| 摘要 |
A locating system in which a network of communication stations are spread over a surveillance area. Each moveable element is provided with a transponder (50) having an associated identification code. A paging signal (F1) sent out over the surveillance area is picked up by the transponders (50) and the one with the identification code provided in the page responds. The response is made at a frequency (TF1) different from the page (F1). The response is picked up by the nearest communication stations. A master station (30) communicates with the communication stations at a frequency (F2) different from that used by the paging signal (F1) or the transponder (TF1). The master station (30) which interrogates all the communication stations locates the paged transponder (50) to within a sector bordered by the communication stations that received the response from the transponder (50). The communication stations can be subdivided into three or more interspersed arrays (40).
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