1、Design and Implementation of Urban Vehicle Information Monitoring System ZHENG Ya-bin, XIE Xin, LIAO Yong, Han HongSchool of Computer Science and EngineeringUESTCChengdu, Chinae-mail: , , , WEI Zhong-jiaSchool of Mechatronics EngineeringUESTCChengdu, Chinae-mail: AbstractUrban traffic information
2、plays a very important role in modern intelligent city. In this paper, a real-time monitoring system of urban traffic information is introduced, in which GPS (Global Position System) module is designed to indicate vehicle locations, multiple sensors are used to detect different parameters (such as o
3、il consuming of vehicles), and GPRS (General Packet Radio Service) module is used to transmit the captured data to Data-base. A server on the Data-base analyzes and processes the basic data to get more valuable information, such as, traffic information, temperature and noise distribution. For any us
4、er who uses smart phone, the information can also be displayed on the electronic map in real time. Test results show that the performance of this system is a real-time level.Keywords: Real-Time Monitoring, intelligent city, GPS, GPRS, Mobile SoftwareI. INTRODUCTIONAlong with the development of socie
5、ty, the number of vehicles is rapidly increasing in the city in China, therefore ITS (Intelligent Transportation System) values much in traffic control 1. To avoid traffic jam, drivers would like to choose a better road to go. Usually, people get the traffic information from radio on their cars, but
6、 it is not a timely and intuitional method. Fortunately Google Map and GPS bring the possibility that allows people to know the traffic information in real-time and choose an unobstructed way to go. In this paper, a monitoring system of urban vehicle information is built not only to implement the fe
7、ature similar with Google Map, but also functionally extend it to show oil consuming, temperature, noise distribution or other extra information on the electronic map of users smart phone. The valuable information will make a good sense for people to know more about where they want to go and go by.
8、Following chapters describe the design, implementation and test of this real-time monitor system.II. SYSTEM DESIGNIn the design of this system 2, three subsystems are divided: detecting terminal, background server and display module on the mobile phone. Details of subsystems cover respectively in fo
9、llowing sections. The system frame is illustrated in Fig. 1.D e t e c t i n g T e r m i n a lM o b i l e P h o n eD e t e c t i n g T e r m i n a lM o b i l e P h o n eG P R S N e t w o r kS e r v e rFigure 1. System Framework.Detecting terminals capture sensors information, and send it to server th
10、rough GPRS wireless network. Server will first add the received information into data-base, and then send it to mobile phones.A. Haerdware Design of the Detecting TerminalThe detecting terminal consists of embedded board, an RTOS (Real-Time Operating System) 3, GPRS module, GPS module, and a group o
11、f sensors. Fig. 2 describes the brief hardware structure of a detecting terminal. Three main components of this system will be discussed respectively in sequential paragraphs: board, GPS /Initialize BSP, drivers.aCoral_Start(); /OS start taking over.GPRS_Task(); /Connect and send /information to ser
12、ver.GPS_Task(); /Receive GPS information /from GPS module.Temperature_Task();/Receiving temperature info.Figure 3. The pseudo code of program in detecting terminalFig. 4 shows the data flow between tasks in OS. Three tasks are created for GPRS, GPS and Temperature. GPS task and Temperature task are
13、in duty of receiving those data, and do some extraction procedure, then mail them to GPRS task. GPRS task first checks whether the information came in time or not. If timeout detected, GPRS task will send a timeout signal to server indicate the corresponding sensors information has missed the deadli
14、ne. Otherwise, GPRS task will combine each sensors information into a complete message, and send it to server.G P S d a t a e x t r a c t i o nG P S m o d u l es e n d s d a t aG P S d a t a a f t e r e x t r a c t i o nT e m p e r a t u r e sd a t a e x t r a c t i o nT e m p e r a t u r e s e n s
15、o r s e n d s d a t aT e m p e r a t u r e d a t a a f t e r e x t r a c t i o nO v e r t i m e j u d g e m e n tT i m e l yT i m e o u tC o m b i n e d a t a t o a c o m p l e t e m e s s a g eS e n d a t i m e o u t s i g n a l t o s e r v e rS e n d a t i m e o u t s i g n a l t o s e r v e rS e
16、n d t h e m e s s a g e t o s e r v e rS e n d t h e m e s s a g e t o s e r v e rM e s s a g eO u t p u tO u t p u tFigure 4. Detecting Terminal DFDC. Background ServerFunctionally, the server in this system has two jobs to do: adding records which converted from information come from detecting ter
17、minals into data-base, and sending the information to client on mobile phones.Table 1. Vehicles information in data-baseField Type Description Remarksid varchar(5) a unique number foreach vehiclePrimarytime varchar(10) information arrived timePrimarydate varchar(6) information arrived datePrimarytem
18、perature varchar(9) temperature longitude varchar(11) longitude latitude varchar(10) latitude Tab .1 shows table structure in data-base, which adopts MySQL. Each record consists of 6 items, which describe a vehicles information at a specific moment.Fig. 5 shows the flow chart of the program in serve
19、r. When server started, a main thread and a main socket were created, which are mainly in duty of establishing new connection to detecting terminals and client on mobile phones. When dealing with detecting terminals, every time gets a connecting request from a terminal, server will create a new thre
20、ad, and then assign a new socket to this thread. Then this new thread will take in charge of the information coming from the corresponding terminal. Once a group of data arrives from terminal, the thread will first mail the data to main thread, add a new record into database, and then set a signal i
21、ndicates that data are ready to be transmitted to phones.And for phones, server maintains a queue for phones that have already connected to server. Every time when gets a connecting request from a phone, server will create a new socket for this phone and add it to the queue mentioned above. Once the
22、 ready signal is set by a terminal thread, server will scan the queue and send the message to every socket in the queue.S e r v e r S t a r tM a i n S o c k e t ( )L i s t e n ( )N e w T e r m i n a l T h r e a d ( )N e w T e r m i n a l S o c k e t ( )N e w P h o n e S o c k e t ( )R e c e i v e D
23、a t aA d d d a t a t o D BS i g n a l d a t a r e a d yt e r m i n a lA d d s o c k e t t o Q u e u eC o n n e c t i n g R e q u e s tR e c e i v e dP h o n e o r T e r m i n a lP h o n eD a t a s i g n a l r e a d y ?N oS e n d D a t a t o e a c h p h o n eY e sFigure 5. Server Flow ChartD. Informa
24、tion Display on Mobile PhoneMobile client, at some point, is the very part that makes this system practical in life. Considered the satisfaction for majority number of people, the client is adopted on two popular mobile OS: Windows Phone and Android.There are several features that the mobile clients
25、 have: Display the exact current location of every terminal on map. At every fixed time, update information of every terminal and polyline them up with different colors. Every historical group of information of a vehicle can be shown on screen.III. SYSTEM IMPLEMENTATIONWith all subsystem been design
26、ed, the urban vehicle information monitoring system was implemented. A real screenshot of the client on Android in Fig. 6 shows how the mobile client turned out to be.A pushpin is used to represent each vehicle on the map and linked up spots is used to represent historical information of the vehicle
27、. Every pushpin and spot can be tapped to show the sensors information at the corresponding moment.Figure 6. Information displayed on Android clientIV. TESTS AND EVALUTATIONIn this section, a series of testing result are provided to tell how well can this system work in real environment (mainly focu
28、s on the performance of response time which values most in real-time monitoring). A graph in Fig .7 shows the results of response time test. The response time is defined in Equation 1. Tterminal is the moment when a detecting terminal sends out its information to the server. Tphone is the moment whe
29、n the client on mobile phone received the corresponding information.Response Time = Tphone - Tterminal (1)Figure 7. Response Time Test ResultsTo test response time, start to record the Tphone and the Tterminal every 10 seconds for 100 continuous times from the moment at which a corresponding mobile
30、software begin to receive information from server (the fixed time for terminal to send a message is 10s). There is an obvious slope among the results depicted in Fig. 7, which indicates a systematic error (caused by the design of detecting terminal).Figure 8. Modified Response Time DistributionA mor
31、e intuitive image is in Fig. 8, which shows the distributions of response time after cleared the systematic error (about 0.08s each time). Despite the fact that there are several response time in the test are relatively long for wireless internet block, about 95% of results are less than 2.0 seconds
32、. Therefore the performance of this system is acceptable.V. CONCLUSIONSThis paper presented an urban vehicle information monitoring system monitoring system, in which the traffic data can be captured by detecting terminals installed on vehicles. The data is sent to the database for store or further
33、analyzing. Then users can access the data by their smart phone, which is displayed on the E-map in real time. Further more, Extra sensors are extended on the detecting terminals, which make the system possible to be applied more widely. Besides this, the captured data is maintained in server, which
34、can be used for data mining. Such as dynamic traffic predict modeling. Thus drivers can obtain the valuable information to determine their optimal route to avoid traffic jam in advance. For real estate developers, the analyzed information can be used to choose the best place to build apartments or c
35、ommunity with lower noise.REFERENCES1 Zhang Fei, “The Current Situation and Development Thinking of the Intelligent Transportation System in China,” International Conference in MACE, 2010, Wuhan, China. pp. 2826 2829.2 H.Gomma, “A Software Design Method for Real-time Systems”J, in Communications of
36、the ACM, No.9, Vol.27, Sep, 1984.3 Luo Lei, “Embedded Real-Time Operating System & Application Development”M, Beijing: Press of Beihang University, 2011.4 Samsung Electronics, “Users Manual for 32-bit COMS Microcontroller S3C2440A”, (Revision 1), 2004.5 HOLUX Technology, “M-87 Specification”, (Versi
37、on 1.0), 2007.6 Dallas Semiconductor, “Datasheet of DS18B20 (Programmable Resolution 1-Wire Digital Thermometer)”.7 SIEMENS Mobile, “MC55/56 Hardware Interface Description”, 2004.8 Readl-Time Computing Lab of UESTC, “Technical Documatation for aCoral”, (Version 1.0), 2010. (http:/www.acoral.org/index.html.)9 H.Gomma, “Software Development of Real-Time Systems”J, in Communications of the ACM, No.7, Vol.29, Jul, 1986.
