filtered out, I the and Q roadbed band signal of output is sat in pole
S is expressed as in mark systemV_ i=A/2*cos (ωtagT) * sin (- θ) and SV_ q=A/2*cos (ωtagt)*cos(-θ)；
Therefore polar amplitude is A1For SV_iAnd SV_qSquare root, angle, θ1For SV_q/SV_iArc tangent.Work as label
It is moved to position 2, if corresponding polar amplitude A2Greater than A1, then label is mobile towards the direction of reading and writing device antenna, conversely,
The direction for leaving reading and writing device antenna is mobile；In addition, corresponding polar angle is θ when label is moved to position 22, then
In conjunction with digital baseband transmission system partial report, in the time of each position, (time of position 1 is recorded as t out1, position 2 when
Between be recorded as t2, so the speed of label movement is ν=(θ2-θ1)*(λ/(2*π))/(t2-t1).λ is the corresponding wavelength of carrier wave.
Application of the above method in vehicle electron identifying and traffic monitoring is also within protection scope of the present invention.
The utility model has the advantages that
Compared with prior art, the present invention, which can solve existing UHF RFID reader, does not have method to go to measure passive mark
The problem of speed and moving direction of label.And the method for the present invention precise and high efficiency, it is simple and easy, it is suitable for large-scale promotion.
Detailed description of the invention
Fig. 1 traditional passive UHF RFID system schematic diagram；
Hardware circuit diagram Fig. 2 of the invention；
The polar coordinates schematic diagram of Fig. 3 I and Q roadbed band signal；
Algorithm flow chart Fig. 4 of the invention.
Specific embodiment
Embodiment 1
In traditional passive UHF RFID system shown in Fig. 1, passive label is with some speed towards reading and writing device antenna
Or the movement of reading and writing device antenna direction is left, traditional UHF RFID reader does not have method to go to measure the speed of passive label
And moving direction.
The invention proposes one to apply the speed of measurement mobile tag and side in passive UHF RFID reader system
To algorithm, as Fig. 2 provides the hardware circuit diagram of this method embodiment.
Wherein, UHF RFID reader includes radio frequency receiving and transmitting front end, digital baseband transmission system and microcontroller, fortune
It is as relationship:
1, the base encoded required for generating of the transmitting baseband Data Profile filter in digital baseband transmission system part
Band data give D/A conversion circuit and become analog signal, the baseband filter by simulation filter out image frequency ingredient and
Analog baseband signal is modulated on required carrier wave by the noise outside band, upper frequency mixer, then passes through drive after the synthesis of the road I and Q
Power output required for dynamic amplifier and power amplifier guarantee；
2, the subsequent coupler of power amplifier completes transmission duplex；
3, down-conversion mixer receives the same phase (sin (ω that the return signal from label is generated with phaselocked loopc) and orthogonal letter t)
Number (cos (ωcT)) mixing generates the I and Q signal of base band, and after capacitor AC coupled, baseband I and Q signal are respectively through over-discharge
Greatly, filtering and analog-to-digital conversion change into digital baseband signal；
4, digital baseband I and Q signal filter out interference and noise outside signal bandwidth by channel model, are sentenced by frame head
Deenergizing once finds label return signal, and energy detection circuit completes the energy measuring of I and Q signal, the road I and Q signal energy
It is denoted as S respectivelyV_ i and SV_ q, and tell microcontroller currently collected I and Q signal energy corresponding time；
5, microcontroller receives the signal S from the road digital baseband I and QV_ i and SV_q；
6, the operation present invention proposes algorithm, can calculate speed and the direction of mobile tag.
A) signal of the label return signal at position 1 in reader receiving end can indicate are as follows: A1(1+cos(ωtagt))cos(ωct+θ1), by orthogonal lower mixing frequency, direct current and high fdrequency component are filtered out, I the and Q roadbed band signal of output is sat in pole
S is expressed as in mark systemV_ i=A/2*cos (ωtagT) * sin (- θ) and SV_ q=A/2*cos (ωtagt)*cos(-θ)；Pole
Indicate that the road I and Q signal is as shown in Figure 3 in coordinate system；
B) therefore polar amplitude is A1For SV_iAnd SV_qSquare root, angle, θ1For SV_q/SV_iArc tangent.Work as mark
Label are moved to position 2, if corresponding polar amplitude A2Greater than A1, then label is mobile towards the direction of reading and writing device antenna, instead
It, the direction for leaving reading and writing device antenna is mobile；In addition, when label is moved to position 2, corresponding polar angle is
θ2, in conjunction with digital baseband transmission system partial report, in the time of each position, (time of position 1 is recorded as t out1, position 2
Time be recorded as t2, so the speed of label movement is ν=(θ2-θ1)*(λ/(2*π))/(t2-t1).λ is the corresponding wave of carrier wave
It is long.
C) the calculating label moving direction and speed run in microcontroller can be carried out according to following algorithm flow, such as be schemed
4:
I. when label has return signal in position 1, digital baseband calculates the signal energy of I and Q, is recorded as S respectivelyV_iWith
Sv_q, and report current time t1；
Ii. microcontroller calculates the amplitude A of current location1And angle, θ1, and save A1=sqrt (SV_i^2+SV_q^2),
θ1=arctan (SV_q/SV_i)；
Iii. it waits digital baseband reporting tag in the signal energy of position 2, if there is signal energy, enters in next step；
If being continued waiting for without signal energy；
Iv. the I and Q signal energy that digital baseband is reported out are SV_I and SV_q, and current time is t2；
V. microcontroller calculates the amplitude A of current location2And angle, θ2, and save A2=sqrt (SV_i^2+SV_q^2),
θ2=arctan (SV_q/SV_i)；
Vi. if A2Greater than A1, label is mobile towards reading and writing device antenna direction, otherwise mobile away from reading and writing device antenna direction；
Label movement speed: ν=(θ2-θ1)*(λ/(2*π))/(t2-t1)。
Embodiment 2
The passive UHF RFID tag movement speed of above-mentioned measurement and the method in direction can be applicable in vehicle electron identifying: every
Automobile has pasted passive electronic label, and the reader equipment at crossing can measure movement speed and direction by electronic tag
Information, so that it may fully known traffic flow information, it is known that whether get congestion or traffic accident, if having more vehicles into
Enter or leave some crossing, if need to adjust anti-collision algorithm and remove the electronic mark for accurately reading each automobile, thus real
The management of existing intelligent transportation.
Claims (2)
1. a kind of method for measuring passive UHF RFID tag movement speed and direction, which is characterized in that including a measurement nothing
The system of source UHF RFID tag movement speed and direction, the system include two transmitting baseband Data Profile filters, the road I letter
Number and the road Q signal become to simulate through D/A conversion circuit after different transmitting baseband Data Profile filter outputs respectively
Signal simultaneously filters off the noise outside image frequency ingredient and band by first filter, then analog signal is modulated to institute through upper frequency mixer
On the carrier wave needed, after power output required for being guaranteed after the synthesis of the road I and Q by driving amplifier and power amplifier,
It is issued by coupler and antenna；Antenna receives the label signal returned and is received through coupler by down-conversion mixer, generates with phaselocked loop
In-phase signal and orthogonal signalling mixing after generate base band the road I signal and the road Q signal；The road the I signal and the road Q signal of base band are logical
After crossing capacitor AC coupled, successively through amplifier amplification, second filter filtering and Analog-digital Converter, become digital baseband I
Road signal and the road digital baseband Q signal；Digital baseband I road signal and the road digital baseband Q signal channel filter filter out interference
After noise, label return signal is found by frame head decision circuitry, is completed by energy detection circuit to digital baseband I road signal
With the energy measuring of the road digital baseband Q signal, and microcontroller currently collected digital baseband I road signal and digital base are told
The energy corresponding time with the road Q signal；
The measurement method includes the following steps:
(1) when system receives label in the return signal of position 1, energy detection circuit calculates the road digital baseband I signal sum number
The energy of the road word base band Q signal, is recorded as S respectivelyV_iAnd SV_q, and current time t is reported to microcontroller1；
(2) microcontroller calculates amplitude A when label is in current location1And angle, θ1；Wherein, A1=sqrt (SV_i 2+SV_q 2),
θ1=arctan (SV_q/SV_i)；
(3) return signal of the label to be received such as system in position 2 enters step (4) if receiving return signal；As not
Return signal is received, then is continued waiting for；
(4) label is recorded in the return signal of position 2 and calculates energy, is recorded as S respectivelyV_iAnd SV_q, and microcontroller report
Accuse current time t2；Microcontroller calculates amplitude A when label is in current location2And angle, θ2, A2=sqrt (SV_i 2+
SV_q 2), θ2=arctan (SV_q/SV_i)；
(5) if A2Greater than A1, then label is mobile towards reading and writing device antenna direction；If A2Less than A1, then label deviates from reading and writing device antenna
Direction is mobile；Label movement speed ν=(θ2-θ1)*(λ/(2*π))/(t2-t1), λ is the wavelength of carrier wave.
2. the passive UHF RFID tag movement speed of measurement described in claim 1 and the method in direction in vehicle electron identifying and
Application in traffic monitoring.
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| CN201511028758.7A CN105572413B (en) | 2015-12-31 | 2015-12-31 | A kind of method and application measuring passive UHF RFID tag movement speed and direction |
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| CN110266340B (en) * | 2019-06-03 | 2021-06-04 | 北京智博晟源科技有限公司 | Passive UHFRFID reader-writer structure and method for rapidly intercepting interference signals |
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| JP2008199411A (en) * | 2007-02-14 | 2008-08-28 | Omron Corp | Frequency switcher, rfid system and distance measuring apparatus incorporating the frequency switcher |
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| US9195862B2 (en) * | 2011-01-14 | 2015-11-24 | Siemens Aktiengesellschaft | Radio frequency identification reader and a method for locating a tag by the radio frequency identification reader |
| CN202196417U (en) * | 2011-05-24 | 2012-04-18 | 中兴通讯股份有限公司 | Radio frequency identification reader module |
| CN205353113U (en) * | 2015-12-31 | 2016-06-29 | 智坤（江苏）半导体有限公司 | System for measure passive UHF RFID label translation rate and direction |
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Effective date of registration: 20220617 Address after: No.9 Mintai Avenue, Yizheng Economic Development Zone, Yangzhou City, Jiangsu Province Patentee after: ZHI KUN (JIANGSU) SEMICONDUCTOR Co.,Ltd. Address before: 211400 No. 9, Mintai Avenue, Yizheng Economic Development Zone, Yizheng City, Yangzhou City, Jiangsu Province Patentee before: ZHI KUN (JIANGSU) SEMICONDUCTOR Co.,Ltd. Patentee before: Shanghai Zhikun Semiconductor Co., Ltd |
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