A method of autonomous navigation of a vehicle, the method comprising: receiving scanning output data generated by a scanning device that scans an area surrounding the vehicle, wherein the scanning device is on-board the vehicle; receiving Inertial Navigation System data indicative of a current location of the vehicle relative to a previous location, wherein the INS is on-board the vehicle; operating at least one computer for: generating, based on the scanning output data, a first map having a first map size, the first map being relative to a location of the vehicle and comprising a first group of cells, each cell in the first group of cells is characterized by a first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; generating, based on the scanning output data, a second map having a second map size, the second map size being smaller than the first map size, the second map being relative to the location of the vehicle and comprising a second group of cells, each cell in the second group of cells is characterized by a second size being smaller than the first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; wherein a non-traversable cell in the first group of cells and the second group of cells includes at least part of an obstacle that covers part or all of an area of the non-traversable cell; wherein the second map at least partly overlaps the first map; the method characterized in that the first size is selected to be larger than an accumulated drift values of the INS over a first predefined distance and the second size is selected to be larger than an accumulated drift values of the INS over a second predefined distance, the second predefined distance being smaller than the first predefined distance; crossing between information from one or more cells in the first map and information from corresponding one or more cells in the second map and deducing based on the crossing, deduced data output characterizing a size of obstacles in the non-traversable cells; and generating navigation instructions for navigating the vehicle while avoiding collision with obstacles, using INS data obtained by the INS and the deduced data output. receiving scanning output data generated by a scanning device that scans an area surrounding the vehicle, wherein the scanning device is on-board the vehicle; receiving Inertial Navigation System data indicative of a current location of the vehicle relative to a previous location, wherein the INS is on-board the vehicle; operating at least one computer for: generating, based on the scanning output data, a first map having a first map size, the first map being relative to a location of the vehicle and comprising a first group of cells, each cell in the first group of cells is characterized by a first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; generating, based on the scanning output data, a second map having a second map size, the second map size being smaller than the first map size, the second map being relative to the location of the vehicle and comprising a second group of cells, each cell in the second group of cells is characterized by a second size being smaller than the first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; wherein a non-traversable cell in the first group of cells and the second group of cells includes at least part of an obstacle that covers part or all of an area of the non-traversable cell; wherein the second map at least partly overlaps the first map; the method characterized in that the first size is generating, based on the scanning output data, a first map having a first map size, the first map being relative to a location of the vehicle and comprising a first group of cells, each cell in the first group of cells is characterized by a first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; generating, based on the scanning output data, a second map having a second map size, the second map size being smaller than the first map size, the second map being relative to the location of the vehicle and comprising a second group of cells, each cell in the second group of cells is characterized by a second size being smaller than the first size and is classified to a class selected from at least two classes, comprising traversable and non-traversable; wherein a non-traversable cell in the first group of cells and the second group of cells includes at least part of an obstacle that covers part or all of an area of the non-traversable cell; wherein the second map at least partly overlaps the first map; the method characterized in that the first size is selected to be larger than an accumulated drift values of the INS over a first predefined distance and the second size is selected to be larger than an accumulated drift values of the INS over a second predefined distance, the second predefined distance being smaller than the first predefined distance; crossing between information from one or more cells in the first map and information from corresponding one or more cells in the second map and deducing based on the crossing, deduced data output characterizing a size of obstacles in the non-traversable cells; and