AbstractSince the development of the first electronic distance-measuring device in 1948, the practising surveyor has been awaiting the day when electronics could provide him also with a modern, inexpensive means of measuring, quickly and simply, the numerous short distances measured hitherto by repetitive laying-out of a tape. Until now, micro-wave equipment has not yet been suitable, as it always involves the use of an active reflector, which is nothing less than a second transmitter/receiver unit, identical therefore also in weight and price. However, the vital requirement in low order survey using mostly the so-called polar, or bearing and distance method is onlyonemaster station and, above all, light and cheap targets. The electro-optical distancers are already much better suited for short ranges, as they operate with the aid of co-operative reflectors, such as plane mirrors or reflecting prisms. Here, however, the difficulty centres firstly around the modulation of the light waves, which is critical in a small unit, and, in addition, requires much power and, secondly, in the fact that visible incoherent light is used as a carrier wave, which is affected by strong absorption and dispersion. In addition, outside light, especially when measuring in the direction of the Sun, produces a very high noise level, thus this type of instrument gives more range by night than by day.