1. A method for detecting and locating material bodies on an at least 2-dimensional occupancy grid G, said grid G having a first resolution stepsize R G , and comprising a set of cells represented by vertices and segments connecting these vertices, each cell of the occupancy grid having an associated probability of occupancy by a material body, the method using a sensor for detecting obstacles which is positioned at a source point S, said sensor being connected to a discretization module, and cell search processing module, said method comprising: a) acquisition by said sensor of a measurement of the position of a material body detected at a point F; b) definition by said discretization module of the coordinates of the points S and F in a space discretized with the aid of a spatial stepsize δ, the spatial stepsize δ being smaller than the resolution stepsize R G of the grid G, the size of the cells being defined by r*δ, with r being an integer, a point M with coordinates (l, m, n) in this discretized space being situated in the continuous space at the point (x, y, z), where 
 x=l·δ 
 y=m·δ the points S and F having respectively coordinates (l S , m S , n S ) and (l F , m F , n F ); the values n, n S and n F being unconsidered or equal to zero in case of a 2D occupancy grid G; and c) determination by said cell search processing module of the cell c s of the occupancy grid G containing the point S; d) determination by said cell search processing module of the coordinates, in the discretized space, of an initial vertex V0 of the cell c s ; e) computation by said cell search processing module of the value of an, integer, error parameter E by using an error function Err d (M) to evaluate, in the discretized space, an offset between a point of the space and a straight line connecting the points S and F, said error parameter E being initialized to the value taken by said error function for said initial vertex V0 of the cell c s , f) computation by said cell search processing module of the value of said error parameter E for at least one first vertex V1 i of the current cell c i of the occupation grid, corresponding to Err d (V1 i ), this computation consisting in carrying out an addition or subtraction operation between integer numbers, between on the one hand said value of the parameter E, obtained for the initial vertex V0 i of the current cell c i , and corresponding to Err d (V0 i ), and on the other hand an integer increment value (Δ) predefined as a function of the coordinates of the points S and F in the discretized space, g) studying by said cell search processing module the previously computed value of the error parameter E with respect to a reference value to determine a following cell c i+1 traversed by the path [SF]; h) computing by said cell search processing module the value of said error parameter E for an initial vertex V0 i+1 of the following cell c i+1 , corresponding to Err d (V0 i+1 ), this computation consisting in carrying out an addition or subtraction operation between integer numbers, between on the one hand said value of the parameter E, obtained for at least one vertex V i of the current cell c i , and corresponding to Err d (V i ), and on the other hand an integer increment value (Δ) predefined as a function of the coordinates of the points S and F in the discretized space, i) using by said cell search processing module this following cell c i+1 and said value of the error parameter E, obtained for said initial vertex V0 i+1 of this cell, as starting point and repeating steps f to h until at least the cell c F containing the final point F is reached, j) determining by said cell search processing module the list {c i } of cells considered in the previous steps and situated on the path [SF] or situated a predefined distance from the path [SF] and updating the probability of occupancy of each listed cell in said occupancy grid G.