Design And Implementation Of Diagnosis GPS Terminal Of Vehicle

In our country, logistics has been an independent industry, and its development route and strategic choice are also diversifying. So it has become a important project.The GPS Monitoring Center could monitor many freight transport cars and logistics cars ,and could find their locations in time in this system. It can allocate the commodities depending on the location of the vehicle , to reduce the moral depreciation and reduce the cost of petrol and the cost of road and bridge, and finally reduce the cost of the operations.Along with the development of logistics industry, car loan industry has occupied more and more portion of the vehicle market. Facing the shirking of personal auto loan, vehicle dealers want to find a way to enhance the management of vehicle in order to reduce the risk of evading repayment personal auto loan extremely anxious. In this case, we developed the diagnosis GPS vehicle terminal, which aims at controlling the consumption of consumer credits and GPS remote after-sales services. The main tasks of this paper are as follows:1,To solve the problem of the car loan, many vehicle factories, dealers, managers and terminal marketing try to think out a way with all their energy. Nowadays, the equipment in the market generally applies the method in which we could cut the oil and the circuit to the evade repayment personal auto loan after receiving the command from the monitor center, and in the way reduce the risk of evading repayment personal auto loan. But this method doesn't involve the internal controlling of the automotive engine, so there are still some disadvantages. As for people familiar with vehicles, it is very easy to change the automotive circuit, and then to avoid the controlling from the monitor center and shirk the car loan. It is described that we combine the vehicle terminal with the automotive engine to improve the degree of difficulty of changing the vehicle circuit through controlling the acting of the engine to reduce the chance of evading repayment personal auto loan.2,GPS vehicle terminal can return the fault information of ECU through GPRS, and we can analyze and save the fault phenomena through analyzing software. We can get the on-line information of the fault diagnosis, or get touch with the nearby department to supply the rescue service. And the GPS vehicle terminal, connecting the vehicle terminal to the CAN of the car, send information of the sensor, the cost of the oil and mileage back to the monitor centre.3,There are two microcontrollers in this system, C8051F022 and S9S08DZ60. The diagnosis controller is a wide-range voltage microcontroller. The power supply is 5v in our system to meet the requirement of 5v interface. To protect the whole secrecy, we separate the diagnosis microcontroller, as to meet the requirement from the vehicle factory. The memory is FM24CL64 of RAMTRON, 8KB. The vehicle terminal can access to the memory extensively in short time, and EEPROM memory will be easy to be destroyed by extensively written and read. The RAMTRON can't be destroyed by written and read infinitesimally almost, and it is a good choice for the vehicle terminal. The diagnosis interface contained CAN and K bus. Because the microcontroller S9S08DZ60 has integrated CAN bus, we just supply a CAN transceiver. CAN transceiver is NXP TJA1050, a high speed transceiver up to 1M baud, combined with criterion ISO11989.4,There are three structure layers, including system layer, device layer and driver layer. The application layer is used to meet the requirement of the customers. The device layer is used to control and monitor the status of the device, deal with the fault, and supply the interface to the applications. The driver layer is used to supply the interface to the device, and realize the writing and reading operation. The theory of hierarchies separate the application and the interface driver and improve the portability.The ability of the 8bit microcontroller is limited, but there are many tasks and interface to deal with. It requires the strong real-time character. We take the tasks into many slices, and every task can be executed one slice or more in one circle, so we can finish the task in some time.Application layer invoke the device interface, and then send the control order word and parameter to the device related layer. If relating layer the device detect the order word or the parameter, and it will allocate the system time slice to accomplish the task. At last the result will be stored into the device structures, and the application layer will detect the status characteristics, and then deal with result.We can improve the influence of Qiming company in GPS field by increasing the market share in the GPS field. In the case of increasing fuel duty, it helps reduce the ratio of shirking car loan , and the loss of the s evading repayment personal auto loan, by analyzing the return fault information of vehicle, supply the service of on-line diagnosis in time, monitor the vehicle real-time running status, dealers can manage the vehicles in unified administration. To sum up, developing this system of controlling credit supervision and GPS remote after-sale service is very significant. Nowadays, this system has been tested in Qiming company lab containing software and hardware, and has achieved the desired results.