The laser distance meter node measures the relative distance between pairs of reference points. One of the two points can be a natural surface or target foils while the node can be placed at the other end point.
Measurement of tunnel convergence is one of the most important controls of the NATM (New Austrian Tunneling Method) construction. Portable devices like tape extensometers, levels and temporarily installed total stations allow sporadic measurements. On the other hand, one of the most commonly used methods, the measuring tape, disrupts construction activities due to the use of aerial work platforms.
Laser distance nodes can be easily relocated along the convergence cross sections up to the excavation front or until the measured relative displacements are stabilised when the required frequency of measurements is reduced. They can also be used when permanent monitoring is required.
In a similar way, the laser distance node measures deformations in underground excavations and mining without causing work disruptions and delays.
The laser distance node is capable of measuring the relative distance and transmitting the data via long-range radio to a gateway connected to the Internet. One gateway can support hundreds of nodes in the same network that is also measuring other sensors installed in the monitoring sections (borehole extensometers, pressure cells, load cells, strain gauges etc). It can be easily configured and connected with a USB cable and an Android phone.