Geomorphology

The microdrone md4-1000 is a miniaturised VTOL (Vertical Take Off and Landing) quadrocopter of 1.7 m span and 2.6 kg weight. It can carry a payload of 1.2 kg and is currently equipped by a Sony α6000 camera. The drone can fly by remote control or automatically via a GPS waypoint navigation system. Flying time is about 50 minutes, when working with a photo camera, and can be flown to a maximum of 100 m above ground and to a maximum distance from the pilot of 1000 m (to guaranty visual contact to the pilot as required by Swiss laws). The device is rain/snow/dust-resistant and tolerates extreme temperatures (-20°C to +50°C). From the aerial images, Digital Elevation Models (DEMs) and orthorectified images can be created and used for landscape (glaciers, rivers, vegetation, etc.)

Thanks to a long range laser pulse, the RIEGL VZ 6000 scanner can achieve three-dimensional data from a distance of up to 6 km. Its capacity to acquire more than 200’000 points per second allows the user to generate dense point clouds in affordable time. Given the precise digital elevation model that can be generated from these point clouds, this technology can be applied to monitor a wide range of landforms. Notably it can be used with snow and ice surfaces, unusual for many normal laser scanners.

With the use of one reference station and one mobile receiver, and with post-processing, a precision in the order of one cm in XY coordinates can be obtained. Main applications are : 1) the monitoring of surface terrain motion (rock glaciers, debris-covered glacier, landslides, etc.), 2) the measurement of ground control points for the creation of digital elevation models from aerial and terrestrial imagery, and 3) the measurement of high precision topographic profiles. Simultaneous use of combined satellite systems allows use of our equipment in mountain regions where sky coverage can be restricted.

A total station is an electronic theodolite which makes also use of a laser beam and a prism reflector for distance measurement. This combination of these technologies allows the surveying of three-dimensional points at short range. Total stations are particularly useful for measuring linear profiles.

An Acoustic Doppler Current Profiler (ADCP) is a hydroacoustic current meter, which is used to measure the 3D velocity of water, sediment transport and bed load velocity in rivers. It allows data collection with high spatial and temporal resolution and based upon the Doppler Effect. The device includes a moving vessel (Trimaran), a high frequency velocity measurement system called a Sontek River Surveyor M9 SmartPulseHD, a computer to receive the data and a RTK-dGPD to subtract the vessel’s own movement from the current data. The instrument tracks water velocity and depth across an entire column of water, continuously. This technic allows the user to use multiple acoustic frequencies (up to three frequencies) for velocity profiling in extreme flood or drought situations.