On qualitative uncertainty in range measurements from 2D laser scanners

This paper describes a research concerning recognition, classification, and correction of qualitative-nature errors in range measurements from 2D laser scanners. Nowadays, such scanners are commonly used on mobile robots for navigation. The main cause of qualitative uncertainty is the mixed measurements. This effect has been investigated experimentally for two different classes of the laser range sensors, and explained by analyzinganalysing the physical phenomena underlying their operation. A local grid map has been proposed as an intermediate data structure, which enables to remove the erroneous range measurements, being either mixed measurements, or being caused by dynamic objects in the vicinity of the robot. A novel fuzzy-set-based algorithm has been employed to update evidence in the grid. The results of tests show, that this algorithm is superior to the common Bayesian approach, when qualitative errors in range measurements are present.