An autonomous water monitoring and sampling system for small-sized ASV operations

In recent years sensorized autonomous vehicles (either AUVs or ASVs) have been widely utilized for in-situ water measurements. However, collection of water samples in depth by small-sized ASVs, remains difficult due to dimensions and weight constraints. This paper addresses this issue and describes the design and preliminary tests of an autonomous water monitoring and sampling system intended for the use onboard man-portable ASVs. The system is composed of a winch lowering a sampling probe up to 50 meter depth. The sampling probe is able to take measurements along the water column and to collect up to five water samples at different selectable depths. Once the probe is returned onboard, a fluidic system supplies the water to the sensors lodged in the ASV or to containers to transport the samples to laboratories. Particular care has been devoted to avoiding samples contamination by using chemically inert materials. This, also considered the possibility of the need of measuring low concentrations of heavy metals in the samples. The design aims at realizing a system characterized by low dimensions and weight with a limited power consumption, to be easily installed and used on an autonomous man-portable ASV. Preliminary tests are reported with the sampling system installed in a robotic catamaran belonging to the HydroNet class ASV (see Fig. 1) [1].