The process comprises acquisition of experimental data from measurements of physical quantities by means of at least one sensor associated to the object. The process comprises a first reliable estimation of a first range of values with a first method. The process comprises at least one additional estimation of an additional range of values with a different method. The methods each present a predetermined reliability. The ranges of values are successively observed in order of decreasing reliability of the corresponding methods. Each additional range of values is compared with the range of values corresponding to the previous method according to said order. The additional range is chosen as result when the additional range is comprised in the range corresponding to one of the previous methods.