发明授权
US07528776B2 Beacon-assisted precision location of untethered client in packet networks
失效
分组网络中无信号客户端的信标辅助精确定位
- 专利标题: Beacon-assisted precision location of untethered client in packet networks
- 专利标题(中): 分组网络中无信号客户端的信标辅助精确定位
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申请号: US11689660申请日: 2007-03-22
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公开(公告)号: US07528776B2公开(公告)日: 2009-05-05
- 发明人: Delfin Y. Montuno , James Aweya , Michel Ouellette , Kent Felske
- 申请人: Delfin Y. Montuno , James Aweya , Michel Ouellette , Kent Felske
- 申请人地址: CA St. Laurent, Quebec
- 专利权人: Nortel Networks Limited
- 当前专利权人: Nortel Networks Limited
- 当前专利权人地址: CA St. Laurent, Quebec
- 代理机构: Anderson Gorecki & Manaras LLP
- 主分类号: G01S3/02
- IPC分类号: G01S3/02
摘要:
A novel beacon-based position location technique for efficient location discovery of untethered clients in packet networks is disclosed. The position location technique utilizes the time-difference-of-arrival (“TDOA”) of a first signal transmitted by a beacon of known location and a second signal transmitted by an untethered client. The TDOA of these two signals is measured locally by at least three non-collinear signal receivers. For each of the receivers, the TDOA is used to calculate a perceived distance to the client. A circle is then calculated for each receiver, centered on the receiver and having a radius equal to the perceived distance. At least two lines defined by points of intersection of the calculated circles are then calculated. The point of intersection of the lines represents the location of the client. To facilitate operation, the signal receivers may be arranged on vertices which define a convex polygon as viewed from above. The location system requires no time (time-of-day) synchronization of the signal receivers, and only the coarse frequency synchronization, on the order of, tens of parts-per-million (ppm). The technique even works for the case where the signal receivers are run asynchronously, provided the frequency accuracies of the signal receivers are on the order of about 50 ppm or better. The technique introduces no communication overhead for the beacon, client and signal receivers. Further, the computation overhead at the signal receivers is relatively low because the location detection algorithm involves only simple algebraic operations over scalar values.
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