NIST Tests of the Wireless Environment in Automobile Manufacturing Facilities
Catherine A. Remley, Galen H. Koepke, Chriss A. Grosvenor, John M. Ladbury, Dennis G. Camell, Jason B. Coder, Robert Johnk
This report describes tests carried out by members of the NIST Electromagnetics Division to study the wireless environment in automotive manufacturing facilities. Testing was performed at three facilities during 2006 and 2007. We studied an assembly plant, a very crowded environment having auto chassis bodies moving continuously along assembly lines; a metal stamping plant, consisting of large metal-working machinery housed in an older facility; and an engine plant, with a more open, assembly-line layout in a modern facility. Three types of tests were carried out in each plant: (1) A background ambient spectrum survey where the existing wireless environment in each facility was monitored over a 24-hour period. These tests indicated the current level of radio activity over time at one location on the factory floor. (2) A detailed spectral analysis of the 802.11b WLAN frequency band. These tests provided a close-up view of the existing use of this common frequency band. (3) Reverberant cavity tests where the physical spacing between a source and receiver was varied to investigate the signal-scattering characteristics of the production floor. These tests provided an indication of the level of direct versus reflected path propagation in the environment. Together, the three sets of tests provided enough information to characterize the propagation environment for many wireless technologies.