通过将IR—UWB穿墙测距NLOS误差建模为由空间结构导致的几何距离误差和脉冲信号波形失真导致的峰值偏移误差.依据高频射线理论推导了基于收发节点距离和墙体参数的几何距离误差限.通过对IR—UWB信号穿墙透射机理的建模,研究了频率依赖性导致的波形失真问题及相应的TOA测距误差.仿真结果表明,几何距离误差主要由墙体障碍物参数决定,受收发节点间距离的影响不大;IR—UWB信号穿墙传播会发生波形畸变,墙体的非均匀性和相对介电常数越大,波形畸变越严重,由此导致的TOA相关峰值偏移误差维持在脉冲信号距离分辨率范围内.
As the TOA ranging error was always corrupted by the direct path blockage and excess delay in complicated indoor environments, the NLOS ranging error due to IR-UWB through wall propagation was mod- eled by dividing it into two parts: the geometrical error caused by the pulse transmitted through wall, and the peak biased error caused by the pulse waveform distortion due to frequency dependence of huge bandwidth. The theoretical geometrical error bound was derived from transceiver distance, wall thickness and materials. The IR-UWB through wall propagation was modeled using sub-band method, and the peak biased errors were investigated through the waveform distortion of IR-UWB signal propagated in different wall structures. The simulation results show that the geometrical error was mainly determined by the obstacles parameters and the peak biased errors caused by IR-UWB waveform distortions were within the distance resolution of IR-UWB signal.