Study On TDOA Localization And NLOS Inhibition Technology Based On Mobile Broadcast Network

With the development of mobile communication technology and the increasing demandof the position information, the outdoor wireless location technology is widely used in allwalks of life. Wireless positioning technology based on mobile broadcast network, uses acombination of satellite and ground supplementary network mode to realize the positioningrange effective coverage. It is superior to the traditional cellular network in anti interferenceand multi-path aspects, has attracted a lot of attention. This thesis carries out research ofmobile broadcast network outdoor positioning technology, focus on the best linear unbiasedestimation localization algorithm in view of the TDOA location algorithm errors and non lineof sight error model based on ray tracing in the communication environment of Non line ofsight and TDOA reconstruction. The main work and innovation are as follows:First of all, the thesis summarizes the reality principle, signal transmission channelmodel and some basic positioning methods of mobile broadcast network positioningtechnology, analysis all kinds of errors existing in the process of positioning, gives thechannel model and method of location positioning for mobile broadcast network.Secondly, according to the measurement errors and NLOS errors existed in the processof signal transmission, presents a TDOA location algorithm based on the optimal linearunbiased estimation. The algorithm combines the advantages of Chan algorithm and Tayloralgorithm, using minimum variance as the evaluation accuracy standard of the positioning,not only improved the positioning accuracy of algorithm, also shortened the positioning time.The simulate comparison experiment results show that, this algorithm is better than Chanalgorithm and Taylor algorithm.Then, according to the problems of ray reflection and diffraction caused by the occlusionof buildings during outdoor radio propagate, put forward a kind of NLOS errors model basedon ray tracing, statistics ray path loss and NLOS delay by simulating ray propagation.According to the different location conditions ropose the model based on geographicalinformation and based on statistical properties NLOS errors, and then simulate experiment onthe different model.Finally, apply NLOS errors model based on ray tracing to TDOA location algorithm, usethe optimal unbiased estimate location algorithm to verify the validity of the model. In thechannel model of COST259, use the NLOS errors model to statistic TDOA delay, reconstructTDOA data. Simulation results show the model can effectively improve the positioningaccuracy in severe NLOS errors downtown environment.