How to recognize and remove qualitative errors in time-of-flight laser range measurements

This article presents results concerning recognition and classification of the qualitative-type range measurement errors in a time-of-flight principle based 2D laser scanner used on mobile robots for navigation. The main source of the qualitative uncertainty are the mixed measurements. This effect has been investigated experimentally and explained by analyzing the physical phenomena underlying the sensor operation. A local grid map has been used to remove the erroneous range measurements. 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.