【作者】 孙洪伟；

【导师】 于枫；

【作者基本信息】 吉林大学 ， 电路与系统， 2008， 硕士

【摘要】 本文研究的是基于GPS和GSM的智能公交系统,该系统是GPS全球定位技术和GSM全球移动通信系统相结合的产物。它通讯范围大、系统运行可靠,而且经济实用、投资少、效益高。论文在对基于GPS和GSM的智能公交系统的构成、系统功能和关键技术进行了深入的研究的基础上提出了设计方案,并在南京航爵科技有限公司开发出了相应的产品。移动定位终端使用AVR的MEGA64L单片机作为控制核心单元和数据处理单元,因为它带有两个串行口能同时与GSM模块、GPS模块进行通信,一个TWI口同MEGA8L进行通信,片内有64k flash程序存储器,2K EEPROM,可编程的看门狗定时器等,采用它可以省去很多外围元器件,提高了系统的稳定性。系统在通信上使用了成熟的工业级GSM模块Siemens公司的TC35I,采用AT指令集进行控制。系统在获取GPS定位信息上使用了可靠性和定位精度非常高的16通道ANTARIS4定位引擎对,158dBm高灵敏度的ATMEL公司的SDT11模块,在恶劣的天气环境和交通环境下都能够保证有最佳的观测信号。系统中的语音芯片采用了美国ISD公司的ISD4004,保证了语音播放的清晰度,系统还使用了具有有机电激发光技术的OLED显示屏作为移动定位终端的本地显示。在软件开发上,我们对系统进行了细化,采用模块化的设计方式,并给出各个模块的实现方法。更多还原

【Abstract】 This paper first compare urban public transport status quo at home and abroad. Having a rapid economic development, china has a relatively backward Chinese urban public transport system. Many foreign countries use advanced information and communication technology for targeting public transport vehicles, vehicle monitoring, automatic driving, computer-aided dispatch and the provision of various public transport information services, in order to improve bus services since the 1980s. So China’s cities have the necessary to strength the modernization construction of the urban public transport system.The paper in the second chapter of the smart bus stops automatically on the system carried out a detailed programme of demonstration. As GPS global positioning system developed rapidly in recent years is a satellite positioning navigation, is the 1970s, the U.S. Department of Defense develop the second generation of satellite navigation systems, global, continuous, high positioning accuracy, bounded error, The advantages of lower cost, can solve mankind on earth navigation and positioning problems, the final choice of GPS global positioning system as a public transport system positioning system; GSM cellular mobile communication is the use of cellular wireless Zuwangfangshi, in the terminal and network equipment Wireless access through the inter-linking it to proceed to achieve in the activities of users can communicate with each other, with its stability and low cost are the characteristics of a wide range of applications, using the GSM short messaging can be a convenient bus to the status of the To the console, the final choice of the GSM system as a vehicle of communication module; voice at the station, in a detailed analysis of the advantages and disadvantages of the traditional programme on the basis of the proposed use of ISD’s ISD4004 system as a voice chip, the Chip using multi-level direct simulation of storage technology, each sample in the value of direct storage in the memory-chip flashing, it can be very real, natural reproduction of voice, music, sound effects and tones, avoiding the general solid recording circuit Due to quantify and reduce noise and to quantify the "metal sound." But also for the future MP3 programme was discussed, in the next bus stop on the voice of a very good choice, but for economic reasons did not consider using.Papers in the third chapter detailed introduction of the GSM and GPS positioning and how the characteristics of communication.Papers in the fourth chapter of the details on the system’s hardware design, including the principle of the whole diagram and the various functional part of the hardware design. First of all sites for the location of latitude and longitude collection, and then stored in the EEPROM MEGA64L, so even if the power-down will not be lost data, vehicles in the exercise of non-stop collection of latitude and longitude, when a station at around 40 meters ahead of schedule by car Speaker conducted at stations, through the serial MEGA8L displayed on the LED screen "of a certain station to a" short message through the stations of the code, vehicle trips to the console, for the rational management of vehicles and scheduling, while outbound Forecasting the next stop after 20 metres, are the same big-screen display. This system MEGA64L with MEGA8L I communicate through TWI, the former as the host, the latter as a slave, mainly large-screen display LED transmission of data, the rate is not high on the request; MEGA64L through a serial port access to GPS data,Porter Porter was set to 9600, 8 data bits, 1 stop bit, no parity bit; MEGA64L through the serial port 0 to communicate with the GSM module, through the AT commands to control the order through the mouth and ISD4004 SPI data transmission, The voice recording, playback, fast forward; MEGA8L through the serial port and large LED screen for data transmission, and display data. Papers detail in Chapter 5 on the part of the system software design, the main function is relatively simple, calling a lot of Functions, after the commencement of procedures in the system initialization, there will be eight seconds of recording time or GPS information collection, If the press the button to set the record button, will enter a recording function, this can be good in accordance with the provisions of the original recording steps if press the keys with the GPS information collection button, will enter GPS information collection function, to be collected at this time At a certain latitude and longitude information, simply have to press the button GPS information collection and pay attention to this GPS data must be a valid data, GPS data that is effective only when the lights acquisition, or the data is invalid data, which was behind the station Will not correct, press the button, taken by latitude and longitude information will be stored in the EEPROM in MEGA64L to, even if such power-down will not lose site of the latitude and longitude information. In eight seconds in the not press any button, the system will scan the keyboard to wait for the cycle. The software system has three parts of interrupted service functions, which are key interrupt service function, GPS data reception interrupt service function and Mike interrupt service function, this will trigger an interrupt any disruption to the implementation of the interrupt service function, which interrupted service function keys, Due to the 12 keys on the flow chart that only a simple click, or will be very cumbersome. Functions are all basically process flowly, some of the initial function is given, in the papers can easily understood. Show that there are two functions, one is used in the digital display on the line, stops, idle time can also be used to show that time and in the system set up at the various status code for the system initialization and the other is the LED Large-screen display functions, as used by the large LED screen integrated character, the function of the design is very simple, just send the code with the Chinese characters can be displayed on the clock. Functions of the various procedures in simple to realize the function and reduce nesting and improve the stability.Papers in the sixth chapter to sum up with Outlook, the system made the simple evaluation and summary of the final of the system raised expectations. Finally, based on GPS and GSM smart bus system can automatically at stations by the Secretary for greatly reduced the labor intensity, increase the intensity of management of the bus operators, bus strengthen the scientific management of the maintenance operation order to enhance operational efficiency, Ensure operational safety and promote the development of intelligent public transportation is of positive significance.更多还原