| 摘要 |
Spaced first and second signposts transmit wireless signals containing different signpost identifications. A first path of travel passes through the transmission range of the first signpost, and a second path of travel passes through the transmission range of the second signpost but not the transmission range of the first signpost. A different configuration includes plural hallways extending away from a common intersection in respective directions, with a respective signpost in each hallway that transmits wireless signals containing a respective different signpost identification. Another configuration includes a hallway with first and second portions of different width, a first signpost in the first portion transmitting wireless signals containing a first signpost identification, and spaced second and third signposts in the second portion each transmitting wireless signals containing a second signpost identification different from the first signpost identification, and having a transmission range less than a width of the second portion. |
