TDOA Based Positioning in the Presence of Unknown Clock Skew
TDOA Based Positioning in the Presence of Unknown Clock Skew
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DOI：
10.1109/tcomm.2013.032013.120381
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发表时间：
2013-03
影响因子：
8.3
通讯作者：
M. R. Gholami;S. Gezici;E. Ström
中科院分区：
文献类型：
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作者：
M. R. Gholami;S. Gezici;E. Ström
本文研究了存在时钟缺陷时基于到达时间差（TDOA）测量的单个目标节点的定位问题。通过对本地时钟的行为采用仿射模型，可以观察到基于 TDOA 的方法会受到模型参数（称为时钟偏差）的影响。本文将时钟偏差建模为干扰参数，研究联合时钟偏差和位置估计。针对该问题推导了最大似然估计器（MLE），该问题高度非凸且难以求解。为了避免求解 MLE 的困难，我们采用适当的近似和松弛，并提出了两种基于半定规划和线性估计的次优估计器。为了进一步提高估计精度，我们还提出了一个细化步骤。此外，还为此问题导出了 Cramér-Rao 下界 (CRLB) 作为基准。仿真结果表明，所提出的次优估计器可以获得 CRLB 以获得足够高的信噪比。
This paper studies the positioning problem of a single target node based on time-difference-of-arrival (TDOA) measurements in the presence of clock imperfections. Employing an affine model for the behaviour of a local clock, it is observed that TDOA based approaches suffer from a parameter of the model, called the clock skew. Modeling the clock skew as a nuisance parameter, this paper investigates joint clock skew and position estimation. The maximum likelihood estimator (MLE) is derived for this problem, which is highly nonconvex and difficult to solve. To avoid the difficulty in solving the MLE, we employ suitable approximations and relaxations and propose two suboptimal estimators based on semidefinite programming and linear estimation. To further improve the estimation accuracy, we also propose a refining step. In addition, the Cramér-Rao lower bound (CRLB) is derived for this problem as a benchmark. Simulation results show that the proposed suboptimal estimators can attain the CRLB for sufficiently high signal-to-noise ratios.