Abstract: There is provided a retroreflector device, comprising: an incident object made of a material transparent to electromagnetic radiation, the incident object designed to refract an incident ray hitting an incident surface to generate a refracted ray that hits a back surface, and a retroreflective surface positioned in proximity to the back surface of the incident object, wherein the retroreflective surface and the incident object are configured to refract the incident ray to generate the refracted ray for hitting the retroreflective surface at an angle of incidence below a threshold.

Abstract: There is provided a computer implemented method of controlling movement of an object, comprising: accessing a current image of a surface relative to an object at a current location, wherein an imaging sensor is set to capture the current image depicting an overlap with a previously captured image of the surface when the object was at a previous location, registering the current image to the overlap of the previously captured image, computing the current location of the object relative to a reference location according to an analysis of the registration, and feeding the current location into a controller for controlling movement of the object.