A method for determining, by a computer on board of an autonomous robot, a pixel map of the probability of at least one of absence and presence of an obstacle in the environment of the robot, said method being characterized in that it comprises: - Initializing, in a memory on-board the robot, a plurality of initial maps (340, 350) defined around the robot and substantially attached to said robot, said map having predefined limits and being paved by pixels of a predefined dimension, where a value of a probability of at least of one of absence or presence of an obstacle in each pixel is set to a predefined value; - Acquiring, from a plurality of complementary sensing procedures, data representative of at least one of absence and presence of an obstacle in the environment of the robot (331, 332); - Concurrently applying, for each one of the plurality of complementary sensing procedures, to an initial map in the plurality of initial maps, procedures for at least: o Modifying values of probabilities of absence or presence of obstacle of previous observations to a value closer to a predefined value; o Updating values of probabilities of at least one of absence and presence of an obstacle in at least one pixel of the initial map from said data; - Merging the plurality of initial maps (340, 350) into a fused map 360) by: o Setting the value of each pixel whose probability of absence of obstacle is below a threshold Ts obs in at least one of the initial maps (910a, 910b) to a value representative of an obstacle in the fused map; o Setting the value of each pixel which is not an obstacle pixel in the fused map and whose probability of absence of obstacle is above a threshold Ts free in at least one of initial maps (920a, 920b) to a value representative of an obstacle free pixel in the fused map. - Initializing, in a memory on-board the robot, a plurality of initial maps (340, 350) defined around the robot and substantially attached to said robot, said map having predefined limits and being paved by pixels of a predefined dimension, where a value of a probability of at least of one of absence or presence of an obstacle in each pixel is set to a predefined value; - Acquiring, from a plurality of complementary sensing procedures, data representative of at least one of absence and presence of an obstacle in the environment of the robot (331, 332); - Concurrently applying, for each one of the plurality of complementary sensing procedures, to an initial map in the plurality of initial maps, procedures for at least: o Modifying values of probabilities of absence or presence of obstacle of previous observations to a value closer to a predefined value; o Updating values of probabilities of at least one of absence and presence of an obstacle in at least one pixel of the initial map from said data; o Modifying values of probabilities of absence or presence of obstacle of previous observations to a value closer to a predefined value; o Updating values of probabilities of at least one of absence and presence of an obstacle in at least one pixel of the initial map from said data; - Merging the plurality of initial maps (340, 350) into a fused map 360) by: o Setting the value of each pixel whose probability of absence of obstacle is below a threshold Ts obs in at least one of the initial maps (910a, 910b) to a value representative of an obstacle in the fused map; o Setting the value of each pixel which is not an obstacle pixel in the fused map and whose probability of absence of obstacle is above a threshold Ts free in at least one of initial maps (920a, 920b) to a value representative of an obstacle free pixel in the fused map. o Setting the value of each pixel whose probability of absence of obstacle is below a threshold Ts obs in at least one of the initial maps (910a, 910b) to a value representative of an obstacle in the fused map; o Setting the value of each pixel which is not an obstacle pixel in the fused map and whose probability of absence of obstacle is above a threshold Ts free in at least one of initial maps (920a, 920b) to a value representative of an obstacle free pixel in the fused map.