With weather, limited flights and long distances, gravel runways at remote airports—particularly in northern Canada—are difficult to get to, let alone to inspect for safety.

So Northeastern University researcher Michal Aibin and his team have developed a more thorough, safer and faster way to inspect such runways using drones, computer vision and artificial intelligence. The work has been published in the journal Drones.

“Basically, what you do is you start the drone, you collect the data and—with coffee in your hand—you can inspect the entire runway,” says Aibin, visiting associate teaching professor of computer science at Northeastern’s Vancouver campus.

There are over 100 airports in Canada that are considered remote, Aibin says, meaning that they have no road or standard means of transportation leading to them. Thus, nearby communities’ food, medicine and other supplies all come by air.

The airports also predominantly feature gravel rather than asphalt runways, making them particularly susceptible to the elements.

But safety inspections are difficult. Engineers who inspect the remote airports must schedule a long flight, often during a narrow window of time dependent on the seasons, weather conditions and more.

A new, more reliable and less time-consuming method was needed.

So, Aibin worked with Northeastern associate teaching professor Lino Coria and student researchers to identify several types of defects for gravel runways, such as surface water pooling, encroaching vegetation, and smoothness defects like frost heaves, potholes and random large rocks.

Collaborating with Transport Canada (the Canadian government’s department of transportation) and Spexi Geospatial Inc., the researchers used computer vision and artificial intelligence to analyze drone images of remote runways in order to detect, characterize and classify defects.

“Our biggest novelty is we take all the images of the runway and we assess all the defects—like there’s some rocks, there’s maybe a hole, there’s maybe some aspects that are not initially visible to the human eye,” Aibin says.

The result is a new procedure for inspecting airport runways using high-resolution photos taken from remote-controlled, commercially available drones and high-powered computing. The new method proved effective when demonstrated at several remote airports, Aibin says.

The process doesn’t totally eliminate humans—a person must fly the drone and evaluate the computer analysis, Aibin notes (although those tasks can be done remotely). But Aibin says the method saves time, reduces the need for inspectors on site, and makes inspecting a remote gravel runway a much less onerous task.

Aibin says that the next step is providing more real-world applications to test the new method. But he sees the method being expanded beyond remote Canada into other remote sections of the world such as in Australia and New Zealand.

“The need to fly an engineer to the site is no longer needed, which was the ultimate goal,” Aibin says. “As long as someone can fly a drone and take images, then it can be sent in the form of a report to speed up the process.”

This story is republished courtesy of Northeastern Global News news.northeastern.edu.

A recently-developed wirelessly-powered 5G relay could accelerate the development of smart factories, report scientists from Tokyo Tech. By adopting a lower operating frequency for wireless power transfer, the proposed relay design solves many of the current limitations, including range and efficiency. In turn, this allows for a more versatile and widespread arrangement of sensors and transceivers in industrial settings.

One of the hallmarks of the Information Age is the transformation of industries towards a greater flow of information. This can be readily seen in high-tech factories and warehouses, where wireless sensors and transceivers are installed in robots, production machinery, and automatic vehicles. In many cases, 5G networks are used to orchestrate operations and communications between these devices.

To avoid relying on cumbersome wired power sources, sensors and transceivers can be energized remotely via wireless power transfer (WPT). However, one problem with conventional WPT designs is that they operate at 24 GHz.

At such high frequencies, transmission beams must be extremely narrow to avoid energy losses. Moreover, power can only be transmitted if there is a clear line of sight between the WPT system and the target device. Since 5G relays are often used to extend the range of 5G base stations, WPT needs to reach even further, which is yet another challenge for 24 GHz systems.

To address the limitations of WPT, a research team from Tokyo Institute of Technology has come up with a clever solution. In a recent study, presented at the 2024 IEEE Symposium on VLSI Technology & Circuits, they developed a novel 5G relay that can be powered wirelessly at a lower frequency of 5.7 GHz.

“By using 5.7 GHz as the WPT frequency, we can get wider coverage than conventional 24 GHz WPT systems, enabling a wider range of devices to operate simultaneously,” explains senior author and Associate Professor Atsushi Shirane.

The proposed wirelessly-powered relay is meant to act as an intermediary receiver and transmitter of 5G signals, which can originate from a 5G base station or wireless devices. The key innovation of this system is the use of a rectifier-type mixer, which performs 4th-order subharmonic mixing while also generating DC power.

Notably, the mixer uses the received 5.7 GHz WPT signal as a local signal. With this local signal, together with multiplying circuits, phase shifters, and a power combiner, the mixer ‘down-converts’ a received 28 GHz signal into a 5.2 GHz signal. Then, this 5.2 GHz signal is internally amplified, up-converted to 28 GHz through the inverse process, and retransmitted to its intended destination.

To drive these internal amplifiers, the proposed system first rectifies the 5.7 GHz WPT signal to produce DC power, which is managed by a dedicated power management unit. This ingenious approach offers several advantages, as Shirane highlights, “Since the 5.7 GHz WPT signal has less path loss than the 24 GHz signal, more power can be obtained from a rectifier. In addition, the 5.7 GHz rectifier has a lower loss than 24 GHz rectifiers and can operate at a higher power conversion efficiency.”

Finally, this proposed circuit design allows for selecting the transistor size, bias voltage, matching, cutoff frequency of the filter, and load to maximize conversion efficiency and conversion gain simultaneously.

Through several experiments, the research team showcased the capabilities of their proposed relay. Occupying only a 1.5 mm by 0.77 mm chip using standard CMOS technology, a single chip can output a high power of 6.45 mW at an input power of 10.7 dBm. Notably, multiple chips could be combined to achieve a higher power output. Considering its many advantages, the proposed 5.7 GHz WPT system could thus greatly contribute to the development of smart factories.