CN106355899B

CN106355899B - Parking lot vehicle sensing and positioning system based on passive UHF RFID

Info

Publication number: CN106355899B
Application number: CN201610989350.4A
Authority: CN
Inventors: 孙增娜
Original assignee: Shanghai Randong Electronic Technology Co ltd
Current assignee: Shanghai Randong Electronic Technology Co ltd
Priority date: 2016-11-10
Filing date: 2016-11-10
Publication date: 2023-01-20
Anticipated expiration: 2036-11-10
Also published as: CN106355899A

Abstract

The invention discloses a parking lot vehicle sensing and positioning system based on a passive UHF RFID, which comprises an automobile electronic identifier, an UHF antenna, an UHF RFID read-write device, a network switch, a server computer and a background visual system, wherein the UHF antenna is connected with the UHF RFID read-write device through a feeder line, the UHF RFID read-write device is connected with the server computer through the network switch, and the background visual system is also connected with the server computer. The UHF RFID technology is adopted, so that the problem of high construction cost in the existing parking lot based on the camera shooting infrared scheme and other schemes can be solved; the problem that a certain automobile electronic identification cannot be accurately positioned due to drift of a plurality of label reflection signals in the common UHF RFID technology can be solved. The invention shortens the passing time of the automobile at the door of the parking lot, accurately positions the position information of the automobile in the parking lot, increases the reverse automobile searching function and shortens the time for searching the parking space by the automobile. The method is accurate, efficient, low in cost, simple and feasible, and suitable for large-scale popularization.

Description

Parking lot vehicle sensing and positioning system based on passive UHF RFID

Technical Field

The invention relates to a positioning system, in particular to a passive UHF RFID-based parking lot vehicle sensing and positioning system.

Background

The construction of traffic infrastructure and the management of vehicle safety are increasingly important issues facing each urban construction planner. The intelligent parking lot is suitable for various public places (communities, enterprises, government offices, airports, railway stations, hotels, supermarkets and the like). The problems of difficult parking and difficult parking management generally exist in the places, particularly, the contradictions among high-grade communities, enterprises and government agencies are increasingly prominent, the parking management is vulnerable, and the dispute between an owner and a property management party is continuous. The RFID parking lot application can effectively solve the problems, so that car owners have a more convenient and comfortable parking environment, and the work of a parking lot management department is more perfect and easier. Not only can establish brand-new property management image, but also can strictly and meticulously charge management flow and effectively strengthen the safety management of vehicles.

The RFID intelligent parking lot is generated based on the mature development and the successful application of the RFID technology which is popular internationally and is regarded as the industry in China gradually. The characteristics of non-preventability, anti-interference performance, anti-impact performance, quick identification performance, intelligent identification performance and the like of the parking lot are undoubtedly provided with a brand-new solution for various parking lot management

RFID (radio frequency identification) is a non-contact automatic identification technology, which automatically identifies a target object by a radio frequency signal and acquires related data. The identification work does not need manual intervention and can work in various severe environments. The RFID technology can identify single and multiple labels at high speed, and is quick and convenient to operate. The RFID has the characteristics of large data capacity, long identification distance, identification of a plurality of targets at one time, global unique codes of each label and the like, and is widely applied to various industries.

At present, based on a lot of parking lot vehicle sensing schemes, the sensing schemes are divided into the following four main categories according to different transmission media: the system comprises a geomagnetic coil perception scheme, an infrared perception scheme, a full-video intelligent perception scheme and a radio frequency identification perception scheme.

Geomagnetic effect is used to the earth magnetism coil perception scheme, has or not the vehicle on judging the parking stall through detecting earth magnetism coil top metal object, nevertheless to ripe parking area, if this system of installation, need at the ground fluting construction wiring, greatly increased the system installation degree of difficulty.

The biggest problem that infrared ray perception scheme exists is, if have when relevant personnel or object stop on the parking stall, also can judge that there is the vehicle in the parking stall, and the erroneous judgement rate improves greatly.

The most widely applied at present is a full-video intelligent perception scheme. However, the following problems of the full video perception scheme also cause the popularization difficulty to be greatly increased. Firstly, the cost is too high, one high-definition camera needs to be equipped in every three parking spaces, and the cost of one high-definition camera is more than ten thousand yuan; secondly, the reaction speed is low, and a large number of arithmetic machines are consumed for uninterruptedly and intelligently identifying the images of thousands of parking spaces; thirdly, due to the influence of factors such as environment, illumination and weather, the number plate recognition rate is low, and illegal behaviors such as fake plate fake-set, intentionally shielded number plate and the like cannot be effectively distinguished through video image recognition. Therefore, the parking space sensing system based on video intelligent identification is not widely applied in China.

A radio frequency sensing scheme. The parking cards currently applied in the radio frequency sensing scheme are mainly classified into passive IC cards, passive IC middle distance cards, active 2.4G cards and the like. The passive IC card only plays a charging role when the card is swiped in and out of a parking lot at a short distance, the passive IC card can only be used in a fixed mature community, and the active 2.4G card has the problem of battery service life and the like. The most direct problem is that all applications based on the cards are concentrated in a parking lot entrance and exit access control system, are not bound with vehicles one by one, and are not expanded in the vehicle positioning of a parking lot. The automobile electronic identification scheme based on the passive UHF RFID technology comprises the following steps:

the passive UHF RFID technology is a technology which is more advanced in a radio frequency perception scheme and accords with market trend. The UHF RFID radio frequency identification technology is applied to the automobile, so that the automobile can be sensed in time, and the urban traffic dynamic and parking space static identification intelligentization can be realized. The RFID technology is applied to automobiles, an electronic tag is arranged on the automobile, the automobile can be sensed in time, relevant data can be collected, sorted and analyzed in real time, and the problems of automatic identification, dynamic monitoring, accurate flow prediction and the like of the automobile in a parking lot are effectively solved.

At present, 6 industrial standards related to the automobile electronic identification (namely, the automobile electronic identification is upgraded to the national standard) based on national standard GB/T29768-2013, which are introduced by the ministry of public security, are being formulated and perfected, wherein the standards comprise automobile electronic identification safety technical requirements, automobile electronic identification general technical conditions, automobile electronic identification installation specifications, automobile electronic identification read-write equipment general technical conditions, automobile electronic identification read-write equipment safety technical requirements and automobile electronic identification read-write equipment installation specifications. The automobile electronic identification project has high requirements on the ultrahigh frequency RFID technology, and is forcedly deployed nationwide in a unified manner to cover more than 2 hundred million automobiles nationwide, so that the project becomes the largest Internet of things project worldwide.

At present, the electronic automobile identifier conforming to the international EPC standard is applied to parking lots in various places in a small-scale mode, but the technology is not formed in a large scale, and is only applied to an import and export management system of the parking lots. With the development of automobile electronic identification projects based on Chinese national standards, automobile electronic identifications are installed on each automobile in the future, and how to expand the automobile electronic identifications to be applied to a parking space sensing and positioning system in a parking lot is the problem to be solved by the system.

Disclosure of Invention

The invention aims to provide a parking lot vehicle sensing and positioning system based on a passive UHF RFID (ultra high frequency radio frequency identification device), so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme:

a parking lot vehicle sensing and positioning system based on a passive UHF RFID comprises an automobile electronic identifier, an UHF antenna, an UHF RFID read-write device, a network switch, a server computer and a background visual system, wherein the UHF antenna is connected with the UHF RFID read-write device through a feeder line, the UHF RFID read-write device is connected with the server computer through the network switch, and the background visual system is also connected with the server computer; the RSSI technology of the UHF RFID is adopted to effectively judge the distance and the movement trend from the automobile electronic identifier to the UHF antenna connected to the UHF RFID read-write equipment by judging and comparing the variation trend and the energy intensity of the reflected signal of the automobile electronic identifier received by each UHF antenna.

As a further scheme of the invention: the RSSI technology of the UHF RFID reading and writing equipment can effectively judge the distance and the direction from the automobile electronic identification to the UHF antenna connected to the UHF RFID reading and writing equipment end.

As a further scheme of the invention: the antenna array technology in the UHF antenna can effectively judge the specific direction of the automobile electronic mark in the space.

As a still further scheme of the invention: the automobile electronic identification is an ultrahigh frequency RFID anti-disassembly ceramic label and consists of release paper, an adhesive layer, a ceramic layer, an antenna layer, an SOT packaged ultrahigh frequency RFID chip, a PVC shell and a surface printing layer from bottom to top.

Compared with the prior art, the invention has the beneficial effects that:

the ultrahigh frequency RFID anti-dismantling ceramic label is adopted, so that the label is prevented from being transferred and cannot be reused, physical anti-counterfeiting and software anti-counterfeiting of the label are realized, and the safety is high;

by adopting an RSSI (received Signal Strength Indication) technology in the UHF RFID, the distance and the movement trend from the automobile electronic identifier to the UHF antenna connected to the UHF RFID read-write equipment end are effectively judged by judging and comparing the variation trend and the energy intensity of the reflected Signal of the automobile electronic identifier received by each UHF antenna.

The antenna array technology in the UHF antenna is adopted to reduce and control the coverage angle and range of each antenna, thereby effectively judging a specific direction of the automobile electronic mark in space.

The RSSI technology and the antenna array technology are combined, so that the problems that the coverage range of an antenna is not accurate, and the reflected signals of a plurality of labels drift, so that a certain automobile electronic mark cannot be accurately positioned, are solved;

the UHF RFID technology is applied to vehicle sensing and positioning in the parking lot, and the high construction cost of the existing parking lot vehicle positioning infrared camera and other schemes is reduced.

Drawings

FIG. 1 is a diagram of the network topology of the system of the present invention;

FIG. 2 is a flow chart of positioning based on RSSI technology;

FIG. 3 is a schematic structural diagram of a UHF RFID reader with RSSI function according to the present invention;

FIG. 4 is a schematic view of the parking space of the parking lot of the present invention;

FIG. 5 is a schematic view of the electronic automobile logo structure of the present invention;

fig. 6 shows a passive UHF RFID reader with RSSI functionality.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

Referring to fig. 1 to 6, in an embodiment of the present invention, a vehicle sensing and positioning system based on a passive UHF RFID parking lot includes an automobile electronic identifier 1, a UHF antenna 2, a UHF RFID read-write device 3, a network switch 4, a server computer 5, and a background visual system 6, where the UHF antenna 2 is connected to the UHF RFID read-write device 3 through a feeder 7, the UHF RFID read-write device 3 is connected to the server computer 5 through the network switch 4, and the background visual system 6 is also connected to the server computer 5; the RSSI technology of the UHF RFID is adopted to effectively judge the distance and the movement trend from the automobile electronic identifier 1 to the UHF antenna 2 connected to the UHF RFID read-write equipment 3 by judging and comparing the variation trend and the energy intensity of the reflected signals of the automobile electronic identifier 1 received by each UHF antenna 2, and the antenna array technology in the UHF antenna reduces and controls the coverage angle and the range of each UHF antenna 2 and effectively judges a specific direction of the automobile electronic identifier 1 in the space.

The RSSI technology of the UHF RFID read-write equipment 3 can effectively judge the distance and the direction from the automobile electronic identifier 1 to the UHF antenna 2 connected to the end of the UHF RFID read-write equipment 3.

The antenna array technology in the UHF antenna 2 can effectively judge the specific direction of the automobile electronic identifier 1 in the space.

The automobile electronic mark 1 is an ultrahigh frequency RFID anti-dismantling ceramic label and consists of release paper 8, an adhesive layer 9, a ceramic layer 10, an antenna layer 11, an SOT packaged ultrahigh frequency RFID chip 12, a PVC shell 13 and a surface printing layer 14 from bottom to top.

In the later-stage system application, a single antenna can be upgraded to be composed of multiple small module antennas, the radiation range of the antenna is narrowed, a signal sector coverage area only covers the head area of a corresponding parking space, and the background complex data calculation amount is reduced.

The RSSI technology and the antenna array technology are combined, so that the problems that the coverage area of an antenna is not accurate, and the reflected signals of a plurality of labels drift, so that a certain automobile electronic identification cannot be accurately positioned, are solved.

The automobile electronic identification is an ultrahigh frequency RFID anti-disassembly ceramic label, the ultrahigh frequency RFID anti-disassembly ceramic label consists of release paper, a glue layer, a ceramic layer, an antenna layer, an SOT packaging ultrahigh frequency RFID chip, a PVC shell and a surface printing layer from bottom to top, and the ultrahigh frequency RFID anti-disassembly ceramic label is adhered to a front windshield and is bound with vehicle information one by one.

The automobile electronic identification is an ultrahigh frequency RFID anti-dismantling ceramic tag, and the tag antenna adopts an antenna line type with a metal resisting function. When materials such as tinfoil and the like are attached to the back of the label, the reading performance of the label is guaranteed to be reduced by only 15 to 20%, and the problem that the label cannot be read when the tinfoil is attached to the back of the original ceramic label is effectively solved.

The automobile electronic identification is an ultrahigh frequency RFID anti-dismantling ceramic label, a ceramic substrate is punched in the middle, and an SOT packaged ultrahigh frequency RFID chip is welded above a gap. The label with the back adhesive is adhered to the windshield of the vehicle and cannot be transferred. If the label is detached forcibly, the electrical performance of the SOT packaged RFID chip is disabled, and the electronic label is disabled.

The automobile electronic identification is an ultrahigh frequency RFID anti-dismantling ceramic label, is provided with an ultrahigh frequency RFID chip, and can be used for writing and storing encrypted data, an encryption algorithm and the like. The first car number is ensured, and cloning and copying are avoided.

And the server computer is connected with the ultrahigh frequency RFID read-write equipment through a network switch. The method has the functions of storing all RFID label information, coordinating the work of a plurality of ultrahigh frequency RFID reading and writing devices, and verifying and counting the automobile electronic identification information acquired by the ultrahigh frequency RFID reading and writing devices.

The automobile electronic mark is shown in figure 4 and mainly comprises release paper (8), an adhesive layer (9), a ceramic layer (10), an antenna layer (11), an SOT packaging ultrahigh frequency RFID chip (12), a PVC shell (13) and a surface printing layer (14).

The measuring method based on the signal strength (RSSI) technology comprises the following steps:

the ranging based on the signal strength (RSSI) is a distance measurement technology with low cost and low complexity, and is widely applied to the distance-based positioning technology of the wireless sensor network. Based on the positioning technology of RSSI ranging, parameters are optimized through linear regression analysis, a Gaussian filter model is introduced, the RSSI value is corrected, and the ranging precision is improved. Iterative calculation is carried out on the position by adopting Taylor series expansion, finally, the 2~3 vehicles are experimentally verified in the parking lot, and the feasibility and the superiority of the algorithm are verified through simulation and experiment. The algorithm reduces the positioning error and improves the positioning precision.

Fig. 6 is a passive UHF RFID reader with RSSI function, which can measure the moving speed and direction of the electronic identifier of the car: when the UHF RFID read-write equipment receives a return signal of an automobile electronic identifier at a position 1, the energy detection circuit calculates the energy of a digital baseband 1-path signal and a digital baseband 2-path signal, respectively records the energy as UV1 and UV2, and reports the current time t1 to the MCU; the MUC calculates the amplitude A1 and the angle 1 when the automobile electronic mark is at the position 1; the UHF RFID read-write equipment waits for receiving a return signal of the automobile electronic identifier at the position 2, and if the return signal is received, the next step is carried out; if the return signal is not received, continuing to wait; 4. when the automobile electronic identification moves to the position 2, recording a return signal at the position 2, calculating energy, and reporting the current time t2 to the MCU; 5, the MCU calculates the amplitude A2 and the angle 2 when the automobile electronic mark is at the position 2, and if A2 is larger than A1, the automobile electronic mark moves towards the direction of the antenna of the read-write equipment; if A2 is smaller than A1, the automobile electronic mark moves away from the direction of the antenna of the reading and writing equipment, and the moving speed of the label can be calculated according to the angle.

The following is a concrete link for applying RSSI technology and antenna array technology to implement accurate sensing when an automobile enters a parking lot. When a vehicle with the automobile electronic identification label enters a parking lot, an automobile owner finds an idle parking space according to an LED guide screen in the parking lot and parks the vehicle. By adopting the array technology, the coverage angle of the antenna is reduced, so that only the electronic identification on the parking spaces adjacent to the parking spaces can be read.

At this time, in the parking lot, when there are vehicles parked in the adjacent parking spaces a and B, there are three possible situations.

The UHF antenna above the 1.A parking space only reads the tag of the vehicle A, and the UHF antenna above the parking space B only reads the tag of the vehicle B. At this time, the A, B antenna transmits the acquired tag data and energy signals to the background.

2. Due to signal drift, the antenna above the parking space A reads the tag of the vehicle A and the tag of the vehicle B at the same time, and the UHF antenna above the parking space B only reads the tag of the vehicle B. At the moment, A, B label data and energy signals which are simultaneously acquired by the antenna above the A parking space are transmitted to the background, because the A, B label is different from the antenna above the A parking space, the energy intensity and the change trend which return to the background are different, the label signals, the energy intensity and the change trend which are transmitted to the background by the antenna above the B parking space are matched, the parking space which the vehicle approaches to is accurately judged, and meanwhile, when the vehicle is static, whether the vehicle stops at the parking space A or the parking space B is judged. For example, the trend of the reflected signal received by the antenna above the parking space A is weakened along with the time, while the trend of the reflected signal of the same identifier received by the antenna above the B is strengthened, which indicates that the vehicle is close to the parking space B; when the vehicle is stationary, the receiving signals of the antenna above A and the antenna above B are basically stable, and the receiving signal of the antenna above B is larger than the receiving signal of the antenna above A, so that the vehicle is judged to stop at the parking space B.

3. Due to signal drift, the antenna above the parking space A reads the tag of the vehicle A and the tag of the vehicle B at the same time, and the antenna above the parking space B also reads the tag of the vehicle B and the tag of the vehicle A at the same time. At this time, there are 4 groups of reflection signal data and trends of the car electronic identifier in the data transmitted to the background. According to the method in 2, the label of the A car in the parking space and the label of the B car in the parking space can be accurately judged according to the variation trend and the intensity of each group of reflected signal data.

Above judgement can be expanded to a plurality of adjacent parking stalls and judge each other.

Experiments show that the passive UHF RFID-based parking lot vehicle sensing system realizes accurate sensing and positioning of vehicles on parking places, and substantially solves the problem of high construction cost in the existing parking lot camera shooting infrared-based scheme in later-stage large-scale application.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Furthermore, it should be understood that although the present specification describes embodiments, not every embodiment includes only a single embodiment, and such description is for clarity purposes only, and it is to be understood that all embodiments may be combined as appropriate by one of ordinary skill in the art to form other embodiments as will be apparent to those of skill in the art from the description herein.

Claims

1.A parking lot vehicle sensing and positioning system based on a passive UHF RFID comprises an automobile electronic identifier, a UHF antenna, a UHF RFID read-write device, a network switch, a server computer and a background visual system, and is characterized in that the UHF antenna is connected with the UHF RFID read-write device through a feeder line, the UHF RFID read-write device is connected with the server computer through the network switch, and the background visual system is also connected with the server computer; the RSSI technology of the UHF RFID is adopted to effectively judge the distance and the movement trend from the automobile electronic mark to the UHF antenna connected to the UHF RFID read-write equipment by judging and comparing the energy intensity and the variation trend of the reflected signal of the automobile electronic mark received by each UHF antenna;

judging the distance and the direction from the automobile electronic identification to a UHF antenna connected to the UHF RFID read-write equipment end by utilizing the RSSI technology of the UHF RFID read-write equipment;

judging the specific direction of the automobile electronic mark in the space by using the antenna array technology in the UHF antenna;

when all there is the vehicle to park on adjacent A parking stall and B parking stall, three kinds of situations appear:

1) The UHF antenna above the parking space A only reads the automobile electronic identification of the automobile A, the UHF antenna above the parking space B only reads the automobile electronic identification of the automobile B, and the A, B antenna transmits the respectively acquired automobile electronic identification data and energy signals to a background;

2) Due to signal drift, an antenna above the A parking space simultaneously reads an automobile electronic identifier of the A vehicle and an automobile electronic identifier of the B vehicle, a UHF antenna above the B parking space only reads the automobile electronic identifier of the B vehicle, at the moment, the antenna above the A parking space transmits automobile electronic identifier data and energy signals of A, B which are simultaneously acquired to a background, because the distance from a A, B label to the antenna above the A parking space is different, the energy intensity returned to the background is different, when the energy intensity of a reflection signal of the automobile electronic identifier of the vehicle received by the antenna above the A parking space is weakened along with time, and the energy intensity of the reflection signal of the automobile electronic identifier of the same vehicle received by the antenna above the B parking space is strengthened, which indicates that the vehicle is close to the B parking space; when the vehicle is stationary, the reflected signals received by the antenna above A and the antenna above B are basically stable, and the energy intensity of the reflected signal received by the antenna above B is greater than that of the reflected signal received by the antenna above A, so that the vehicle is judged to stop at the parking space B;

3) According to the method in the case 2, when the energy intensity of a reflected signal of the electronic identifier of the vehicle B received by the antenna above the parking space A weakens along with time, and the energy intensity of a reflected signal of the electronic identifier of the vehicle B received by the antenna above the parking space B is enhanced, so that the vehicle B is close to the parking space B, when the vehicle B is stationary, the reflected signals received by the antenna above the A and the antenna above the B are basically stable, and at the moment, the energy intensity of the reflected signal of the vehicle B received by the antenna above the B is greater than the energy intensity of the reflected signal of the vehicle B received by the antenna above the A, so that the vehicle B is judged to stop at the parking space B; similarly, when the energy intensity of the reflected signal of the electronic identifier of the vehicle a received by the antenna above the parking space a increases with time, and the energy intensity of the reflected signal of the electronic identifier of the vehicle a received by the antenna above the parking space B decreases, which indicates that the vehicle a is near the parking space a, after the vehicle a is stationary, the reflected signals received by the antenna above the a and the antenna above the B are basically stable, and at this time, the energy intensity of the reflected signal of the vehicle a received by the antenna above the parking space a is greater than the energy intensity of the reflected signal of the vehicle a received by the antenna above the parking space B, that is, the vehicle a is judged to stop at the parking space a, and therefore, the vehicle tag at the parking space a and the vehicle tag at the parking space B are cut off according to the energy intensity of each group of reflected signals.

2. The passive UHF RFID-based parking lot vehicle sensing and positioning system of claim 1, wherein the automobile electronic identifier is an ultrahigh frequency RFID anti-detachment ceramic tag which is composed of release paper, an adhesive layer, a ceramic layer, an antenna layer, an SOT packaged ultrahigh frequency RFID chip, a PVC shell and a surface printing layer from bottom to top.