Localization schemes used for positioning are currently based on either range-based or range-free principles. We propose a unified approach that combines the strengths of both methods while overcoming their limitations. Range-based methods rely on taking reliable measurements in which geometric techniques are then applied. These techniques are very susceptible to imprecision in captured measurements. Range-free methods do not consider the actual numerical sensor value, rather comparing magnitudes across sensors. These comparisons are not always reliable and may lead to an accumulation of errors. Our unified approach mitigates these effects by first using a range-based method to determine an approximate location followed by a range-free method to refine the positioning estimate further. Our experiments show the mean estimation error improves when applying our localization scheme to a Bluetooth system.
['Anthony Quattrone', 'Lars Kulik', 'Egemen Tanin']
Combining range-based and range-free methods: a unified approach for localization