Overview of the application of vehicle remote service system based on GPS/GPRS

With the development of the automobile industry, modern electronic control technology has penetrated into all parts of automobiles. The structure of automobiles has become more and more complex, and the degree of automation has become higher and higher. There is a growing shortage of maintenance technicians and experts who can track and master high-tech in the automobile field. The Internet has developed rapidly with the advancement of the global information process, which provides a fast and free way for resource sharing and information exchange among automobile maintenance industries, and also makes it possible to establish an open automobile remote fault diagnosis system based on computer network communication and processing. As a complex interdisciplinary system involving many research fields, the remote service system has always been valued by researchers and governments in various countries, and has invested a lot of money to carry out research on basic theories and application products. In recent years, with the gradual improvement of various supporting technologies, remote services have been widely used in many fields.

The vehicle remote service system is a new high-tech product developed based on advanced GPS global positioning technology and GPRS remote communication technology, integrating automobile electronic control technology, automobile diagnosis technology, and remote communication technology, as shown in Figure 1. It can closely connect automobile manufacturers, dealers, fleet service centers, vehicles, and users into a network, and easily realize functions such as data transmission, target tracking, automatic alarm, and drivers and passengers obtaining various public information and practical information services. It not only provides customers with timely vehicle maintenance services, but also can promote its own services to finance, leasing, insurance, remanufacturing, logistics, management and other business fields through this network, expanding the scope of manufacturers' business services and creating rich economic benefits for manufacturers.

How to deal with faulty vehicles in a timely manner and accurately locate the fault location of the vehicle has always been a difficult problem for automobile after-sales service. The application of remote service systems has gradually solved this problem. In the event of a vehicle failure, the various sensors on the vehicle collect various information inside the vehicle, providing rich data for remote vehicle monitoring; the GPRS network system can accurately determine the location of the vehicle, and the fault information can be used to preliminarily determine the location of the fault. Vehicle maintenance personnel and back-end experts determine the best fault solution through computer networks and databases, so that vehicle faults can be quickly repaired. The information storage module of the remote service system can provide a scientific basis for vehicle failures and provide a useful reference for vehicle design improvements.

Figure 2 is a product image of a GPS/GPRS vehicle-mounted remote service system developed by a domestic manufacturer. The entire system consists of a control box, GPS/GPRS antenna, and vehicle interface harness. The control box contains a GPS/GPRS communication module, which is responsible for the communication management and data collection of the entire system. This product is widely used in 4S store after-sales management, logistics fleet management, truck leasing and loan sales management, and command and dispatch systems for special industry vehicles.

A vehicle-mounted remote service system based on GPS/GPRS is often composed of online data collection, remote diagnosis, expert diagnosis, information retrieval services and other major parts. It mainly includes GPS receiver, GPRS wireless communication module, central controller, power module and other components. Its working principle is: the GPS receiver in the terminal device installed on the vehicle calculates the current positioning information of the vehicle based on the received satellite information, and the communication processor extracts the required position, speed, altitude, time and other related information from the signal output by the GPS receiver; the vehicle-mounted mobile terminal collects the vehicle operation status data to obtain the vehicle real-time information, and at the same time, various sensor signals, vehicle operation status, fault information and other messages obtained from the vehicle bus form a comprehensive data packet, and then the collected real-time signals are sent to the GPRS network system and sent to the monitoring center through the wireless channel. The monitoring center receives the sent data, extracts the vehicle location information from it, and displays it on the electronic map of the monitoring center, as shown in Figure 3.

At the same time, professional engineers at the control center can remotely analyze and diagnose the vehicle based on the vehicle's operating status data and fault information, achieve two-way interaction with the remote fault diagnosis center through the network system, and finally obtain the diagnosis results. They will then feedback the solution and the nearest service station to the user, thereby realizing remote service.

GPS is the abbreviation of Global Positioning System. The GPS system consists of three parts: the space part - GPS satellite constellation; the ground control part - ground support system; the user equipment part - GPS signal receiver, as shown in Figure 4.

The GPS signal receiver captures the signals of the satellites to be measured selected according to a certain satellite altitude cutoff angle, tracks the movement of these satellites, transforms, amplifies and processes the received GPS signals, so as to measure the propagation time of the GPS signal from the satellite to the receiver antenna, parse the information messages sent by the GPS satellite, and calculate the three-dimensional position, speed, time and other information of the measuring station in real time.

GPRS is the full name of General Packet Radio Service in English, and its Chinese meaning is General Packet Radio Service. It is a wireless transmission method developed using the concept of "packet switching". The information to be transmitted is divided into packets (groups) of a certain length, and each packet information carries the identification of the receiving address and the sending address; before transmitting the data, a virtual connection is established first, and then sent in sequence. At present, China Mobile's GPRS network has covered all provinces, municipalities, and autonomous regions in the country, and the network covers more than 240 cities. Using the widely distributed GPRS network, wireless transmission of data in different places can be easily realized, and the price is very low. GPRS has the following advantages:

①Always online: Once the GPRS application is activated, it will always stay online without any disconnection issues, similar to a wireless dedicated line network.

②Billing by traffic: Although you are always online, you don’t have to worry about the cost, because you are only charged when communication traffic is generated. It is a usage-oriented billing method with a more scientific and reasonable billing method.

③Quick login: The new group service eliminates the need for the long dial-up process to establish a connection.

④ Easy switching: Voice and data services can be switched, allowing you to make calls and surf the Internet at the same time.

⑤ High-speed transmission: The maximum theoretical transmission speed of GPRS is 171.2kbit/s. Currently, GPRS can support a transmission rate of about 40kbit/s.

In the domestic heavy truck market, the GPS/GPRS vehicle-mounted remote diagnosis system has been gradually applied. A concrete enterprise in Gongshu District, Hangzhou, installed GPS/GPRS systems on more than 1,800 concrete mixer trucks. Gongshu District, Xiasha (Economic Development Zone), Xihu District and Jianggan District have established GPS positioning system monitoring workstations respectively, using a unified platform to implement remote monitoring of vehicles and standardize the routes and speeds of concrete mixer trucks. "Disabled" vehicles with hidden faults are refused to enter the city. Concrete mixer trucks equipped with GPS/GPRS systems will put a "rein" on the "running" engineering vehicles. According to statistics, the company had 9 vehicle safety accidents from January to July 2008, 0 injuries, 1 death, and economic losses of 422,800 yuan; and after installing the GPS/GPRS system in 2009, there were 6 vehicle safety accidents from January to July, 0 injuries, 0 deaths, and economic losses of 13,900 yuan, a year-on-year decrease of 328%.

The automobile remote service system is a complex network system, involving computer networks, communication technology, virtual reality technology, electronic technology, automobile fault diagnosis technology and other details. A practical remote service system can only be continuously developed and improved with the coordinated support of auto repair companies, scientific research institutes and automobile manufacturers. However, it is certain that due to its accuracy and efficiency, this emerging technology will have broad application prospects with the rapid development of my country's automobile industry.