Patent ID: 6034764
Filing Date: 2000-03-07
Classification: B60T,G01C,G01S

Abstract:
An apparatus for determining an elevational clearance delimited between an upper border and a lower border, said apparatus comprising:range-signaling means for generating a data signal correlatable to a true range between a base point of said apparatus, and, one of the upper and lower borders, the range-signaling means including a radiation emitter and receiver for emitting radiation and receiving reflections of the emitted radiation, respectively;optical means for optically aiming the radiation emitter at said one of the upper and lower borders along a given line that extends between the base point and the said one of the upper and lower borders;level-signaling means for generating a data signal correlatable to a given horizontal datum;angle-encoding means for encoding a data signal correlatable to an elevational angle between the horizontal datum and the given line;axis-finding signaling means for finding an axis that extends between the base point and the other of said upper and lower borders, as well as, for generating a data signal correlatable to an elevational angle defined between the axis and the horizontal datum; and,processing means for processing the various data signals to output a message signal which can be decoded as the computed vertical clearance between the upper and lower borders;wherein the axis-finding signaling means comprises an optical assembly including a reticle, an adjustable cross-hair, and manual controls to allow manual finding of said axis.