CN102183760A - Location method based on power scanning of radio frequency identification (RFID) reader-writer antenna - Google Patents
Location method based on power scanning of radio frequency identification (RFID) reader-writer antenna Download PDFInfo
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Abstract
本发明公开了一种基于RFID读写器天线功率扫描的定位方法。首先建立读写器天线功率与其感测范围直径的关系模型，然后基于此提出根据功率扫描的定位估计算法。在监控区域放置若干个RFID天线，通过多个天线功率扫描对同一目标标签进行状态读取，进而根据天线的辐射图在平面上的相交区域来确定目标标签。本发明在以标签为定位目标的基础上，以UHF RFID标签定位系统进行试验，结果证明本方法进一步提高了UHF RFID标签定位系统的定位精度，且根据目标标签的位置实时调节天线的功率，降低了定位系统的能耗。
The invention discloses a positioning method based on antenna power scanning of an RFID reader-writer. First, the relationship model between the reader antenna power and the diameter of the sensing range is established, and then a location estimation algorithm based on power scanning is proposed based on this. Place several RFID antennas in the monitoring area, read the status of the same target tag through multiple antenna power scans, and then determine the target tag according to the intersection area of the radiation pattern of the antenna on the plane. The present invention uses the UHF RFID tag positioning system to test on the basis of the tag as the positioning target. The results prove that the method further improves the positioning accuracy of the UHF RFID tag positioning system, and adjusts the power of the antenna in real time according to the position of the target tag, reducing the energy consumption of the positioning system.
Description
Technical field
The present invention relates to fields such as automatic positioning technology, radio-frequency (RF) identification (RFID) technology and Internet of Things, especially based on the tag location technology of RFID.
Background technology
Along with the development of wireless network and the appearance of ubiquitous calculating, increasing application need is known the positional information of object, and automatic positioning technology more and more is subjected to people's attention.Existing indoor automatic station-keeping system mainly contains infrared ray, IEEE802.11, ultrasound wave and RFID, these positioning systems respectively have advantage, compare with other technologies, the RFID technology utilize contactless automatic identification, accommodative ability of environment strong, swift to operate, can discern high-speed moving object and multiple goal and advantage such as read and receive much concern.On the other hand, along with the proposition and the development of Internet of Things, RFID is widely used in fields such as logistics, asset management, medical treatment, retail as one of its gordian technique, and its location technology also becomes the focus of people's research.
With regard to present progress, with regard to present progress, have much based on the localization method of RFID, use precision that the RFID of different frequency range can arrive also without identical.Generally, can be divided into two classes based on the RFID targeting scheme: tag location scheme and read write line targeting scheme.Wherein, the former as localizing objects, read write line and relevant reference label are come the position of estimating target label as being distributed in guarded region with reference to point by the known location of read write line and reference label with label; As localizing objects, a large amount of reference label are distributed in guarded region to the latter with read write line, and the position of each reference label is corresponding with its ID number, and the target read write line is determined its position by reading these reference label.The research of at present most RFID location technology mainly concentrates on the read write line positioning system, and reaches comparatively ideal bearing accuracy, and existing UHF rfid interrogator positioning system bearing accuracy when the 60cm of reference label interval can reach below the 30cm.
Need to such an extent that be pointed out that: all there is limitation separately in above-mentioned two kinds of technology paths.The read write line positioning system needs a large amount of reference label, and be merely able to locate the object that rfid interrogator is housed, and general read write line cost height and volume are big, therefore, similar system is not suitable for the location of voluminous object and the location of little article, and its application scenarios is subjected to great restriction.Though effectively avoided these problems in the tag location system, the bearing accuracy of present tag location system is not ideal enough, and existing UHF RFID tag location system accuracy has only 1.6m.
Summary of the invention
In view of the deficiency of the existing program of above statement, the present invention aims to provide a kind of flexible, high-precision RFID tag location method, as localizing objects, has reduced the cost of system with label, and localizing objects is not limited by body form, and is applicable to the multiple goal location; Do not need reference label, reduced the complexity of system, this method is applied to UHF RFID object locating system can realize that bearing accuracy is below 30cm.
Purpose of the present invention realizes by following means.
A kind of localization method based on the scanning of rfid interrogator antenna power, by rfid interrogator based on adjustable power, the RFID positioning system that at least two poliarizing antennas that are connected with described rfid interrogator (RFID antenna) and some target labels constitute; Poliarizing antenna by being positioned over different directions reads the target labels state in the process that changes power, and described target labels state Input Data Process is calculated each antenna come the position of estimating target label in the center of intersection region in the plane.
The inventive method has following advantage: on the basis that does not need reference label, the power sensing by regulating a plurality of antennas is to target labels, under the prerequisite of the dirigibility of positioning system, improved the bearing accuracy of tag location system greatly; If the locating area size changes, only need corresponding rfid interrogator of increase and RFID antenna can increase guarded region, simple to operate efficient.
Description of drawings is as follows:
Fig. 1. system architecture schematic diagram of the present invention.
Fig. 2. concrete enforcement example of the present invention.
Fig. 3. positioning principle figure of the present invention: (a) two antennas; (b) three antennas.
Fig. 4. antenna power and its sensing range diameter Relationship model.
Fig. 5. the experimental result of two Antenna Positioning: (a) scatter diagram of target location and estimated position; (b) error of coordinate between target location and estimated position.
Fig. 6. influence the factor of Antenna Positioning: (a) the different antennae number is to affect positioning; (b) antenna power changes step-length to affect positioning.
Embodiment
Below in conjunction with accompanying drawing enforcement of the present invention is further described.
As shown in Figure 1, positioning system 100 has comprised the RFID label (101 of a plurality of needs location
1～101
N), main control computer 102, a plurality of rfid interrogator (103
1～103
N), corresponding a plurality of antennas (106
11～106
1NBy read write line 103
1Control; 106
N1～106
NNBy read write line 103
NControl), rfid interrogator adopt antenna gain adjustable or fixedly output power add the adjustable attenuator antenna and finish power scan, be that antenna need have gain (or output power) adjustable function (also can adopt fixing output antenna to add adjustable attenuator and form, promptly 104 and 105).The quantity of noting the antenna amount of rfid interrogator control and antenna positioned area size and needed bearing accuracy as required can be adjusted.Related similar system structure and principle are also in this patent covering scope.
Guarded region is carried out five equilibrium according to the maximum sensing diameter of RFID read-write system, in each zonule, two or more RFID antennas is separately fixed at the center of the different length of sides of zonule, a summit with guarded region is that true origin is set up rectangular coordinate system, notes the coordinate of each antenna.Change the power of read write line single port at first gradually, and measure the maximum distance that read write line can read under each power (direction on vertical antenna plane), set up the relational model of antenna power and maximum read distance; Secondly, for the target labels in the guarded region, change the power of each antenna respectively, just in time can read target labels up to each antenna, record this moment each antenna port performance number, and the maximum that substitution antenna power and the model that reads distance are obtained the current power of each antenna reads radius; Make at last the plane propagation model of antenna according to the coordinate position of the sensing diameter of antenna and antenna, the center of calculating the plane propagation model intersecting area of each antenna is the estimated position of target labels.
The experimental system of the inventive method is that the zone of 400cm*400cm constitutes by the UHF rfid interrogator of one four antenna port, two UHF RFID antennas (XCAF-12L), target labels and area, wherein each antenna port adjustable power of rfid interrogator.
Show as Fig. 2, at first two antennas be separately fixed on the both sides of guarded region and (, can between read write line and antenna, add adjustable attenuator) that the coordinate of antenna is respectively (210,0) and (0,230) (unit be centimetre) for the fixing read write line of power; Then target labels is placed in the guarded region at random, measures after deployment is finished and set up the output power of antenna port and the relational model of antenna sensing range.By above-mentioned introduction as can be known, the maximum read distance of antenna is along the dead ahead perpendicular to antenna surface.Antenna port power to x axle and y axle both direction is step change with 1dBm respectively, measure the value of 10dBm to the interior maximum read distance of 17dBm scope, at last the measured value of each power is asked on average, and the relation of deriving power and sensing diameter by curve fitting as shown in Figure 4, that is:
D(p)＝38.71p-319.37 (1)
D (p) expression sensing diameter wherein, i.e. the diameter of antenna pattern (cm) under the current power, p represents the power (dBm) of antenna.
Based on power---sensing diameter model can position estimation to the target labels in the guarded region.At first, the power that changes the antenna on the x direction of principal axis is gradually write down the performance number p of this moment up to sensing target labels
x, similarly, change the antenna power on the y direction of principal axis and write down the minimal power values p that senses target labels
ySecondly, with p
xAnd p
ySubstitution formula (1) obtains the diameter D of antenna pattern
xAnd D
yAt last, make the radiation pattern of two antenna current power respectively and less than the radiation pattern of current power 0.5dBm by antenna coordinate, center of circle direction and diameter, as shown in Figure 2, can try to achieve intersecting area by formula (2), calculate this regional center get final product the estimated position of impact point.Be the feasibility of proof scheme, we have carried out ten experiments, and experimental result is illustrated in fig. 5 shown below, and (a) is diffusing some distribution plan of target location and estimated position, (b) is the error of coordinate curve of estimated position.
According to the such scheme principle, we have done further analysis to the precision influence factor of targeting scheme.Simulation result shows that three Antenna Positioning are significantly improved than two Antenna Positioning, shown in Fig. 6 (a).Then, antenna be not many more might as well, three antennas that are positioned of four antennas of presentation of results of Fig. 6 (a) are compared and are had only less improvement, if consider the cost of system, the targeting scheme of three antennas should be optimal selection.The presentation of results of Fig. 6 (b) reduces the change step-length of antenna power, can further improve system accuracy.
According to basic scheme of the present invention, multiple different selection when implementing, reality can be arranged also.For example: target labels can be passive label or active label; Antenna can be circular polarized antenna, linear polarized antenna or the combination of the two; Antenna can be high frequency (HF, 13.54MHz), ultrahigh frequency (UHF, 850MHz～910MFz) and microwave (2.45GHz) frequency range; An available rfid interrogator with at least two antenna ports also can be made of the reading and writing device system of two single antenna ports at least.
In sum, major advantage of the present invention has following 3 points: (1) based on the RFID tag location system enhancement of power scan the precision of existing tag location system, three antennas can realize that precision is the location in the 30cm, and the step-length that reduces variable power can further improve precision; (2) need not reference label, make targeting scheme simply efficient, and be applicable to guarded region and different types of rfid system (as the rfid system of active label) that scene changes; (3) size of guarded region can change flexibly, only needs corresponding rfid interrogator of interpolation and RFID antenna can increase guarded region, and is simple to operate efficient; (4) power of each antenna of system changes according to the difference of target labels, can effectively reduce the power consumption of system.
Claims (8)
1. localization method based on rfid interrogator antenna power scanning, by rfid interrogator based on adjustable power, the RFID positioning system of at least two poliarizing antennas that are connected with described rfid interrogator and some target labels formation; Poliarizing antenna by being positioned over different directions reads the target labels state in the process that changes power, and described target labels state Input Data Process is calculated each antenna come the position of estimating target label in the center of intersection region in the plane.
2. the localization method based on rfid interrogator antenna power scanning according to claim 1, it is characterized in that, may further comprise the steps: the center that at least two poliarizing antennas is separately fixed at the different edge of guarded region, a summit with described guarded region is that true origin is set up rectangular coordinate system, notes the coordinate of each antenna; Change the power of read write line single port afterwards gradually and measure the maximum distance that read write line can read under each power, set up the relational model of antenna power and maximum read distance; Secondly, for the target labels in the guarded region, change the power of each antenna respectively, just in time can read target labels up to each antenna, record this moment each antenna port performance number, and the maximum that substitution antenna power and the model that reads distance are obtained the current power of each antenna reads radius; Make at last the plane propagation model of antenna according to the coordinate position of the sensing diameter of antenna and antenna, the center of calculating the plane propagation model intersecting area of each antenna is the estimated position of target labels.
3. according to claim 1 or 2 described localization methods, it is characterized in that, three poliarizing antennas are set in a guarded region based on the scanning of rfid interrogator antenna power.
4. the localization method based on rfid interrogator antenna power scanning according to claim 1 is characterized in that, described rfid interrogator adopt antenna gain adjustable or fixedly output power add the adjustable attenuator antenna and finish power scan.
5. the localization method based on rfid interrogator antenna power scanning according to claim 1 is characterized in that described target labels can be passive label or active label.
6. the localization method based on rfid interrogator antenna power scanning according to claim 4 is characterized in that described antenna can be high frequency, ultrahigh frequency and microwave frequency band.
7. the localization method based on rfid interrogator antenna power scanning according to claim 4 is characterized in that described antenna can be circular polarized antenna, linear polarized antenna or the combination of the two.
8. the localization method based on rfid interrogator antenna power scanning according to claim 1 is characterized in that the rfid interrogator with at least two antenna ports also can be made of the reading and writing device system of two single antenna ports at least.
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Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103839092A (en) * | 2014-03-06 | 2014-06-04 | 太仓欧卡网络服务有限公司 | Ultrahigh-frequency RFID reader-writer |
| CN104597427A (en) * | 2014-12-04 | 2015-05-06 | 广东技术师范学院 | Locating method and system for passive UHF type RFID variable power |
| CN105093216A (en) * | 2014-05-19 | 2015-11-25 | 深圳德创投科技有限公司 | Electronic label positioning method and electronic label positioning device |
| CN104198990B (en) * | 2014-09-23 | 2017-05-10 | 天津工业大学 | RFID (radio frequency identification devices) positioning system capable of expanding positioning range |
| CN109727475A (en) * | 2017-10-27 | 2019-05-07 | 中移（杭州）信息技术有限公司 | Vehicle search method, device and communication device based on parking lot |
| CN109978098A (en) * | 2019-03-30 | 2019-07-05 | 浙江清华长三角研究院 | Gap bridge fitting identifying system based on RFID |
| CN111929636A (en) * | 2020-06-16 | 2020-11-13 | 宜宾电子科技大学研究院 | Intelligent identification and marking positioning method for metal container |
| CN112084800A (en) * | 2019-06-12 | 2020-12-15 | 芯恩（青岛）集成电路有限公司 | Passive electronic tag positioning device and method based on RFID |
| CN112560524A (en) * | 2020-12-23 | 2021-03-26 | 上海岚盛电子科技有限公司 | Archival repository RFID track monitoring system |
| CN113705264A (en) * | 2020-05-22 | 2021-11-26 | 技嘉科技股份有限公司 | Identification tag reading system |
| CN113923589A (en) * | 2021-09-24 | 2022-01-11 | 郑州大学 | Non-contact multi-target positioning method |
| CN118070822A (en) * | 2023-11-06 | 2024-05-24 | 江苏云涌电子科技股份有限公司 | Step-by-step positioning method based on ultrahigh frequency RFID tag |
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|---|---|---|---|---|
| CN103839092A (en) * | 2014-03-06 | 2014-06-04 | 太仓欧卡网络服务有限公司 | Ultrahigh-frequency RFID reader-writer |
| CN103839092B (en) * | 2014-03-06 | 2017-10-27 | 太仓欧卡网络服务有限公司 | A kind of ultrahigh frequency radio frequency identification (RFID) reader |
| CN105093216A (en) * | 2014-05-19 | 2015-11-25 | 深圳德创投科技有限公司 | Electronic label positioning method and electronic label positioning device |
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| CN104198990B (en) * | 2014-09-23 | 2017-05-10 | 天津工业大学 | RFID (radio frequency identification devices) positioning system capable of expanding positioning range |
| CN104597427A (en) * | 2014-12-04 | 2015-05-06 | 广东技术师范学院 | Locating method and system for passive UHF type RFID variable power |
| CN104597427B (en) * | 2014-12-04 | 2017-07-18 | 广东技术师范学院 | Passive UHF type RFID Variable powers localization method and system |
| CN109727475A (en) * | 2017-10-27 | 2019-05-07 | 中移（杭州）信息技术有限公司 | Vehicle search method, device and communication device based on parking lot |
| CN109978098A (en) * | 2019-03-30 | 2019-07-05 | 浙江清华长三角研究院 | Gap bridge fitting identifying system based on RFID |
| CN109978098B (en) * | 2019-03-30 | 2022-04-15 | 浙江清华长三角研究院 | RFID-based bridge fitting identification system |
| CN112084800A (en) * | 2019-06-12 | 2020-12-15 | 芯恩（青岛）集成电路有限公司 | Passive electronic tag positioning device and method based on RFID |
| CN113705264A (en) * | 2020-05-22 | 2021-11-26 | 技嘉科技股份有限公司 | Identification tag reading system |
| CN113705264B (en) * | 2020-05-22 | 2025-05-16 | 技嘉科技股份有限公司 | Identification tag reading system |
| CN111929636A (en) * | 2020-06-16 | 2020-11-13 | 宜宾电子科技大学研究院 | Intelligent identification and marking positioning method for metal container |
| CN111929636B (en) * | 2020-06-16 | 2024-03-26 | 宜宾电子科技大学研究院 | Intelligent identification and marking positioning method for metal container |
| CN112560524A (en) * | 2020-12-23 | 2021-03-26 | 上海岚盛电子科技有限公司 | Archival repository RFID track monitoring system |
| CN113923589A (en) * | 2021-09-24 | 2022-01-11 | 郑州大学 | Non-contact multi-target positioning method |
| CN113923589B (en) * | 2021-09-24 | 2023-05-23 | 郑州大学 | Non-contact type multi-target positioning method |
| CN118070822A (en) * | 2023-11-06 | 2024-05-24 | 江苏云涌电子科技股份有限公司 | Step-by-step positioning method based on ultrahigh frequency RFID tag |
| CN118070822B (en) * | 2023-11-06 | 2024-08-13 | 江苏云涌电子科技股份有限公司 | Step-by-step positioning method based on ultrahigh frequency RFID tag |
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Application publication date: 20110914 |