Realization of Vehicle Intelligent Control System Based on GPS

0 Introduction GPS is a navigation and positioning system widely used in the world. It can provide accurate positioning, speed measurement and timing service for users in military and civilian fields. At present, mobile phones that are large enough to be used in airplanes, ships, and small palms, as long as they are equipped with the necessary GPS modules, can easily enjoy the precise and fast service provided by GPS. Assembling a GPS terminal on a car. With a single click, people can go all over the world with the help of GPS. In addition to being used by individual car users, GPS terminals can also provide services for group companies with a large number of vehicles. For example, taxi companies, bus companies and other large group users can use GPS related services to centrally monitor and manage their vehicles. . This paper introduces a vehicle intelligent control system (hereinafter referred to as the management and control system) based on GPS-related services, tailored for large group customers, integrating vehicle management, positioning, security and anti-theft.

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1 The hardware platform of the control system consists of two parts: the vehicle terminal and the monitoring center. The main functions of the vehicle terminal include: reception of GPS positioning information, transmission and reception of GSM/GPRS packet data (SMS, telephone), detection of vehicle status, and processing of alarm information.
The vehicle terminal is mainly composed of three parts: microprocessor, GSM/GPRS module, alarm sensor and control circuit. The block diagram is shown in Figure 1.

The main functions of the monitoring center: the reception of packet data and the transmission of control commands, monitoring and scheduling vehicle operation. The monitoring center is mainly composed of primary and secondary GPRSDTU, monitoring computer and software (including database). Its block diagram is shown in Figure 2.

2 Main functions and working principle of the control system The vehicle intelligent control system is a multi-functional integrated control system integrating functions such as vehicle positioning and tracking, vehicle management, vehicle safety and burglar alarm.
2.1 Vehicle Positioning and Tracking The monitoring center of the system can display the running position of the currently monitored vehicle in real time and dynamically, and can view the running track of the vehicle at any time. In addition, the system also has a tracking function: that is, in special cases, when the vehicle terminal does not send positioning information, the system can also view the location information of the vehicle, which is the tracking function of the vehicle. When the tracking function is activated, the monitoring center will send a tracking command to the vehicle terminal. When the vehicle terminal receives the tracking command, it will automatically send the current location information to the monitoring center.
2.2 Vehicle Management Vehicle management function is a basic function of the system. It is a general term for a series of system sub-functions, including vehicle management, maintenance management, fueling management, personnel management, etc.: Vehicle management includes vehicle registration, Carriage registration, departure inquiry and vehicle registration; vehicle maintenance management functions include maintenance registration, maintenance completion registration and maintenance inquiry; vehicle fueling management functions include fuel registration and fueling inquiry; vehicle personnel management functions include driving Member information registration and driver information inquiry.
2.3 Vehicle safety anti-theft and alarm The vehicle's safety anti-theft alarm function is a new and practical function of the system. The system is equipped with a number of safety detection functions, such as door detection, vehicle vibration detection, and license plate detection. After the security burglar alarm function is activated. As long as any abnormality occurs, the vehicle terminal will send a short message or telephone alarm to the monitoring center, driver or vehicle management person. In addition, the vehicle terminal is also equipped with a vehicle anti-riot and anti-grab alarm button, and the driver can press the button to report to the monitoring center when an accidental attack or other injury occurs.

3 The main technical difficulties and solutions
3.1 GPS information reception and vehicle position information data transmission problem system In order to realize the vehicle positioning function, the vehicle terminal needs to receive the GPS satellite positioning information, send the positioning information to the microprocessor for processing, and then send it to GSM/GPRS after encryption processing. The module is sent to the monitoring center. GPS and GSM/GPRS data require microprocessor processing at the same time, so the microprocessor needs to have at least two serial ports. The choice of high-performance, stable and reliable microprocessor with two serial ports is a difficult problem to be solved in system design. After comparing the performance of several microprocessors, the final system chose to use Winbond's W77LE532 microprocessor, which is an 8-bit processor with fast speed (one machine cycle is 4 clock cycles), dual independent working serial port. Large storage space (128K ROM) and other features.
3.2 Monitoring Center Data Access Problem Monitoring data access mode is another major problem in system design. The data center access methods can be divided into two categories: wireless access mode and wired access mode. The wireless access mode can be divided into primary and secondary GPRS-DTU+ mobile intranet dynamic IP+ mobile DNS resolution service mode and main The secondary GPRS-DTU+ mobile APN private network fixed IP mode; the wired access mode can also be divided into: adopting public network fixed IP or public network dynamic IP+DNS resolution service mode and APN private line + intranet fixed IP mode.
Considering the application specificity of some special systems and the economic burden of the unit, the system design finally adopts the fixed IP mode of the main and secondary GPRS-DTU+ mobile APN private network. This method is convenient for pick-up, and the monitoring center has wireless mobility, which is suitable for the movement of the monitoring center such as maneuvering and transfer of the fleet, and has high safety and reliability.
3.3 Positioning information dynamic display problem The dynamic display of vehicle position information and position query display is the main function of the monitoring center. To realize this important function, the system uses the electronic map control technology based on MapX control to make it receive. The GPS position information (longitude, latitude, etc.) is visually displayed on the electronic map, which realizes the direct and dynamic display of the vehicle position, which is convenient for the manager to know the running status of the vehicle in real time.
3.4 System compatibility issues with previous management software Currently, there are many vehicle management software. Many units may already have some control software running, but the related software functions may be relatively simple and cannot meet the new requirements of vehicle management and control. If the original system is opened and a new system is used, the original control data may be lost and a serious waste of resources may be caused. Therefore, in order to facilitate the user to upgrade the old management system, the new system needs to be compatible with the previous management system. It is able to realize database import and information compatibility, which is one of the system design challenges.
The monitoring center application software uses Delphi object-oriented development tools and database technology in design, enhances the system database import function, and is fully compatible with various common types of databases, which can facilitate users to quickly upgrade and transform the system.

4 Conclusion Vehicle management is an important part of the daily work of large group users. Due to the constant facing new problems, the difficulty of vehicle management is increasing. The traditional static management is far from meeting the needs of most users. A new vehicle management and control system with real-time and dynamic remote monitoring capability. The development of the vehicle intelligent control system has solved the above problems very well. After the system was developed, it was tested repeatedly. Continuous improvement and improvement of functions, system stability, reliability and safety have been greatly improved, and can meet the various needs of the relevant dedicated vehicle control systems. The use of this system will greatly improve the management level and efficiency of vehicle management and control of relevant units, and save vehicle management funds, which will be welcomed by vehicle management departments and drivers.