Research On Channel Estimation And Equalization In High-Accuracy Ultra-wideband Positioning

Ultra-wideband (UWB) positioning technology has great potentials in short-distance wireless positioning today. Widely application of UWB positioning depends on highly positioning accuracy. Because of the complicated UWB channel, it is difficult to improve positioning accuracy more.UWB channel model is analyzed and estimated. A novel equalization technology is proposed which can significantly improve the positioning accuracy, Improved scheme that can improve the accuracy in the stage of position calculate are proposed. The main contributions of the thesis are as follows:1. IEEE802.15.4a UWB channel model and its impact to UWB positioning are investigated. The channel is estimated by the maximum-likelihood(ML) algorithm and the least-square(LS) algorithm. Simulation results show that in the case of longer training sequence, ML and LS algorithm has a good performance,which is important to eliminate the impact of multipath.2. A high-precision TDOA ranging scheme is proposed, which is based on delay-fixed LMS equalizer and multi-phase matched filter. Simulation results show that this equalizer restored the character of original sampled waveform and the sampling locations can be obtained by the multi-phase matched filter. High-precision ranging can be realized under conditions of complicated channel.3. Different TDOA location algorithms are simulated and an improved position scheme is proposed.Chooseing the best result from a group of results by adding a redundant anchor node,the whole positioning accuracy can be improved notable. Simulation results show that precision of the position scheme is:2cm and 3cm for the two-dimensional and three-dimensional respectivly.