An overview of wireless local positioning system configurations

Over the last years tremendous improvements of wireless positioning systems have been achieved. System accuracy has improved drastically and maturity changed from hand-soldered lab demonstrators to commercial products. In parallel applications moved from small, experimental installations to coverage of complete sites. Consequently the research focus shifts away from the positioning core technology to system aspects. Critical issues now are simultaneous handling of a large amount of mobile units like tags or vehicles with acceptable update rate, coverage of large areas requiring multiple cells and cell-handover, quick exchange of positioning data and fusion with other local information. This paper reviews the most common approaches to wireless positioning from the system perspective. Requirements on the infrastructure are pointed out, the communication effort is analyzed, energy consumption of the mobile unit is evaluated and feasibility of sensor fusion with other available information is investigated.