Techniques are discussed for generating a spatial grid based on radar sensor data. The spatial grid may include cells, which may be designated as being occupied, occluded, and/or free space. A cell may be designated as being occupied if radar sensor data is associated with a region of an environment associated with the cell. A field may be designated as being occluded if a region of the environment associated with the cell is obstructed, relative to a radar sensor, by a cell that is designated as being occupied. In some instances, objects may be detected and/or tracked in occluded regions. A cell may be designated as being free space if a region associated with the cell is within a field of view of a radar sensor and is unoccupied and un-occluded. In some instances, the spatial grid may be used to control a vehicle, such as an autonomous vehicle, in the environment.