A volumetric sensor for mobile robot navigation to avoid obstacles in the robot's path includes a laser volumetric sensor on a platform with a laser and detector directed to a tiltable mirror in a cylinder that is rotatable through 360.degree. by a motor, a rotatable cam in the cylinder tilts the mirror to provide a laser scan and distance measurements of obstacles near the robot. A stereo camera is held by the platform, that camera being rotatable by a motor to provide distance measurements to more remote objects.