Abstract: Retroreflective target for laser ranging embodying at least one hollow cube corner retroreflector constituted by three reflective surfaces which are substantially planar and perpendicular to each other and intersect at three edges which are substantially orthogonal and converge at an apex (S), the cube corner retroreflector being associated with a geometrical normal at the same angle to each of the edges, the target including a reference point (O) substantially on the normal on the opposite side to the reflective surfaces at a distance e..sqroot.

Abstract: Elements of an optical system are placed at points (A) and the spatial coordinates of these points are measured. The optical system comprises on the one hand an optical device which may be mounted on board an aircraft (2) and on the other hand reflectors (10) such as reflectors of the cube corner type. The optical device includes a pulsed laser source and a detector which is sensitive to the radiation emanating from the laser source. The desired spatial coordinates are determined from measurements of transit times of reflected laser pulses.The pulses (8) emitted by the laser source are caused to diverge in order to increase the width of their angular field and the radiation reflected from the reflectors (10) is collected in a wide field and transmitted to the detector.The system is applicable in particular to high-precision topography for the purpose of analyzing land subsidence.