Research On The Doppler Wireless Location Techniques Based On DSSS

Because of the complex condition, the accident rate of coal mine remains high in China. At the time of accident, it has become an important issue which requires urgent solution that how to determine the number and location of the underground staff to carry out effective and accurate location of the rescue, and also to minimize the loss. Therefore the study of positioning system has been imminent at current. However, as a result of the complex environment underground, the attenuation and distortion in the course of the spread of electromagnetic waves is very serious. And some of the positioning system doesn't work at all. This dissertation presents a positioning system based on Direct Sequence Spread Spectrum (DSSS) communication and Doppler positioning method to improve the accuracy.This dissertation analyzes the present situations of mine location in domestic and foreign in practical application at current and discusses the problems of location. And then detailed analysis of the spread spectrum communication system in principle, signal characteristics and anti-jamming capabilities is made. The basic principles and excellent characters of the method of"Doppler frequency shift positioning"and"Doppler phase positioning"are also discussed. And on the basis, the DSSS techniques and Doppler method are combined to overcome the conflict of transmission and anti-jamming capabilities. At the same time, the simulation of Doppler rotating antenna is introduced to solve the problem of rotating antenna. As a result, a realizable system is given which is very stably and has strong anti-jamming capabilities. It's easy to use and implement. If the system is put into use, the cost can be effectively controlled. It can guarantee the accurate location of the victims when landslides and other critical conditions break out. Finally, the Monte Carlo simulation is made based on software platform and the expected positioning accuracy is gained. The complexity of the channel is fully considered of to make the channel model structures as true as possible while the tunnel transmission model is also introduced. At last the dissertation gives relevant positioning results and analysis of different parameters on the impact of positioning accuracy which has certain practical significance.