JPS5522111A - Calibration target for laser radar - Google Patents

Abstract

PURPOSE:To make easy and accurate the measurement calibration of a system delay and the optical axis adjustment by constituting an optical reflecting system of a double reflected light which is reflected on such two reflecting surface and sphere as are arranged separately. CONSTITUTION:Reflecting surfaces 11 and 12 having curvatures are arrenged at a spacing l corresponding to the spacing between the optical axes of the transmitter and receiver of a laser radar. Then, the laser beam 16, which is emitted with an angle of divergence thetat from a transmitter 13 to the reflecting surface 11, has its optical axis adjusted in parallel with the beam 16 through the double reflections on the surfaces 11 and 12 thereby to form optical passages 17 and 18 which are to be received by a receiving telescope 14 toward the surface 12. As a result, if the combination of those two reflecting curved surfaces is constructed as one target, the laser beam 16 emitting from the transmitter 13 is reflected thereby to easily determine the optical path up to the telescope 14 in a high accuracy. If the radii of curvature r1 and r2 are sufficiently small in comparison with the range finding accuracy of the target, considerable accuracy can be obtained even if the passage joining the centers of the curvatures of the two curved surfaces is assumed.