Desenvolvimento de um sistema costeiro baseado em sensores industriais para monitoramento em tempo real do ambiente marinho

Abstract

This study presents the development of a coastal measurement platform that integrates industrial sensors in an embedded system to monitor in real time the variation of the physical properties of the marine environment. The system is designed to operate alone or as a node integrated into a wireless sensor network. The construction of the measurement platform was based on four main subsystems: power, detection, processing and wireless communication. All equipment is powered by batteries that store the energy generated by solar panels, allowing its installation in remote locations. The sensor information and the acquisition control are managed by a system embedded in a micro controlled device, with the flexibility to update its firmware and to integrate new sensors. To perform real-time telemetry, radio link equipment is used that allows its configuration point-to-point and point-to-multipoint topologies. The whole system is expandable in relation to the transmission distance as well as the quantity, depth and types of sensors. The vertical temperature profile was chosen as the first component of the sensor subsystem to be developed. The digital thermometer chain was initially designed to monitor the ambient temperature and the thermal gradient of a 10-meter-deep water column. The thermometers calibration methodology was presented, and the results demonstrated a gain of accuracy higher than the value informed in the manufacturer's data sheet. The platform was installed at Enseada dos Anjos, in Arraial do Cabo-RJ, where a tide gauge is operated under the responsibility of the Navy. The sea level sensor was integrated into the system and, during the tests, it was possible to record temperature variations with evidence of the occurrence of the coastal upwelling phenomenon and cold-water intrusions after the tidal cycles. The continuous series of data obtained by the developed system was presented as a strategic tool for oceanographic studies in the region.