Based On The Design Of Hybrid Positioning System Gps And Gsm

This paper proposed a technology of designing a combined location system, which is based on GPS and GSM. First, this paper represents both development and application field of location technology of the world. As followed, the architecture and advantage of this system are also described. And then it describes the hardware architecture of mobile location terminal, performance of signal chip that is used in this terminal, technology of I2C bus and software architecture in detail. According to these, the idea of modularization of both hardware and software is proposed. Both the theory and the composition of GPS are described because GPS position technology is the main location technology in this system. Certainly both characteristic of hardware and operation of software of GPS receiver, which is used in this system, are described too. As for this location system, communication between control center and mobile location terminal is based on SMS (short message service) wireless access of GSM network. So the SMS wireless access technology, include encoding and mode of short message, is discussed. Moreover, wireless access module of siemens cellular engine is illuminated in detail. In the last part of this paper, arithmetic of signal strength location ,which is applied in this system,is discussed. This applied arithmetic is based on maximum likelihood function. Accuracy of location is high because this estimation method is based on statistics. Moreover, loss of propagation of signal strength is very important to computing location, in order to make the result more accurate, a propagation model of radio wave, which is called corrected akumura hata propagation model educed from much real data, is proposed. And so mean-loss of signal strength educed from this model was closer to real data. At the end of this paper, location result is listed and some relative problems are analyzed.