Yahong Rosa Zheng, an expert in underwater wireless communications and a Professor in the Lehigh University Electrical and Computer Engineering department, is at the forefront of a National Science Foundation (NSF)-funded initiative.
ECE professor Yahong Rosa Zheng. Image Credit: Lehigh University
The team under her leadership is working on creating an innovative prototype for an Autonomous Observatory Node. This prototype aims to transmit data from undersea sensors without the constraints and expenses associated with traditional cables.
The ocean is frequently regarded as the ultimate frontier. Over the last two decades, sensor systems for observatories have been installed along coastlines to gather and transmit extensive data encompassing physical, chemical, geological, and biological aspects.
However, these technologies presently rely on subsea cables, imposing constraints on their operating distance from shore and, consequently, restricting our understanding of scientifically intriguing regions.
Each one of those nodes costs hundreds of millions of dollars, in large part because of the cables that support their power and communications. The cost of running a cable from the shore is too prohibitive for studying the deep ocean.
Yahong Rosa Zheng, Professor, Electrical and Computer Engineering, Rossin College of Engineering and Applied Science, Lehigh University
Heading an interdisciplinary team comprising researchers from multiple universities, Zheng has secured backing from the National Science Foundation's Division of Ocean Sciences. The objective is to craft a prototype for an Autonomous Observatory Node (AON) that integrates an underwater acoustic communication subsystem and an Underwater MicroGrid (UMG) subsystem.
Think of it as a service station with a Wi-Fi hot spot. The node will have a power source for its sensors and autonomous underwater vehicles (AUVs) and the ability to transmit data up through the water to the internet.
Yahong Rosa Zheng, Professor, Electrical and Computer Engineering, Rossin College of Engineering and Applied Science, Lehigh University
Zheng is also an expert in underwater wireless communications and signal processing.
Zheng leads the team responsible for developing the communication system. Their strategy involves crafting an acoustic subsystem employing numerous transducers—devices that convert energy, much like a loudspeaker transforms a signal into sound waves—to receive data from seafloor sensors and Autonomous Underwater Vehicles (AUVs).
Subsequently, this data will be transmitted to a glider positioned on the ocean’s surface. From there, it will be relayed to satellites and eventually reach researchers’ computers.
What makes this endeavor unique is that, until now, it has only existed in simulations. The team’s objective is to construct the actual hardware and demonstrate its functionality.
According to Zheng, the system necessitates a multitude of transducers because the team plans to utilize high-frequency signals that are undetectable by—and do not adversely impact—marine mammals.
Dolphins can hear up to 150 kilohertz. So we’re aiming for an even higher frequency. But high frequencies can’t travel very far in water, which is why we use many transducers, each at low power, to transmit the data to the ocean’s surface.
Yahong Rosa Zheng, Professor, Electrical and Computer Engineering, Rossin College of Engineering and Applied Science, Lehigh University
The objective is to develop a deployable prototype with the capability to function at a depth of 1000 m, matching the operating depth of the cabled nodes.
Zheng added, “We want to show that our design is compatible with the current technology. But the ultimate goal, of course, is to go much deeper.”
Navigating extreme depths presents costly challenges, requiring the node to be reinforced to withstand water pressure.
This scenario also presents specific challenges to the second half of Zheng's team, which focuses on the underwater microgrid. This subgroup is exploring the use of rechargeable batteries or fuel cells to supply power to the system, along with wireless charging for the Autonomous Underwater Vehicles (AUVs).
While the technical hurdles are substantial, the potential applications of an autonomous observatory are extensive. For instance, data collected from the deep ocean could significantly enhance researchers’ capabilities to detect seismic activity, thereby improving early warning systems for earthquakes.
Zheng added, “Something like this has never been built before. To this point, they’ve only been simulated. Our goal is to build the hardware and demonstrate that it works.”