Research and Application on a Wireless GPS Data Collection and Display

Research and Application on a Wireless GPS Data Collection and Display System 1 Yikui Zhang, 2 Liwei Zhu, 3 Yisheng Lai, 4 Yan Zhang 1,2,4 School of Computer Software, Tianjin University Tianjin City, 300072, P. R. China zhangyk@tju.edu.cn 3 International School, Beijing University of Posts & Telecom Beijing City, 102209, P. R. China tommylys@gmail.com Abstract The main purpose of this paper is to build a system that can complete the whole process from collecting GPS data, transmitting through GSM network, processing GPS data, to displaying position in maps. Also, two further applications relied on this system is proposed in this paper. There are two modules in this system. One is GPSLogger, which can collect instant position data and transmit those data into the server, running on AVR Atmage64 microcontroller. The other one is GPSTracer that can gather GPS data from the logger calculate the geographic information and display position on the map. Keywords: GPS, Logger, Tracer, GPRS, Atmega64, Google Map JavaScript API, NMEA 1. Introduction GPS (Global Positioning System) is a brand-new space satellite navigation Positioning System. The original intention of developing this system is for U.S. troops to provide navigation services and some other military purposes. However, with the development of computers, communication and space technology, the needs of the navigation equipments are increasing. GPS now has been used widely in people s daily life and the scientific research. [1] In the past, the object of GPS is the cars, ships, aircraft, moving objects. But the GPS system itself has certain limitations. It can receive the GPS satellite transmitted data to access the users location of the 3D coordinate, movement direction, speed and so on. [2] But it did not have the ability to analyze path information (for example calculation length, calculation path center). This paper studies the problems from the needs of everyday life and research. Based on the traditional GPS technology, this study creates a separate system of the GPS data to process and display in the customer's network terminal. This paper explains the complete realization of GPS data receiving, real-time transmission storage, processing, and the function of display. Through the results in this paper, the customer can review their own trajectory more intuitively. At the same time, they can obtain and share the position of information with others. Furthermore, by the research in this paper, it will be possible to design an easy navigation algorithm and develop abundant applications on GPS, like booking intelligent taxi and the platform of making friends based on position, which provide more diversified GPS service for the vehicles and pedestrians. This paper mainly introduces the general structure of the system in the second part of the paper. It is composed of two parts. One is realizing the GPS recorder of being used for collecting and transmitting in the client; the other is realizing data collection and handling software, which is used for the function of GPS data collection, treatment and display in the server. In the third part of this paper, it mainly introduces the process of the system operation, including the relationship and sequencer of each module between the two parts. The fourth part of the paper tests the whole system. A group of testers with GPSLogger walk on campus, another group observes the first group s location and the path in real-time through the GPSTracer. The last part, or the fifth part, puts forward two possible applications based on this system. Taking two applications, for example, this paper proves practicability of the study, which also obtains the purpose of this study. International Journal of Digital Content Technology and its Applications(JDCTA) Volume6,Number1,January 2012 doi:10.4156/jdcta.vol6.issue1.55 454

2. System structure The system developed by this work can be divided as two parts, the GPSLogger and the GPSTracer, which are based on a different platform and taken respective responsibilities to fulfill the whole function [3]. The GPSLogger is a portable mobile device, with embedded GPS module, can collect GPS data in real time, sent data to the server and record them in the SD card plotted in the device. The GPSTracer is software installed on PC side, can gather and store data from the GPSLogger and can display the position or moving path on Google Map. The overall structure of the system is shown in Fig. 1. Figure 1. Overall System Structure Diagram Through this structure, user can access the terminal s instant location information using the GPSTracer, to determine the location, motion parameters of terminals and show on the map, which enables many remote real-time monitoring and tracking applications. The two aspects of the system will be explained in more details. 2.1 GPSLogger The GPSLogger system includes the following functions: System Initialize, GPS data process, GPS data collect, network transmit. The structure of the system function is shown in Fig. 2. The System Initialization function contains all the initialization work need in the system, such as clearing the registers in the processor, setting USART serial port, enabling the receive and transmit interrupts, setting the GPS geodetic system for GPS-52D module [4]. Then the system needs the GPS Data Process function. In this function, receiving GPS data should be checked, if invalid the data will be discarded. If valid the key information will be resolved according to the NMEA-0138 protocol and store into appropriate intermediate variables. Next is the GPS Data Collect function which includes the ISR function to catch interrupts. Every time, the GPS data are collected in USART, it will be stored in the buffer. This part will call the function of GPS Data Process and finally store the data in SD card. The last and important function is network Transmit, covering two modules, can upload the data in SD card to the server every minutes, enabling the real-time updating of user information. When the condition of networks is bad, the information will be hold and wait for retransmit. The first module is 455

Figure 2. GPSLogger system function Diagram the transmit control, which can ensure the QoS of the transmission and fulfill UDP protocol. The other module is the GPRS module, can communicate with server through the GSM network [5]. 2.2 GPSTracer The GPSTracer contains 5 main system functions, Data gather, GPS Data Calculate, Parameter Configure, HTML map file dispose, GUI Design and Process. The function diagram is shown in Fig. 3. Figure 3. GPSTracer system function diagram Data Gather function includes two parts, first is monitoring network port to gather information sending from GPSLogger and store those data, second is read data from SD card, which is manually selected, can copy all information from the SD card into system. Then, the GPS Data Calculate function can generate all kinds of data files needed in the program, such as path script file, standard data files. Also, this function can be used to compute some geographical parameters, for instance, overage altitude, path length and center path. Further, the function of parameter configure need to implement interact with configuration files with software that should allows the ability of read and write with configuration files. Moreover, the HTML Map File function need to generate the map html files contains the Google Map API, which will be called by WebKit in QT to display maps in applications [6]. Also, it needs to provide the javascript files including all kinds of configuration information. Last is the GUI Design and Process function, which will write a UI file representing the whole interface of the software by the QT Designer. In this part, all interface element event handing mechanism have been considered and every event has a rational processing method. 3. Operation sequence In this part, the operation sequence of GPSLogger and GPSTracer are mainly discussed. GPSLogger, which run at AVR Atmega64, is first focused. Its sequence is shown in Fig. 4 [7]. 456

When switch power on, the first thing GPSLogger do is to get everything initialized. Then Logger will enter the receive loop, which means the processor will continue try to receive GPS data. If success, data process module will be called. Then data validation will be checked according to NMEA protocol. If the data is invalid, it will be discarded and program will return to receive next data. Otherwise, the data will be parsed by NMEA to extract key information and then write into SD card [8]. Then the data process module will also be ended and return to data collect loop. In addition, the transmission module will be triggered every 60 seconds and try to send the latest GPS data to the server. The amount of data to be transmitted will be decided by a data pointer. If the transmission succeeds, the data pointer will be move to the end of data. If failed, the module will try another 3 times. If all these attempts are failed, the data pointer will remain in the last position and these data will be retransmit in next time. Then the GPSTracer s operation sequence is discussed. The data gather function will always run in the background waiting for data transmission. It will follow the UDP protocol to receive and analyze the data packet. However, the map display part is called on demand. So it doesn t have a definite operate sequence. The core operation rounding the software configuration file is shown in Fig. 5. The map and moving path is display according to the parameters in the configuration file provided by GUI interface. Thus, every time the program run, the configuration file is needed. If the reading process failed, the default configuration will be invoked. And after the process is ended, the configuration parameters will be automatically saved for next time using. Another important function in the GPSTracer is generating standard data file and path script based on the GPS data gathered from GPSLogger. These two modules make up the function of GPS Data Calculate. Its operation is shown in Fig. 6. Standard data file is used to calculate geographic parameters, such as overage altitude, path length and center of path. The result of the path length is got by adding all the great-circle distance of adjacent points. To calculate the great-circle distance from the longitudes and latitudes of points, haversine formula is admitted [9]. The file is store in ASCII format, which makes it convenient to read and write for the GPSTracer, and have the same data content as GPS data file. Instead, the Path Script will extract the grid location of all points from GPS data. Then store the latitude and longitude information in a Javascript file for the map module to display path on the map. System Initialization GPS Data Collect Collect Success? New Configuration Files GPS Data Check Save Succeed? Use Default File Data Valid? GPS Data Process HTML Map File Read Configuration File Save Application Write in SD card Use Default Configure Read Succeed? Continue? Display Map Figure 4. GPSLogger Operate Sequence Figure 5. GPSTracer Operation Sequence Diagram 457

Figure 6. GPS Data Calculate Module Operation 4. System test Followed by the above design, the whole system has been build and tested. In this part, the result of the work will be shown. Fig. 7 shows the raw GPS data collected by GPSLogger. Figure 7. Screenshot of data collect by GPSLogger Then after the data process function in GPSLogger, the key information is extracted and stored. Fig. 8 shows the data processed by GPSLogger and will transmit to GPSTracer. These data in Fig. 8 is gathered from the raw data in Fig. 7. When GPSTracer receive these data, it will rearrange these data to generate the standard data file for further using in reading and writing. The standard data file is shown in Fig. 9 are got from above data. Figure 8. Screenshot of the Processed Data Figure 9. Standard Data File The initial UI of the GPSTracer is shown in Fig. 10. The default map will display and user can adjust the map parameter in the right hand side panel. 458

Figure 10. Initial Interface of GPSTracer When the GPS data file is open, the path will be display in the map. As shown in Fig. 11. By adjusting the button in the right, the pattern of the path can be changed. Also, information of the path can be calculated by GPSTracer, such as the start and end time, the total length of the path. This function is shown in Fig. 12. Figure 11. Path displayed in the map Figure 12. Display of path information 5. Related application The creating of GPS is for the military programs in the United States at the beginning, and then it has developed as dual-use in the field of military and common people. It has brought earthshaking changes on the scientific research of human beings, Engineering Technology, Military technology and daily life, which once again leads to the improvement of Human productivity. In the United States, the market of GPS alone has reached 3 billion dollars. And in China, it almost has reached 5 billion RMB. Thus, it can be seen that the market of GPS Technology has an optimistic perspective. Based on the creating combination of the technology on GPS record and display with instant transmit by wireless Network, the study applies this innovation to the research on following the tracks of a special crowd such as children and the elder and children with the mental disabilities, escorting the precious valuables, Car Black Box and inductor between taxis and customers [11]. In the application to special people, this study embedded this kind of product on special groups. Then the wireless network will upload the position of carriers in real-time to make terminal managers see the location of the objectives and his mobile route so as to achieve the purpose of tracking and preventing getting lost. What s more, because of the function of record and display in the SD card, the application can also record the route even if it lost contract with wireless networks, which will display the track route once connecting a wireless network or meet the same GPS device. The function of display track route not only reduces the burden of people who has the worries about losing children and the elder and children with mental disabilities but also strengthen the protection of these special people. In the same way, this technique can be used in escorting valuables to ensure a safe and effective tracking route for valuables. Based on the research of technology has been applied, this paper has a realizable future design. The structure of the system is shown in Fig. 13. 459

The taxis and mass population are all equipped this GPS real-time record and display device. Due to the terminal management, people actually can learn other people s location by authorization. So with this device, people can clearly see what sections of traffic are blocked so that they can avoid unknowingly crowded and easing the traffic pressure [12]. Furthermore, by uploading the location of these taxis and pedestrian, taxis could directly search for the passengers nearby, which effectively avoid unnecessary looking for customers, reduce the energy consumption, save the time of pedestrians and taxi drivers. This research produces a breakthrough of the embedded GPS chip with the real-time position information of data acquisition [11]. The service handles all uploaded information and put the entire position signal back to the message sender, which effectively shares the location of related people. And because of the service provider which makes the embedded chip access mobile phone applied to individuals and ensures accurate flows of information between people and vehicles [13]. It will truly realize the GPS application s low-cost and high performance. In other aspects, the high-quality data produced by the GPS record and display device can be used as black box s reference data. After the traffic accident, this device can provide the speed and route information at accident time to help person analysis the reason of the accident. Based on the technology, this study will concentrate on further designing the easy navigation algorithms that can provide vehicles and pedestrians more diversified GPS service. 6. Conclusion Figure 13. The Structure of Taxi s Monitoring System This paper mainly introduces the structure of a real-time GPS record and display system with wireless network, its operation process, the results and related applications. Different from traditional GPS navigation, the innovation of this study is to store the received GPS data with a specific file format in the SD card according to the analytical of NMEA protocol and record the real-time movement track by using the GSM module connecting the wireless network which eventually delivery the location information to the server. This study realizes the low cost high performance of the GPS innovation system that no matter when and where you are can it track mobile location. In the public life, this study greatly increases the convenience of travel and ensures the special people s security, reducing the burden of the special groups guardian. We believe as in this paper that the low-cost and high performance GPS system will create inestimable value in the future, and it is also waiting for more and more excellent explorers to study together. 460

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