Implementation of RFID Technology in Parking Lot Access Control System

Transcription

1 Implementation of RFID Technology in Parking Lot Access Control System G. Ostojic, S. Stankovski, M. Lazarevic Faculty of Technical Sciences Novi Sad, Trg D. Obradovica 6, Novi Sad, Republic of Serbia Vukica Jovanovic College of Technology, Digital Enterprise Center, Purdue University, 1419 Knoy Hall, N.Grant St.,West Lafayette IN 47907, USA Abstract-Parking plays an important role in the traffic system since all vehicles require a storage location when they are not being used to transport passengers. Whether it is a parking lot or on-street parking there is a problem of parking revenue convenience. Implementation of the RFID technology could be a good solution for this problem. I INTRODUCTION Radio Frequency Identification (RFID) is becoming an important identification technology in applications such as inventory management, security access, personnel identification, factory automation, automotive toll debiting, and vehicle identification to name just a few. During the last four decades numerous parking search models have been developed [1, 2, 3, 4, 5, 6, 7, 8, 9, and 10]. Since parking plays an important role in the traffic system one of the problem concerning this area is parking revenue. RFID technology was chosen for the implementation in parking system of city of Novi Sad, Republic of Serbia. Territory of the city of Novi Sad encompasses the surface of km2 with population of about 310,000. We anticipate that there are more than 130,000 vehicles. Having this in mind there is a huge traffic and parking problem in city of Novi Sad. At Faculty of Technical Sciences Novi Sad, Department of Traffic Engineering, the stationary traffic study was done with the analysis of the status of stationary traffic and definition of solutions for occupation of public running surfaces, analysis and exploitation of public garages and parking lots. According with the stationary traffic study new parking system is released in II PARKING SYSTEM IN CITY OF NovI SAD There are different types of parking system in city of Novi Sad: on-street parking, parking lots and garages. On street parking is organized in three zones: red, blue and white. Parking revenue is done by a Parkomat, SMS (Short Message Service) message over mobile phone and by parking ticket. Instead of parking revenue collectors there are parking checkers (checking parking price payment). Parking revenue for parking lots and garages is done by parking collectors, because the parking price varies with the time spent on a parking lot or in a garage. Parking operators face a number of challenges such as: 1) The inability to accurately and intelligently identify, collect and record the data of the vehicles that enter and leave the parking lot then processing this data to better analyze traffic patterns and facilitate client billings. 2) Need to increase the security (and user integrity) of the parking lot. 3) Adding human resources, especially in peak traffic times that burdens operating costs and reduces profitability. 4) Line-ups created for parking payments, especially during peak traffic times that reduces the service levels to customers. Automated parking revenue systems enable convenience when dealing with already mentioned challenges. A. On-streetparking On-street parking places are located in over 90 streets in center of the city of Novi Sad. Traffic in these streets is unobstructed. A parking place user sends SMS message by a mobile phone to an adequate number (for the parking zone). Message contains license plate number (e.g.,,ns "). Every message sent by a parking place user is forwarded from mobile operator (Telenor or Telekom) to company for parking revenue server over the Frame Relay (see Fig. 1.). Afterwards, confirmation/failure message is sent to a user about parking revenue. If a user has correctly entered license plate number and has enough funds on his/hers account needed amount of money is reserved for parking revenue and confirmation SMS message is sent to a user. Money reservation is accomplished by server which sends query to mobile operator billing system over Frame Relay (see Fig. 1.). SERVER ROUTER ROUTER FRAME_ RELAY Fig. 1. Communication between server and mobile operator server.

2 SERVER ROUTER ROUTER n ft 4 [MOBILE OPERATOR ControL center Exit Parking lot FRAME RELAY PDA Automatic barries _... Indicating Lights (red I green) Fig. 2. Communication between PDA and server. If a user gets confirmation message the reserved money is obligated, and if, for any reason, user doesn't gets confirmation message in 5 minutes transaction is stopped and reserved money is released. All messages are sent to a user by Frame Relay to mobile operator and then from SMS mobile operator center to user over GSM (Global System for Mobile Communications). Checking of the parking revenue payment is done by parking checkers. They are using PDA (Personal Digital Assistant). They print penalty ticket and enter license plate number and send query to database. If a user haven't paid parking price or the time for parking is overdue a parking checker enters data for the parked vehicle (license plate number, vehicle type, time and place etc.). These data is sent over GPRS (General Packet Radio Service) to mobile operator and after that over Frame Relay to server (Fig. 2.). From database server, license plate number is sending to the police (in text file), and the police sends back vehicle owner data to the database. Every penalty ticket has a unique number. On the PC (Personal Computer) there is an application for selecting recording penalty tickets from E-bank database (Microsoft Access) and transfers it to database on the server (PostgreSQL). B. Parking lots and garages There are several parking lots and garages which are dislocated all over city of Novi Sad. They have one or several entry/exit. Parking entry/exit on these parking lots is being controlled by arm barriers. Parking revenue is done by parking collectors, because the parking price varies with the time spent on a parking lot or in a garage. A parking place user stops a vehicle on inductive loop (in front of arm barrier) and with a hand presses pushbutton placed on a control center side. Afterwards arm of the automatic barrier lifts thus enabling entering a parking lot. Also a user gets printed parking ticket with encoded entering parking lot (or garage) time (see Fig. 3.). On entry barrier there is display with indicating light (red/green) with display. On a display number of free parking places is shown. If there is no free parking places arm of a barrier will not lift. There is a GPRS communication between barriers controlling systems, when the entry and exit barriers are dislocated. Exit barrier, sends a signal to an entry barrier with every arm lift. According to received signals control system calculates number of free parking places on parking lot or garage and sends number to the display. Exit Enter Induot ive Loop Pu button rfireader Fig. 3. Entry/exit parking lot (garage) system. When a user of a parking place wants to leave a parking lot or garage he/she stops a vehicle on exit inductive loop (in front of arm barrier) and gives a parking ticket to a parking collector. A parking collector then reads a barcode printed on a parking ticket (with a barcode reader). Afterwards, times spend on parking place and a price for the parking service is displayed on the PC monitor. Those data could be seen by both a parking collector and a parking place user. After paying for the parking service, parking collector prints a receipt and exit barrier arm lifts, so the user can leave a parking lot or garage. III CONTROL CENTER OF A PARKING LOT OR GARAGE Regulation of vehicle entry/exit parking lot or garage is accomplished by the control center. In control center basic component liked to all the others is programmable logic controller (PLC) FESTO, type FEC FC440. This PLC has 16 digital inputs and 8 digital outputs, 2 serial ports and one Ethernet interface. Other components connected on PLC at entry side of parking lot are: inductive loops, capacitive sensor, barcode printer, display and GSM modem (see Fig. 4.). GPRS communication between entry and exit barriers is accomplished by Siemens MC 39i modem connected with TTL RS232 cable to EXT port (serial port-extension interface) of PLC. The exit control center of the parking lot or a garage also has PLC, but there is a difference with the components connected to it. Besides inductive loop and GSM modem which are also present in the entry control center, there is a PC, a receipt printer and barcode reader (see Fig. 4.). According to the momentary status of inputs (sensors) like inductive loops and demand for printing ticket at the entry part of a parking lot PLC sends output signals to arm barriers and semaphore (indicating lights). Inductive loops are used to detect metal objects (vehicles in front, beneath and behind barriers).

3 GPRS G~P1RS Display Fig. 4. The entry/exit control center of a parking lot or garage. A ticket printer is connected by RS232 cable to first serial port while display for indicating number of free parking places at the parking lot is connected to the second. Communication between the PC and PLC is over Ethernet interface (twisted pair interface- I OBaseT) on a switch. On a PC there is application for trifling parking service (according to the time spent on a parking lot or garage) which uses PostgreSQL database. Also, there is an application that gives the command to the exit barrier to raise the arm. The PLC is programmed according to IEC standard. IV IMPLEMENTATION OF RFID TECHNOLOGY IN CONTROL CENTER OF A PARKING LOT OR GARAGE Since RFID technology is contactless identification technology a suggestion was given to use this technology in parking systems. Advantages of RFID technology in comparison to other technologies are: * No need for physical contact between data carrier and the communication device * Tags can be used repeatedly * Robust tags can withstand extreme conditions and temperature * Low maintenance costs * Tags available materials in a range of types, sizes and * Non-line-of-sight communication makes it possible to read and write Tags in dirty conditions. * RFID tags may be read by the RFID system at one time. * Extremely low error rate. We have implemented RFID technology in entire parking system of city of Novi Sad, meaning both on-street parking and parking lots and garages, thus creating intelligent parking control management system which integrates RFID technology, automatic control technology and applications software. We have chosen RFID system that is working on frequency of MHz because: * tags are less expensive due to their limited coil requirement and * Some MHz tags are anti-collision. In designed parking system verification of parking service revenue is done by using passive RFID tags (ISO 15693). There are several types of RFID tags-tickets: * for invalids (free of charge), * for people living in parking zone (monthly or yearly payment but only for limited parking area), * for all others (golden card, only for one month but for all garages, parking lots and on-street parking, see Fig. 5) Fig. 5. Golden card - RFID tag.

4 Reading distance for these passive RFID tags is 7 cm. Their weight is 3.4 g, so they are light, easy to use and to carry with the user (they look like a credit card). Also these tags are read/writable (64's block memory space for user define, each block can be written 4 bytes data). A. Entry control center ofa parking lot or garage A parking place user stops a vehicle on inductive loop (in front of arm barrier) and puts RFID tag in front of a RFID reader (mounted on a control center, see Fig. 3.). Afterwards arm of the automatic barrier lifts thus enabling entering a parking lot. In this case he or she doesn't get printed parking ticket with encoded entering parking lot (or garage) time. There are defined terms which must be achieved in order to lift the arm of an entry barrier like: * Vehicle must stop on inductive loop. * Data written on RFID tag must be correct like: * Validity period (day, month, year), * Integrity, * Is the user vehicle out of the parking lot (or not). RFID reader is connected by RS232 cable to EXT port of PLC. PLC is programmed to communicate with RFID reader and to send read and write commands to RFID reader. Principle is next: after a parking place user stops a vehicle on inductive loop and puts RFID tag in front of a RFID reader, reader query's a RFID tag. The RFID tag detects the interrogating signal and transmits a response signal containing encoded data back to the receiver. This data is: UID - Unique Identification-encode check, validity period - locked data for date, time, and year, so that the tag can be used only in defined period (after locking this data no one can unlock these blocks for reuse), check bit (one block memory) to determine is the user's vehicle already is in the parking lot or not. This check is practiced for prevention of malversation. One user of a parking place could borrow RFID card to another user. Mi GPRS RFID PLC software analyses gathered data and if the UID is correct, if validity period is correct and the user's vehicle is not already in the parking lot sends a signal to barrier to lift an arm and sends a command to RFID reader to write on RFID tag information that the vehicle is entering parking lot. While PLC is processing information, green led diode is blinking, thus informing a user of activity of checking and writing information on tag process. After writing data to RFID tag green led diode stops blinking and user can drive in to parking lot (or garage). If one or all of the named data are not correct, system will inform a user by lighting red led diode. An arm of a barrier will not lift a user can't enter in a parking lot. If a user still wants to enter in a parking lot (or a garage) he or she must press the pushbutton, placed on a control center side and follow the procedure already mentioned above. B. Exit control center ofa parking lot or garage Working procedure at the exit barrier is next: after a parking place user stops a vehicle on inductive loop and puts RFID tag in front of a RFID reader, reader query's a RFID tag. The RFID tag detects the interrogating signal and transmits a response signal containing encoded data back to the receiver. This data is: validity period and check bit to determine if the user's vehicle is in the parking lot or not. PLC software (see Fig. 7.) analyses gathered data and if a validity period is correct and the user's vehicle is at the parking lot sends a signal to barrier to lift an arm and sends a command to RFID reader to write on RFID tag information that the vehicle exit's the parking lot. While PLC is processing information, green led diode is blinking, thus informing a user of activity of checking and writing information on tag process. After writing data to RFID tag green led diode stops blinking and user can drive in to parking lot (or garage). In this case a parking place user doesn't pay for the parking service and doesn't get a receipt. RIRFID IL) retod&r Fig. 6. New control center of a parking lot or garage.

5 V CONCLUSION Fig.7. PLC software for control center of a parking lot or garage. If named data are not correct, system will inform a user by lighting red led diode. An arm of a barrier will not lift a user can't exit a parking lot. In this case a parking collector checks an RFID tag to determine the problem. If a problem is related with the validity period parking collector calculates revenue for the time spent from the end of the validity period till now. Calculated time and a price for the parking service are displayed on the PC monitor. Those data could be seen by both a parking collector and a parking place user. After paying for the parking service, parking collector prints a receipt and exit barrier arm lifts, so the user can leave a parking lot or garage. If the problem relates to the value of the check bit then a user of a RFID tag an authorized institution deals with this problem. Parking collectors at parking lots and garages are authorized to visually check, every now and then, validity period and quality of graphics printed on a RFID tag (in case of a forgery). In this way, parking collectors are checking parking revenue for the on-street parking (for the users who has RFID tags). C. Summary New control centers of a parking lot or garage in city of Novi Sad, where we implemented RFID technology has been in use since January Till now collection of the parking service tariff has been increased for 17%. For the on-street parking, one of the reasons for the increase is simple procedure for getting RFID tag (approximately twice as much time needed for buying a ticket for on-street parking). People realize that the time they have to spend waiting in line to buy the tickets (sometimes several tickets for different parking zones) they can spend doing something else. For the parking lot or garage users, one of the reasons for the increase in parking service tariff collection is much less time spend waiting at the entry and exit barriers. Also they don't have to worry about amount of time spend at parking lot or do they have enough cash to pay for the parking service. Implementation of the RFID technology, in an existing parking lot access control system, has given benefits to all interest parts (the Parking Operator, parking place users and parking collectors). Parking Operator has gain robust system, easy to operate, easy for maintenance, with the reliable RFID tag-ticket check for the prevention of malversation. Also, RFID reader is placed in a way that it doesn't violate exterior. Till now collection of the parking service tariff has been increased for 1700 Ṗeople using parking place are spending much less time in waiting in line to buy the tickets for the on-street parking and much less time waiting at the entry and exit barriers of a parking lot or garage. Parking collectors that are working at parking lots and garages are much less involved in collecting tariff. They are only active when dealing with parking place users who don't have correct RFID tag-ticket and, of course, when they have to charge for the parking place users who don't have RFID tag-ticket. Future research will be directed towards the designing a parking system so that a parking place user will be able just to drive thru and enter/exit parking lot or garage. Also we will try to automate the in and out privileges of the subscriber and then transfer this data to the enterprise software for the traffic analysis that will allow optimization of the human resources needed for traffic flow in and out. For customer payment, the RFID tag could be read to debit a pre-pay system or charge the parking services against a credit card. All of this will facilitate customers entering and leaving and this improves service levels and increases capacity in the parking lot. These benefits will drive higher revenues. REFERENCES [1] D. V. Goot, "A model to describe the choice of parking places, transportation Research" 16A, 1982, pp [2] K.W. Axhausen and J. Polak, "Choice of parking: Stated preference approach, Transportation" 18, 1991, pp [3] J. Polak and K.W. Axhausen, "Parking search behavior: A review of current research and future prospects." Transport Studies Units, Working Paper 540, Oxford University, [4] W. Young, M.A.P. Taylor, R.G. Thompson, I. 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