MEANS FOR MEASURING DISTANCE WHEN IT IS CONSIDERED PROBABLE THAT FOREIGN OBJECTS OR PARTICLES ARE BETWEEN THE MEASURING INSTRUMENT AND THE OBJECT TO WHICH THE DISTANCE IS TO BE MEASURED

摘要

An arrangement for measuring distance under conditions when disturbances of various types may be expected to occur between the measuring instrument and the object to which the distance is to be measured comprises an emitter unit arranged to emit a series of electro-magnetic pulses in the direction of the object and a receiver unit, which only registers the very first echo from each single pulse emitted, and the echo which of all those registered has covered the longest distance is considered to comprise a measurement of the distance to the object in question.