现实生活中针对居家老人的安全防护主要是通过固定通讯设备被动询问,危险发生时难以及时获得老人的状况,造成不可预知的严重后果。室内人员预警系统的设计依据信号到达时差(Time Difference of Arrival,TDOA)和基于球面的空间定位组合(S...现实生活中针对居家老人的安全防护主要是通过固定通讯设备被动询问,危险发生时难以及时获得老人的状况,造成不可预知的严重后果。室内人员预警系统的设计依据信号到达时差(Time Difference of Arrival,TDOA)和基于球面的空间定位组合(Sphere-Based Localization Scheme,SBLS)原理对定位节点(老人)实施三维定位,采用实时主动跟踪被定位节点的三维位置信息,通过动态对空间信息和时间信息的综合比对判断定位节点是否处在设定的"危险状态"并进行实时预警,经过实际测试15m2面积上4个测量节点基本能够监测到定位节点的位置变化情况。当定位节点处在"危险状态"时系统通过所携带设备发出震动和响声提示此刻是"危险状态";实时预警是对外部(如:子女,医院等)进行电话预警。整套系统不需要被动查询老人状态,通过全方位监测和实时预警使居家老人的安全防护得到改善和提高。展开更多
This paper presents a source localization algorithm based on the source signal's time-difference-of-arrival(TDOA) for asynchronous wireless sensor network.To obtain synchronization among anchors,all anchors broadc...This paper presents a source localization algorithm based on the source signal's time-difference-of-arrival(TDOA) for asynchronous wireless sensor network.To obtain synchronization among anchors,all anchors broadcast signals periodically,the clock offsets and skews of anchor pairs can be estimated using broadcasting signal's time-of-arrivals(TOA) at anchors.A kalman filter is adopted to improve the accuracy of clock offsets and track the clock drifts due to random fluctuations.Once the source transmits signal,the TOAs at anchors are stamped respectively and source's TDOA error due to clock offset and skew of anchor pair can be mitigated by a compensation operation.Based on a Gaussian noise model,maximum likelihood estimation(MLE) for the source position is obtained.Performance issues are addressed by evaluating the Cramer-Rao lower bound and the selection of broadcasting period.The proposed algorithm is simple and effective,which has close performance with synchronous TDOA algorithm.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61571452 and No.61201331
文摘This paper presents a source localization algorithm based on the source signal's time-difference-of-arrival(TDOA) for asynchronous wireless sensor network.To obtain synchronization among anchors,all anchors broadcast signals periodically,the clock offsets and skews of anchor pairs can be estimated using broadcasting signal's time-of-arrivals(TOA) at anchors.A kalman filter is adopted to improve the accuracy of clock offsets and track the clock drifts due to random fluctuations.Once the source transmits signal,the TOAs at anchors are stamped respectively and source's TDOA error due to clock offset and skew of anchor pair can be mitigated by a compensation operation.Based on a Gaussian noise model,maximum likelihood estimation(MLE) for the source position is obtained.Performance issues are addressed by evaluating the Cramer-Rao lower bound and the selection of broadcasting period.The proposed algorithm is simple and effective,which has close performance with synchronous TDOA algorithm.
