There are many reasons why a simple, direct distance measurement is not always sufficient to complete your measurement tasks. Either the distances to be measured are difficult to access, e.g. via a ladder or by climbing a roof, or when more complex geometries are to be captured where the three-dimensional position of the measured points is of importance. This applies, for example, to rooms with non-rectangular corners, to points that do not lie on the same plane or when geometries have to be captured in such a way that they can subsequently be imported into a CAD program for further processing.
Such measurements are very time-consuming, require the support of assistants, or you basically have to hand them over to measurement experts with much more sophisticated measuring equipment. This costs time and, above all, creates additional costs.
Back in 2015, Leica Geosystems developed and successfully launched the Leica DISTO S910, its first hand-held measuring device with Point-to-Point (P2P) measurement capabilities. The technology is very cost-effective and easy to use compared to other measurement technologies and is therefore becoming increasingly popular. Also for this reason, just a few years later the Leica DST 360 adapter was introduced for the X-series of Leica DISTO devices to extend the function of simple, compact laser measuring devices for P2P measurements.
The technology used was designed by Leica Geosystems. By using new, highly developed and compact sensors, angles can be determined with an accuracy of ± 0.1°. As the sensors work passively, i.e. with almost no energy consumption, the power is supplied via gold-plated spring contacts from the Leica DISTO. This means that there is no need to change the batteries in the sensor separately, and the number of possible measurements with the Leica DISTO is also not affected by the use on the Leica DST 360 adapter. The communication of the measurement information of the Leica DST 360 adapter also takes place via these contacts. The liquid bubble integrated in the base is used to roughly level the adapter first. The precise levelling relevant for the measurement is carried out by the tilt sensor integrated in the Leica DISTO. By determining the measuring plane by twisting the system 2 times, precise calibration takes place during the levelling process. The mechanical multiple mounting of the DISTO unit and the locking screw with torque limiter (screw turns if over-tightened) ensure that only minor deviations can occur due to the mechanical mounting. The adapter is made of cast aluminum, which is particularly stable over its lifetime - even if frequently used. Since the precise aiming of measuring points is of course directly reflected in the accuracy, the Leica DST 360 has horizontal and vertical fine adjustment drives. A slipping clutch allows quick aiming by turning by hand, while fine drives can then be used for precise aiming. This means optimum user-friendliness.
The basic principle with the measuring sensors and the tilt sensor is also used in the Leica DISTO S910. Here, however, in the form of a fold-out base (Smartbase), which can be screwed onto a purely mechanical adapter, which then only mechanically guides the device when aiming.
From a purely technical point of view, the accuracy of a Point-to-Point (P2P) measurement essentially depends on the accuracy of the distance meter and the horizontal or vertical angle sensor. Since a calibration of the tilt sensor in the Leica DISTO takes place during the levelling process, this can almost be neglected. This results in a deviation for a P2P measurement of typically 5 mm at a measuring distance of 5 m. This then increases proportionally with the distance. We are talking about a typical accuracy, i.e. this deviation can usually occur with most measurements *).
When carrying out P2P measurements, however, the aiming or the geometric arrangement of measuring points is particularly important. Deviations in aiming are of course directly reflected in the accuracy. It is worthwhile to check the position of the laser point by maximizing the magnification of the digital Pointfinder or even by stepping up to the measuring point. Also, having the laser dot hit a target at a right angle is definitely an advantage. If the laser hits a target flatter, the possible measurement deviation also increases. You can easily imagine this if you adjust the laser slightly via the fine drive. If I measure at an angle to a wall, the laser point moves significantly more towards the actual measuring point than if I aim at a target object at a right angle. Accordingly, the possible deviation of ± 0.1° per sensor is much more noticeable! So you can well imagine what this means for the result.
With the Leica DISTO S910 the P2P adapter is integrated in the housing, but due to the compact design the same accuracy is achieved as with the design in an external adapter.