Research Of Positioning Technology For Train Based On Wireless Sensor Network

Chinese railway lines have been increasing since 1876 Chinese first railway was born. Railway locomotive traction also across the evolution from the age of steam machine to the age of the internal combustion engine and the age of electrification, the train speed is speeded up six times. The train positioning technology must be realized continuously in real time to ensure safe and efficient operation of the train, however, the current positioning of some technology has this limitation so that location information of the train cannot be updated in real time.With the rapid development of electronics and wireless communication technology, making low cost and low power consumption of multifunctional wireless sensor development and widely application be possible. Based on the research and application of wireless sensor network is booming. Wireless sensor network can real-time update the location information of the train, as long as nodes can be arranged reasonably especially in mountain area or forest, tunnel, it can play a good role. At present, wireless sensor network localization has some algorithms. TDOA(time difference of arrival) and AOA(angle of arrival) have special requirements on the hardware. TOA(time of arrival) requires accurate clock synchronization, but RSSI(received signal strength instructions) has no additional requirements on the hardware, its main use is a radio signal strength. Because sensor nodes with wireless communication capabilities, this is a low-power, inexpensive and based on distance measuring technology localization algorithm. And the use of GPS positioning principle to achieve WSN positioning is also a feasible positioning idea. Two localization algorithms of wireless sensor network are used in this thesis.The first is the Improve RSSI Modified Weighted Centroid Localization Algorithm. The traditional Weighted Centroid Localization Algorithm Based on RSSI because the dynamic train in each carriage is relatively static, on a moving train positioning error correction plan is proposed in theory.The second is WSN Positioning Algorithm Based on the Positioning Theory of GPS. Based on the positioning Theory of GPS, this thesis proposes a WSN location algorithm based on GPS positioning theory. The beacon node as a space satellite, to be the location of the train is the ground receiver. The estimation of the distance between two points are based on the transmission time of the signal from the beacon node to the unknown node to estimate the position of the train. In order to reduce the positioning error, the train position is modeled and analyzed in this thesis. The noise generated in the calculation result is filtered out. Finally, the simulation results show that the WSN Positioning Algorithm Based on GPS is not only feasible, but also the positioning error is less than the traditional RSSI Modified Weighted Centroid Localization Algorithm and the Improved RSSI Modified Weighted Centroid Localization Algorithm. Algorithm stability is better than these two kinds.Finally, in order to verify the feasibility and superiority of the algorithm, the car instead of train built a small verification system. The CC2530 development boards of the sleep mode as sensors to test and analysis the dynamic positioning error of algorithm. Experiments show that the WSN Positioning Algorithm Based on GPS Positioning Theory has better stability, and the average positioning error is maintained at about 3 m in different operating speeds. The error fluctuation range is always smaller than that of the Improved RSSI Modified Weighted Centroid Localization Algorithm.