New positioning techniques are needed. To implement a GPS-free and fixed-grids-independent three-dimensionalpositioning system is challenging in multi-hop wireless networks.
实现不依赖GPS和固定网络设施的三维定位，是多跳移动自组网络中具有挑战性的新课题。
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Objective: Measuring the secure depths and angles of Yamen acupoint with three-dimensionalpositioning MRI to provide the reference datas of secure depths and angles for clinic.
Objective: To approach the feasibility of the three-dimensionalpositioning and navigation with regular catheter electrodes in intracavitary with a low-frequency electrical field.