On Thursday, part of the team traveled to Alcácer do Sal (translated from Arabic roughly as "The Salt Castle"). This is an historical town that has been occupied continuously over the last 27 centuries by different civilizations. The main reason was that Sado River could be used as a highway to trade salt, bronze and other products. As a result, a lot of archaeological artifacts have been found in the village and many more are expected to be found in Sado's river bed.
This time, however, we weren't looking for sunken treasures. Instead, we wanted to test our vehicles for their applicability for archaeological surveys under these conditions. The challenge is that Sado is a muddy river and all suspended sediments can absorb the sound pulses used by the sonars to map the bottom.
LSTS used one LAUV equipped with sidescan and multibeam sonars for the operational tests. Fortunately, the results were very promising in that the currents were not too strong and the river bed could be seen clearly using the used sensors and vehicle. We are thrilled to know that our system is capable for this type of operations and that, in the near future, more surveys shall be possible under a collaboration with recently formed CANAL (Nautical Archeology Center of Littoral Alentejo).
Many thanks to CANAL and CM Alcácer for the operational help.