Zhou Zilong, Rui Yichao, Cai Xin
School of Resources and Safety Engineering, Central South University, Changsha 410083, China.
School of Resources and Safety Engineering, Central South University, Changsha 410083, China.
Ultrasonics. 2021 Aug;115:106458. doi: 10.1016/j.ultras.2021.106458. Epub 2021 May 9.
To improve the noise immunity to time-difference-of-arrival (TDOA) measurements and reduce the influence of wave velocity measurement error on localization accuracy, a novel linear-correction localization method of acoustic emission (AE) source for velocity-free system based on the TDOA measurements is proposed in this paper. First, the linear equations with unknown wave velocity are constructed by introducing two intermediate variables, and they are solved for the unconstrained least square (LS) solution. Second, the weight matrix is obtained by estimating the equation residuals. Third, the weight matrix and quadratic constraint are imposed on LS estimate to construct the constrained weighted least square (CWLS) criterion. Finally, the linear correction technique is used to minimize the CWLS criterion and obtain the optimal estimate. The proposed method is verified by pencil-lead breaks experiment. The results show that the locating accuracy and stability of the proposed method are higher than those of the traditional methods. Furthermore, simulation tests prove that the proposed method holds the optimal positioning performance and can reach Cramér-Rao lower bound (CRLB) under different TDOA noise powers.
为提高到达时间差（TDOA）测量的抗噪声能力，减少波速测量误差对定位精度的影响，本文提出了一种基于TDOA测量的无速度系统声发射（AE）源线性校正定位新方法。首先，通过引入两个中间变量构建含未知波速的线性方程组，并求解无约束最小二乘（LS）解。其次，通过估计方程残差获得权重矩阵。第三，将权重矩阵和二次约束施加于LS估计以构建约束加权最小二乘（CWLS）准则。最后，采用线性校正技术使CWLS准则最小化并获得最优估计。通过铅笔芯断裂实验验证了所提方法。结果表明，所提方法的定位精度和稳定性高于传统方法。此外，仿真测试证明所提方法具有最优定位性能，且在不同TDOA噪声功率下能达到克拉美罗下界（CRLB）。
