South African researchers developed world-leading underwater Wi-Fi technology

The Council for Scientific and Industrial Research (CSIR) is pushing the boundaries of underwater exploration with a breakthrough technology that could transform how we map, monitor, and secure the ocean floor. By combining advanced sonar imaging with high-speed underwater communication, researchers are bringing something close to “underwater Wi-Fi” to life.

At the heart of this innovation are two complementary systems: synthetic aperture sonar (SAS) and broadband underwater acoustic communication. Together, they solve a longstanding challenge in marine technology—capturing high-resolution images underwater and transmitting them in near real time.

Traditionally, underwater vehicles such as drones or towed platforms have struggled with two major limitations. First, sonar images captured at a distance often lack clarity and detail. Second, even when high-quality data is collected, it typically cannot be accessed until the vehicle resurfaces, delaying analysis and decision-making.

CSIR researchers, led by Kiri Nicolaides, are addressing both issues simultaneously. Their synthetic aperture sonar system dramatically improves imaging quality by using sophisticated signal processing algorithms and newly developed wide-bandwidth transducers—devices that act like underwater antennas for sound waves. These transducers offer up to four times more bandwidth than conventional systems, resulting in sharper, more detailed images with fewer errors.

As Josiah Jideani explains, “SAS is like the high-definition television version of sonar.” It is particularly effective at detecting small or subtle objects that traditional sonar might miss, making it invaluable for applications such as pipeline inspections, underwater cable monitoring, and even detecting hidden mines.

The second half of the breakthrough lies in communication. Because radio waves degrade rapidly underwater, conventional wireless technologies are ineffective beneath the surface. Instead, CSIR engineers are turning to sound waves, which travel efficiently through water.

According to Elna Niemann, the team is developing a broadband acoustic communication system capable of delivering “internet-like” speeds underwater. Their custom-designed ultra-wide bandwidth transducers provide up to five times more bandwidth than existing commercial acoustic modems—systems that typically operate at much slower, almost telegraph-like speeds.

This means underwater drones equipped with the technology could soon transmit high-resolution sonar images in near real time, without needing to surface. The implications are significant: faster inspections of subsea infrastructure, improved environmental monitoring, enhanced mineral exploration, and more effective maritime security operations.

The system has already undergone sea trials in Simon’s Town, where researchers tested its performance in real-world conditions. Back in Pretoria, at CSIR’s controlled testing facility, the team continues to refine the technology—calibrating equipment, improving algorithms, and iterating based on field data.

One of the key challenges remains maintaining stability during data collection. Synthetic aperture sonar requires a steady speed and straight trajectory, but ocean conditions—waves, currents, and platform motion—can introduce disturbances. To counter this, the team relies on advanced motion correction and autofocusing algorithms.

This continuous cycle of testing, refinement, and redeployment is central to the project’s success.

As the technology matures, it promises to redefine underwater operations. What was once a slow, delayed process could soon become instantaneous—bringing the ocean’s hidden world into focus faster and more clearly than ever before.

South African researchers developed world-leading underwater Wi-Fi technology