An autonomous moving object comprising: a radar sensor configured to, during movement of the moving object along a movement path along a surface , acquire radar reflection data sets representing radar reflections originating from reflecting surface portions located within a measurement distance range, wherein the radar sensor is configured to, at each measurement occasion of a temporal sequence of measurement occasions during the movement of the moving object along the movement path, illuminate a respective surface region (12-1, 12-2, 12-3) and acquire a radar reflection data set pertaining to the illuminated surface region, the radar reflection data set representing, for each measurement distance of a set of measurement distances within said measurement distance range, an amplitude and a phase of reflected radar signals received from reflecting surface portions located at said measurement distance, and wherein said respective surface regions comprise a common sub-region which is illuminated at each one of said measurement occasions, wherein said common sub-region is at least 1 cm 2 ; a radar signal processor configured to receive the acquired radar reflection data sets acquired at each one of said sequence of measurement occasions, wherein the received acquired radar reflection data sets form a collection of radar reflection data sets, wherein each radar reflection data set of said collection comprises a radar reflection data subset pertaining to said common sub-region ; and a surface classifier processor configured to output a classification of a surface type of the surface based on said collection comprising said reflection data subsets pertaining to said common sub-region . a radar sensor configured to, during movement of the moving object along a movement path along a surface , acquire radar reflection data sets representing radar reflections originating from reflecting surface portions located within a measurement distance range, wherein the radar sensor is configured to, at each measurement occasion of a temporal sequence of measurement occasions during the movement of the moving object along the movement path, illuminate a respective surface region (12-1, 12-2, 12-3) and acquire a radar reflection data set pertaining to the illuminated surface region, the radar reflection data set representing, for each measurement distance of a set of measurement distances within said measurement distance range, an amplitude and a phase of reflected radar signals received from reflecting surface portions located at said measurement distance, and wherein said respective surface regions comprise a common sub-region which is illuminated at each one of said measurement occasions, wherein said common sub-region is at least 1 cm 2 ; a radar signal processor configured to receive the acquired radar reflection data sets acquired at each one of said sequence of measurement occasions, wherein the received acquired radar reflection data sets form a collection of radar reflection data sets, wherein each radar reflection data set of said collection comprises a radar reflection data subset pertaining to said common sub-region ; and a surface classifier processor configured to output a classification of a surface type of the surface based on said collection comprising said reflection data subsets pertaining to said common sub-region . <EOS>