Protótipo de liberador acústico utilizando algoritmo de decisão por filtragem casada

Abstract

Acoustic releasers are employed in oceanographic research and are commonly used to recover submerged equipment, such as sensors and markers installed in the ocean along the water column to collect data and study marine life. They are also used in offshore oil and gas industry to recover equipment in activities of exploration and production. Its operation consists in activating a mechanism of release designed to separate the desired part from the submerged assembly when receiving a specific acoustic signal. Its has the main advantage of reducing diving activities or reaching regions where diving would not be possible. The acoustic signal transmitted through water can travel long distances, making it an effective way of remote trigger. Al- though they are useful within the research and industry, in Brazil, this equipment is sold at a high cost and usually involves importation. This factor discourages its use. This research aimed to develop a low-cost acoustic releaser prototype bringing to- gether the main characteristics necessary for the reliable operation of this equipment in shallow water environment. A constructive option is presented for the watertight enclosure and for the release mechanism, detailed along with all the development related to the choice and testing of the triggering signal. Employing the matched filtering technique, with proper evaluation of the transmission parameters between projector and receiver, evaluation of the effect of the marine channel on the propaga- tion of the signal and due pre-processing, a sufficiently accurate decision algorithm is presented to compose the standalone device platform. The results proves to via- bility of the prototype and the possibility of expanding the role of this equipment in brazilian territory.