An apparatus for transporting a sensor having a sensing surface at an operational distance from a target surface is disclosed. The apparatus includes an upper frame and spaced apart parallel front and rear struts. The upper ends of the struts are connected to the upper frame. The lower ends of the struts are connected to the sensor. The front and rear struts pivot about the upper frame to move the sensor in response to an obstacle on the target surface, The sensor pivots about the lower ends of the front and rear struts to maintain the sensing surface in substantially parallel orientation to the target surface. The angle between the sensing surface and the front and rear struts is less than 90.degree..