Development of an acoustic telemetry platform for underwater sensing

With the advancement of electromagnetic communication technologies, it is now possible to transmit data wirelessly over tens of kilometers using a limited energy source which enables industries and researchers to build sophisticated wireless sensor networks in the terrestrial environment for various use cases. While there has been much progress in terrestrial electromagnetic wireless communication in recent years, underwater wireless communication has not received the same focus, and unsolved problems remain in terms of power consumption, miniaturisation, and data rates in marine-based underwater wireless sensor networks. Currently, there are a variety of sensors that can be deployed underwater, but to retrieve their data, either they must have a wired connection to the surface, or they must be physically collected to download the data after retrieval. Having a wireless underwater telemetry platform can significantly reduce the cost and efforts of deployment of marine sensors, eliminate the need for periodic sensor collection for data download, improve the reliability of underwater sensors by eliminating the need for wires and cables and provide real-time insights into the underwater sensory condition for multiple applications. IMPAQT is a European research project aiming at the development of the technologies and methods to promote and support inland, coastal zone, and offshore Integrated Multi-Trophic Aquaculture (IMTA) sites. An underwater wireless sensor network can be hugely beneficial to the farmers as a monitoring tool that can provide real-time data sets as to the conditions in an IMTA site to help optimise conditions for growth and maximise the productivity of the aquaculture activities, as well as to potentially lead to taking early interventions against adverse events. This thesis describes the design of the IMPAQT underwater ultrasonic wireless telemetry platform that has the potential to enable the building of small, dense wireless sensor monitoring underwater. The IMPAQT underwater telemetry platform provides a general-purpose, low-cost, low-power, miniaturized transmitter node, in a one-way communication platform for marine sensor data collection. The IMPAQT underwater telemetry platform consists of ultrasonic transmitter nodes which can be configured in a star network and a receiver node to be used as a data aggregator and surface link for the transmitter (sensor) nodes. The transmitter node runs on a battery and provides an I/O interface through wired SPI/UART connection, wired analogue ports, and optical UART communication to be used with a variety of commonly used underwater sensors. The transmitter node periodically collects sensor information and transmits it wirelessly to the receiver node. The receiver node, which is designed to exist above the surface of the water (in a buoy or mounted on a cage), logs the transmitted information for manual collection or for transfer of the collected information to the cloud via long-range radios, e.g., GSM/LoRa to an inland data aggregator