TOA-based distributed localisation with unknown internal delays and clock frequency offsets in wireless sensor networks
TOA-based distributed localisation with unknown internal delays and clock frequency offsets in wireless sensor networks
复制标题
DOI：
10.1049/iet-spr:20080029
复制
发表时间：
2009-03-01
影响因子：
1.7
通讯作者：
Hedley, M.
中科院分区：
文献类型：
--
作者：
Yu, K.;Guo, Y. J.;Hedley, M.
在自组织无线传感器网络（WSN）中定位传感器节点是一项具有挑战性的任务。一般来说，网络节点是不同步的，节点内部的延迟是未知的。本文研究了在时钟时间偏移、时钟频率偏移和系统内部延迟等实际参数的情况下，基于到达时间（TOA）的定位。TOA测量在无线电范围内的每对节点之间进行。首先，推导了一种有效的频偏估计算法。然后，提出了一种两阶段定位方案。在第一阶段，本地化从拥有最多相邻锚点的节点开始，优先级总是给予拥有更多相邻锚点和/或本地化节点的节点。在第二阶段，利用所有相邻节点的位置来提高定位精度。提出了两种迭代算法：基于泰勒级数的最小二乘（TS-LS）方法和顺序二次规划（SQP）优化方法。在定位过程中，为了避免异常误差，减少误差传播，采取了一系列措施来保证每个位置估计的可靠性。此外，还推导出了Cramer-Rao下界来衡量定位精度。
Locating sensor nodes in an ad hoc wireless sensor network (WSN) is a challenging task. In general, the network nodes are not synchronised and the internal delays within the nodes are unknown. Here, time-of-arrival (TOA)-based localisation is investigated when practical parameters such as clock time offset, clock frequency offset and system internal delay are all involved. The TOA measurements are made between each pair of nodes that are within radio range. First, an efficient frequency offset (FO) estimation algorithm is derived. Then, a two-stage localisation scheme is proposed. In the first stage, localisation starts from the nodes with the largest numbers of neighbouring anchors and priority is always given to nodes with more neighbouring anchors and/or localised nodes. In the second stage, the locations of all neighbouring nodes are exploited to improve location accuracy. Two iterative algorithms are developed: the Taylor series-based least squares (TS-LS) method and the sequential quadratic programming (SQP) optimisation method. During the localisation process, a number of measures are taken to ensure the reliability of each location estimate to avoid abnormal errors and reduce error propagation. The Cramer-Rao lower bound is also derived to benchmark the location accuracy.